High blood pressure before pregnancy may increase risk of miscarriage
High blood pressure before conception may increase the risk of miscarriage for healthy young women with a history of lost pregnancies, according to a new study.
The study, published Monday in the American Heart Association journal Hypertension, was the first to focus specifically on differences in preconception blood pressure among young women with a history of pregnancy loss but not high blood pressure. Previous research has linked poor cardiovascular health with pregnancy loss in women who were already pregnant or older.
“This study shows that maintaining normal levels of blood pressure isn’t only important for cardiovascular health, but it may also be important for reproductive health,” said the study’s lead author Dr. Enrique F. Schisterman, a senior investigator and chief of epidemiology at the National Institutes of Health. “This is the first time we’ve evaluated the effects of blood pressure early on.”
About 6 percent to 15 percent of U.S. women attempting pregnancy experience infertility, and of those who become pregnant, 20 percent to 30 percent experience pregnancy loss, according to the study.
Researchers examined data from 1,228 women whose average age was about 29, measuring their blood pressure before pregnancy and in early pregnancy. The risk of pregnancy loss increased 18 percent in women with every 10-unit increase in preconception diastolic blood pressure, the study found. (Diastolic blood pressure is the bottom number on a reading.)
The study results underscore the need for young women to maintain normal blood pressure even if they aren’t trying to become pregnant, Schisterman said.
According to the Centers for Disease Control and Prevention, 45 percent of U.S. pregnancies were unintended in 2011, the most recent statistics available.
“With so many pregnancies unplanned, many women are not thinking about cardiovascular risk factors before they become pregnant,” Schisterman said. “Now we have an additional component that shows how important it is to maintain a good cardiovascular profile early in life, in our teens and 20s and 30s.”
Dr. Monique V. Chireau, assistant professor of obstetrics and gynecology at Duke University School of Medicine, said the study was well-designed and “adds another important piece to the puzzle of pregnancy loss.”
“Pregnancy loss is devastating to a woman in any situation,” said Chireau, who was not involved in the study. “This should get people’s attention in a positive way so women will recognize that being young and feeling fine doesn’t mean they’re not at risk for a miscarriage.”
Doctors should also take heed of the results, Chireau said.
“The idea of preconceptual care is gaining increasing traction with physicians, and I think this study adds to the idea that even younger women should have their blood pressure monitored. It’s likely that there are a lot of young women out there with stage 1 and stage 2 hypertension who are not diagnosed.”
The study falls short of establishing a definitive cause-effect relationship between high blood pressure and pregnancy loss, Schisterman and Chireau both said.
Chireau said she’d like to see future studies that focus on women who do not have a history of miscarriage. Schisterman called for more studies to pinpoint the best ways to reduce high blood pressure in women before they get pregnant.
Both agreed that the results should be a wake-up call for how society views women’s health.
“The study continues to push us toward greater collaboration between internists, cardiologists and OB-GYNs as we try to reduce the risk of both poor pregnancy outcomes and long-term cardiovascular disease,” Chireau said.