DALLAS, April 2, 2018 - Elevated blood pressure before becoming pregnant and early in pregnancy may increase the risk of pregnancy loss, even if the woman doesn't have a hypertension diagnosis, according to new research in the American Heart Association's journal Hypertension.
"Elevated blood pressure among young adults is associated with a higher risk of heart disease later in life, and this study suggests it may also have an effect on reproductive health," said Carrie J. Nobles, Ph.D., lead author of the study and a postdoctoral fellow in the Epidemiology Branch of the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD) in Bethesda, Maryland.
The study - which cannot reach a cause-and-effect conclusion - is the first to look at preconception blood pressure and reproductive outcomes in healthy women not diagnosed with high blood pressure or heart disease.
Researchers studied 1,228 women (average age 28.7 years, 95 percent white) who had already experienced 1-2 pregnancy losses and were currently trying to become pregnant. The women were part of a clinical trial to determine whether taking low-dose aspirin might reduce the risk of miscarriage.
During the study, women had their blood pressure measured when they were trying to become pregnant and again during early pregnancy. Average blood pressure prior to pregnancy was 111.6 mm Hg /72.5 mm Hg. Of the 797 women who conceived within six months, 24 percent suffered a pregnancy loss.
Researchers also found:
- Every 10-point increase in diastolic blood pressure (lower number) was associated with an 18 percent increased risk of pregnancy loss.
- Every 10-point increase in mean arterial pressure (an average of the lower and higher numbers) was associated with a 17 percent increased risk of pregnancy loss.
- The findings were similar for preconception and early-pregnancy blood pressure.
"The impact of cardiovascular risk factors starts really early in life. Physicians treating women of reproductive age should pay attention to slightly elevated blood pressure because it may have other not-well-recognized effects, such as adverse pregnancy outcome," said Enrique F. Schisterman, Ph.D., senior author of the study and Senior Investigator and Chief of the Epidemiology Branch of NICHD. "Preconception is a previously unrecognized critical window for intervention such as lifestyle changes that can help prevent later heart disease and may also improve reproductive health."
Whether women had been randomly assigned to take low-dose aspirin as part of this clinical trial (Effects of Aspirin in Gestation and Reproduction) made no difference in the impact of blood pressure on pregnancy loss, the researchers found.
Because the study was conducted in women who already had experienced a miscarriage, it is unclear whether the results can be generalized to all young women. Additionally, the study was mostly composed of white participants, and further research is needed to ensure the results apply to women of different races.
###
Other co-authors are Pauline Mendola, Ph.D.; Sunni L. Mumford, Ph.D.; Ashley I. Naimi, Ph.D.; Edwina H. Yeung, Ph.D.; Keewan Kim, Ph.D.; Hyojun Park, Ph.D.; Brian Wilcox, M.D., Ph.D.; Robert M. Silver, M.D.; Neil J. Perkins, Ph.D.; and Lindsey Sjaarda, Ph.D. The authors reported no conflicts of interest.
The Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (National Institutes of Health) in Bethesda, Maryland funded the study.
Additional Resources:
- Available multimedia is on the right column of the release link - https://newsroom.heart.org/news/higher-blood-pressure-before-pregnancy-may-increase-miscarriage-risk?preview=a1fc35c8ab32f90486ece1dfa15cf22a
- After April 2, view the manuscript online.
- Learn more about High Blood Pressure
- High Blood Pressure and Women
- Follow AHA/ASA news on Twitter @HeartNews
- For the updates and new science from the Hypertension journal follow @HyperAHA
Statements and conclusions of study authors published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association's policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations and health insurance providers are available at http://www.heart.org/corporatefunding.
About the American Heart Association
The American Heart Association is devoted to saving people from heart disease and stroke - the two leading causes of death in the world. We team with millions of volunteers to fund innovative research, fight for stronger public health policies and provide lifesaving tools and information to prevent and treat these diseases. The Dallas-based association is the nation's oldest and largest voluntary organization dedicated to fighting heart disease and stroke. To learn more or to get involved, call 1-800-AHA-USA1, visit heart.org or call any of our offices around the country. Follow us on Facebook and Twitter.