In a recently published study on late-term pregnancy, the American Heart Association (AHA) found that previously unaffected women who develop prehypertension may be more predisposed to having underweight or stillborn infants than other prospective mothers.
Previously identified as a marker for those outcomes, hypertension occurring late in gestation has now come under the AHA’s scrutiny in what may be the largest study to date. Doctors assessed diastolic pressure — the pressure measured in arteries between heartbeats, or the “bottom” number — as compared to systolic pressure, commonly associated with the “top” number in blood pressure readings.
Scientists found that mothers developing prehypertension at 36 weeks’ gestation were 69 percent more likely to have a baby with a low birth weight and 70 percent more likely to deliver a stillborn infant. A further distinction showed that women experiencing an increase of 15 points or more doubled their odds of giving birth to an abnormally small baby.
“Working as a clinical doctor in obstetrics, I often meet women with ‘borderline high blood pressure,’ and I wanted to find out if they had increased risks of adverse fetal outcomes,” Dr. Anna-Karin Wikström, lead author of the study, said.
Research spanned six years and included over 150,000 women in Sweden who carried for 37 or more weeks before delivery. Comparative blood pressure readings were taken before 20 weeks and again after 34 weeks of pregnancy.