Volume 11, Issue 3 (September 2026)
J Environ Health Sustain Dev 2026, 11(3): 3169-3180 |
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Eslami H, Bagheri F D, Amrollahi M. Pregnant Women Exposure to Heavy Metals and Hypertensive Disorders of Pregnancy: A Narrative Review. J Environ Health Sustain Dev 2026; 11 (3) :3169-3180
URL: http://jehsd.ssu.ac.ir/article-1-1090-en.html
URL: http://jehsd.ssu.ac.ir/article-1-1090-en.html
Occupational Safety and Health Research Center, NICICO, World Safety Organization and Rafsanjan University of Medical Sciences, Rafsanjan, Iran & Department of Environmental Health Engineering, School of Health, Occupational Environment Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
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Pregnant Women Exposure to Heavy Metals and Hypertensive Disorders of Pregnancy: A Narrative Review
Hadi Eslami 1,2* , Fateme Diba Bagheri 3 , Mohsen Amrollahi 4
1 Occupational Safety and Health Research Center, NICICO, World Safety Organization and Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
2 Department of Environmental Health Engineering, School of Health, Occupational Environment Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
3 Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
4 Department of Research and Technology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
Hadi Eslami 1,2*
1 Occupational Safety and Health Research Center, NICICO, World Safety Organization and Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
2 Department of Environmental Health Engineering, School of Health, Occupational Environment Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
3 Student Research Committee, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
4 Department of Research and Technology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
| A R T I C L E I N F O | ABSTRACT | |
| REVIEW ARTICLE | Introduction: Pregnant women are exposed to heavy metals through the consumption of contaminated food, water, and air. Toxic heavy metals are among the most dangerous environmental pollutants and can cause hypertensive disorders during pregnancy. This study aimed to review the exposure of pregnant women and fetuses to heavy metals, their relationship with pregnancy blood pressure disorders, and strategies to reduce exposure. Materials and Methods: In this narrative review study, PubMed, Web of Science, Scopus, Science Direct, and Google Scholar databases were used to search for scientific published papers between 2005 and 2025 with the main keywords "Pregnant women,” "Maternal Exposure,” "Heavy metals,” "Hypertension," and "Blood pressure.” Results: The most important exposure routes for pregnant women to heavy metals are contaminated drinking water and food, cosmetics, dental practices, cigarette smoke, and indoor and ambient air pollutants. The most influential heavy metals on hypertensive disorders of pregnancy (HDP) in pregnant women are lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), chromium (Cr), and copper (Cu). Heavy metals disrupt the function of endothelial cells by producing free radicals and causing oxidative stress and increasing lipid peroxides, which can cause hypertensive disorders of pregnancy. Conclusion: Therefore, lifestyle modification and the use of safety foods containing iron, calcium, and selenium, as well as a healthy diet containing protein, dairy products, especially milk, vegetables, and organic fruits, can play a significant role in reducing exposure to heavy metals and expelling these from the body. |
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Article History: Received: 04 June 2026 Revised: 14 August 2026 Accepted: 20 August 2026 |
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*Corresponding Author: Hadi Eslami Email: Hadieslami1986@yahoo.com Tel: +3431315241 |
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Keywords: Heavy Metals; Pregnant Women; Hypertension; Blood Pressure. |
Citation: Eslami H, Diba Bagheri F, Amrollahi M. Pregnant Women Exposure to Heavy Metals and Hypertensive Disorders of Pregnancy: A Narrative Review. J Environ Health Sustain Dev. 2026; 11(3): 3169-80.
Introduction
Today, with the development of agriculture and industries and the consumption of fossil fuels, various pollutants are produced and enter to the water, soil and air resources 1. One of the most important pollutants found in abundance in environmental sources is heavy metals 2. Heavy metals are divided into two categories: non-toxic and toxic metals for the growth of living organisms. Essential metal elements such as Zinc (Zn), Copper (Cu), Cobalt (Co), and manganese (Mn), which have important physiological roles such as cofactor role, oxidation and reduction reactions and ligand binding 3. Non-essential or toxic heavy metals include Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb) and Mercury (Hg), which disrupt the physiological and metabolic processes of the body due to their high stability and accumulation in the body of living organisms 4, 5. Heavy metals are the main constituent of the earth's crust that do not decompose through chemical and biological processes in nature. Heavy metals occur naturally in soil, water, and air (as a result of volcanic eruptions, soil erosion, and weathering) 6. It also enters the environment through human activities and the consumption of fossil fuels in industries, vehicle fuel, agricultural activities, and mining activities 7. Toxic heavy metals are stable, persistent and non-degradable compounds that not only reduce the quality of water and soil resources, but also pose a serious threat to the atmosphere and food products, which in turn threatens the health of living organisms and humans 8, 9. These metals, when entering water and soil resources, are absorbed by plants, agricultural crops, and fruit trees through the roots and leaves. Then, they are stored in the leaves and fruits of agricultural products and enter the food chain of humans through the consumption of these products 10, 11. Humans and living organisms are exposed to heavy metals, directly and indirectly, through the consumption of agricultural products, food, drinking water, breathing polluted air, and contact with contaminated materials and products such as cosmetics and personal care products 12. Exposure through the digestive system and consumption of contaminated food and water is the most important route of exposure to heavy metals 5, 13. Toxic metals accumulate in various body tissues such as the liver, kidneys, bladder, and bones, causing various adverse effects on various body systems such as the renal and urinary tract systems, cardiovascular systems, respiratory and lung systems, and central nervous systems, and can cause many types of cancers 14-17.
