Pregnancy rates and outcomes in women with cystic fibrosis in the UK: comparisons with the general population before and after the introduction of disease-modifying treatment, 2003–17

Objective To compare pregnancy rates and outcomes for women with cystic fibrosis in the UK with the general population and assess the effect of introduction of disease modifying treatment. Design A population-based longitudinal study, 2003-17Setting United Kingdom Population Women aged 15-44 years in the UK CF Registry compared to women in England and Wales. Methods We calculated pregnancy and live birth rates for the CF and England and Wales (E&W) populations. For women with CF we compared pregnancy rates before and after ivacaftor was introduced in 2013. We further used CF registry data to assess pregnancy outcomes for mothers with CF, and to assess the relationship between maternal pre-pregnancy lung function and nutritional status and child gestational age. Main outcome measures Pregnancy and live birth rates; and child gestational age. Results Of 3,831 women with CF, 661 reported 818 pregnancies. Compared E&W the pregnancy rate was 3.3 times lower in the CF population (23.5 vs. 77.7 per 1,000 women years); the live birth rate was 3.5 times lower (17.4 vs. 61.4 per 1,000 women years) with 70% of pregnancies in CF women resulting in live births; abortion rates were also lower (9% vs. 22%). Pregnancy rates increased post-ivacaftor for eligible women with CF, from 29.7 to 45.7 per 1,000 women years. There was no association between pre-pregnancy lung function/nutrition status and gestational age. Conclusions Pregnancy rates in women with CF are about a third of the rates in E&W with favourable outcomes, and increased for eligible women post-ivacaftor.