The bulk of clinical research on cardiovascular disease still focuses on men, but change is afoot to pay more attention to women’s hearts.
In July 2019, Heart & Stroke and McGill University launched the first research chair in Quebec in women’s cardiac health.
It kicked off with a breastfeeding study aimed at women who suffer from preeclampsia, a serious condition characterized by high blood pressure in pregnancy.
Those complications put them at higher risk for heart disease. But can breastfeeding play a protective role and help ward off that risk?
That’s a question Dr. Natalie Dayan, who was awarded the first McGill and Heart & Stroke Early-Career Professorship in Women’s Heart Health, will examine in the newly launched study.
Preeclampsia typically goes away after delivery – blood pressure generally improves in the following days or weeks and protein disappears from urine. However, doctors now know the condition “probably has a long-term effect on their blood vessels,” says Dayan, BSc’01, MDCM’06, MSc’14 a clinician-scientist in the Cardiovascular Health across the Lifespan Program at the Research Institute of the McGill University Health Centre (RI-MUHC).
“There is an increased risk of heart disease in these women, especially if the preeclampsia was severe or associated with pre-term birth – before 37 weeks – and if it reoccurs in subsequent pregnancies,” adds Dayan.
“We do know now that preeclampsia, even if it goes away, is an important risk factor, specific to women, for early-onset heart disease – so in a woman’s 40s, prior to menopause.”
Her research will test whether breast-feeding is beneficial for blood pressure as retrospective studies have suggested.
Those studies, which featured cohorts of women reflecting on their past breastfeeding practices, consistently showed that mothers that breastfed longer or more tended to have lower blood pressure, better metabolic profiles, lower weight and lower risk of heart disease, Dayan says.
Over 12 months post-partum, half the women in the McGill-led study will be randomly assigned to an extra nursing-led intervention to promote breastfeeding, where they’ll meet one-on-one with a nurse. The other half will receive the usual clinical care. Both groups will be followed at the Maternal Cardiovascular Health Clinic at the MUHC, which Dayan started.
“We’re going to follow them up, measure their blood pressure, blood sugar and cholesterol, serially over time,” Dayan says. She and her research team also want to know if these women have a harder time breastfeeding either for biological or psychological reasons. For instance, they may be traumatized by their severe pregnancy complication and their baby likely spent time in a neonatal intensive care unit.
Dayan points out that no studies have assessed breastfeeding to see if it immediately provides protective qualities at the vascular level.
If breastfeeding helps their metabolic profile, “we’re sort of looking at it as a drug because we know it does have effects on blood vessels. There are certain hormones that are released, and certain other proteins that are released in the circulation when a women does breastfeed.”
The research team will look at whether the extra nursing-led intervention boosts breastfeeding among study participants, lowers their blood pressure and reduces the need for blood pressure medication.
Longitudinal follow-up to understand who develops heart disease
The team is also collecting lots of data, including mental health data and physical and biological measurements. Dayan hopes to link the data they collect with electronic health records, so they can follow the women over time and track hospitalizations for heart-related issues to better understand who does – and doesn’t – develop heart disease.
Nearly 30 women from the MUHC’s Glen site have been recruited into the study so far. A partner site at Queen’s University is part of the study and other sites in Montreal will be added to reach the target of about 350 participants.
The experience of pregnancy, childrearing and breastfeeding is just one example of how women and men differ – and how pregnancy events are risk factors that we need to pay attention to, Dayan says. “And how certain biological and natural behaviors may also be naturally protective and something that we should be emphasizing and helping to support such as breastfeeding.”
The women’s cardiac health research chair is the fifth in Canada funded by Heart & Stroke.
“We always knew that heart disease was one of the No. 1 killers for both men and women in Canada”, says Dayan. But in the past 10 or 15 years there has been a recognition that it affects women and men differently.
“So we do need to look at them differently as far as risk factors for heart disease, the symptoms that women and men present with may at times be different, and the way they respond to treatment may be different as well,” she says.
“I think it’s very positive that there is more attention being paid to women’s heart health.”