Pregnancy is a period when women are more vulnerable and sensitive to exposure to environmental pollutants, especially toxic heavy metals 18. Pregnancy is a time when significant hormonal and physiological changes occur in pregnant women, which can lead to increased nutritional needs and subsequent nutrient deficiencies. These deficiencies alter the absorption and metabolism of toxic heavy metals in the pregnant woman's body, causing the release of heavy metals stored in the body and their transfer to the placenta 13. The most important consequences of exposure to heavy metals during pregnancy include spontaneous abortion, premature birth, infertility, and hormonal disorders in pregnant women 11, 19. As a result, exposure to toxic heavy metals during pregnancy can have negative effects on fetal development and dangerous consequences such as miscarriage, stillbirth, and low birth weight 20, 21. Long-term exposure to toxic heavy metals is one of the most important risk factors for blood pressure in humans 22. Hypertension is one of the chronic diseases, is considered one of the main causes of death in societies with high prevalent due to dysfunction of vital organs such as the brain, heart, and other organs 23. Hypertensive disorders of pregnancy (HDP) is one of the most common diseases among pregnant women, which pose a high risk of adverse outcomes for pregnant women and fetuses, such as miscarriage and premature birth 24. HDP is a major cause of maternal and perinatal morbidity and mortality 25. In the latest classification, HDP comprises four subgroups based on symptoms and time of onset: gestational hypertension (GH), preeclampsia (PE), superimposed preeclampsia, and eclampsia 26. Based on epidemiological studies, the global prevalence rates of HDP, gestational hypertension, and preeclampsia are 5.2–8.2%, 1.8–4.4%, and 0.2–9.2%, respectively 26, 27. The most important risk factors associated with HDP are include body mass index, anemia, education level, tobacco and alcohol use, advanced maternal age, family and genetic history, and exposure to environmental pollutants and toxins 26, 28, 29. Toxic heavy metals are among the most significant environmental pollutants, and exposure to them may be associated with HDP 29. Studies show that heavy metals such as Pb and Cd have a high risk for blood pressure during pregnancy 30.
Therefore, considering the serious risks of exposure to toxic heavy metals and their effects on health, and considering the sensitivity during pregnancy and the risks that exposure to these metals through drinking water, food, and air can have for the mother and fetus, and on the other hand, there is a need to categorize existing information and studies in the field of pregnancy blood pressure due to heavy metals exposure, this study aimed to review studies related to pregnant women's exposure to heavy metals and its effect on pregnancy blood pressure and HDP, and to determine the mechanism of influence, as well as to provide control strategies to reduce exposure.
Materials and Methods
PubMed, Web of Science, Scopus, Science Direct, and Google Scholar databases were used to search for published paper between 2005 to 2025. The search strategy in this study was based on the use of the main keywords includes "Pregnant women", "Pregnant People", Maternal Exposure", "Metals, Heavy", "hypertensive disorders of pregnancy", "Hypertension", "Blood pressure" and "Arterial Pressure" were performed. Then, out of the 64 articles found, after reviewing the articles, finally 15 relevant papers were selected and reviewed based on their similarity and proximity to the subject of study, which was specifically in the field of HDP and heavy metals. The main heavy metals reviewed in this study were include: Pb, Cd, Hg, As, Cr, and Cu.
Toxic heavy metals health risks
The term heavy metals refers to metals and metalloids with a specific gravity greater than 5 grams per cubic centimeter, with the potential to bioaccumulate along the food chain 8. With the increasing development of industry and agriculture, the problems of environmental pollution caused by toxic metals have taken on serious dimensions, and today, environmental pollution, especially toxic heavy metals, has become a serious problem worldwide 1.
The bioaccumulation of heavy metals absorbed in plant in concentrations exceeding the standard levels, in addition to reducing the growth and yield of agricultural products, leads to contamination of the food chain and endangering the health of human communities 6. Human activities such as industrial and energy production activities, vehicle exhaust emissions, chemical fertilizer discharges, and fuel and coal combustion are all potential sources of heavy metals discharge to agricultural soils. The main sources of heavy metals are the atmosphere, mining, industries, fossil fuel combustion, ash residue deposition from coal combustion, traffic and vehicles, or the use of pesticides and chemical fertilizers in agriculture 10. In addition, toxic heavy metals can also enter the food products during the production and packaging process. For example, heavy metals including Pb and Cd may be released from polyethylene packaging. Polyethylene terephthalate (PET) is transferred to food during long-term storage and heating, and there is even the potential for heavy metals to be transferred to food packaging 31. The following are the most important toxic heavy metals that affect the reproductive system and the effects of exposure to them, especially during pregnancy.
Lead (Pb)
The bioavailability of Pb depends on its structure (organic or inorganic), the amount it enters the body, the age and diet of the individual. Pb has the potential to cause cancer in humans 32. In adults, the cessation of hemoglobin synthesis is also associated with low levels of Pb in the blood. At higher levels of Pb in the blood, signs of neurotoxicity such as decreased central nervous system conduction velocity, as well as nephrotoxicity, are observed. In children, toxic effects of Pb, such as growth retardation, balance problems, and other neurobehavioral signs, have been associated with blood Pb levels (10 µg/dL) 33. Pregnant women are at high risk for exposure to Pb metal due to Pb mobility during this period, because bones are catabolized during pregnancy to help form the fetal skeleton 34. Chemical biosynthesis disorders and anemia, increased blood pressure, kidney damage, miscarriage and premature birth, nervous system disorders, brain damage, and male infertility are some of the complications of Pb exposure, especially during pregnancy 35.
Cadmium (Cd)
Cd, with a concentration of 0.06 to 1.1 mg/kg of soil, is considered one of the most important and mobile heavy metals in soil. Poisoning with this metal causes serious damage to the kidneys, bones, and nervous system 36. Cd is classified as carcinogenic by IARC in Group 1, and by OSHA in it is also known as a carcinogen 37. The primary route of exposure to Cd is inhalation. Depending on its structure, 15-35% of inhaled Cd is absorbed into the blood. When Cd is absorbed into the blood, it forms a bond with albumin and is transported to the liver and causes liver damage and increases in liver enzymes 38. Studies show that the female reproductive system is very vulnerable to Cd. Consuming water, food, and breathing air contaminated with Cd, It can affect the functioning of the reproductive system in women, especially the uterus, and Cd inhibits and alters important biochemical processes in the reproductive system 39. Cd disrupts the function of the ovaries and placenta by causing changes in steroidogenesis. Cd can also cause delayed puberty, loss of reproductive hormones during pregnancy, menstrual cycle disruption, premature birth, and low birth weight in pregnant women 40.
