A strong association exists between lactation duration and substantial reductions in both systolic and diastolic blood pressure (BP) a year after childbirth in overweight and obese individuals with a hypertensive disorder of pregnancy (HDP), a recent study issued in the 'Circulation' journal revealed. This study conducted by Renee Hart, Janet M Catov and Alisse Hauspurg, underscores the critical role of lactation in promoting long-term cardiovascular health.

HDP is known to heighten the risk of maternal cardiovascular disease, and lactation has previously been associated with favorable metabolic and cardiovascular profiles. However, its specific impact on BP recovery post-HDP is still inconclusive. The researchers hypothesized that an extended duration of lactation would correlate with lower systolic and diastolic BP throughout the first year postpartum.  Data was used from a randomized clinical trial involving overweight and obese individuals with a history of HDP but no pre-pregnancy hypertension.

BP was assessed through various methods. This included triply measuring BP and self-reporting lactation status at enrollment and follow-up, with hypertension defined as ≥130/80 mmHg or the use of anti-hypertensive medications. Daily home BP monitoring was conducted for the first six weeks postpartum and then weekly for the subsequent months. Demographic and cardiometabolic outcomes were compared based on lactation status using statistical tests.

Multivariable logistic regression models were employed to analyze the relationship between lactation and hypertension, while mixed-effects linear regression models assessed BP recovery over time by lactation status.  Analysis of data was done from 129 participants, including 14,177 home BP measurements. Of the participants, 81% initiated lactation with a mean duration of 5.8 ± 4.0 months postpartum. At a follow-up at 10.9 ± 2.1 months postpartum, women who lactated exhibited lower systolic (p=0.004) and diastolic (p=0.008) BP compared to non-lactating women. Additionally, each month of lactation was linked with a 12% decreased odds of hypertension at one year postpartum (adjusted odds ratio 0.88).

This association remained robust even after modifying for characteristics such as age, race, education and body mass index. Lactating individuals demonstrated a healthier BP recovery profile in the first year postpartum, as indicated by significantly lower systolic and diastolic BP (p<0.01). The study not only highlights the potential benefits of lactation in mitigating hypertension but also emphasizes the importance of addressing barriers to lactation to enhance long-term cardiovascular health in overweight and obese individuals with a history of HDP.