High preconception blood pressure is associated with a greater risk of pregnancy loss, according to analysis of data from a randomized clinical trial of aspirin and pregnancy outcomes.
Researchers in the EAGeR (Effects of Aspirin on Gestational and Reproduction) trial analyzed data from 1,228 women attempting pregnancy with a history of pregnancy loss. After researchers adjusted for treatment assignment, body mass index (BMI), race, marital status, smoking, parity, and time from last pregnancy loss, an increase in all blood pressure measures was associated with a 17% increase in the risk of pregnancy loss (Hypertension. doi: 10.1161/hypertensionaha.117.10705).
Each 10–mm Hg increase in mean arterial pressure or in diastolic blood pressure was associated with a 14% greater risk of pregnancy loss.
Women with blood pressure levels higher than the thresholds for stage I and stage II hypertension had a 15% and 18% higher risk of pregnancy loss, respectively, compared with women with normal blood pressure, although the authors noted that group sizes were small.
Overall, one-quarter of the women enrolled in the study met the criteria for hypertension stage I, and 4.3% met the criteria for hypertension stage II.
“Screening and lifestyle interventions targeting maintenance of healthy blood pressure levels among reproductive-aged women may have additional important short-term benefits on reproductive health,” wrote Carrie J. Nobles, MD , of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, and coauthors.
The authors also saw an impact of early pregnancy blood pressure on pregnancy loss, with an 18% greater risk of loss with each 10–mm Hg increase in mean arterial pressure.
Higher blood pressure during preconception was also associated with a decrease in the chance of live birth, but this association disappeared after adjusting for other confounders.
The study also examined the relationship between preconception blood pressure and the probability of conception. While the unadjusted models suggested 10% lower odds of fecundability, adjusting for all covariates except for BMI found similar effect estimates.
“We observed no clear associations of preconception blood pressure with fecundability after adjustment for BMI, suggesting that pathways related to BMI, which is strongly related to fecundability, may explain the marginal association of blood pressure with fecundability,” the authors wrote.
There was also some evidence that aspirin may influence the association between higher preconception blood pressure and pregnancy loss, as this association was marginally stronger in the placebo group than in the group randomized to low-dose aspirin.
“Pregnancy loss and other adverse reproductive outcomes may serve as sensitive markers of early-stage progression toward cardiometabolic disease in young adults,” Dr. Noble and coauthors wrote. “Further elucidating the cardiometabolic risk factors for pregnancy loss may help identify early intervention strategies, such as regular physical activity and following a DASH -type (Dietary Approaches to Stop Hypertension) diet.”
The study was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. No conflicts of interest were declared.
SOURCE: Nobles CJ et al. Hypertension. 2018 Apr 2;71. doi: 10.1161/hypertensionaha.117.10705.