Chromium (Cr)
Cr compounds are mainly present in the environment in two main forms, trivalent and hexavalent. Hexavalent Cr is widely used in various industries. Hexavalent Cr compounds are highly toxic to biological systems. In terms of carcinogenicity, hexavalent Cr compounds are classified by IARC as Group 1, and are considered carcinogenic to humans 41. Some studies show that hexavalent Cr, after entering the body through the consumption of water, food or contaminated air, is extremely harmful and toxic to human tissues due to its high solubility in water. Its solubility increases the active transport of chromate across biological membranes, which, as soon as it enters the cell, causes its mutagenic and carcinogenic effects 42, 43. Cr toxicity to pregnant women is related to adverse effects on fetal development and pregnancy. Cr, especially in its hexavalent form, can Pb to various reproductive problems. Cr exposure during pregnancy has been associated with reduced fetal growth, low birth weight, premature birth, and other complications. These effects are often through mechanisms such as oxidative stress and placental dysfunction 44.
Arsenic (As)
Long-term exposure to As, as a dangerous toxic heavy metal, can cause numerous health problems and complications for humans, the most important of which include the development of various cancers, especially skin, liver, bladder, and lung cancer, blood pressure, diabetes, cardiovascular diseases, reproductive system toxicity, and skin lesions 14, 45. As is one of the most important toxic metals for the reproductive system in female and male. Studies show that exposure of pregnant women to As through consumption of contaminated water, food or air can cause oxidative stress, spontaneous abortion, disruption of the reproductive cycle, HDP, decreased progesterone and testosterone levels and impaired fertility 11.
Mercury (Hg)
Hg, one Neurotoxin It is present in the environment through various natural and human sources. The most important effects related to exposure to Hg include cellular toxicity, adverse effects on the cardiovascular, hematopoietic, pulmonary, renal, and nervous, endocrine, reproductive and embryonic systems 46. The toxic Hg poses significant risks to pregnant women and their fetuses due to its ability to bioaccumulate and cross the placenta. Hg exposure is mainly through the consumption of seafood, especially fish. Toxic effects of Hg can Pb to various adverse health consequences, including developmental problems in infants and high blood pressure disorders in pregnant women 47.
Hypertensive disorders of pregnancy (HDP)
Fertility is one of the most important aspects of human life and its goal is to have healthy children. Fertility is affected by a variety of factors, and environmental hazards can make it difficult to have a successful pregnancy, healthy baby, and successful birth 18. Hypertensive disorders of pregnancy (HDP) are among the most common health problems during pregnancy and in pregnant women, which can increase the risk of fetal and maternal mortality 47. These disorders are seen in two forms: gestational hypertension and preeclampsia (PE) 48. Gestational hypertension is defined as a systolic blood pressure greater than or equal to 140 mmHg or a diastolic blood pressure greater than or equal to 90 mmHg 49. Preeclampsia is associated with adverse pregnancy outcomes for the mother and fetus and increased maternal blood pressure, and the risk of mortality in mothers with a history of preeclampsia is 7 to 8 times higher than others 50. The main risk factors related to HDP are included family history of high blood pressure, high body mass index (BMI), inactivity, being over 35 years old at the time of pregnancy, gestational diabetes, pre-pregnancy diabetes, psychological stress during pregnancy, diet and environmental exposures 51.
The relationship between heavy metal exposure and HDP
Environmental risk factors, especially heavy metals, can affect both individual fertility and pregnancy, as well as childbirth, fetal and child health. Studies show that exposure to heavy metals such as Pb, Cd, Hg, and As can have adverse effects on pregnant women and the fetus 28, 52. The most important heavy metals exposure routes in pregnant women are through the drinking water, food, cosmetics, cigarette smoke, and indoor and outdoor air pollutants 5. Nowadays, environmental exposures, especially exposure to heavy metals, have been considered as one of the risk factors for HDP 24. Table 1, shows various studies related to heavy metals exposure and HDP in pregnant women. Studies show that the most important heavy metals affecting on HDP are include Pb, Cd, Hg, As, Cr, and Cu (Table 1).
According to a study by Morimoto et al., in Japan, which was conducted on 88,670 pregnant women with an average age of 31, to determine the relationship between exposure to heavy metals Pb, Cd , and Hg in the blood during the second and third trimesters of pregnancy and HDP, the results showed that the HDP was positively and significantly associated with the concentration of Pb (with an odds ratio ( OR ) of 1.58), Cd (odds ratio of 1.3), and Hg (odds ratio of 1.15) in the blood 53. Pb can cross the placenta during pregnancy and is associated with intrauterine fetal death, preterm delivery, and low birth weight 24. Cd also targets tissues of the heart and blood vessels, kidneys, lungs, and brain, causing cardiovascular disease, high blood pressure, liver damage, and a weakened immune system 23. According to previous studies, there is a positive and significant relationship between exposure to Cd and high blood pressure 23. In a study conducted by Mahmood and Al-Helaly in Iraq on 153 pregnant women In two groups of pregnant women with hypertension (75 people) and healthy pregnant women (78 people) and by measuring the heavy metals Pb, Cd and Cr in the amniotic fluid, the results showed that with increasing heavy metal concentrations in pregnant women with hypertension, blood pressure increased significantly compared to the control group 54.
The toxic metal Hg is found in pesticides, fungicides, fish, dental fillings, and other industrial processes. Women who are dental assistants or female dentists who handle Hg for dental fillings have higher exposures to Hg than the general population 55. In a study by de Oliveira et al., on the association between Hg exposure during pregnancy and blood pressure in pregnant women, the results showed that pregnant women's exposure to Hg and the presence of Hg in their urine and blood were positively and significantly associated with high blood pressure in the exposed groups compared to the control groups 47. In a study conducted by Ma et al., in China, 146 women with HDP and 292 normal pregnant women at 10 and 19 weeks of pregnancy were investigated in the context of the relationship between HDP and exposure to heavy metals Cu, Pb, Hg, aluminum (Al), nickel (Ni), and vanadium (V). The results showed that there was a positive and significant relationship between exposure to heavy metals Hg, Al, Ni, and V. There is an association with HDP, and the highest odds were observed in exposure to Hg 29.
Exposure to Cu is through the water pipes, contraceptives, swimming pools and jewelry. Studies have confirmed a positive association between Cu exposure and HDP in women and during pregnancy 56. In a study conducted by Lewandowska et al., in Poland on 121 pregnant women with high blood pressure and 363 pregnant women with normal blood pressure at 10 and 14 weeks of pregnancy on the relationship between exposure to Cu and Zn metals and pregnancy blood pressure, the results showed that low Cu concentration in the blood in early pregnancy in pregnant women was significantly associated with an increased risk of pregnancy blood pressure 56.
