Can breastfeeding reduce mothers’ heart risk?

New Heart & Stroke research chair could provide important answers

Dr. Natalie Dayan

What happens in pregnancy doesn’t just stay in pregnancy, especially when it comes to heart health. Dr. Natalie Dayan, assistant professor of medicine at McGill University and director of obstetrical medicine at the McGill University Health Centre, studies how heart problems in pregnant women can sometimes impact them for life.

“My overall aim is to improve women’s heart health after complications during pregnancy,” says Dr. Dayan.

She was recently awarded the first McGill University and Heart & Stroke Early-Career Professorship in Women’s Heart Health. The award will fund her latest study, looking at how breastfeeding impacts women’s health after a pregnancy with heart-related complications.

Her team will follow approximately 350 women who had conditions such as gestational hypertension (high blood pressure) or pre-eclampsia, which involves both high blood pressure and signs of damage to the organs such as the kidneys or liver.

The study builds on previous research that shows breastfeeding has positive health impacts for women, including lowering blood pressure. Now Dr. Dayan wants to know if breastfeeding can help these women both right after pregnancy and years later.

Risks after pregnancy

As a clinical researcher, she sees such women in her practice all the time. She knows they have double the lifetime risk of developing heart disease or stroke. While she notes that their absolute risk of significant heart disease may be as low as 3%, “these are young women who are mothers to young children, so this is something we want to avoid.”

These women are often sent home with suggestions for lifestyle changes. Dr. Dayan says that isn’t enough: they have newborns, busy work and family lives, and many have another baby soon after. Plus, she adds, there is no evidence to guide prevention of cardiovascular disease using medications in this group. “The guidelines don’t quite fit with this population and are really based on what we know about older women and men.”

She wants to come up with concrete prevention tools for these mothers.

Dr. Dayan’s team will follow the selected mothers at three, six and 12 months after delivery; then she plans to continue following them via electronic health records for another 10 to 15 years. This long-term prospective data is really lacking and can provide essential information on those at highest risk.

Short-term results will evaluate breastfeeding as a drug that may relax blood vessels via circulating hormones such as oxytocin. Longer-term data will help Dr. Dayan and her team pinpoint the lingering impact of breastfeeding, and which of these women are more at risk for developing cardiovascular problems.

Novel breastfeeding support

Some women in the study will get special breastfeeding support from nursing staff, aimed at building their confidence as well as helping them with technical issues like latch.

‟We will verify whether this intervention improves breastfeeding practices in these women and whether it also helps to lower blood pressure or need for blood pressure medication at 12 months postpartum,” explains Dr. Dayan.

She believes that complications in pregnancy may have wider health implications for women’s health, and that healthcare providers could soon look at them as early warning signs for issues to come. “Pregnancy is like a stress test. More and more we’re are realizing that.”