A provider survey assessing fetal impact of CFTR modulator use in males with CF during assisted and unassisted reproduction and partner pregnancy.

Background: Most males with cystic fibrosis (mwCF) are infertile but with CF transmembrane conductance regulator (CFTR) modulator-conferred benefits, more are utilizing assisted reproductive technologies (ART). Administration of normal human doses of modulators in animal reproductive models caused no genotoxicity; no human data exists. Potential health decline following modulator discontinuation makes the decision to withhold therapy during reproduction challenging.

Methods: From August-October 2021, international CF clinicians completed an anonymous questionnaire regarding mwCF who used modulators during reproduction.

Results: We received 42 surveys for mwCF with partner pregnancies. Forty of 42 mwCF utilized ART; 35 continued modulators during sperm retrieval and 40/42 during partner pregnancy. One of four males who discontinued modulators experienced clinical deterioration. First trimester miscarriages occurred in 11.9 % of partner pregnancies. No congenital anomalies were reported.

Conclusions: Use of CFTR modulators during reproduction and partner pregnancy in mwCF did not result in a higher-than-expected miscarriage rate nor congenital anomalies.