Risk factors associated with preterm delivery in women with cardiac disease

The purpose of this study was to identify clinical characteristics of preterm delivery at less than 37 weeks of gestation (PD37G) and prenatal events associated with preterm delivery at less than 35 weeks of gestation (PD35G) in women with cardiac disease (WCD).

A case-control study was conducted of 599 pregnancies in 479 single pregnant women with congenital or acquired cardiac lesions or cardiac arrhythmias. The relevant variables were compared between women who had PD35G (n=37) and the controls (n=562). Cardiac dysfunction was defined as the appearance of clinical symptoms of heart failure, abnormal electrocardiogram, or cardiac ultrasonography.

PD37G occurred in 77 cases (12.9%). The spontaneous and indicated preterm delivery was 26 (33.8%) and 51 (66.2%) cases, respectively. The presence of cardiac dysfunction [odds ratio (OR) 21.82, 95% confidence interval (CI) 8.3-57.49], New York Heart Association class II (OR 3.96, 95% CI 1.05-14.93), cardiomyopathy (OR 7.74, 95% CI 1.69-35.45) and pregnancy-induced hypertension (PIH) (OR 3.15, 95% CI 1.37-7.24) was significantly associated with an increased risk of PD35G. No maternal death was seen within one year after delivery.

Although pregnancy and delivery are generally safe in WCD, it is necessary to be aware of the risk factors of cardiac dysfunction, cardiomyopathy, and PIH from the aspect of PD35G.