Pregnancy and neonatal outcome following in utero exposure to CFTR modulators: A multicentre prospective case series

Clinical data regarding in utero exposure to CFTR modulators (CFTRm) are limited. Our objective was to describe pregnancy outcomes, with particular attention to malformations, and neonatal adverse outcomes among prospective pregnancies exposed to CFTRm, using clinical data from the French Network of Pharmacovigilance Centres and the Teratology Information Service CRAT (Centre de Reference sur les Agents Tératogènes).

An observational multicentre study was performed on the reported CFTRm-exposed pregnancies with an expected delivery date between 2018 and 2023. We described prospective cases, defined as pregnancies for which the outcome was unknown and no adverse prenatal outcome was diagnosed at the time of first contact with the healthcare professional. Major congenital anomalies (MCA) were classified according to criteria of the European Registration of Congenital Anomalies and Twins.

Fifty-eight pregnancies were included, mainly exposed to elezacaftor/tezacaftor/ivacaftor throughout pregnancy (87.9 %).There were 53 live births, four spontaneous abortions and one medical abortion (fetus with cystic fibrosis). One atrial septal defect and one acrania/anencephaly were observed, resulting in a MCA prevalence of 3.4 % (IC95 %: 0.4- 11.9). There were three neonatal adverse outcomes without a clearly identified cause: one sudden massive alveolar hemorrhage, one delayed respiratory distress and one delayed transient hypotonia. No cataract was found in children who had an ophthalmological examination (n = 10).

This prospective case series - the largest to date - does not suggest a high rate of MCA or neonatal adverse outcomes in CFTRm-exposed pregnancies. Further studies including long-term follow-up of in utero exposed children are needed to confirm these findings.