Further illuminating the intense strain that parenthood puts on the human body, new research from the Universities of Cambridge and North Carolina found that women who gave birth to five or more children were 38 percent more likely to have a heart attack compared with women who carried only one or two pregnancies to term.
After examining 30 years-worth of health data from 8,583 white and African-American women aged 45 to 64 years, the investigators also discovered that study subjects with five or more live births had a 25 percent and 17 percent greater risk of stroke and heart failure, respectively, whereas women with three to four children had a modestly increased risk of serious health implications.
“The aim of my research is not to scare women but to bring to their attention as early as possible whether they might be at increased risk of heart attacks,” lead researcher Dr Clare Oliver-Williams stated. “We know that pregnancy and childbirth put a tremendous strain on the heart, and raising children can be very stressful, too. We don’t want to add to the stress people have in their everyday lives but equip them with the knowledge to do something about it.”
Dr Oliver-Williams told IFLScience that her team’s statistical analysis was adjusted for numerous other factors known to affect women’s health, including age, race, location, socioeconomic status, health insurance, smoking status, years of reproductive life, use of oral contraceptive pills, and use of hormone replacement therapy. The model also took into account the women's’ age at first pregnancy and how long they breastfed. (Previous investigations have linked breastfeeding to improved cardiovascular health in mothers.)
Women who had multiple miscarriages during the study period showed a 60 percent greater rate of heart disease and 45 percent greater rate of heart failure compared to women who had one to two live births – an outcome that the team attributes to underlying medical issues that both complicate pregnancy and impact cardiovascular health.
One limitation of the study is that its design makes it impossible to separate whether the physiological damage that led to subjects' cardiovascular events came from the toll of repeated pregnancies, the exhausting demands of raising the children afterward, or both. An in-depth overview of the study was presented by Dr Oliver-Williams today at the British Cardiovascular Society Conference.
“While it’s perhaps not surprising that having more children can mean that mums have less time to look after their own health, this research brings home just how important it is for everyone to keep an eye on their heart health, particularly busy parents,” commented Professor Jeremy Pearson, associate medical director at the British Heart Foundation.
“Research like this reminds us that – regardless of the stereotype of the overweight, middle-aged man having a heart attack – heart disease strikes men and women alike.”