Pregnancy can be a taxing experience both physically and emotionally. Science (and moms) have known this for a long time, but it was also believed that once a pregnancy was over, the associated risks for certain health conditions went away, too. Now several studies have shown that pregnancy may contribute to heart problems later in life, and the more pregnancies a woman has, the greater her risk may be.
There are a lot of factors that influence our risk for cardiovascular disease throughout our lifetimes. Genetics play a big role, as do our lifestyle choices. Making sure we get regular physical activity that gets our blood pumping, eating a wide variety of nutritious foods, and avoiding habits like cigarette smoking are all helpful in keeping our hearts healthy.
During pregnancy, the human body undergoes some major changes. Those changes can include inflammation and hormonal shifts that researchers now think could contribute lasting changes to the body, including the cardiovascular system. It's those characteristics of pregnancy — and some that are likely not yet known or well-understood — that seem to influence just how much of a physical stress to the body it is, according to a new review of multiple research studies.
One thing that's been observed is that a woman's risk of developing an abnormal heart rhythm, called atrial fibrillation (or a-fib) increases when she's pregnant. New research indicates that the risk doesn't go away when she's no longer carrying a fetus, and in fact, that each subsequent pregnancy she has increases her risk. A woman who has had six pregnancies, the study says, could have a 50 percent increased risk of developing a-fib. In general, women who have been pregnant have a 15 percent higher risk of a-fib than women who have never been pregnant, according to data from the Women's Health Study at Harvard Medical School and Brigham and Women's Hospital.
Another recent study found that women who deliver a baby preterm have an elevated risk of developing heart disease that doesn't go away after the baby is born. Scientists have long thought that the physical stressors of pregnancy and their associated health risks resolved when the pregnancy was over— but this study in particular seems to show the opposite may be true. Scientists are wondering if each additional pregnancy makes it harder for those usually temporary structural changes to revert back to their pre-pregnancy state.
Researchers in both studies are quick to point out that this isn't necessarily causation: it's not that pregnancy necessarily causes heart problems. It may be, in the latter case especially, that women who have multiple factors predisposing them to heart disease in their lifetimes are also more likely to deliver babies preterm. Scientists are still looking for a more definitive answer about what these two things have in common, and why a woman who has delivered a baby early — but may not have other risk factors associated with cardiovascular disease — could still have an elevated risk for heart problems.
Heart disease in women is an area of medicine that still needs significant research. While we know now that women experience different symptoms of a heart attack than men do, those symptoms still can go unnoticed. Heart disease is actually the number one killer of women, according to the American Heart Association — whether she's had children or not.
For science, understanding this link will be essential to helping women stay healthy. For now, they say women shouldn't let worries about developing heart disease keep them from having a family if they want one. While there are some risk factors — like genetics — that can't be helped, there are a lot of steps a women can take to protect her cardiovascular health.
It's never too soon to develop good habits, either: things like being physically active, keeping tabs on measures of health like your blood pressure or cholesterol levels, eating a well-balanced diet and avoiding cigarette smoke are all positive steps you can take to reduce your risk, whether you plan to get pregnant or not.