Abstract
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.