BPA is associated with slower growth before birth.
Snijder, CA, D Heederik, FH Pierik, A Hofman, VW Jaddoe, HM Koch, MP Longnecker and A Burdorf. 2013. Fetal growth and prenatal exposure to bisphenol A: The Generation R Study. Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.1205296.
A pregnant woman's exposure to bisphenol A may affect the growth of her developing baby, according to a study from the Netherlands.
The study is one of only a few that have examined the link between prenatal BPA exposure and growth in humans. It is unique because BPA was measured multiple times during the pregnancy, which provides more accurate estimates of exposure and stronger results than prior studies based on only one sample.
The babies born to women with higher amounts of BPA had smaller heads and grew slower in the womb than babies whose moms had the lowest amount of BPA. Head sizes were 11 percent smaller and growth rates 20 percent lower in babies whose mothers had the highest exposures.
BPA is an endocrine-disrupting chemical that can act like estrogen in the body. Experts are especially concerned about exposures in pregnant women, the developing fetus and growing children. Human and animal studies have linked the ubiquitous chemical to reproductive, behavior and endocrine effects.
The few studies that have examined maternal BPA exposure and fetal weight gain are inconsistent. One reason for this may be that BPA is difficult to measure in people because it is quickly eliminated from the body.
A unique aspect of this study was that it addressed that concern. Urine BPA levels were measured 1 to 3 times during pregnancy. More measurements improves the accuracy of estimating BPA exposure by smoothing out the fluctuations that occur over time, as levels in people vary and can change frequently.
Interestingly, the relationships between maternal BPA and fetal growth were only observed in the group that had the mothers' urine measured three times.
BPA is used to make polycarbonate plastics and resins and is commonly found in some plastic food and beverage containers, the lining of metal cans, thermal receipts and dental sealants. Because of the widespread use of BPA-containing products, nearly everyone has small quantities in their bodies.
In recent years, concern about the harmful health effects of BPA has led to a reduction in use, particularly in products used by infants and children. In addition, California announced in late January that it intends to declare BPA a reproductive hazard.
The study group consisted of 219 pregnant women from Rotterdam in the Netherlands. Urine was collected from the pregnant women between February 2004 and November 2005. Urine BPA was measured once in 99 women, twice in 40 women and three times in 80 women. Fetal size was determined from ultrasound images in the second and third trimesters. At birth, weight, length and head circumference were measured. Growth rate was calculated from these before and after birth measures.
The researchers accounted for personal and socioeconomic factors, such as maternal age, smoking, education and ethnicity.
A limitation of the study was that only BPA exposure was considered and other endocrine-disrupting chemicals in the women’s bodies were not measured.
Future work should investigate the effects of BPA replacements – such as bisphenol S and bisphenol AF – on fetal growth.
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