The impact of pregnancy on mortality and lung function in cystic fibrosis patients

As the lifespan of people with cystic fibrosis (pwCF) improves, more individuals are pursuing pregnancy. Historically, pregnancy was not recommended in this population; however, more recent evidence has revealed inconsistent survival and lung function outcomes. Our aim was to assess the differences in survival and lung function between pregnant and never-pregnant pwCF and to provide updated recommendations for contemporary clinical practice.

In this retrospective matched parallel cohort study, data was collected from the American Cystic Fibrosis Foundation Patient Registry (CFFPR) from 1999 to 2019. 1743 adult pwCF with a reported pregnancy were matched with 1743 never-pregnant patients. Regression models were developed to estimate associations between patient characteristics, pregnancy, and outcomes. The primary endpoint was the probability of survival comparing pregnant and never-pregnant pwCF, while the secondary endpoint was lung function over time.

The study cohort (n = 3486) had a mean age of 24.96 years. There was no significant difference in survival probabilities between pregnant and never-pregnant pwCF (56.2 %, CI^{95 %}: 51.3 %-61.5 % vs. 55.8 %, CI^{95 %}: 52.1 %-59.7 %, p = 0.5). The multivariable time-dependent Cox regression analysis resulted in a significantly lower mortality hazard rate for pregnant cohorts (HR:0.78, p < 0.01). There was no significant association between pregnancy and lung function over time (0.99, p = 0.21).

Pregnancy was associated with a reduced hazard of death compared to never-pregnant pwCF and did not demonstrate a significant impact on lung function. Therefore, pregnancy should not be generally discouraged in pwCF and clinicians should evaluate pregnancy risks and benefits on an individualized basis.