Breastfeeding for six months or more appears to reduce the risk of cardiovascular problems developing in mothers for at least three years after delivery, a new South Australian study has found.

The surprising cardio-metabolic benefit for maternal health is particularly important for women who experienced a complicated pregnancy, which can increase their chance of developing cardiovascular disease (CVD) later in life.

The new results – published this month in the International Breastfeeding Journal by experts from the University of Adelaide and Flinders University – stem from a long-running study of 160 breastfeeding mothers who took part in follow-up health checks after delivery of their babies.

The study found women who breastfed baby for at least six months experienced lower blood pressure and body-weight recovery (or BMI) for up to three years after the birth of their baby.

Senior author, Professor Claire Roberts, who leads the Pregnancy Health and Beyond (‘PHaB Lab’) research group at Flinders University, says the study was positive for women with pregnancy complications, as they recorded lower blood pressure and improved cholesterol measures at three years postpartum.

“That means that breastfeeding improves women’s cardio metabolic risk factors, which is good news for new mothers who might be at risk of developing future cardiovascular and metabolic diseases,” says Matthew Flinders Professor Roberts, from Flinders College of Medicine and Public Health.

“Pregnancy complications are associated with later cardiovascular disease risk and their children are also at risk of impaired metabolic health earlier in life.

“Along with neurological and other health benefits for babies, the World Health Organization recommends breastfeeding exclusively for up to six months, and breastfeeding over 12 months to promote a significant reduction in both chronic hypertension and diabetes in women.”

The new South Australian study was led by University of Adelaide PhD Dr Maleesa Pathirana and colleagues from the Robinson Research Institute, Lyell McEwin Hospital cardiology department and Flinders University, who conducted the follow-up of 280 women and their children from the Screening Tests to Predict Outcomes of Pregnancy (STOP) study between 2018 and 2021.

“We found that women who breastfed for at least six months had significantly lower body mass index (BMI), lower blood pressure, mean arterial pressure and lower central blood pressure than those who did not,” says Dr Pathirana.

“We found that if women with at least one major pregnancy complication – like preeclampsia, gestational hypertension and gestational diabetes – breastfed for at least six months, they had significantly lower blood pressure, improved cholesterol profile and lower insulin compared to those who did not breastfeed for at least six months.

“These findings indicate an overall improvement in cardiovascular health.”

The SA researchers recommended further investigations in a larger sample size of women who breastfeed compared to those who choose not to breastfeed.

They also recommended more interventions that support breastfeeding in disadvantaged or low socioeconomic areas, particularly for women with pregnancy complications to reduce their lifetime risk of cardiovascular disease.

The article, The association of breast feeding for at least six months with hemodynamic and metabolic health of women and their children aged three years: an observational cohort study (2023) by Maleesa M Pathirana, Prabha H Andraweera, Emily Aldridge, Madeline Harrison, Jade Harrison, Shalem Leemaqz, Margaret A Arstall, Gustaaf A Dekker and Claire T Roberts has been published in the International Breastfeeding Journal (2023) 18:35 https://doi.org/10.1186/s13006-023-00571-3

Acknowledgements: NHMRC Peter Doherty BioMedical Postdoctoral Fellowship awarded to PHA (GNT1090778). Channel 7 Children’s Research Foundation project grant awarded to PHA, GAD and CTR (GNT161305). CTR is supported by a NHMRC Investigator Grant (GNT1174971) and a Matthew Flinders Fellowship from Flinders University. University of Adelaide Health and Medical Sciences Divisional Scholarship awarded to MMP