Lactation associated with improved blood pressure after gestational hypertension

1. Among women with gestational hypertension, those who breastfed had lower postpartum blood pressures than those who did not.

2. Breastfeeding was not associated with differences in postpartum blood pressure in women with preeclampsia or those with normotension in pregnancy.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Hypertensive disorders of pregnancy, which include chronic hypertension, gestational hypertension, preeclampsia, and eclampsia are increasing in incidence among expectant mothers in the United States. Gestational hypertension, or the new onset of hypertension after week 20 of pregnancy, and preeclampsia, which is defined as the new onset of hypertension after week 20 of pregnancy with proteinuria or other signs of end organ damage, are associated with increased maternal and perinatal morbidity. Additionally, studies have demonstrated increased long-term risk of hypertension and cardiovascular disease among women who experience these conditions during pregnancy. This is of particular concern to women who are overweight or obese who are at greater risk for both hypertensive disorders of pregnancy and cardiovascular disease. Prior studies found that women who breastfed have a reduced risk of cardiovascular disease, hypertension, lipid disorders and diabetes. In the present work, authors evaluated the relationship between lactation and postpartum blood pressure and found that in women with gestational hypertension, lactation was associated with decreased blood pressure.

Strengths of the study were prospective data collection and overrepresentation of overweight and obese women, the population at greatest risk for hypertensive disorders of pregnancy. The study had a small sample size and limited generalizability to non-obese populations. Additional population-based studies are needed to confirm the results observed in this study. Follow-up of long term cardiovascular outcomes is also needed to better understand the clinical impact of lactation.

Click to read the study in AJOG

Relevant Reading: Lactation and maternal measures of subclinical cardiovascular disease

In-Depth [prospective cohort]: This study evaluated the relationship between lactation and postpartum blood pressure in women who experienced gestational hypertension (n = 42), preeclampsia (n = 33), and normotension during pregnancy (n = 304). Preeclampsia was defined as new-onset hypertension with proteinuria. The primary outcome of interest was blood pressure at the follow-up visit, which occurred from 6 to 24 months postpartum.

Among women with gestational hypertension, lactation for ≥6 months was associated with lower systolic (β = -16.1 mmHg, CI -27.7- -4.5) and diastolic blood pressures (β = -16.9 mm Hg, CI -27.8- 6.0). Breastfeeding was not associated with differences in postpartum blood pressure in women with preeclampsia or those with normotension in pregnancy.

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