Fetal impact of cystic fibrosis transmembrane conductance regulator modulator use during assisted and natural reproduction and partner pregnancy in men with cystic fibrosis

ABSTRACT

Background: Increasing availability of highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulator therapy (HEMT) has improved the quality of life and long-term prognosis for many people with CF. Thus, more people with CF are considering parenthood. Almost all menwith CF (MwCF) are infertile because of congenital bilateral absence of the vas deferens (CBAVD). Based on CF animal models, CBAVD occurs early in gestation and is unlikely to be reversible using HEMT, but assisted reproductive techniques (ARTs) can enable MwCF to father children using the sperm in their testes. Animal reproductive models suggest no HEMT teratogenicity, and the amount of exposure of the fetus to HEMT via absorption of seminal fluid through the vaginal wall is predicted to be negligible, although to ensure no sperm exposure to HEMT, the life span of sperm would require MwCF to discontinue CFTR modulators for approximately 3 months before ART. Because abrupt discontinuation of CFTR modulators may result in health decline, MwCF and their providers must consider all potential risks. There are no published data in MwCF regarding use of HEMT during conception and partner pregnancy. Method(s) Beginning in August 2021, CF center staff in the United States, United Kingdom, and Australia completed a two-page anonymous questionnaire regarding MwCF who used CFTR modulators during ART (sperm retrieval and in vitro fertilization) or natural conception with subsequent partner pregnancy. Result(s) Providers have submitted 34 surveys for MwCF on CFTR modulators whose partner became pregnant after use of ART (n = 32) or natural conception (n = 2). The median age of the samplewas 32 (range 24- 43). Fifteen were homozygous for F508del, median percentage predicted forced expiratory volume in 1 second was 76% (range (22-111%), and median body mass index was 24 kg/m2 (range 18.5-32.1). Twenty-three were taking elexacaftor/tezacaftor/ivacaftor. The median time that MwCF were taking CFTR modulators before partner conception was 18 months (range 0-82). One newly diagnosed man initiated HEMT after sperm retrieval. Four MwCF stopped CFTR modulators before sperm retrieval, one of whom experienced pulmonary decline. None of the 19 MwCF whose condom use during pregnancy was known used condoms. Fetal complications in partners of MwCF included three first-trimester miscarriages, two* COVID, two breech presentation, two* vaginal bleeding, and one vasa previa. None of the complications were deemed definitively related to use of CFTR modulators. One MwCF experienced testicular infection after sperm retrieval#. Postpartum complications included three# infants with hypoxemia requiring neonatal intensive care unit stay, three maternal blood loss, one forceps delivery, and one caesarean section. No congenital anomalies were reported for any infant. (*/# overlap). Conclusion(s) Use of CFTR modulator therapy during partner conception and pregnancy in 34 MwCF has not resulted in higher-than-expected miscarriage rates or congenital anomalies. Providers should consider the risk to the health of MwCF combined with the lack of teratogenicity in animal reproductive models and limited safety data in the human fetus before discontinuing CFTR modulators before ART or natural partner conception. Survey collection is ongoing;results will be updated for presentationCopyright © 2022, European Cystic Fibrosis Society. All rights reserved