Does pregnancy impact subsequent health outcomes in the maternal Fontan circulation?

Pregnancy in women with a Fontan circulation is understood to have a significantly increased risk of maternal morbidity and mortality. Potential longer-term effects on health outcomes remain unknown.

Ascertainment of adverse events, post-delivery, in women from the Australia and New Zealand (ANZ) Fontan Registry. Comparator data from women without pregnancy and men was utilised.

Living adults were identified (n = 263 women, 280 men) with Registry analysis ascertaining cardiac morphology, type of Fontan procedure, pregnancy and significant cardiac adverse events. Data are described descriptively for morphology and as median (inter quartile range) for other variables. Thirty women reported 45 pregnancies beyond 20 weeks' gestation. Despite being older, these women, pre-delivery, had the lowest cardiac morbidity burden, compared to both male and female controls (OR = 3.25 (95% CI 1.44-8.35, p = 0.008 and OR = 2.59 (95% CI 1.14-6.70), p = 0.03). These differences were not present post-delivery. Median follow-up time post-delivery was 3.6 (1.2-7.5) years. Thrombus documentation and thromboembolic events were more common post-delivery, although differences were not significant in a propensity analysis model (adjusting for post-Fontan follow-up time, age and type of Fontan). There were no differences in arrhythmia, cardioversion, heart transplant, Fontan conversion or mortality between women post-delivery and either male or female controls.

The apparent increase in thromboembolic events post pregnancy requires further investigation in a larger group of women over a longer period of follow-up time. This may have potential implications for post-partum anticoagulation, and for future health outcomes.