Brain MRI activity during the year before pregnancy can predict post-partum clinical relapses.

BACKGROUND There are fewer multiple sclerosis (MS) relapses during pregnancy, although relapse risk increases in the early post-partum period, as has been predicted by pre-pregnancy or pregnancy disease activity in some studies. OBJECTIVE The aim of this study was to evaluate the correlation between magnetic resonance imaging (MRI) changes in the year before pregnancy and the relapse rate in the year post-partum. METHODS An observational retrospective case-control study included 172 pregnancies in 118 females with MS. Statistical analyses were used to evaluate the correlation between MRI and post-partum relapses. Clustered logistic regression was used to investigate the predictors of early post-partum relapses. RESULTS We found a significant correlation for an active-MRI pre-pregnancy and relapses in the first 3 months post-partum (p < 0.001). Expanded Disability Status Scale (EDSS) pre-pregnancy and relapses in the first 3 months post-partum were also significantly correlated (p = 0.009). Using a multivariate model, we predicted which women will not experience post-partum relapse by EDSS and by an active-MRI pre-pregnancy (96.7% specificity; p < 0.001). CONCLUSION An active-MRI pre-pregnancy is a strong and sensitive predictor of early post-partum relapse, regardless of whether the woman had clinical evidence of disease activity prior to conception and delivery. This finding could provide clinicians with a strategy to minimize post-partum relapse risk in women with MS planning pregnancy.