Cystic fibrosis

Cystic fibrosis (CF) is a common genetic disease occurring in about 1 in 1500 white people and 1 in 17,000 black people. It is an autosomal recessive disorder affecting the CF transmembrane conductance regulator protein, a chloride ion channel.

Although fertility may be impaired due to thickened cervical mucous, ovarian dysfunction (22) and malnutrition, about 50% of women with CF are able to conceive naturally (23). Pregnancy in CF patients may be associated with adverse fetal and maternal outcomes, but case series now demonstrate good maternal and neonatal outcome in women with CF, with appropriate management (24, 25). Pregnancy does not appear to negatively impact CF prognosis (26). The rate of hospitalization and outpatient visits increases during pregnancy but the rate of decline in lung function is not higher in women who have been pregnant. FVC less than 50% predicted and the presence of pul­monary hypertension are associated with an increased risk.

Complications during pregnancy include gestational diabetes and increased perinatal mortality, related predominantly to preterm de­livery occurring spontaneously or due to maternal complications of CF. A review of 680 pregnant women enrolled in a United States registry demonstrated that survival was better in this group than in 3327 matched control patients with CF (26). Women with CF who became pregnant had less severe disease based on FEVi and body weight. However, even after adjustment for severity of illness, preg­nancy did not appear to shorten survival. Nevertheless, most studies suggest that risk of pregnancy stratifies according to severity of ill­ness, and prepregnancy counselling is essential to mitigate maternal and fetal risk. Reports from centres with significant experience dem­onstrate good outcome with normal birth weight and near-term ges­tation, although women with more severe respiratory disease tend to have lower-weight babies (24, 25).

Management of the pregnant woman with CF requires a multidis­ciplinary team approach with close attention to nutrition and glucose control (27). Hypoglycaemia may occur postpartum. Exacerbations of lung disease require early aggressive therapy, with consideration of the potential fetal toxicity of antibiotics such as aminoglycosides and quinolones. Genetic testing of the partner and genetic counsel­ling is obviously also essential.