Pregnancy at an Advanced Age May Up Stroke Risk After Menopause
Women who gave birth after age 40 may have an increased risk for hemorrhagic stroke.
The risk for hemorrhagic stroke after menopause is greater for women whose last pregnancy occurred at an advanced age compared with women whose pregnancies occurred before age 40 years, according to a large cohort study of postmenopausal women conducted by Adnan Qureshi, MD, and colleagues.
The findings were presented at the 2016 International Stroke Conference in Los Angeles.
Researchers examined data on 72 221 post-menopausal women (aged 50 to 79 years) to determine the effect of pregnancy at advanced age on the risk for later cardiovascular events (CV), including myocardial infarction (MI), CV death, and ischemic or hemorrhagic stroke. These women were enrolled in the observational arm of the National Institutes of Health's Women's Health Initiative Study, which was implemented to address and prevent common causes of morbidity, mortality, disability, and reduced quality of life in postmenopausal women.
As Dr Qureshi explained to Cardiology Advisor, his team divided the women into 2 groups — those who had their last pregnancy before age 40 years, and those who had their last pregnancy at age 40 years or older (3306, or 4% of the women) — and then followed them by close surveillance for several decades.
In multivariate analysis, after adjusting for age, race/ethnicity, congestive heart failure, systolic blood pressure, atrial fibrillation, alcohol use, and cigarette smoking, the study determined that women with a history of pregnancy at advanced age were 60% more likely to suffer hemorrhagic stroke (hazard ratio [HR]=1.6; 95% CI, 1.1-2.4) after menopause than women with pregnancies at normal age.
Before adjusting for confounders, the data revealed that, compared with pregnancy before age 40, pregnancy at age 40 or older was associated with a significantly higher rate of ischemic stroke (2.4% vs 3.8%; P<.0001), hemorrhagic stroke (0.5% vs 1.0%; P<.0001), MI (2.5% vs 3.0%; P<.0001), and CV death (2.3% vs 3.9%; P<.0001) in the postmenopausal period. After adjustment for confounders, however, there was no significant difference in the rates of ischemic stroke, MI, or CV death between the 2 groups.
As the authors noted, advances in assisted reproductive technology have led to an increased incidence of pregnancy in older women, but the potential long-term maternal health effects of pregnancy at advanced age are unknown.
“It is well-known that women who have pregnancy at [age 40 or older] have higher risk of developing complications during and immediately after pregnancy,” Dr Qureshi said in an interview. “The current study suggests that there may be long-term consequences as well.”
It remains unclear, he added, “whether women who become pregnant at [age 40 or older] can modify or reduce the risk in later life,” but “regular screening and more rigorous risk factor modification may be a logical step.” The study, he said, “simply provides additional information regarding long-term consequences that women need to take into account.”
- Qureshi AI, Saeed O, Malik AA, et al. Abstract WMP 50. Pregnancy in advanced age increases the risk of hemorrhagic stroke in post-menopausal women. Analysis of Women's Health Initiative Study. Presented at the International Stroke Conference; February 17-19, 2016: Los Angeles, CA.