Document resource
Background Evidence on relapse activity in relapsing-remitting multiple sclerosis (RRMS) after assisted reproductive technology (ART) treatment differs. We investigated whether relapse activity increased after ART initiation.Methods Women with RRMS from the Danish MS Registry who underwent ART treatment from 1995 to 2018 were eligible. The annualised relapse rate (ARR) and corresponding 95% CI at 3 and 9 months post-ART initiation versus 12 months pre-ART were investigated using a negative binomial regression model. Analyses were stratified for live births within 12 months post-ART and disease-modifying therapy (DMT) use pre-ART. Clinical and demographic factors associated with relapse risk were identified.Results At ART initiation, 162 women, median age 33 years (IQR: 30–37), median Expanded Disability Status Scale score 1.5 (IQR: 1.0–2.5) were included; 55 (34.0%) were exposed to DMT. 27 relapses were recorded (ARR (95% CI) 0.17 (0.11 to 0.26)) at 12 months pre-ART; 7 relapses and 0.17 (0.08 to 0.36) at 3 months post-ART initiation, and 16 relapses and 0.13 (0.08 to 0.23) at 9 months post-ART initiation. When stratified by ART outcomes, relapse counts in subgroups became small. Women continuing DMT at ART initiation showed a statistically non-significant increase in ARR at 3 months post-ART.Conclusions Women with RRMS in Denmark did not, on average, have increased relapse activity at 3 and 9 months post-ART initiation compared with 12 months pre-ART. Women with disease activity pre-ART initiation may have a potentially elevated relapse risk post-ART.