Bisphenol en zwangerschap*
Uit een studie blijkt dat regelmatige blootstelling tijdens de zwangerschap aan de stof Bisphenol A (BPA) een duidelijk grotere kans geeft op een laag geboortegewicht. Uit een andere studie blijkt dat hoge bloedwaarden bisphenol, als gevolg van het vaak eten van voeding en drank uit blik en voeding, in plastic verpakking uit de magnetron tijdens de zwangerschap bij de baby later duidelijk problemen geeft bij de gedragsneurologische ontwikkeling. BPA heeft hormoonachtige
eigenschappen in het menselijke lichaam. BPA is een chemische stof die wordt
gebruikt voor de productie van polycarbonaat, een transparante plastic die onder
andere gebruikt wordt als drager van CD's en DVD's en voor onbreekbare flessen
voor (baby)voeding, voor tafelbestek, en voorwerpen voor gebruik in
microgolfovens. Het wordt ook gebruikt in epoxyharsen die als beschermende
coating aan de binnenkant van voedingsverpakkingen in blik of karton worden
aangebracht, of in leidingen en reservoirs voor drinkwater. Bisfenol A wordt ook
gebruikt in vlamvertragende middelen, ook in tandvullingen en als oplosmiddel
voor drukinkten. Het is bewezen dat BPA kan vrijkomen uit de verpakking en in de
voeding terechtkomt.
Parental Exposure to BPA During Pregnancy Associated With Decreased Birth Weight in Offspring
Parental exposure to bisphenol A (BPA) during pregnancy is associated with decreased birth weight of offspring, compared with offspring from families without parental BPA exposure in the workplace, according to Kaiser Permanente researchers.
The observational study is published in Reproductive Toxicology.
Researchers explained that there was a greater magnitude of decrease in birth weight in children whose mothers were directly exposed to high BPA levels in the workplace during pregnancy, followed by those whose mothers were exposed to low levels of BPA in the workplace, then by those whose mothers had BPA exposure through father's high occupational BPA exposure, and finally, the least decrease in birth weight in the offspring whose mothers had BPA exposure through father's low occupational exposure.
Although the finding needs to be confirmed by additional studies, the study provides preliminary evidence that maternal exposure to BPA during pregnancy may have an adverse effect on fetal growth, said De-Kun Li, MD, PhD, the principal investigator of the study, senior author of the new publication, and a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif.
Exposure to BPA has been reported to reduce birth weight in animal studies at relatively high levels of exposure. Both animal and human studies have shown that BPA can pass through the placental barrier and that fetuses are likely to be exposed to similar (if not higher) levels of BPA as those of mothers, explained the researchers.
The study population was identified from a larger study of more than 1,000 male and female workers in factories in China. It compared workers in BPA-exposing facilities with a control group of workers in factories where no BPA was present. BPA-exposed (from the manufacturers of BPA and epoxy resin) and unexposed workers (from industries without BPA exposure), including their spouses and offspring, were recruited from 2003-2008.
Mothers in the mother-exposed group worked for at least three months during pregnancy. The researchers explained that it is possible that offspring in this group had relatively higher levels of in-utero BPA exposure than those in other groups. Spouses of exposed fathers, although not directly exposed to BPA in the workplace, were more likely to have a higher BPA exposure level than women in the unexposed group. Exposure in this group could occur through exposure to contaminated clothing, through workplace visits with spouses, and through residence proximity to factories, explained the researchers.
This study is the fourth in a series published by Dr. Li and his colleagues that examine the effect of BPA in humans. The first study, published in November 2009 in the Oxford Journals' Human Reproduction, found that exposure to high levels of BPA in the workplace increases the risk of reduced sexual function in men. The second study, published in May 2010 in the Journal of Andrology, found that increasing BPA levels in urine are associated with worsening male sexual function. The third study, published in Fertility and Sterility, showed that an increasing urine BPA level was significantly associated with decreased sperm concentration, decreased total sperm count, decreased sperm vitality and decreased sperm motility.
Funded by the U.S. National Institute of Occupational Safety and Health, this latest study adds to emerging human evidence questioning the safety of BPA, a chemical created in the production of polycarbonated plastics and epoxy resins found in baby bottles, plastic containers, the linings of cans used for food and beverages, and in dental sealants.
The researchers explained that BPA is believed by some to be a highly suspect human endocrine disrupter, likely affecting both male and female reproductive systems. These findings provide epidemiological evidence that has been lacking as the U.S. Food and Drug Administration and various other U.S. government panels have explored this controversial topic.
The present study was limited by the small sample size in the exposed group. Due to the retrospective nature of the study, estimated exposure levels in the past, rather than maternal urine BPA level, was used to classify the exposure dosage during the index pregnancy. Although researchers have demonstrated that the estimated BPA exposure was correlated with current urine BPA, it is still possible that the association between BPA exposure and birth weight was impacted due to inaccurate classification of BPA exposure categories.