Studies show that exposure to As, a dangerous toxic and carcinogenic metal, can also increase the risk of blood pressure and cardiovascular diseases in pregnant women. In a study conducted by Wang et al. on 1038 pregnant women, it was shown that there is a positive and significant association between increased As concentration and increased systolic and diastolic blood pressure in pregnant women 57.
The main mechanisms of pregnancy-induced hypertension due to heavy metals exposure in pregnant women include the changes and dysfunction in endothelial function, activation of inflammatory reactions and oxidative stress 58, 59. In fact, increased exposure to heavy metals increases lipid peroxides and oxygen free radicals, causing disruption or damage to endothelial cells and can play a role in the development or exacerbation of HDP 60. Exposure to heavy metals can reduce the activity of Myosin ATPase, increased arterial wall tension due to calcium overload in vascular smooth muscle, may increase blood pressure in pregnant women 61.
Today, with the development of agriculture and industries and the consumption of fossil fuels, various pollutants are produced and enter to the water, soil and air resources 1. One of the most important pollutants found in abundance in environmental sources is heavy metals 2. Heavy metals are divided into two categories: non-toxic and toxic metals for the growth of living organisms. Essential metal elements such as Zinc (Zn), Copper (Cu), Cobalt (Co), and manganese (Mn), which have important physiological roles such as cofactor role, oxidation and reduction reactions and ligand binding 3. Non-essential or toxic heavy metals include Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb) and Mercury (Hg), which disrupt the physiological and metabolic processes of the body due to their high stability and accumulation in the body of living organisms 4, 5. Heavy metals are the main constituent of the earth's crust that do not decompose through chemical and biological processes in nature. Heavy metals occur naturally in soil, water, and air (as a result of volcanic eruptions, soil erosion, and weathering) 6. It also enters the environment through human activities and the consumption of fossil fuels in industries, vehicle fuel, agricultural activities, and mining activities 7. Toxic heavy metals are stable, persistent and non-degradable compounds that not only reduce the quality of water and soil resources, but also pose a serious threat to the atmosphere and food products, which in turn threatens the health of living organisms and humans 8, 9. These metals, when entering water and soil resources, are absorbed by plants, agricultural crops, and fruit trees through the roots and leaves. Then, they are stored in the leaves and fruits of agricultural products and enter the food chain of humans through the consumption of these products 10, 11. Humans and living organisms are exposed to heavy metals, directly and indirectly, through the consumption of agricultural products, food, drinking water, breathing polluted air, and contact with contaminated materials and products such as cosmetics and personal care products 12. Exposure through the digestive system and consumption of contaminated food and water is the most important route of exposure to heavy metals 5, 13. Toxic metals accumulate in various body tissues such as the liver, kidneys, bladder, and bones, causing various adverse effects on various body systems such as the renal and urinary tract systems, cardiovascular systems, respiratory and lung systems, and central nervous systems, and can cause many types of cancers 14-17.
Pregnancy is a period when women are more vulnerable and sensitive to exposure to environmental pollutants, especially toxic heavy metals 18. Pregnancy is a time when significant hormonal and physiological changes occur in pregnant women, which can lead to increased nutritional needs and subsequent nutrient deficiencies. These deficiencies alter the absorption and metabolism of toxic heavy metals in the pregnant woman's body, causing the release of heavy metals stored in the body and their transfer to the placenta 13. The most important consequences of exposure to heavy metals during pregnancy include spontaneous abortion, premature birth, infertility, and hormonal disorders in pregnant women 11, 19. As a result, exposure to toxic heavy metals during pregnancy can have negative effects on fetal development and dangerous consequences such as miscarriage, stillbirth, and low birth weight 20, 21. Long-term exposure to toxic heavy metals is one of the most important risk factors for blood pressure in humans 22. Hypertension is one of the chronic diseases, is considered one of the main causes of death in societies with high prevalent due to dysfunction of vital organs such as the brain, heart, and other organs 23. Hypertensive disorders of pregnancy (HDP) is one of the most common diseases among pregnant women, which pose a high risk of adverse outcomes for pregnant women and fetuses, such as miscarriage and premature birth 24. HDP is a major cause of maternal and perinatal morbidity and mortality 25. In the latest classification, HDP comprises four subgroups based on symptoms and time of onset: gestational hypertension (GH), preeclampsia (PE), superimposed preeclampsia, and eclampsia 26. Based on epidemiological studies, the global prevalence rates of HDP, gestational hypertension, and preeclampsia are 5.2–8.2%, 1.8–4.4%, and 0.2–9.2%, respectively 26, 27. The most important risk factors associated with HDP are include body mass index, anemia, education level, tobacco and alcohol use, advanced maternal age, family and genetic history, and exposure to environmental pollutants and toxins 26, 28, 29. Toxic heavy metals are among the most significant environmental pollutants, and exposure to them may be associated with HDP 29. Studies show that heavy metals such as Pb and Cd have a high risk for blood pressure during pregnancy 30.
Therefore, considering the serious risks of exposure to toxic heavy metals and their effects on health, and considering the sensitivity during pregnancy and the risks that exposure to these metals through drinking water, food, and air can have for the mother and fetus, and on the other hand, there is a need to categorize existing information and studies in the field of pregnancy blood pressure due to heavy metals exposure, this study aimed to review studies related to pregnant women's exposure to heavy metals and its effect on pregnancy blood pressure and HDP, and to determine the mechanism of influence, as well as to provide control strategies to reduce exposure.
Materials and Methods
PubMed, Web of Science, Scopus, Science Direct, and Google Scholar databases were used to search for published paper between 2005 to 2025. The search strategy in this study was based on the use of the main keywords includes "Pregnant women", "Pregnant People", Maternal Exposure", "Metals, Heavy", "hypertensive disorders of pregnancy", "Hypertension", "Blood pressure" and "Arterial Pressure" were performed. Then, out of the 64 articles found, after reviewing the articles, finally 15 relevant papers were selected and reviewed based on their similarity and proximity to the subject of study, which was specifically in the field of HDP and heavy metals. The main heavy metals reviewed in this study were include: Pb, Cd, Hg, As, Cr, and Cu.
