Pregnant women with cardiomyopathy at increased risk for adverse outcomes

Adverse maternal and cardiovascular outcomes were more likely in pregnant women with cardiomyopathy compared with those who had a different or no heart disease, findings of a systematic review and meta-analysis showed.

“Our results highlight the importance of prenatal counseling to ensure that women with cardiomyopathy make informed choices about the risks associated with pregnancy and emphasize the need for close antenatal surveillance by experienced multidisciplinary maternal cardiology teams in view of the increased likelihood of severe adverse maternal outcomes,” Elizabeth J. Eggleton, BSc, a trainee health care scientist at the Newcastle University Medical School in Newcastle upon Tyne, England, and colleagues wrote in the American Journal of Obstetrics & Gynecology.

Eggleton and colleagues reviewed 14 studies published before April 24, 2022, that compared outcomes in women with cardiomyopathy with those in women with no known heart disease — which the researchers designated as healthy women — or with non-cardiomyopathy heart disease. The studies examined predefined measures for mode of delivery, left ventricular ejection fraction, major adverse cardiovascular events (MACE) outcomes and non-MACE outcomes.

Of the 14 studies reviewed — which included 57,539,306 pregnancies from across the world — eight had a low bias risk, one had a moderate bias risk and five had a high bias risk. However, the studies with high risk for bias did not affect the results of the meta-analyses, the researchers said.

Mode of delivery

Women with cardiomyopathy were most likely to have a cesarean delivery compared with healthy women (OR = 2.96; 95% CI, 2.47-3.55) and women with non-cardiomyopathy heart disease (OR = 1.9; 95% CI, 1.62-2.22), according to the researchers. Additionally, women with cardiomyopathy were less likely to have a spontaneous vaginal delivery compared with those with no known heart disease (OR = 0.28; 95% CI, 0.23-0.36) and those with other forms of heart disease (OR = 0.61; 95% CI, 0.37-1.01), despite current guidance.

“Current guidelines recommend that vaginal delivery is appropriate for the majority [of] women with heart disease due to reduced risk of heavy blood loss and avoidance of major surgery,” Eggleton and colleagues wrote.

Left ventricular ejection fraction

Results also showed that the left ventricular ejection fraction was significantly lower among women with cardiomyopathy compared with healthy controls — by approximately 25% (mean difference, –25.17; 95% CI, –38.98 to –11.35) — and it was about 14% less than in women with other forms of heart disease (mean difference, –14.15; 95% CI, –16.7 to –11.59).

MACE outcomes

The researchers found that a composite MACE outcome was more common in women with cardiomyopathy compared with healthy women (OR = 206.64; 95% CI, 192.09-222.28) and women with non-cardiomyopathy heart disease (OR = 7.09; 95% CI, 6.08-8.27).

In-hospital mortality was significantly more common in women with cardiomyopathy compared with those with no known heart disease (OR = 126.67; 95% CI, 43.01-373.07). They were also more likely to die in the hospital compared with those with non-cardiomyopathy heart disease (OR = 4.3; 95% CI, 3.42-5.4), which Eggleton and colleagues wrote was a “key concern.”

Individual MACE analyses showed that women with cardiomyopathy were more likely to experience cardiac arrest, heart failure, myocardial infarction, arrythmia, pulmonary embolism, anesthesia complications and cardiorespiratory or respiratory failure during pregnancy. However, the risk for cerebrovascular events was greater in women with cardiomyopathy compared with healthy women, but not compared with women with other heart disease, and there were no differences in the rate of aortic dissection between groups.

Non-MACE outcomes

Rates of admission to an intensive therapy unit among women with cardiomyopathy and healthy controls were reported in one study, which showed women with cardiomyopathy were significantly more likely to be admitted (OR = 12.22; 95% CI, 2.51-59.51). In four studies comparing the rate of admission between women with cardiomyopathy and other forms of heart disease, those with cardiomyopathy were more likely to be admitted (OR = 4.02; 95% CI, 1.57-10.32).

Additionally, women with cardiomyopathy were more likely to be readmitted within 30 days and have a longer postdelivery stay compared with both control groups.

Moving forward, Eggleton and colleagues suggested that large, international studies examine rates of adverse maternal outcomes by cardiomyopathy subtype to strengthen their findings.