Use of CFTR modulators in pregnancy: new information for neonatal, paediatrics and midwifery teams

Cystic fibrosis (CF) is common, multisystem, life-limiting genetic condition, predominantly in the Caucasian population. There have been recent advances in the management of CF, in particular in the last 5 years following approval of cystic fibrosis transmembrane conductance regulator (CFTR) protein modulators by the National Health Service (NHS) for use in people with CF (pwCF). Traditionally, almost 40% of female patients with CF (fwCF) and over 95% of male patients with CF (mwCF) have issues with subfertility or infertility. CFTR modulators have transformed the lives of pwCF who have the specific genetic variants that respond to the treatment. Women taking CFTR modulators, particularly highly effective CFTR modulators (elexacaftor, tezacaftor and ivacaftor), have shown resolution of infertility and successful pregnancies without fertility treatment. At present male patients taking CFTR modulators have not shown improvement in infertility. Unplanned pregnancies are on the increase in fwCF. fwCF have had significantly improved general health when taking CFTR modulators. Subsequently many fwCF now become pregnant and choose to continue their pregnancies to term, with positive outcomes. Clinical and biochemical status of the newborn babies with CF, who are born to fwCF on CFTR modulators, can be very different when compared with the other babies with CF who are unexposed to CFTR modulators in utero. New opportunities bring new challenges. This review highlights how infants exposed to CFTR modulators in utero can be affected, and suggests how they should be monitored.