The effect of pregnancy on survival in women with cystic fibrosis

Study objectives: Patients with cystic fibrosis (CF) are currently living to their fourth decade and are making reproductive decisions. Information concerning the reproductive health of women with CF has been limited to small or single-center studies. Design: We conducted a matched parallel-cohort study to assess the impact of pregnancy on the survival of women with CF. Participants: A parallel-cohort study included all women > 12 years of age who were enrolled in the US Cystic Fibrosis Foundation National Patient Registry from 1985 to 1997. Measurements and results: Six hundred eighty of the 8, 136 women in the cohort became pregnant. These 680 women were matched on an index year to 3,327 control women with CF. At the inception of entry into the cohort, women who reported pregnancy were more likely to have had a higher percentage of predicted FEV1 (67.5% predicted vs 61.7% predicted, respectively; p < 0.001) and a higher weight (52.9 vs 46.4 kg, respectively; p < 0.001). Using Kaplan-Meier survival curves, the 10-year survival rate in pregnant women (77%; 95% confidence interval [CI], 71 to 82%) was higher than in those women who did not become pregnant (58%; 95% CI, 55 to 62%). A separate analysis, matching pregnant patients on FEV1 percent predicted, age, Pseudomonas aeruginosa colonization, and pancreatic function, obtained similar results. Using Cox proportional hazard modeling to adjust for baseline age, FEV1 percent predicted, weight, height, and pulmonary exacerbation rate per year, pregnancy was not associated with an increase risk of death. Pregnancy was not harmful in any subgroup including patients with FEV1 < 40% of predicted or diabetes mellitus. Conclusions: Women with CF who became pregnant were initially healthier and had better 10-year survival rates than women with CF who did not become pregnant. After adjustment for the initial severity of illness, women who became pregnant did not have a significantly shortened survival.