Relationship of Postpartum Levels of Cystatin and High-Sensitivity C-Reactive Protein and Duration of Lactation in Mothers with Previous Gestational Hypertension or Preeclampsia.

Women with hypertensive disorders of pregnancy are at increased risk of cardiovascular disease in later life. We sought to determine the association between lactation and markers of maternal cardiovascular health among postpartum women with and without hypertensive disorders of pregnancy via measures of inflammation (high-sensitivity C-reactive protein [hsCRP]) and renal function (cystatin C). This prospective cohort study enrolled primarily overweight and obese women during early pregnancy. At a postpartum study visit occurring 6-24 months after delivery, we collected data on lactation duration and measured hsCRP and cystatin C. We assessed associations between lactation duration and levels of hsCRP and cystatin C among normotensive women and women with preeclampsia or gestational hypertension using analysis of variance and chi-squared tests. Linear regression models adjusted for age, race, education, prepregnancy body mass index, current smoking, and time since delivery. Of 425 women, 37 (9%) had preeclampsia and 48 (11%) had gestational hypertension during enrollment pregnancy. The postpartum visit occurred at a mean of 8.6 ± 4.4 months after delivery. Women with a history of preeclampsia had significantly higher levels of cystatin C (mean 0.86 versus 0.78 mg/L;  = 0.03) compared with normotensive women, but nonsignificant elevation in hsCRP (mean 8.39 versus 6.04 mg/L;  = 0.08). Women with gestational hypertension had no differences in mean hsCRP or cystatin C compared with normotensive women. Among the 237 women with any lactation, 78 (18%) lactated for at least 6 months. Lactation duration both in the overall sample and among women with gestational hypertension or preeclampsia was not associated with levels of hsCRP or cystatin C. Preeclampsia history was associated with elevated postpartum levels of cystatin C; however, duration of lactation was not associated with postpartum hsCRP or cystatin C, regardless of history of gestational hypertension or preeclampsia. Further research is needed on mechanisms through which lactation may affect maternal risk of cardiovascular disease.