Maternal Hypertensive Disorders in Pregnancy and Postpartum Plasma B Vitamin and Homocysteine Profiles in a High-Risk Multiethnic U.S., Population

Background: Hypertensive disorders of pregnancy are a recognized risk factor of a woman's future cardiovascular risk. The potential role of micronutrients in mitigating hypertensive disorders is not fully understood. This study examined maternal postpartum plasma B vitamin profiles by hypertensive disorders of pregnancy in a high-risk multiethnic U.S. population. Materials and Methods: The analyses included 2584 mothers enrolled within 3 days postpartum at the Boston Medical Center. Hypertensive disorders of pregnancy included gestational hypertension and pre-eclampsia disorders (pre-eclampsia, eclampsia, hemolysis, elevated liver enzymes, and/or low platelets syndrome) as documented in the medical records. Plasma folate, vitamin B12, and homocysteine levels were measured in blood samples collected at enrollment. Kernel density plots and multivariable regressions were used to examine the relationship between hypertensive disorders and postpartum B vitamin profiles. Results: Of the 2584 mothers, 10% had pre-eclampsia disorders that were associated with significantly lower plasma folate (adjusted beta coefficient (aβ): -0.10; 95% CI: -0.22 to -0.06) and increased homocysteine (aβ: 0.08; 95% CI: 0.04-0.13), but not with vitamin B12 concentrations. These associations remained robust after adjusting for a range of pertinent covariables and were more pronounced in non-Hispanic Black women compared with other groups. However, gestational hypertension was not significantly associated with any postpartum biomarker. Conclusions: We found that pre-eclampsia disorders, but not gestational hypertension, was associated with lower folate and higher homocysteine levels postpartum, especially among Black mothers. This finding, if further confirmed, may have implications for postpartum care, including attention to maternal micronutrient status to reduce and prevent hypertensive disorders in pregnancy-associated consequences in subsequent pregnancies and lifespan. Registration date: July 25, 2017; Registry website: https://clinicaltrials.gov/ct2/show/NCT03228875.