Toxic heavy metals health risks
The term heavy metals refers to metals and metalloids with a specific gravity greater than 5 grams per cubic centimeter, with the potential to bioaccumulate along the food chain 8. With the increasing development of industry and agriculture, the problems of environmental pollution caused by toxic metals have taken on serious dimensions, and today, environmental pollution, especially toxic heavy metals, has become a serious problem worldwide 1.
The bioaccumulation of heavy metals absorbed in plant in concentrations exceeding the standard levels, in addition to reducing the growth and yield of agricultural products, leads to contamination of the food chain and endangering the health of human communities 6. Human activities such as industrial and energy production activities, vehicle exhaust emissions, chemical fertilizer discharges, and fuel and coal combustion are all potential sources of heavy metals discharge to agricultural soils. The main sources of heavy metals are the atmosphere, mining, industries, fossil fuel combustion, ash residue deposition from coal combustion, traffic and vehicles, or the use of pesticides and chemical fertilizers in agriculture 10. In addition, toxic heavy metals can also enter the food products during the production and packaging process. For example, heavy metals including Pb and Cd may be released from polyethylene packaging. Polyethylene terephthalate (PET) is transferred to food during long-term storage and heating, and there is even the potential for heavy metals to be transferred to food packaging 31. The following are the most important toxic heavy metals that affect the reproductive system and the effects of exposure to them, especially during pregnancy.
Lead (Pb)
The bioavailability of Pb depends on its structure (organic or inorganic), the amount it enters the body, the age and diet of the individual. Pb has the potential to cause cancer in humans 32. In adults, the cessation of hemoglobin synthesis is also associated with low levels of Pb in the blood. At higher levels of Pb in the blood, signs of neurotoxicity such as decreased central nervous system conduction velocity, as well as nephrotoxicity, are observed. In children, toxic effects of Pb, such as growth retardation, balance problems, and other neurobehavioral signs, have been associated with blood Pb levels (10 µg/dL) 33. Pregnant women are at high risk for exposure to Pb metal due to Pb mobility during this period, because bones are catabolized during pregnancy to help form the fetal skeleton 34. Chemical biosynthesis disorders and anemia, increased blood pressure, kidney damage, miscarriage and premature birth, nervous system disorders, brain damage, and male infertility are some of the complications of Pb exposure, especially during pregnancy 35.
Cadmium (Cd)
Cd, with a concentration of 0.06 to 1.1 mg/kg of soil, is considered one of the most important and mobile heavy metals in soil. Poisoning with this metal causes serious damage to the kidneys, bones, and nervous system 36. Cd is classified as carcinogenic by IARC in Group 1, and by OSHA in it is also known as a carcinogen 37. The primary route of exposure to Cd is inhalation. Depending on its structure, 15-35% of inhaled Cd is absorbed into the blood. When Cd is absorbed into the blood, it forms a bond with albumin and is transported to the liver and causes liver damage and increases in liver enzymes 38. Studies show that the female reproductive system is very vulnerable to Cd. Consuming water, food, and breathing air contaminated with Cd, It can affect the functioning of the reproductive system in women, especially the uterus, and Cd inhibits and alters important biochemical processes in the reproductive system 39. Cd disrupts the function of the ovaries and placenta by causing changes in steroidogenesis. Cd can also cause delayed puberty, loss of reproductive hormones during pregnancy, menstrual cycle disruption, premature birth, and low birth weight in pregnant women 40.
Chromium (Cr)
Cr compounds are mainly present in the environment in two main forms, trivalent and hexavalent. Hexavalent Cr is widely used in various industries. Hexavalent Cr compounds are highly toxic to biological systems. In terms of carcinogenicity, hexavalent Cr compounds are classified by IARC as Group 1, and are considered carcinogenic to humans 41. Some studies show that hexavalent Cr, after entering the body through the consumption of water, food or contaminated air, is extremely harmful and toxic to human tissues due to its high solubility in water. Its solubility increases the active transport of chromate across biological membranes, which, as soon as it enters the cell, causes its mutagenic and carcinogenic effects 42, 43. Cr toxicity to pregnant women is related to adverse effects on fetal development and pregnancy. Cr, especially in its hexavalent form, can Pb to various reproductive problems. Cr exposure during pregnancy has been associated with reduced fetal growth, low birth weight, premature birth, and other complications. These effects are often through mechanisms such as oxidative stress and placental dysfunction 44.
Arsenic (As)
Long-term exposure to As, as a dangerous toxic heavy metal, can cause numerous health problems and complications for humans, the most important of which include the development of various cancers, especially skin, liver, bladder, and lung cancer, blood pressure, diabetes, cardiovascular diseases, reproductive system toxicity, and skin lesions 14, 45. As is one of the most important toxic metals for the reproductive system in female and male. Studies show that exposure of pregnant women to As through consumption of contaminated water, food or air can cause oxidative stress, spontaneous abortion, disruption of the reproductive cycle, HDP, decreased progesterone and testosterone levels and impaired fertility 11.
Mercury (Hg)
Hg, one Neurotoxin It is present in the environment through various natural and human sources. The most important effects related to exposure to Hg include cellular toxicity, adverse effects on the cardiovascular, hematopoietic, pulmonary, renal, and nervous, endocrine, reproductive and embryonic systems 46. The toxic Hg poses significant risks to pregnant women and their fetuses due to its ability to bioaccumulate and cross the placenta. Hg exposure is mainly through the consumption of seafood, especially fish. Toxic effects of Hg can Pb to various adverse health consequences, including developmental problems in infants and high blood pressure disorders in pregnant women 47.
