Birth outcomes in newborns fathered by men with multiple sclerosis exposed to disease-modifying drugs

The aim of this study was to determine the incidence of births fathered by men with multiple sclerosis (MS) exposed to a disease-modifying drug (DMD) around the time of conception, and investigate the association between DMD exposure and birth outcomes in newborns of exposed and unexposed MS fathers.

Population-based databases in British Columbia (BC), Canada, (the BCMS database, Vital Statistics Birth Registry, Population Data BC Consolidation File/Census GeoData, BC PharmaNet and the BC Perinatal Database Registry) were linked in this retrospective cohort study (1996 to 2010). Multivariate models were used to examine the association between interferon-beta (IFNβ) or glatiramer acetate (GA) exposure (within 64 days prior to or at conception; i.e., the duration of spermatogenesis) with birth weight and gestational age of newborns.

Of 195 births fathered by men with relapsing-onset MS, 80 births (41%) were to fathers treated with a DMD before their child was born, with 53/195 (27%) exposed within 64 days prior to or at the time of conception. Of the 53 exposed births, 37 were to IFNβ and 16 to GA. Mean birth weight of IFNβ-exposed and GA-exposed newborns was similar to that of unexposed newborns (adjusted difference: -107 g for both, p>0.3). IFNβ-exposed and GA-exposed newborns also had comparable mean gestational ages relative to unexposed newborns (adjusted difference: -0.5 and -0.3 weeks, respectively, p>0.2).

About one in three would-be fathers with MS were exposed to IFNβ or GA around the time of conception; there was no compelling evidence to suggest that exposure was associated with either lower birth weight or gestational age.