Small Bump in BP During Pregnancy Might Harm Baby
Risks for low birth weight and stillbirth increase, research suggests
By Steven Reinberg
MONDAY, Feb. 1, 2016 (HealthDay News) -- Even slightly elevated blood pressure in late pregnancy may increase the risk of having an underweight or stillborn infant, new research suggests.
Women with prehypertension -- sometimes called borderline high blood pressure -- at 36 weeks of pregnancy had about 70 percent greater odds for low birth weight or stillbirth compared to women with normal blood pressure, the new Swedish study found.
But even mothers-to-be whose blood pressure rose in late pregnancy without becoming prehypertensive were more likely to have small babies, researchers said.
The researchers stressed, however, that their study showed only an association, not a cause-and- effect relationship, between blood pressure and fetal outcomes.
Infants with low birth weight are more likely to have health problems than normal-weight babies, according to the U.S. Centers for Disease Control and Prevention.
The study authors said prevention, rather than treatment, is key.
"We do not suggest treating women with medications, since earlier studies have not shown that this is beneficial to the mother or unborn child," said lead researcher Dr. Anna-Karin Wikstrom, an associate professor of obstetrics at Uppsala University in Sweden.
For the study, Wikstrom and colleagues collected data on more than 150,000 women listed in a Swedish obstetric database. Only women who carried their babies for 37 weeks or longer, whose blood pressure never rose above 140/90 millimeters of mercury (mm Hg) during pregnancy, and were having a single baby were included in the study.
Prehypertension is a systolic pressure (the top number) between 120-139 mm Hg or a diastolic pressure (the bottom number) between 80-89 mm Hg, or both.
High blood pressure -- 140/90 mm Hg or more -- has been linked with low birth weight and stillbirth, but it wasn't known if borderline high blood pressure is related to birth complications.
About 11 percent of the women in the study developed prehypertension. Overall, more than 2,400 babies were born underweight and 194 were stillborn, the researchers found.
Woman whose diastolic blood pressure rose 15 points or more and developed prehypertension were more likely to have an underweight baby, Wikstrom said.