Hypertensive disorders of pregnancy (HDP)
Fertility is one of the most important aspects of human life and its goal is to have healthy children. Fertility is affected by a variety of factors, and environmental hazards can make it difficult to have a successful pregnancy, healthy baby, and successful birth 18. Hypertensive disorders of pregnancy (HDP) are among the most common health problems during pregnancy and in pregnant women, which can increase the risk of fetal and maternal mortality 47. These disorders are seen in two forms: gestational hypertension and preeclampsia (PE) 48. Gestational hypertension is defined as a systolic blood pressure greater than or equal to 140 mmHg or a diastolic blood pressure greater than or equal to 90 mmHg 49. Preeclampsia is associated with adverse pregnancy outcomes for the mother and fetus and increased maternal blood pressure, and the risk of mortality in mothers with a history of preeclampsia is 7 to 8 times higher than others 50. The main risk factors related to HDP are included family history of high blood pressure, high body mass index (BMI), inactivity, being over 35 years old at the time of pregnancy, gestational diabetes, pre-pregnancy diabetes, psychological stress during pregnancy, diet and environmental exposures 51.
The relationship between heavy metal exposure and HDP
Environmental risk factors, especially heavy metals, can affect both individual fertility and pregnancy, as well as childbirth, fetal and child health. Studies show that exposure to heavy metals such as Pb, Cd, Hg, and As can have adverse effects on pregnant women and the fetus 28, 52. The most important heavy metals exposure routes in pregnant women are through the drinking water, food, cosmetics, cigarette smoke, and indoor and outdoor air pollutants 5. Nowadays, environmental exposures, especially exposure to heavy metals, have been considered as one of the risk factors for HDP 24. Table 1, shows various studies related to heavy metals exposure and HDP in pregnant women. Studies show that the most important heavy metals affecting on HDP are include Pb, Cd, Hg, As, Cr, and Cu (Table 1).
According to a study by Morimoto et al., in Japan, which was conducted on 88,670 pregnant women with an average age of 31, to determine the relationship between exposure to heavy metals Pb, Cd , and Hg in the blood during the second and third trimesters of pregnancy and HDP, the results showed that the HDP was positively and significantly associated with the concentration of Pb (with an odds ratio ( OR ) of 1.58), Cd (odds ratio of 1.3), and Hg (odds ratio of 1.15) in the blood 53. Pb can cross the placenta during pregnancy and is associated with intrauterine fetal death, preterm delivery, and low birth weight 24. Cd also targets tissues of the heart and blood vessels, kidneys, lungs, and brain, causing cardiovascular disease, high blood pressure, liver damage, and a weakened immune system 23. According to previous studies, there is a positive and significant relationship between exposure to Cd and high blood pressure 23. In a study conducted by Mahmood and Al-Helaly in Iraq on 153 pregnant women In two groups of pregnant women with hypertension (75 people) and healthy pregnant women (78 people) and by measuring the heavy metals Pb, Cd and Cr in the amniotic fluid, the results showed that with increasing heavy metal concentrations in pregnant women with hypertension, blood pressure increased significantly compared to the control group 54.
The toxic metal Hg is found in pesticides, fungicides, fish, dental fillings, and other industrial processes. Women who are dental assistants or female dentists who handle Hg for dental fillings have higher exposures to Hg than the general population 55. In a study by de Oliveira et al., on the association between Hg exposure during pregnancy and blood pressure in pregnant women, the results showed that pregnant women's exposure to Hg and the presence of Hg in their urine and blood were positively and significantly associated with high blood pressure in the exposed groups compared to the control groups 47. In a study conducted by Ma et al., in China, 146 women with HDP and 292 normal pregnant women at 10 and 19 weeks of pregnancy were investigated in the context of the relationship between HDP and exposure to heavy metals Cu, Pb, Hg, aluminum (Al), nickel (Ni), and vanadium (V). The results showed that there was a positive and significant relationship between exposure to heavy metals Hg, Al, Ni, and V. There is an association with HDP, and the highest odds were observed in exposure to Hg 29.
Exposure to Cu is through the water pipes, contraceptives, swimming pools and jewelry. Studies have confirmed a positive association between Cu exposure and HDP in women and during pregnancy 56. In a study conducted by Lewandowska et al., in Poland on 121 pregnant women with high blood pressure and 363 pregnant women with normal blood pressure at 10 and 14 weeks of pregnancy on the relationship between exposure to Cu and Zn metals and pregnancy blood pressure, the results showed that low Cu concentration in the blood in early pregnancy in pregnant women was significantly associated with an increased risk of pregnancy blood pressure 56.
Studies show that exposure to As, a dangerous toxic and carcinogenic metal, can also increase the risk of blood pressure and cardiovascular diseases in pregnant women. In a study conducted by Wang et al. on 1038 pregnant women, it was shown that there is a positive and significant association between increased As concentration and increased systolic and diastolic blood pressure in pregnant women 57.
The main mechanisms of pregnancy-induced hypertension due to heavy metals exposure in pregnant women include the changes and dysfunction in endothelial function, activation of inflammatory reactions and oxidative stress 58, 59. In fact, increased exposure to heavy metals increases lipid peroxides and oxygen free radicals, causing disruption or damage to endothelial cells and can play a role in the development or exacerbation of HDP 60. Exposure to heavy metals can reduce the activity of Myosin ATPase, increased arterial wall tension due to calcium overload in vascular smooth muscle, may increase blood pressure in pregnant women 61.
Table 1. Different studies related to heavy metals exposure and the hypertensive disorders of pregnancy.
