Brain MRI activity during the year before pregnancy can predict long-term clinical worsening in patients with Multiple Sclerosis

Background: Pregnancy has been observed to reduce the frequency of relapses in Multiple Sclerosis (MS) patients, but the relapse risk tends to increase during the early post-partum period. Increased pre- and post-partum disease activity may predict a poor long-term prognosis. This study aimed to evaluate the correlation between magnetic resonance imaging (MRI) activity during the year before pregnancy and long-term clinically meaningful worsening in Expanded Disability Status Scale (EDSS). Methods: This observational, retrospective, case–control study included 141 pregnancies in 99 females with MS. Statistical analyses were used to evaluate the correlation between MRI activity during the year pre-pregnancy and post-partum clinical worsening during a 5-year follow-up. Clustered logistic regression was used to investigate the predictors of 5-year clinically meaningful worsening in EDSS (lt-EDSS). Results: We found a significant correlation between an active MRI pre-pregnancy and lt-EDSS (p = 0.0006). EDSS pre-pregnancy and lt-EDSS were also significantly correlated (p = 0.043). Using a multivariate model, we predicted which females would not experience long-term clinical deterioration by a stable MRI pre-pregnancy (92.7% specificity; p = 0.004). Conclusions: An active MRI pre-conception is a strong predictor of lt-EDSS and a higher annual relapse rate during the follow-up period, regardless of whether the female had clinical evidence of disease activity prior to conception and delivery. Optimizing disease control and achieving imaging stability prior to conception may reduce the risk of long-term clinical deterioration.