Background

The effects of pregnancy on multiple sclerosis (MS) inflammatory activity are not well described in women with moderate to severe disabilities.

Objective

To quantify the peripartum annualized relapse rate (ARR) in women with MS with an Expanded Disability Status Scale (EDSS) ≥ 3.

Methods

We performed a retrospective cohort study of 85 pregnancies in 74 subjects with preconception EDSS ≥ 3. We quantified peripartum ARR and tested for risk factors predictive of peripartum relapses, postpartum brain magnetic resonance imaging activity (new T2 or gadolinium-enhancing lesions), and disability worsening.

Results

There were 74 live births, with a 56% operative delivery rate. In subjects with relapsing-remitting MS, ARR decreased to 0.11 during the third trimester of pregnancy compared to 0.59 in the year preconception and increased to 1.22 in the 3 months postpartum. Women with a higher preconception EDSS had higher odds of postpartum relapses and clinically significant worsening of disability as compared to subjects with a lower EDSS.

Conclusions

Moderately to severely disabled women with MS have a lower risk of relapse during pregnancy as compared to preconception, followed by a marked increase postpartum. Further studies are needed to identify ways to reduce peripartum inflammatory activity and disability progression in women with MS with moderate to severe disability.