Background: Adverse pregnancy outcomes (APOs) (i.e. hypertensive disorders, gestational diabetes, preterm delivery and small-for-gestational age infants) are independent risk factors for premature coronary artery disease. While breastfeeding is associated with reduced long-term CVD risk, its impact on early postpartum outcomes following APOs is unclear. This study assessed the association between lactation intensity and early postpartum cardiovascular risk factors.
Methods: This cross-sectional registry analysis included 200 outpatients with previous APOs attending a postpartum clinic at Lyell McEwin Hospital, South Australia. Cardiovascular risk factors assessed included anthropometrics, haemodynamic and biochemical measures. Breastfeeding frequency at approximately 6 months postpartum was quantified using a lactation intensity ratio, defined as the proportion of breastfeeds per day relative to formula or mixed feeding. Participants were categorised as high (>80%), moderate (21-79%), or low (<20%) lactation intensity. Groups were analysed using one-way ANOVA and Tukey HSD post-hoc testing.
Results: Breastfeeding initiation was reported in 95% of participants. At a median of 8 months postpartum, 53% reported low lactation intensity. High lactation intensity was associated with lower peripheral and central systolic and diastolic blood pressure, reduced arterial stiffness (augmentation index), and higher HDL cholesterol compared with low intensity (p<0.05). Associations remained after adjustment for obesity, smoking status, and individual APOs.
Conclusions: Higher lactation intensity is associated with favourable early postpartum risk profiles, among women with APOs. These findings support incorporating breastfeeding support and protection into postpartum cardiovascular counselling for patients. Future research should examine prospective lactation intensity and psychosocial or physical barriers to breastfeeding in this high-risk population.