Testicular Defects in Newborns Linked to Prenatal Chemical Exposure

(Beyond Pesticides, September 17, 2008)

A new study has found a link between total chemical contamination in the bodies of pregnant women and the risk of cryptorchidism in their male babies. Mothers whose babies were born with the defect had the highest concentrations of persistent organic pollutants (POPs), mostly organochlorines like PCB and DDE, in their breast milk.

The study, entitled “Cryptorchidism at birth in Nice area (France) is associated with higher prenatal exposure to PCBs and DDE, as assessed by colostrum concentrations,” and published in the journal Human Reproduction, compared prebirth exposure to chemicals, as measured through their mother’s milk, and the risk of undescended testicles or cryptorchidism, during a three-year period. 164 mother/infant pairs were used and within 3-5 days of delivery, the researchers collected samples of colostrums, or “first milk” from the mother. Colostrum is a form of breast milk that is produced late in pregnancy and immediately after birth before the more creamy milk comes in. It is used as a proxy for what was circulating in the mother’s body and in her fetus during pregnancy. The colostrum was analyzed for three different chemical pollutants including seven polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloro-ethylene (DDE) and dibutyl phthalate (DBP). Umbilical cord blood was also measured.

While all subjects in the study had detectable levels of these chemicals in either their blood or breast milk, the researchers found that mothers in the highest exposure group for PCBs and DDE in breast milk had two-fold greater odds of giving birth to a boy baby with cryptorchidism, as compared to moms with low to medium exposure. DBP did not appear to be associated with an increased risk of cryptorchidism, but four boys whose mothers had high exposures to DBP in their jobs were born with the defect. While this number is too small to be significant statistically, researchers found it to be an interesting observation.

These findings complement a host of other studies which have associated prenatal chemical exposures to a series of birth defects. The occurrence of cryptorchidism indicates that testosterone production and/or hormone signaling conditions in the womb have gone awry. Both of these conditions are related to sperm production and the risk of testicular cancer later in life. Cryptorchidism is seen in about 3% of male full-term births, 30% of premature births and is one cause of male infertility.

Results like these emphasize the long term and destructive effects persistent chemicals can have on human populations. DDT (the precursor to DDE) and PCBs have been banned is much of the world for several decades. However, like other POPs, they continue to circulate in the environment, accumulate in the food chain and contribute to health problems, such as the reproductive abnormalities observed in this study. These chemicals accumulate in fatty tissue and humans are exposed via meat, fish and dairy products. These persistent pollutants have also been linked to childhood obesity, non-Hodgkin’s Lymphoma, and cancer, among others.

Although exposures to these chemicals can be correlated to adverse health effects, they are also indicators of a much wider problem; exposures to mixtures of chemicals are negatively influencing hormones and fetal development in humans.