Epub: Hughes et al. Predictors and dynamics of postpartum relapses in women with multiple sclerosis. Mult Scler. 2013 Oct 9.
BACKGROUND: Several studies have shown that pregnancy reduces MS relapses, which increase in the early postpartum period. Postpartum relapse risk has been predicted by pre-pregnancy disease activity in some studies.
OBJECTIVE: To re-examine effect of pregnancy on relapses using the large international MSBase Registry, examining predictors of early postpartum relapse.
METHODS: An observational case-control study was performed including pregnancies post-MS onset. Annualised relapse rate (ARR) and median Expanded Disability Status Scale (EDSS) scores were compared for the 24 months pre-conception, pregnancy and 24 months postpartum periods. Clustered logistic regression was used to investigate predictors of early postpartum relapses.
RESULTS: The study included 893 pregnancies in 674 females with MS. ARR (standard error) pre-pregnancy was 0.32 (0.02), which fell to 0.13 (0.03) in the third trimester and rose to 0.61 (0.06) in the first three months postpartum. Median EDSS remained unchanged. Pre-conception ARR and disease-modifying treatment (DMT) predicted early postpartum relapse in a multivariable model.
CONCLUSION: Results confirm a favourable effect on relapses as pregnancy proceeds, and an early post-partum peak. Pre-conception DMT exposure and low ARR were independently protective against postpartum relapse. This novel finding could provide clinicians with a strategy to minimise post-partum relapse risk in women with MS planning pregnancy.