Other authors on this study include: J.R. Ferber, MPH, and L.J. Herrinton of the Kaiser Permanente Division of Research; Z. Zhou, PhD, MD, and Y. He, PhD, of the Department of Occupational Health and Toxicology, School of Public Health and WHO Collaborating Center for Occupational Health, Fudan University, Shanghai, China; M. Miao, PhD, J. Wang, PhD, E. Gao, MD, MPH, PhD, and W. Yuan of Shanghai Institute of Planned Parenthood Research and National Population and Family Planning Key Laboratory of Contraceptive Drugs and Devices.
Highest Reported BPA Level in Pregnant Woman and Associated Abnormalities in Infant
A new case study examining an infant's neurobehavioral abnormalities and extremely high bisphenol A (BPA) concentration of the baby's mother suggests a link between the two. The study, Environmental Health Perspectives: A Case Study of High Prenatal Bisphenol A Exposure and Infant Neonatal Neurobehavior, was led by researcher Sheela Sathyanarayana, MD of Seattle Children's Research Institute, and recently published online in Environmental Health Perspectives.
BPA, a synthetic, human-made chemical, is used in a wide variety of products including: can linings; hard polycarbonate plastics such as baby bottles and reusable cups; and dental sealants. Food may be the single largest source of BPA exposure due to contamination of foods during preparation and processing. BPA has estrogenic (hormone-like) properties. In animal studies, exposure to BPA early in life can lead to a variety of abnormalities in early development of the brain, behavior, prostate gland and breast tissues.
In human studies, exposure to BPA early in life has not been studied extensively. However, one study found an association between BPA exposure in pregnancy and abnormal acting out behaviors in female children. In adults, increased BPA exposure has been associated with changes in hormone concentrations, sperm quality, and endometriosis.
"Pregnant women are often exposed to BPA in their daily lives," said Sathyanarayana, pediatrician and environmental health specialist at Seattle Children's and assistant professor of pediatrics at the University of Washington School of Medicine. "It's important that they are aware of the potential sources of BPA, so they can take steps to avoid unnecessary exposures."
In this case study, Sathyanarayana and co-investigators reported on a specific mother/infant pair from a larger study (Health Outcomes and Measures of the Environment -- HOME study) that examined BPA exposures in pregnant women and then examined their infants for neurodevelopmental outcomes. At 27 weeks of pregnancy, the mother had the highest reported urinary BPA concentration of anyone in the general population. She reported consuming canned foods and beverages, and using and microwaving plastic food storage containers consistently during this pregnancy time period. All of these exposures could have led to her extremely high BPA concentration. Her infant had a normal newborn neurobehavioral exam but had many neurobehavioral abnormalities at the one-month study visit including: increased muscle tone, tremors, and abnormal movements. The child went on to have normal neurobehavioral assessments yearly from one to five years of age.
This case study confirms previous studies documenting multiple sources of BPA exposure in humans. Additionally, it highlights the need for medical providers to be aware of the harmful effects of BPA exposures so they may counsel families appropriately about prevention. The study also identifies potential sources of BPA exposure that can be targeted to reduce exposures in the future. "Families can decrease their exposure to BPA by eating fresh fruit and vegetables (as opposed to processed and canned foods) and by decreasing use of plastic food storage containers," said Sathyanarayana. "Check the recycling code of your plastics on the bottom. If it shows #7, then the plastic may contain BPA."
This research project was supported by grants from the National Institutes of Health and the National Institute of Environmental Health Sciences. Along with Sathyanarayana, the research team included: Joe M. Braun, PhD, from Harvard School of Public Heath; Kimberly Yolton, PhD, and Bruce P. Lanphear, MD, from Cincinnati Children's Hospital Medical Center; and Stacey Liddy, MS, from BC Children's Hospital.
Tips for reducing exposure of BPA for pregnant women and other parents and caregivers:
You may not be able to completely avoid BPA, but there are steps you can take to reduce your family's exposure to it:
1. Limit the amount of canned foods your family eats.
2. Rinse canned fruits and vegetables before eating. When possible, choose fresh fruits and vegetables instead.
3. Limit the amount of canned beverages your family drinks.
4. Avoid using plastic food and beverage storage containers with #7 on the bottom. If the recycling code is #7, then the plastic may contain BPA.
5. Avoid using plastic baby bottles with #7 on the bottom.
6. Decrease the use of all plastic food storage containers.
7. Avoid using plastic food storage containers to heat food in the microwave. (High temperatures increase the chance of food absorbing BPA.)
8. Use ceramic, glass, or other microwaveable dishes when heating food in the microwave.
9. Avoid canned infant formula. Instead, use powdered formula or liquid formula sold in plastic or glass containers.
(September 2011)
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