Pfizer’s vaccine against respiratory syncytial virus (RSV) may be associated with certain health problems in pregnant women, including hypertensive disorders, researchers said in a study published on April 21.
Ashley Michnick, a research scientist at Harvard Medical School, and researchers with Pfizer and other entities analyzed data from five systems, including CVS Health and Kaiser Permanente Northwest.
They analyzed pregnancies that occurred from Sept. 22, 2023, through Aug. 9, 2024, and found that pregnant mothers received Pfizer’s vaccine between 32 and 36 weeks of gestation. The number of included pregnancies was 13,619.
Compared with pregnant women who received a different vaccine, such as an influenza shot, during the same gestational weeks during the study period, the women who received the RSV vaccine were more likely to have pregnancy-associated hypertensive disorders, such as inpatient gestational hypertension.
The risk was also higher when the RSV vaccine recipients were compared with women who had given birth in previous years, or a historical comparator group.
The researchers also recorded an elevated risk for premature rupture of membranes among RSV vaccine recipients.
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