MONTEREY, CALIF. – Parturients with congenital heart disease do have a rockier obstetric course, but generally fare quite well in the peripartum period, a retrospective cohort study found.

Researchers at the University of Colorado Hospital in Denver led by Christine M. Warrick found that roughly 1% of women delivering there over a 4-year period had congenital heart disease.

This group had higher rates of cesarean delivery and neonatal ICU admission than did parturients overall, according to results reported in a poster session at the annual meeting of the Society for Obstetric Anesthesia and Perinatology. Maternal ICU admissions were rare, however, and there were no cases of maternal mortality.

"Congenital heart disease is definitely a risk factor for maternal and fetal complications, but overall the women seemed to do pretty well. The main things to look out for would be neonatal ICU admissions and respiratory distress in the babies," Ms. Warrick commented in an interview.

In additional study findings, although the large majority of women received regional anesthesia for labor and delivery, only a minority had an epidural placed early, before 4 cm of cervical dilation.

"There is some literature that suggests that early epidural placement is beneficial for these women because it decreases the stress on the heart secondary to pain," she noted. "Some of these women come [to the hospital] in labor and they are already beyond 4 cm of dilation, so that may be a big reason why there weren’t so many early epidurals placed."

In a related poster discussion session, comoderator Dr. Katherine W. Arendt of the Mayo Clinic in Rochester, Minn., asked, "Do you believe that the geographical elevation of your hospital improved or worsened your outcomes compared to a sea-level hospital?"

"It’s difficult to say exactly how the elevation affected all of these women, since we had so many different varieties of congenital heart disease," replied Ms. Warrick, who is a fourth-year medical student at the University of Colorado in Aurora. "But it is possible that women with more severe congenital heart disease would not tolerate a lower partial pressure of oxygen in our environment, and there were some women who were advised to deliver at lower altitudes because of this. So that probably improved our outcomes in women who received adequate prenatal care. I also think that points to the importance of prenatal care in these women."

"We know that more women are surviving to childbearing age with congenital heart disease due to the recent advances in surgical repair of these defects, and it is actually one of the major causes of cardiac diseases in pregnant women in the United States," she said. Many of the normal changes of pregnancy, labor, and delivery put stress on the heart and would be expected to exacerbate matters.

The investigators studied 13,109 parturients in the hospital’s perinatal database between October 2005 and December 2009. Medical history and record review identified 75 women, or 0.6%, as having congenital heart disease.

These women had a mean age of 26 years. The majority were non-Hispanic white (60%) and nulliparous (55%). Fully 34% were overweight or obese, and 8% smoked.

According to cardiologists’ notes of symptoms during the third trimester of pregnancy, 60%, 33%, and 7% of the women had New York Heart Association functional class I, II, and III, respectively. The leading congenital anomalies were atrial septal defects (28%), valvular disorders (19%), and tetralogy of Fallot (11%).

In terms of cardiac outcomes, 11% of the women had an arrhythmia in the peripartum period, and 5% required diuresis, Ms. Warrick reported. Although 87% received regional anesthesia for labor and delivery, only 31% received an early epidural.

Some 19% of the women had a preterm birth (one occurring before 37 weeks’ gestation), and 45% had a prolonged hospital stay (lasting more than 2 days after a vaginal delivery or more than 3 days after a cesarean delivery).

Although 3% of the women were admitted to the ICU for prophylactic monitoring, there were no maternal deaths in the peripartum period.

Compared with parturients overall, those with congenital heart disease were more likely to have a cesarean delivery (31% vs. 27%) and a neonatal ICU admission (23% vs. 15%). The majority of the neonatal ICU admissions were for prematurity or respiratory distress.

"In anyone with congenital heart disease, prenatal care is very important, and a lot of these women were followed closely by a team of physicians [specializing in high-risk pregnancies]," noted Ms. Warrick.

"All in all, pregnant women with congenital heart disease can undergo labor and delivery without many complications, but tend to have longer hospital stays and more neonatal ICU admissions," she concluded.

Ms. Warrick disclosed no relevant conflicts of interest.

Obstetric Outcomes Fairly Good Despite Maternal CHD