Most women with heart disease can safely go through pregnancy, although striking differences in outcome were found by type of heart disease and between countries, a novel international registry shows.
Maternal mortality was 1%, but this was still 100 times higher than the mortality of 0.007% in the normal pregnant population. Seven of the 13 maternal deaths were due to cardiac events, three to thromboembolic events, and three to sepsis.
Maternal mortality was highest in women with cardiomyopathy at 2.4%, compared with 2.1% for those with valvular heart disease, 0.5% with congenital heart disease, and 0% for ischemic heart disease.
In addition, women with cardiomyopathy experienced higher rates of heart failure (24% vs. 18%, 8%, and 8%) and ventricular arrhythmias (11% vs. 0.6%, 1.6%, and 0%) than did those with valvular heart disease, congenital heart disease, and ischemic heart disease, cardiologist Dr. Jolien Roos-Hesselink and her associates reported (Eur. Heart J. 2012 [doi:10.1093/eurheartj/ehs270]).
Although cardiomyopathy is uncommon during pregnancy, it is difficult to manage in the context of left ventricular dysfunction or peripartum cardiomyopathy, with a high risk of an adverse outcome for both the mother and the baby, observed Dr. Roos-Hesselink of Erasmus Medical Center, Rotterdam, the Netherlands, and associates.
The analysis was based on 1,321 pregnant patients with structural or ischemic heart disease enrolled from 60 hospitals in 28 countries from 2008 to June 2011 in the European Registry on Pregnancy and Heart Disease, the world’s first registry to focus on this challenging clinical scenario.
The patients’ median age was 30 (range 16-53), median duration of pregnancy 38 weeks, 56% had one or more previous pregnancy, and 54% had undergone at least one prior cardiac intervention. About 50 patients were from the United States.
Most patients were New York Heart Association class I (70%), and only 0.3% were class IV. More women with cardiomyopathy were NYHA class III (8%), while those with ischemic heart disease were older, more likely to suffer from hypertension and diabetes, and more likely to be smokers.
Outcomes in women with congenital heart disease, the largest subgroup in the registry at 872 patients, were relatively good compared with other subgroups. The authors attributed this to the high rate of successful prior cardiac corrective surgery (66%), favorable NYHA class (76% class I and 21% class II) and low use of any medication (20%).
Even in this group, however, the rate of cesarean delivery was higher (38% vs. 23%) and mean birth weight was lower than in the background population (3,056 grams vs. 3,190 grams), Dr. Roos-Hesselink and associates noted.
Overall, 41% of the cohort had a cesarean delivery, with the highest rate in women with ischemic heart disease (60%) or cardiomyopathy (58%).
Cesarean delivery rates also varied widely between countries, with the highest rate reported in Italy, not the United States, she said in an interview.
"C-section rates are the product both of the background rates of a particular country and the numbers of women with severe heart disease, so that if the background rate was high and there were more women with severe heart disease in that group, then that country’s rates were higher," she explained.
During pregnancy, 338 patients (26%) were hospitalized, most (76%) only once. In all, 162 patients (12%) "had at least one period of heart failure during or after pregnancy, while this is rarely, if ever, seen in the general population," the investigators said.
Fetal mortality was significantly higher in the cohort than in the normal population (1.7% vs. 0.35%). In the cohort, 62% of the deaths were intrauterine fetal deaths with no further information, 21% were obviously due to the maternal condition, and 17% were because of structural fetal abnormalities. Neonatal death rates did not differ significantly between the cohort and the normal population (0.6% vs. 0.4%).
As for whether certain women with heart disease should avoid pregnancy, the data show there are certain groups of women who have a very high chance of experiencing an adverse outcome during pregnancy, but ultimately it is an individual’s choice whether to undergo a pregnancy, coauthor Dr. Mark R. Johnson, clinical chair in obstetrics at Imperial College, London, said in an interview.
The doctor’s job is to give advice about the risks," he said. One of the reasons the registry is so important is that "it gives us a more robust source to base our advice on."
Dr. Roos-Hesselink pointed out that guidelines published in Europe last year do consider some groups to be contraindicated for pregnancy including patients with pulmonary hypertension, patients with severe cyanosis, and patients with earlier peripartum cardiomyopathy and still diminished ventricular function.