Women who exhibited normal blood pressure during pregnancy and breastfed children for at least six months had better cardiovascular health years later compared to women who did not breastfeed, according to new research to be presented at the American College of Cardiology’s 67th Annual Scientific Session.
Researchers noted a general hypothesis that breastfeeding increases oxytocin, a hormone that can in turn can lower blood pressure. Another hypothesis is lactation can counteract some of the metabolic changes that occur during pregnancy.
“There’s a lot we still don’t understand about the accumulation of cardiovascular risks in women,” said lead author Malamo Countouris, MD, from the University of Pittsburgh, and colleagues. “Examining how pregnancy may increase or perhaps mitigate some of that risk can give us insights into the unique presentation and development of heart disease risk in women.”
The study cohort included 678 women from more than 50 clinics in Michigan between 1998 and 2004. The women were pregnant during enrollment and participated in follow-up health assessments an average of 11 years later.
During the follow-up assessment, the study subjects were asked the length of time they breastfed after each pregnancy. Physicians also measured participants’ blood pressure, cholesterol, triglycerides and the diameter and thickness of the carotid artery.
The study subjects were divided into three groups: 157 women who never breastfed, 284 women who breastfed for less than six months per pregnancy and 133 women who breastfed six months or more per pregnancy. Women exhibiting normal and high blood pressure were assessed separately.
Notable results included:
- Women with normal blood pressure during pregnancy who breastfed for six months or more had higher levels of HDL, lower triglycerides and healthier carotid artery thickness compared to those who never breastfed.
- There was no evidence of cardiovascular benefit from breastfeeding among women who had high blood pressure during pregnancy.
“There’s a lot we still don’t understand about the accumulation of cardiovascular risks in women,” Countouris said. “Examining how pregnancy may increase or perhaps mitigate some of that risk can give us insights into the unique presentation and development of heart disease risk in women.”