Preconception Blood Pressure Associated With Pregnancy Loss

Enrique F. Schisterman, PhD, MA

New study findings have suggested that blood pressure prior to conception among healthy young women is associated with pregnancy loss, but targeted lifestyle interventions could be utilized to favorably impact reproductive health.

Despite a strong rationale in the biology, very little research has evaluated whether incremental increases in preconception blood pressure could have consequences for reproductive health early on in pregnancy.

“These findings are important in that they suggest that early, subclinical cardiovascular risk factors may be associated with a higher risk of pregnancy loss,” Enrique F. Schisterman, PhD, MA, a senior investigator of reproductive epidemiology at the National Institutes of Health, and coauthor, told MD Magazine. “Prior to this study, research had found that women with pre-existing cardiovascular disease were at increased risk of adverse pregnancy events. Our findings suggest that this increased risk may be present before a woman meets clinical criteria for cardiovascular disease and adds to the evidence base suggesting that strategies for maintaining healthy blood pressure levels are important even among young adults.”

The study evaluated data from the EAGeR trial to explore preconception blood pressure and fecundability, pregnancy loss, and live birth in 1228 women with a history of pregnancy loss that were attempting another pregnancy. Systolic and diastolic blood pressure were measured during the first observed menstrual cycle and in early pregnancy and used to determine the mean arterial pressure.

The mean preconception systolic blood pressure was 111.6 mm Hg (standard deviation [SD], 12.1) and diastolic blood pressure was 72.5 (SD, 9.4) mm Hg. The risk of pregnancy loss increased 18% per each 10 mm Hg increase in diastolic blood pressure (95% CI, 1.03—1.36) and 17% per each 10 mm Hg increase in mean arterial pressure (95% CI, 1.02–1.35) in the adjusted analyses.

Schisterman and colleagues reported similar findings for early pregnancy blood pressure, however, preconception blood pressure was not related to fecundability or live birth in the adjusted analyses.

“The study highlights the fact that preconception counseling, particularly in women with recurrent pregnancy losses, must take a comprehensive approach and look at the woman’s overall health,” Zev Williams, MD, PhD, the chief of the Division of Reproductive Endocrinology and Infertility and an associate professor of Obstetrics and Gynecology at Columbia University Medical Center, told MD Magazine.

Schisterman noted that more research will be required to establish whether blood pressure is a direct cause of pregnancy loss, or if factors related to both blood pressure and pregnancy loss may explain the findings, as this study does not reveal cause and effect.

“However, our findings do add to growing evidence that addressing cardiovascular health in young adults is important and suggest that maintaining healthy blood pressure in young adulthood may not only be associated with long-term benefits for cardiovascular disease prevention but additional short-term benefits for reproductive health,” he said.

Williams commented that women who experience 1 or 2 miscarriages, most commonly, experience chromosomal abnormalities in the fetus. He added that embryonic genetics are the superseding aspect of pregnancy success.

“The challenge is in identifying and correcting the underlying problem in women who have miscarriages of what appears to be genetically normal losses,” Williams said. “For them, the key is to optimize all aspects of their health such as correcting any hormonal imbalance, hypertension, uterine problems and clotting disorders. An emerging area of research is in identifying genetic causes of the pregnancy losses that may be missed with existing technology.”

“There is still much we need to learn about the risk factors for pregnancy loss,” Schisterman said. “Young adulthood is an important window to implement strategies to reduce risk of cardiovascular disease, and per our findings, these strategies may have short-term benefits for reproductive health as well.”

Schisterman said that the findings emphasized the importance of a renewed focus on addressing subclinical high blood pressure levels.

Williams noted that many steps must occur correctly for a pregnancy to successfully progress and get to term. “A problem in any one of them can result in a pregnancy loss. So, like with other chronic medical problems that can result in a pregnancy loss such as thyroid disease, insulin resistance, blood disorders, it seems quite reasonable that blood pressure should also be well controlled,” he said.

The study, “Preconception Blood Pressure Levels and Reproductive Outcomes in a Prospective Cohort of Women Attempting Pregnancy,” was published in Hypertension.