78. Association of perfluoroalkyl substances with gestational hypertension and preeclampsia in the MIREC study (lay summary)

Borghese, M.M, Walker M, Helewa, M.E, Fraser WD, Arbuckle TE. Environment International. 2020 May 11;141:105789. doi: 10.1016/j.envint.2020.105789

Exposure to environmental chemicals has been linked with pregnancy conditions, such as gestational hypertension and preeclampsia. Gestational hypertension refers to high blood pressure that develops during pregnancy. Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had been normal.  With preeclampsia, there is high blood pressure as well as signs of damage to another organ system, most often the liver and kidneys. Both conditions can negatively impact the health of pregnant women and their babies.

One group of chemicals known as perfluoroalkyl substances, or PFAS, might contribute to these pregnancy conditions. PFAS are used to make a wide range of consumer products, including non-stick cookware, food packaging, personal care and beauty products, fire retardant foams, and carpet treatment applications. Nearly all Canadians are regularly exposed to low doses of PFAS through food, drinking water, and household dust. These chemicals don’t breakdown very easily in the environment or in the body, so they tend to accumulate over time.

Researchers used data from the MIREC study to see if higher PFAS levels in pregnant women were associated with gestational hypertension or preeclampsia. Levels of three PFAS were measured in the plasma of pregnant women – PFOA, PFOS, and PFHxS. Blood pressure measurements and clinical lab tests were used to diagnose gestational hypertension and preeclampsia according to standard Canadian clinical guidelines. Statistical models were used to assess the relationship between PFAS and gestational hypertension and preeclampsia.  The researchers also looked to see if any effect was more pronounced among women giving birth to males or females.

Data from 1739 participants were analyzed. 90% of women had normal blood pressure, 7% developed gestational hypertension, and 3% developed preeclampsia. Women with higher levels of PFHxS, but not PFOA nor PFOS, were more likely to develop preeclampsia, especially those women giving birth to females. Among women who gave birth to male infants, those with higher levels of PFOS and PFHxS, but not PFOA, were more likely to develop gestational hypertension. Higher levels of all three PFAS were linked with higher diastolic blood pressure, while higher levels of PFOA and PFHxS were also linked with higher systolic blood pressure.

In this sample of pregnant Canadian women, higher levels of PFHxS were associated with the development of preeclampsia, but not gestational hypertension. Effects of PFAS on gestational hypertension were only found among women who gave birth to males.  We show, for the first time, that infant sex plays an important role in the association between PFAS and gestational hypertension and preeclampsia. This will need to be verified by future studies.