| Region/year | Study type | Sample size | Exposure routes | Measurement technique | Heavy metals | Results | References |
| Iraq, 2019 | A case-control study | 153 pregnant women in two groups: pregnant women with hypertension (75 sample) and healthy pregnant women (78 sample) | Amniotic fluid sampling from pregnant women via the vagina with a sterile syringe | Atomic absorption spectrometry (AAS) | Pb, Cd and Cr | -With increasing heavy metal concentrations, blood pressure significantly increased in pregnant women with hypertension compared to that in the control group. Heavy metal concentrations were higher in pregnant women who smoked than in non-smokers. |
54 |
| Canada, 2023 | Pregnancy cohort | 1560 pregnant women | Blood samples from the first and third trimesters of pregnancy | Inductively coupled plasma mass spectrometry (ICP-MS) | Pb, Cd, As and Hg | - Increased concentrations of Pb and As in the blood increase the risk of preeclampsia and gestational hypertension. | 52 |
| Japan, 2025 | Pregnancy cohort | 88670 pregnant women | Blood samples from the second and third trimesters of pregnancy with blood pressure ≥ 140/90 | ICP-MS | Pb, Cd, and Hg | - A positive and significant association was observed between exposure to heavy metals Pb, Cd, and Hg with hypertensive disorders of pregnancy | 53 |
| China, 2022 | A case-control study | 146 women with gestational hypertension and 292 normal pregnant women in the control group | Blood sample at 10 and 16 weeks of pregnancy with blood pressure ≥ 140/90 | ICP-MS | Pb, Hg, Cu, Al, Ni, and V | - Positive and significant association was observed between exposure to heavy metals Hg, Al, Ni and V with hypertensive disorders of pregnancy The highest odds ratio was observed for exposure to Hg. |
29 |
| Poland, 2019 | A case-control study | 121 pregnant women with high blood pressure and 363 pregnant women with normal blood pressure | Blood samples of Pregnant women with blood pressure ≥ 140/90 | ICP-MS | Cu and Zn | - Low blood Cu levels in early pregnancy were significantly associated with an increased risk of gestational hypertension in pregnant women | 56 |
Strategies to reduce heavy metals exposure in pregnant women
Given the health risks of toxic heavy metals exposure and the vulnerability of pregnant women and fetuses during pregnancy, it is essential to pay attention to strategies for preventing and reducing exposure to heavy metals. Studies show that strategies for reducing exposure to toxic heavy metals for pregnant women, fetuses, and children in early life can include the production and use of organic agricultural products and foods that are free of heavy metals, especially rice and wheat (bread) as commonly consumed foods. Also, the use of home air purifiers, especially in industrial areas during pregnancy and early life, can be an effective strategy to reduce exposure to particulate matter (PM) containing toxic heavy metals 62, 63.
Lifestyle changes, especially in the nutrition and diet, are also effective in reducing blood pressure during pregnancy. It is recommended to use diets containing essential nutrients that can reduce the bioaccumulation of heavy metals and increase their excretion. For example, foods rich in iron and calcium can reduce the bioaccumulation of Pb in the body, or selenium, which is effective in reducing the bioaccumulation of Hg 64. A healthy diet containing protein, dairy products, especially milk, vegetables and fruits prepared organically can also play a significant role in the excretion and reduction of heavy metal concentrations from the body 65. The results of studies also show that diet can also play a role in pregnancy-induced hypertension. Potential positive effects of certain nutrients such as magnesium, omega-3 fatty acids and vitamins with antioxidant properties in HDP prevention confirmed in several studies 52.
Increasing public awareness, especially among pregnant women, about the dangers and risks associated to toxic heavy metals exposure in order to increase the perceived sensitivity and practice of this group of people to reduce consumption of food or water contaminated with heavy metals can be effective in reducing potential impacts 66. The use of advanced methods for treatment of contaminated water and soil resources, such as phytoremediation, as well as the use of membranes processes for advanced purification of drinking water can also contribute to reducing exposure to heavy metals 67. Sustainable development, monitoring and surveillance of agricultural products, food and drinking water distributed in different areas are also long-term solutions to reduce exposure to heavy metals 68.
Conclusion
In this study, a review of studies related to pregnant women's exposure to heavy metals and their effects on HDP was conducted. Studies show that the most important heavy metals affecting HDP are include Pb, Cd, Hg, As, and Cu at high concentrations. The mechanism of HDP caused by heavy metals exposure in pregnant women includes an increase in lipid peroxides and oxygenated free radicals and the creation of disorders or damage to endothelial cells. Prevention and reduction strategies to reduce pregnant women's exposure to heavy metals are include the use of organic food products free of heavy metals, the use of home air purifiers. Consequently, the use of organic food products, the use of home water or air purifiers, the use of foods rich in iron, calcium and selenium and a healthy diet containing antioxidants such as dairy products and organic vegetables and fruits can be strategies to reduce the exposure of pregnant women to heavy metals.
Acknowledgements
The authors gratefully acknowledge the support provided by Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Conflict of Interest
The authors declare no relevant financial or non-financial interests.
Funding
Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Ethical Considerations
Not applicable
Code of Ethics
Not applicable
Authors' Contributions
All authors contributed to the study conception and design. Studies search and review were performed by H. E. and F.D.B.. The first draft written and revision of the manuscript were performed by H.E, F.D.B, and M.A. All authors approved the final manuscript.
This is an Open-Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt, and build upon this work for commercial use.
References
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Given the health risks of toxic heavy metals exposure and the vulnerability of pregnant women and fetuses during pregnancy, it is essential to pay attention to strategies for preventing and reducing exposure to heavy metals. Studies show that strategies for reducing exposure to toxic heavy metals for pregnant women, fetuses, and children in early life can include the production and use of organic agricultural products and foods that are free of heavy metals, especially rice and wheat (bread) as commonly consumed foods. Also, the use of home air purifiers, especially in industrial areas during pregnancy and early life, can be an effective strategy to reduce exposure to particulate matter (PM) containing toxic heavy metals 62, 63.
Lifestyle changes, especially in the nutrition and diet, are also effective in reducing blood pressure during pregnancy. It is recommended to use diets containing essential nutrients that can reduce the bioaccumulation of heavy metals and increase their excretion. For example, foods rich in iron and calcium can reduce the bioaccumulation of Pb in the body, or selenium, which is effective in reducing the bioaccumulation of Hg 64. A healthy diet containing protein, dairy products, especially milk, vegetables and fruits prepared organically can also play a significant role in the excretion and reduction of heavy metal concentrations from the body 65. The results of studies also show that diet can also play a role in pregnancy-induced hypertension. Potential positive effects of certain nutrients such as magnesium, omega-3 fatty acids and vitamins with antioxidant properties in HDP prevention confirmed in several studies 52.
Increasing public awareness, especially among pregnant women, about the dangers and risks associated to toxic heavy metals exposure in order to increase the perceived sensitivity and practice of this group of people to reduce consumption of food or water contaminated with heavy metals can be effective in reducing potential impacts 66. The use of advanced methods for treatment of contaminated water and soil resources, such as phytoremediation, as well as the use of membranes processes for advanced purification of drinking water can also contribute to reducing exposure to heavy metals 67. Sustainable development, monitoring and surveillance of agricultural products, food and drinking water distributed in different areas are also long-term solutions to reduce exposure to heavy metals 68.
