Do metals in pregnant women have association to preterm births?
Metals are widely distributed in the environment. Recent reports have demonstrated the risk of preterm birth following heavy metal exposure. Preterm births include those occurring before 37 completed weeks of pregnancy, and the rate of preterm births is increasing in almost all countries. Preterm births are divided into several groups. For example, preterm births are classified as early (< 34 weeks) and late (34 to < 37 weeks). Early preterm babies are at a higher risk of mortality, heart failure, immunologic/infectious morbidities and disabilities. In addition, preterm birth is a burden not only to the health of newborns, but also to that of the mothers. It is thus necessary to investigate whether metal exposure in fact affects preterm birth, especially early preterm birth, and if so, which metals strongly influence preterm births in order to protect the health of both mothers and babies.
Therefore, we analyzed the association between maternal whole blood concentrations of metals, such as cadmium (Cd), lead (Pb), mercury (Hg), selenium (Se), and manganese (Mn) that are common toxicants in Japan, and preterm births.
The data of 14,847 pregnant women who were participants of the Japan Environment and Children’s Study (JECS) were used. Data of the self-questionnaire pertaining to the first trimester (T1), second/third trimester (T2), and medical records after delivery were analyzed. We divided preterm birth into two groups: early preterm (22 to < 34 weeks) and late preterm (34 to < 37 weeks). Maternal blood samples for measuring metal concentrations were collected in T2. The participants were classified into four quartiles (Q1–Q4) according to increasing metal levels.
The rate of preterm birth was 4.5%. After controlling for confounding factors, such as age, pre-pregnancy body mass index, smoking, partner’s smoking, drinking habits, gravidity, parity, number of cesarean deliveries, uterine infections, household income, educational levels, and sex of infant, Cd levels were found, by multivariable logistic regression analysis, to be significantly associated with early preterm birth, with odds ratio for early preterm birth of 1.91 (95% confidence interval: 1.12–3.27, P = 0.018) in subjects of Q4 compared with in subjects with term birth (≧ 37 weeks). In other words, there was a relationship between high whole blood concentrations of Cd in pregnant women and risk of early preterm births, but no relationship between Cd concentration and risk of late preterm births.
This is the first study to analyze the relationship between multiple metal concentrations and early and late preterm births in a large-scale cohort. Identification of the main sources of Cd and reductions of maternal Cd exposure may contribute to the prevention of early preterm births and health maintenance of mothers and their infants in the future.
Department of Environmental Health, University of Occupational and Environmental Health, Japan
The association between whole blood concentrations of heavy metals in pregnant women and premature births: The Japan Environment and Children’s Study (JECS).
Tsuji M, Shibata E, Morokuma S, Tanaka R, Senju A, Araki S, Sanefuji M, Koriyama C, Yamamoto M, Ishihara Y, Kusuhara K, Kawamoto T; Japan Environment & Children’s Study Group
Environ Res. 2018 Oct
|Heavy metal resistant–plant growth promoting… In the present era, pollution of water, soil and air with heavy metals is increasing rapidly. Industrialization and technological advancement have caused serious damage to the ecosystem by releasing large…|
|Cuddling of babies born extremely preterm before… Delivery of a baby before 37 weeks’ gestation is known as premature birth. Some babies may be born more than 12 weeks early – at 27 weeks’ gestation or even…|
|Trends in heart failure diagnosis for women and men… Heart failure remains a significant cause of death and disability for women and men. It is estimated that 1 in 5 individuals will be diagnosed with heart failure in their…|
|Sex differences in heart failure outcomes in Ontario, Canada Heart failure is a leading cause of death in women and men around the world. Despite recent advances in the management of heart failure, much still need to be learned…|
|Extracellular enzymes detecting heavy metal… India with more than 1.25 billion peoples is facing a significant challenge in meeting the growing water supply needs of burgeoning human population. Ganga, the most sacred river of India,…|
|Tobacco use in women of reproductive age Despite reductions in rates of cigarette smoking among U.S. adults over the last 50 years, rates of smoking among women have decreased at a lesser rate compared to men. In…|