Chemical exposures cause some of their most profound effects on the child during pregnancy. The 9-month gestation period is a finely tuned orchestra that relies on chemical messengers and precise genetic expression to bring a child from a single fertilized cell to a full-grown baby with a litany of complex systems. Any type of chemical interference with this process can lead to profound consequences.

“The nature of vulnerability changes with each stage of development, almost on a day-to-day basis,” write Philip & Alice Shabecoff. “Interferrence at different stages and from different substances will lead to different outcomes. Even temporary disruption at the wrong moment can cause lifelong disabilities. …In the first weeks after conception, before major organs begin developing, the new life can be killed by a single ‘hit’ of a toxic substance, causing a spontaneous abortion. As pediatrician and children’s health advocate Dr. Philip Landigran noted, ‘Most chemicals do their damage and then disappear. The mom might not even be aware that she was exposed to the chemical.’” (2010, p. 26)

Unfortunately, pregnant women can also be magnets for chemicals. A woman’s body contains more body fat to begin with, and this increases during pregnancy. Body fat also happens to be the primary way chemicals accumulate in the body. So a pregnant woman can have more of these toxic exposures stored up in her body fat that are then passed on to baby. Pregnant women also eat, drink, and breathe slightly more, which can mean higher rates of chemicals. This chemical exposure is more pronounced if the mother also experiences other stressors during pregnancy, such as poverty or family conflict, which can lower her immune defenses and result in more of these chemicals circulating in places they shouldn’t.

The fetus itself is also more vulnerable. Aside from its small size and rapidly developing body (which means lots of rapidly dividing cells that can be sent astray by a chemical exposure), the fetal thyroid system doesn’t mature until the third trimester, so even small amounts of thyroid disrupting chemicals before this point can have a harmful effect.

Fetal death & miscarriage as a result of chemical exposure

A recent study of tap water suggested that excessively high trihalomethanes, the byproducts of chlorinated drinking water, could cause as many as 137,000 miscarriages a year. (Schettler et al., 2001) Just about any chemical is capable of causing fetal death in high enough doses, often times snuffing out a young life before the woman even realizes she is pregnant.

Chemical-related birth defects

When a chemical exposure interferes with the chemical messaging or DNA expression that is telling a fetus how to develop (grow an arm here, a leg there, start the development of sexual organs, and so on), a variety of birth defects can result. One of the more common chemically-related birth defects is a malformed palate (cleft lip, cleft palate, etc.). Another is sexual abnormalities (babies born intersex; inverted urethra or malformed penis in boys; vaginal or uterus malformations in girls, etc.), likely because so many of our chemicals mimic gender-specific hormones. The trihalomethanes described above have been linked to neural tube defects. (ibid) But toxic exposures can also trigger more severe birth defects like missing limbs or severe mental retardation.

Chemicals might cause different birth defects depending on when the exposure occurs. In one study, different birth defects in lab animals occurred depending on whether the chemical was administered on day 10 or day 12 of gestation. The drug thalidomide, which was once widely prescribed for morning sickness, can induce limb defects in human children if given between days 20 and 24 of fetal development. (Sadler, 2004)

Another study of pregnant women who had a genetic risk for birth defects found that their odds of having a second child with a birth defect dropped in half if the family moved out of town to a less polluted area, suggesting a possible link to the environment. (Lie et al., 1994) Studies like this demonstrate the interconnectivity of genes and environment: Chemical exposure may trigger a genetic risk that otherwise would lie dormant.

Other poor pregnancy outcomes

Chemical exposures can be directly or indirectly related to other poor pregnancy outcomes. Texas, one of the most polluted states in the nation, is seeing a “mysterious” spike in maternal deaths after childbirth. (Jervis, 9-12-2016) While it’s unknown what role chemical pollution might be playing in these statistics (the U.S. maternal mortality rate is nearly 10-times that of many other nations), it is known that things like obesity, diabetes and high blood pressure play a role, and chemical pollutants have been linked to all of these conditions.