Conclusion
In this study, a review of studies related to pregnant women's exposure to heavy metals and their effects on HDP was conducted. Studies show that the most important heavy metals affecting HDP are include Pb, Cd, Hg, As, and Cu at high concentrations. The mechanism of HDP caused by heavy metals exposure in pregnant women includes an increase in lipid peroxides and oxygenated free radicals and the creation of disorders or damage to endothelial cells. Prevention and reduction strategies to reduce pregnant women's exposure to heavy metals are include the use of organic food products free of heavy metals, the use of home air purifiers. Consequently, the use of organic food products, the use of home water or air purifiers, the use of foods rich in iron, calcium and selenium and a healthy diet containing antioxidants such as dairy products and organic vegetables and fruits can be strategies to reduce the exposure of pregnant women to heavy metals.
Acknowledgements
The authors gratefully acknowledge the support provided by Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Conflict of Interest
The authors declare no relevant financial or non-financial interests.
Funding
Rafsanjan University of Medical Sciences, Rafsanjan, Iran
Ethical Considerations
Not applicable
Code of Ethics
Not applicable
Authors' Contributions
All authors contributed to the study conception and design. Studies search and review were performed by H. E. and F.D.B.. The first draft written and revision of the manuscript were performed by H.E, F.D.B, and M.A. All authors approved the final manuscript.
This is an Open-Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt, and build upon this work for commercial use.
References
1. Eslami H, Hasanshahi N, Ebrahimi Z, et al. Assessment of heavy metal concentrations in water purifier devices in Rafsanjan city. Journal of Environmental Health and Sustainable Development. 2023 ; 8(2): 1988-98.
2. Ma Y, Liang C, Wang Z, et al. Association between prenatal metals exposure and blood pressure in 5–6 years children: a birth cohort study. Environ Res. 2023;219:114974.
3. Ngu YJ, Skalny AV, Tinkov AA, et al. Association between essential and non-essential metals, body composition, and metabolic syndrome in adults. Biol Trace Elem Res. 2022;200(12):4903-15.
4. Dubey S, Shri M, Gupta A, et al. Toxicity and detoxification of heavy metals during plant growth and metabolism. Environ Chem Lett. 2018;16(4):1169-92.
5. Eslami H, Esmaeili A, Razaeian M, et al. Potentially toxic metal concentration, spatial distribution, and health risk assessment in drinking groundwater resources of southeast Iran. Geosci Front. 2022;13(1):101276.
6. de Almeida Ribeiro Carvalho M, Botero WG, de Oliveira LC. Natural and anthropogenic sources of potentially toxic elements to aquatic environment: a systematic literature review. Environ Sci Pollut Res Int. 2022;29(34):51318-38.
7. Daripa A, Malav LC, Yadav DK, et al. Metal contamination in water resources due to various anthropogenic activities. InMetals in water: Elsevier; 2023pp. 111-27.
8. Eslami H, Ebrahimi E, Baberi F, et al. Ecological risk assessment of heavy metals in Morus alba leaves in Rafsanjan and Sarcheshmeh, the southeast area of Iran. Spatial Information Research. 2024;32(5):531-40.
9. Kankia H, Abdulhamid Y. Determination of accumulated heavy metals in benthic invertebrates found in Ajiwa Dam, Katsina State, Northern Nigeria. 2014.
10. Angon PB, Islam MS, Das A, et al. Sources, effects and present perspectives of heavy metals contamination: soil, plants and human food chain. Heliyon. 2024;10(7).
11. Eslami H, Askari FR, Mahdavi M, et al. Environmental arsenic exposure and reproductive system toxicity in male and female and mitigatory strategies: a review. Environ Geochem Health. 2024;46(10):420.
12. Wang M, Chen Z, Song W, et al. A review on cadmium exposure in the population and intervention strategies against cadmium toxicity. Bull Environ Contam Toxicol. 2021;106(1):65-74.
13. Okubo H, Nakayama SF. Periconceptional diet quality and its relation to blood heavy metal concentrations among pregnant women: the Japan environment and children’s study. Environ Res. 2023;225:115649.
14. Baghery F, Lau LDW, Mohamadi M, et al. Risk of urinary tract cancers following arsenic exposure and tobacco smoking: a review. Environ Geochem Health. 2023;45(8):5579-98.
15. Chen T, Dai K, Wu H. Effect of lead exposure on respiratory health: a systematic review and meta-analysis. Air Qual Atmos Health. 2024;17(12):3031-44.
16. Duan H, Yu L, Tian F, et al. Gut microbiota: a target for heavy metal toxicity and a probiotic protective strategy. Sci Total Environ. 2020;742:140429.
17. Kuo C-C, Balakrishnan P, Gribble MO, et al. The association of arsenic exposure and arsenic metabolism with all-cause, cardiovascular and cancer mortality in the Strong Heart Study. Environ Int. 2022;159:107029.
18. Iglesias-Vázquez L, Binter A-C, Canals J, et al. Maternal exposure to air pollution during pregnancy and child's cognitive, language, and motor function: ECLIPSES study. Environ Res. 2022;212:113501.
19. Dutta S, Gorain B, Choudhury H, et al. Environmental and occupational exposure of metals and female reproductive health. Environ Sci Pollut Res Int. 2022;29(41):62067-92.
20. Amegah AK, Sewor C, Jaakkola JJ. Cadmium exposure and risk of adverse pregnancy and birth outcomes: a systematic review and dose–response meta-analysis of cohort and cohort-based case–control studies. J Expo Sci Environ Epidemiol. 2021;31(2):299-317.
21. Flannery BM, Schaefer HR, Middleton KB. A scoping review of infant and children health effects associated with cadmium exposure. Regul Toxicol Pharmacol. 2022;131:105155.
22. Li W, Huang G, Tang N, et al. Effects of heavy metal exposure on hypertension: a machine learning modeling approach. Chemosphere. 2023;337:139435.
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Type of Study: Narrative review |
Subject:
Environmental Health, Sciences, and Engineering
Received: 2026/06/4 | Accepted: 2026/08/20 | Published: 2026/09/10
Received: 2026/06/4 | Accepted: 2026/08/20 | Published: 2026/09/10
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