Disclosures: The authors report no relevant financial disclosures.
February 04, 2022
3 min read

Pregnancy loss may be independent predictor of future CVD, CHD, stroke

Disclosures: The authors report no relevant financial disclosures.
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A history of pregnancy loss may be an independent risk factor for future CVD, CHD and stroke, according to an analysis of the Nurses’ Health Study II published in the European Heart Journal.

Additionally, researchers found that younger maternal age at pregnancy loss was tied to greater risk for future incident CVD.

Graphical depiction of data presented in article
Data were derived from Wang YX, et al. Eur Heart J. 2021;doi:10.1093/eurheartj/ehab737.

“Spontaneous pregnancy loss, most of which occur before 20 weeks of gestation, is a common adverse outcome of pregnancy that affects 12% to 24% of clinically recognized pregnancies. A history of pregnancy loss, particularly recurrent pregnancy loss, has been linked to a higher risk of CHD, but not stroke, in most previous population studies,” Yi-Xin Wang, PhD, postdoctoral research fellow in the department of nutrition at the Harvard T.H. Chan School of Public Health, and colleagues wrote. “However, the underlying mechanisms behind these associations, which have the potential to identify high-risk women for early screening and intervention, remain unclear.”

Therefore, researchers investigated the association between pregnancy loss and the incidence of CVD as well as the extent to which this association is mediated by subsequent cardiometabolic disorders. The analysis included 95,465 ever-gravid women who participated in the Nurses’ Health Study II from 1993 to 2017.

Pregnancy loss and risk for CVD

By the end of follow-up, 25.6% of the total cohort had experienced at least one pregnancy loss.

The age-adjusted risk for CVD among women who experienced a pregnancy loss during follow-up was greater compared with those with no pregnancy loss (adjusted HR = 1.23; 95% CI, 1.12-1.35), according to the researchers. Adjustment for time-varying lifestyle CVD risk had minimal impact on the association.

Risk for CHD or stroke was similar to CVD risk after pregnancy loss compared with no loss (aHR for CHD = 1.2; 95% CI, 1.07-1.35; P = .002; aHR for stroke = 1.23; 95% CI, 1.04-1.44; P = .01).

Researchers also observed that risk increased as the number of pregnancy losses experienced by an individual increased:

  • risk for CVD (aHR for one pregnancy loss = 1.18; 95% CI, 1.06-1.31; aHR for 2 pregnancy losses = 1.34; 95% CI, 1.13-1.59; P < .001);
  • risk for CHD (aHR for one pregnancy loss = 1.15; 95% CI, 1.01-1.3; aHR for 2 pregnancy losses = 1.44; 95% CI, 1.17-1.76; P < .001); and
  • risk for stroke (aHR for one pregnancy loss = 1.23; 95% CI, 1.03-1.47; aHR for 2 pregnancy losses = 1.21; 95% CI, 0.88-1.65; P = .002).

According to the study, risk for CVD was greater when pregnancy loss occurred earlier in life, with decreasing risk with increasing age and no increased risk when pregnancy loss occurred after the age of 30 (HR for age 23 years = 1.4; 95% CI, 1.21-1.62; HR for age 24-29 years = 1.25; 95% CI, 1.09-1.43; HR for age 30 years = 1.03; 95% CI, 0.88-1.19; P < .001).

Evaluation by subsequent cardiometabolic factors

When the researchers classified participants based on presence of hypertension, hypercholesterolemia and diabetes, CVD risk after experiencing a pregnancy loss was elevated independent of subsequent development of cardiometabolic disorders, each mediating less than 1.8% of the association.

The association between pregnancy loss and CVD was also not mediated by ovulation stimulation treatment, depression or phobic anxiety symptom scores (proportion mediated, < 2.2%).

Moreover, researchers reported that there was no convincing association between induced abortion and CVD risk.

“Our study participants were all health professionals and predominantly non-Hispanic white women whose obesity prevalence is much lower than that of minority women,” the researchers wrote. “Results from this large prospective cohort showed that pregnancy loss was associated with a greater risk of CVD, including both CHD and stroke, among young and middle-aged women. Our findings emphasize the importance of considering a woman’s reproductive history when evaluating her CVD risk. However, future studies should further assess the mechanisms underlying this relationship to aid efforts to prevent CVD in women.”