Women With Congenital Heart Defects at Risk During Delivery

Caroline Helwick

February 10, 2014

NEW ORLEANS — Pregnant women with congenital heart defects (CHDs) are more likely to die or experience medical and obstetric complications at the time of delivery than women without such defects, according an analysis of the Nationwide Inpatient Sample.

"We found that women with CHD are at increased risk of certain obstetric morbidities, but we found no differences in preterm labor or fetal demise," said Jennifer Thompson, MD, from Duke University in Durham, North Carolina.

She presented the findings here at the Society for Maternal-Fetal Medicine 34th Annual Meeting.

Ten years ago, an estimated 1 million adults had a CHD, most commonly ventricular and atrial septal defects. It is anticipated that this will increase by 5% per year.

Data are limited on the occurrence of cardiac events and on obstetric and neonatal complications in women with CHD. Dr. Thompson and her colleagues aimed to fill this information gap by analyzing the Nationwide Inpatient Sample and comparing pregnant women with and without CHD.

More Than 10,000 Women With CHD Studied

From 2008 to 2010, the Nationwide Inpatient Sample registered 10,871 deliveries to women with CHD (8.6 per 10,000) and 12,617,875 to women without CHD. Women with CHD were more likely to be white (P = .0001), and those without CHD were more likely to be black or Hispanic (P < .0001).

Age, multiple gestations, and pre-existing medical complications were controlled for in the analyses.

Strikingly, women with CHD had an 11-fold risk for an adverse cardiac outcome, defined as a composite of death, mechanical ventilation, myocardial infarction, cardiac arrest, acute heart failure, and arrhythmia, Dr. Thompson reported.

Numerous medical morbidities were observed in this population.

Table 1. Selected Medical Morbidities at Delivery in Women With CHD

Morbidity Odds Ratio
Maternal death 10.1
Mechanical ventilation 6.0
Myocardial infarction 24.7
Cardiac arrest 13.4
Acute heart failure 15.9
Arrhythmia 10.3
Composite cardiac outcome 11.1


The risk for composite cardiac outcome was higher with some CHD abnormalities than others. The highest risks were for Ebstein's anomaly, transposition of the great vessels, and coarctation of the aorta. Half of the 19 deaths in this CHD population were in patients with ventricular septal defect, Dr. Thompson reported.

Obstetrical Morbidity Increased

Women with CHD were at higher risk for obstetric complications than those without CHD. However, the incidence of preterm labor was lower in those with CHD (odds ratio, 0.3).

Table 2. Obstetric Morbidities in Women With CHD

Obstetric Complication Odds Ratio
Cesarean delivery 1.3
Operative vaginal delivery 1.5
Placental abruption 1.4
Fetal growth retardation 2.1
Oligohydramnios 1.3
Preterm rupture of membranes 1.6
Placenta previa 2.1
Fetal demise 1.2


The rate of death in women with ventricular septal defects was surprisingly high, noted Thomas Easterling, MD, director of the maternal hypertension clinic at the University of Washington School of Medicine in Seattle. He said he thinks that that "something else is being captured in this population that is not obvious."

Dr. Thompson noted that the subtleties of these conditions are not known because information was derived from a database and is limited by the coding system. "For example, we can't determine which women had repair of their ventricular septal defect. Based on previous studies, their risk for a significant complication would be much lower," she explained.

This is one of the world's largest studies of maternal CHD, noted session moderator Mary D'Alton, MD, the Willard C. Rappleye professor of obstetrics and gynecology at the Columbia University College of Physicians and Surgeons in New York City. "Although data from such a database are sometimes limited, they represent the need to have all women with any complicated congenital heart disease delivered in a tertiary care center with a multidisciplinary team," she told Medscape Medical News.

"It is my impression that if such a policy could be instituted, there would be the potential for a reduction in maternal death and morbidity," Dr. D'Alton added.

Dr. Thompson and Dr. D'Alton have disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 34th Annual Meeting: Abstract 43. Presented February 6, 2014.


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