Science1 publisherNot yet confirmed elsewhere2 min readPublished
Study of 548 Puerto Rican pregnancies ties PFAS to doubled risk of high blood pressure
Northeastern University researchers found PFAS-exposed pregnant women in Puerto Rico were twice as likely to have high blood pressure later in pregnancy. The study's finding that girl pregnancies carry the most risk contradicts earlier work, so targeting monitoring by PFAS level needs replication first.
The Scientist · Science desk
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What happened
- Julia Varshavsky's team measured PFAS in the blood of 548 women at 16 to 20 weeks of pregnancy and compared it with blood pressure taken then and again at 24 to 28 weeks.
- The women are part of PROTECT, a Northeastern-led study that has followed Puerto Rican women and their children since 2010.
- The link between PFAS and later high blood pressure was strongest in first-time mothers and in women carrying girls.
- Gestational hypertension, high blood pressure first appearing after 20 weeks, affects 13% of U.S. pregnant women, and women of Puerto Rican descent face the highest risk among Hispanic women.
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Why it matters
- contradiction This cohort places the extra risk in girl pregnancies and earlier studies place it in boy pregnancies, so the baby's sex cannot yet be used to decide who gets closer blood pressure checks.
- constraint Because blood pressure was followed only to 24 to 28 weeks, the findings cannot yet guide monitoring decisions for the rest of pregnancy.
- cost If PFAS do raise blood pressure in pregnancy, the cost runs past delivery: Rubin said hypertensive disorders of pregnancy "predict a woman's heart health for life."
Timing is the design's main strength. The PFAS blood draw came first, and the second blood pressure reading followed about eight weeks later [3][11], so the chemical measurement comes before the outcome it is tested against. The study is still observational [3]. It shows an association and cannot by itself separate PFAS from other exposures that come with it. Puerto Rico, where the cohort lives, has many hazardous waste sites [5].
"Exposed" also needs a definition. PFAS are in the blood of just about every person, including babies still in the womb [6]. The doubling [1] therefore has to compare women carrying more PFAS with women carrying less. The news account of the study does not say which compounds were measured, what concentrations were compared, or how many of the 548 women developed hypertension. A rough scale is still possible. If the lower-exposure women developed gestational hypertension at the national 13% rate [4], a doubling would put the higher-exposure women near 26% [16]. That figure is an illustration. Given this population's higher baseline risk [4], the cohort's real rates may sit above it.
Julia Varshavsky, the Northeastern assistant professor behind the study [1], explains the split by the baby's sex through the fetus. "There is different hormone signaling going on depending on the sex of the baby," she said [13]. Earlier research points the other way. "Other studies have shown the opposite," she said, with the higher risk showing up in women carrying boys [14]. Splitting 548 women by the sex of the baby leaves smaller groups, and chance is an explanation any hormone account has to rule out first.
Pregnancy is already hard on the heart [10]. "The blood volume has to increase by up to 50% by the end of pregnancy," Varshavsky said [9]. "Researchers often describe pregnancy as a cardiovascular 'stress test,'" Rainbow Rubin, director of science at the advocacy group Breast Cancer Prevention Partners, told Northeastern Global News [7].
The coverage presents the finding as a way for clinicians to catch dangerous spikes earlier in the most vulnerable women [15]. In my view it supports a replication first, in a larger and more varied population and with the concentration groups published. Of the two subgroup signals, the one in first-time mothers [12] is the cleaner candidate for that test.
What to watch
- Compound-level results and case counts from the paper, enough to turn the doubling into an absolute risk for these pregnancies.
- A replication outside Puerto Rico that tests whether the excess risk sits in girl or boy pregnancies.
- PROTECT follow-up past 28 weeks and after delivery, showing whether the PFAS association with blood pressure persists.