The impact of maternal congenital heart disease on pregnancy outcomes in Malta: a retrospective study

Background: Most female patients with congenital heart disease (CHD) are becoming pregnant. Maternal CHD can have a negative impact on mother and fetus. This is the first study investigating pregnancy outcomes in Maltese grown-up congenital heart disease (GUCH) patients and one of few to compare these with outcomes in women without heart disease. Methods: Known GUCH pregnancies for the period of 2007-2014 were extracted from our database (GUCH cohort) and cardiovascular outcomes retrieved from hospital notes. A control cohort of 540 pregnancies in women without cardiovascular disease was generated through twenty-fold random matching based on subject age from among all pregnancies in Maltese nationals for the same 8-year period. Obstetric and offspring outcomes were compared between the two cohorts. Results: The GUCH cohort consisted of 27 pregnancies in 24 women. Cardiovascular complications occurred in only 1/27 (3.7%) pregnancies. Elective Caesarean sections were commoner (29.6% vs. 15.4%) and unassisted vaginal deliveries less frequent (51.9% vs. 64.6%) in the GUCH cohort (p=0.02). Obstetric complication rates were similar. GUCH women had smaller babies (median 3030 g vs. 3230 g; p=0.045) and showed a trend towards more small-for-gestational age babies (18.5% vs. 8.4%; p=0.08) and congenital malformations (7.4% vs. 2.4%; p=0.06). Conclusions: Despite the potential adverse effects of maternal CHD on mother and fetus, most pregnancies are uncomplicated and outcomes comparable to those in women without heart disease, particularly if baseline clinical status is good. Based on our findings, it is being proposed that prospective mothers be counselled about the possibility of having smaller infants.