Adverse Pregnancy Outcomes and Incident Heart Failure in the Women’s Health Initiative: A Review

By Manijeh “Mani” Berenji

Pregnancy causes significant changes in metabolism and blood circulation, allowing the fetus to grow (1). And in some women, there can be the development of hypertensive disorders of pregnancy (hypertension, preeclampsia or eclampsia), gestational diabetes and preterm birth, which can continue after pregnancy. Research shows a direct association between these disorders and increased risk of future cardiovascular disease (CVD), including hypertension, ischemic heart disease, heart failure and stroke) and diabetes mellitus (2–7).

When looking at heart failure (HF), there are two distinct types. There is heart failure (HF) with preserved ejection fraction or HFpEF and then there is HF with reduced ejection fraction or HFrEF. HFpEF accounts for the majority of HF cases during pregnancy (6). However, there has not been research to-date looking at specifically what factors lead to the development of HFpEF and HFrEF can lead to adverse outcomes for the mother after pregnancy.

To better assess HF outcomes after pregnancy, Hansen and fellow researchers analyzed HF data from the Women’s Health Initiative (WHI) (2). WHI is a longitudinal prospective cohort study of ethnically-diverse postmenopausal women. These women were between the ages of 50 to 79 when first enrolled in the study (1993–1998). During this time, these women participated in 1 or more of 3 clinical trials (of hormone therapy, dietary modification, and calcium or vitamin D supplementation) or were part of an observational study. Of the 161,808 women in the WHI cohort, 44,174 participants were in the HF subgroup. The present study was based on women in the HF subgroup who had no clinical diagnoses of HF at baseline. These women were given a survey assessing for gestational diabetes, preeclampsia, gestational hypertension, pre-term delivery, low birth weight or high birth weight. The study investigators wanted to know whether anyone in this subgroup developed HF and if so, which type (HFrEF or HFpEF).

Out of the 44,174 women in the HF subgroup, 27,204 of them had a history of pregnancy lasting for more than 6 months, were alive, and were still participating in the WHI at the time of the survey. Out of this 27,204, only 10,292 responded to the survey. This was the official study population that Hansen and colleagues looked at. Out of this 10,292, 336 (3.3%) had a diagnosis of HF, 180 (1.8%) had HFpEF, and 111 (1.1%) had HFrEF. Women who had experienced adverse pregnancy outcomes had a higher prevalence of hypertension, diabetes, coronary heart disease, or smoking. When doing the statistical analyses, Hansen and colleagues found that having a hypertensive disorder during pregnancy was significantly associated with HF and with HFpEF. The researchers thus concluded that having a history of hypertensive disorder during pregnancy was independently associated with a 1.75-fold likelihood of developing subsequent HF. The reason for why this occurs is still not entirely clear. There have been links between a history of hypertension and obesity with the development of HF (8). Moreover, women who have had a history of hypertensive disorder during pregnancy have noted structural differences in the heart and microvasculature as well as less heart flow reserve, which persisted up to 25 years after the pregnancy event (2, 9–11). With this knowledge, the study authors recommend that identifying women who develop hypertensive disorder during pregnancy and ensuring that there are interventions made early in their lives can help prevent subsequent development of HF.

References:

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