A growing number of health advocates are raising concerns about possible links between the estrogen-like chemical BPA and breast cancer.
Consumer concern about BPA, or bisphenol A, has led manufacturers to remove it from baby bottles and infant formula packaging.
Still, BPA also could pose a risk to children long before they take their first sip of milk, according to a September report from the Breast Cancer Fund, an advocacy group. Babies also are exposed in the womb, the report finds.
A developing fetus is especially vulnerable during the first 11 weeks of pregnancy, says co-author Sharima Rasanayagam, director of science at the Breast Cancer Fund. “Everything is being developed” at this stage, she says. “The building blocks are being laid down for future health.”
The report cites 60 animal and human studies, which link prenatal BPA exposure to an increased risk of a variety of health problems, from breast cancer and prostate cancer to decreased fertility, early puberty, neurological problems and immune system changes.
In a September paper, too new to be included in the report, Tufts University’s Ana Soto found that BPA increased the risk of mammary cancers in rats. In two studies of rhesus monkeys published last year, other researchers found that BPA disrupted egg development, damaged chromosomes and caused changes in the mammary gland that made animals more susceptible to cancer.
Soto says it’s possible that prenatal BPA exposure makes fetuses more sensitive to estrogen, a hormone that drives the growth of most breast cancers. In that way, BPA could indirectly increase the risk of breast cancer later in life. She notes that even small changes in prenatal estrogen exposure — such as that produced by the extra placenta in a uterus containing fraternal twins — increases the risk of breast cancer in girls and prostate cancer in boys.
In a separate action, the American College of Obstetricians and Gynecologists and the American Society of Reproductive Medicine also have released a joint report on the broader issue of prenatal exposure to toxins, from BPA to pesticides and other chemicals. That September report notes that in utero exposure to environmental chemicals has been linked to miscarriage and stillbirth, impaired fetal growth and low birth weight, preterm birth, childhood cancers, birth defects, intellectual impairment and thyroid problems.In 2011, the American Medical Association labeled BPA an “endocrine-disrupting agent” because of evidence suggesting that it disrupts the body’s normal hormonal regulation.
In 2009, the Endocrine Society — a group of doctors and researchers specializing in the hormonal system — called hormone-disrupting chemicals such as BPA a “significant concern for public health,” possibly causing infertility, cancer and malformations.
“Every pregnant woman in America is exposed to many different chemicals in the environment,” says Jeanne Conry, president of the obstetrics-gynecology group.
More than 90% of American have BPA in their bodies, research shows. Ten studies have found BPA in fetal tissue, including umbilical cord blood, as well as in amniotic fluid, the Breast Cancer Fund report notes.
BPA was originally developed in the 1930s. Researchers stopped developing BPA as an estrogen after another synthetic hormone, DES, or diethylstilbestrol, was found to be far more potent, according to the Breast Cancer Fund report.
Conry says she’s concerned that exposure to BPA could, like DES, change the way that a developing fetus reacts to estrogen for the rest of its life.
Millions of pregnant women took DES from 1941 to 1971 to prevent miscarriage, until studies found that women exposed to DES before birth had a high rate of rare vaginal cancers. Studies later linked DES to breast cancer, as well.
