Methotrexate use among men-association with fertility and the perinatal health of their children: a Swedish nationwide register study.

ABSTRACT

OBJECTIVE: To study the effect of methotrexate on male fertility and subsequent effects on their children, for which data are scarce and contradictory. DESIGN: Nationwide multiregister cohort study. SETTING: Not applicable. SUBJECT(S) All children born alive in Sweden between 2006 and 2014 and their fathers. Three cohorts were defined children to fathers with periconceptional methotrexate exposure (exposed cohort), children whose fathers stopped methotrexate intake ≥2 years before conception (previously exposed cohort), and children to fathers with no methotrexate exposure (control cohort). EXPOSURE(S) The father having at least one dispensed methotrexate prescription from pharmacies 0-3 months before conception, along with at least one more dispensed methotrexate prescription 0-12 months before conception (periconceptional exposure). Previously exposed cohort the father having no dispensed methotrexate prescriptions in the 2 years before conception, but having at least two dispensed prescriptions before that. MAIN OUTCOME MEASURES: Congenital anomalies (major and any; primary outcomes), preterm birth (PTB) and being small for gestational age (SGA; secondary outcomes), as well as need of intracytoplasmic sperm injection (ICSI) to achieve pregnancy (primary outcome in exposed cohort vs. controls, exploratory outcome in previously exposed cohort vs. controls). Outcomes were analyzed using logistic regression. RESULTS: A total of 223 children to fathers with periconceptional methotrexate exposure were identified, along with 356 children whose fathers stopped methotrexate intake ≥2 years before conception and 809,706 not methotrexate-treated controls. In children with fathers periconceptionally exposed to methotrexate, the adjusted and unadjusted odds ratios (95% confidence intervals) for major congenital anomalies were 1.1 (0.4-2.6) and 1.1 (0.4-2.4), any congenital anomalies 1.3 (0.7-2.4) and 1.4 (0.7-2.3), PTB 1.0 (0.5-1.8) and 1.0 (0.5-1.8), SGA 1.1 (0.4-2.6) and 1.0 (0.4-2.2), and conception by use of ICSI 3.9 (2.2-7.1) and 4.6 (2.5-7.7). Use of ICSI was not increased among fathers who stopped methotrexate intake ≥2 years before conception, having adjusted and unadjusted odds ratios 0.9 (0.4-1.9) and 1.5 (0.6-2.9). CONCLUSION: This study suggests that paternal periconceptional methotrexate use does not increase risk of congenital anomalies, PTB, or SGA in the offspring but may temporarily reduce fertility.