Pregnancy loss and risk of cardiovascular disease: a prospective population-based cohort study (EPIC-Heidelberg), Kharazmi et.al., Heart 97:49-54, 2011.
These investigators set out to examine whether pregnancy loss (miscarriage, abortion or stillbirth) is associated with a higher risk of myocardial infarction (MI) and stroke. The participants included 11,518 women who had previously been pregnant. Out of the participants, 2876 (25%) had at least one miscarriage, 2053 (18%) had at least one elective abortion and 209 (2%) had at least one stillbirth. During the follow-up, 82 cases of MI and 112 of stroke (confirmed by medical records) occurred in these women. Each stillbirth increased the risk of MI 2.65 times (95% CI for age-adjusted HR 1.37 to 5.12). When adjusted for age, smoking, alcohol consumption, body mass index, waist to hip ratio, physical activity, education, number of pregnancies, hypertension, hyperlipidemia and diabetes mellitus the risk was 2.32 (95% CI 1.19 to 4.50). Recurrent miscarriage (>3) was associated with a five to nine times higher risk of MI (age-adjusted HR=8.90, 95% CI 3.18 to 24.90; and fully adjusted HR=5.06, 95% CI 1.26 to 20.29). No significant association was found between elective abortion and MI or between any type of pregnancy loss and stroke. Each miscarriage the women had increased her risk of heart attack by 40 percent.
Dr. Albrecht’s comments:
The findings in this study potentially have great significance given the fact that 15 to 20 percent of women have had a miscarriage. This study with fairly large numbers of study participants showed that women with repeated pregnancy losses whether early or late belong to a high-risk group for cardiovascular disease.
Women in this study who had losses tended to be older, heavier, and more sedentary. Many of the medical conditions that predispose to recurrent miscarriage and stillbirth can also predispose towards heart disease. Underlying risk factors for miscarriage or stillbirth, such as high blood pressure, diabetes, or blood-vessel dysfunction may also contribute to heart disease later in life. However, even when these obvious heart disease risk factors were controlled for, the women with losses still had an increased risk for heart attacks.
Other health conditions, such as polycystic ovarian syndrome (that has been linked to heart disease), infections such as chlamydia (that contributes to plaque build-up in the arteries and an increase in MIs), and coagulopathies/thrombophillias (that may increase the risk of blood clots on plaques in the cardiac vessels) were not controlled for in this study and may be an explanation for the findings. Perhaps if these risk factors had also been evaluated and controlled for, the increased risk of MIs in patients with pregnancy losses might disappear. Further research is needed to elucidate what underlying factors for pregnancy loss might also strongly predispose to cardiovascular disease.
If we consider women who experience repeated pregnancy losses to be at high-risk for cardiovascular disease, then the take home message is that the known modifiable risk factors of cardiovascular disease should be controlled in these women even when they are young and have no symptoms of heart disease.