Studies link bisphenol A to lower birth weight and infant wheezing

In the first, research by Kaiser Permanente has raised concerns that parental exposure to the substance during pregnancy was associated with decreased birth weight in offspring.

The observational study by Dr De-Kun Li PhD et al said there was a greater magnitude of decrease of birth weight in infants depending on the levels of maternal workplace exposure to the chemical.

They found a correlation between the extent of weight loss and either direct or indirect maternal exposure to BPA during pregnancy.

Sliding scale​

The scientists found a sliding scale of results – with the greatest effect noticed in offspring of mothers directly exposed to the chemical in the workplace during pregnancy, followed by those with low level exposure.

Infants whose mothers were exposed to the substance via husbands who had high workplace exposure registered the next pronounced weight loss, with the least decrease in birth weight discovered in the offspring whose mothers had BPA exposure through the father's low occupational exposure.

Dr Li said the findings, published in the journal Reproductive Toxicology, needed to be verified by further research. However they did provide preliminary evidence that maternal exposure to BPA during pregnancy could have a negative effect on foetal weight, he added.

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 between 2003 and 2008.

Researchers acknowledged the study was limited by the small sample size in the exposed group and the fact it was retrospective in nature. This meant that estimated exposure levels in the past, rather than maternal urine BPA level, were used to classify the exposure dosage during the pregnancy

Wheezing​

A separate study found children of women exposed to bisphenol A (BPA) during pregnancy – particularly during the first trimester – may have a higher risk of wheezing in early life, said research presented at the Paediatric Academic Societies (PAS) annual meeting in the US last week.

Dr Adam J. Spanier, lead author and professor of paediatrics and public health sciences at Penn State College of Medicine, said that while more research was needed on the possible link, women of child-bearing age should consider avoiding products made with BPA.

The study of 367 pairs of mothers and infants examined the possible relationship between prenatal BPA exposure and the breathing problem for infants.

Levels of the chemical were measured in the urine of pregnant women at 16 weeks, 26 weeks and at birth. Some 99 per cent of women had detectable levels of the chemical in their urine during pregnancy. Parents were asked every six months for three years whether their child suffered from wheezing.

The study found, however, that the amount of BPA detected in a mother's urine was related to wheeze only in the youngest group of children.

“At 6 months of age, infants whose mothers had high levels of BPA during pregnancy were twice as likely to wheeze as babies whose mothers had low levels of BPA. However, no differences in wheezing rates were found by 3 years of age,”​ said the researchers.

Informed choices​

The study also found there was a link between preponderance for child wheezing where high levels of BPA were detected in mothers’ urine at 16 weeks gestation – but no correlation if elevated levels were detected at 26 weeks.

"Consumers need more information about the chemicals in the products they purchase so they can make informed decisions,"​ said Spanier.