Published case reports and series have provided information on the use of CFTR modulators during pregnancy in several populations: first, women with CF who are pregnant with infants not affected by CF, second, women with CF who are pregnant with infants affected by CF, and third, women without CF pregnant with a fetus with CF who take CFTR modulators off label to provide potential benefit to the fetus. This evidence concerns the gene CFTR and cystic fibrosis.