Pregnancy in Multiple Sclerosis: A Portuguese cohort study

Pregnancy in Multiple Sclerosis (MS) has been a controversial issue, without international standardized treatment recommendations. The goal of our study was to evaluate the clinical course of MS during pregnancy and the respective therapeutic options, obstetrical outcomes and breastfeeding data.

This was a retrospective study including women with a diagnosis of relapsing-remitting MS at least one year before pregnancy. Three periods were evaluated: one year prior to pregnancy, pregnancy and one year postpartum. Information acquired included demographic and disease activity data, treatment options, and obstetrical and breastfeeding data.

From a cohort of 1134 patients and 777 women, we included 127 pregnancies in 97 women (111 deliveries of a live infant, 11 spontaneous abortions, 3 fetal deaths and 2 voluntary abortions). The annualized relapse rate (ARR) decreased during pregnancy, mainly in the third trimester (prior to pregnancy 0.6 ± 0.8 vs. during pregnancy 0.3 ± 0.6, p = 0.006). There were no significant changes in the ARR in the year after delivery compared to baseline (0.6 ± 0.8 vs. 0.6 ± 0.8, p = 0.895). Patients with relapses in the postpartum period had a shorter disease duration at conception (5.4 ± 3.9 vs. 7.4 ± 4.7; p = 0.029) and breastfed less (53.5% vs. 72.1%, p = 0.046). In the multivariate analysis, relapses during pregnancy predicted postpartum relapses (OR = 4.9, p < 0.005). Neither the previous use of disease modifying therapy (DMT), given to 80.2% of women, nor breastfeeding, caesarean delivery (CD) or epidural analgesia (EA) had an impact on the presence of postpartum relapses. Compared to baseline, the Expanded Disability Status Scale (EDSS) increased in pregnancy and the postpartum period (1.6 ± 0.7 vs. 1.7 ± 0.9 vs. 2.1 ± 1.0, p < 0.001). CD was performed in 43.3% of patients, mainly because of fetal-pelvic incompatibility (35.7%) and EA was performed in 63.9%. The most frequent complications were restriction of fetal growth (4.5%) and gestational diabetes mellitus (3.6%). Concerning newborns, 6.4% had birth asphyxia and 6.1% low birth weight. No malformations were registered.

Despite a reduction in the relapse rate during pregnancy, the presence of relapses during pregnancy predicted postpartum relapses, with impact on disability. DMT appeared to have no influence on clinical or obstetrical outcome. MS did not have a deleterious effect on the pregnancy course. CD and EA were safe procedures, with a tendency towards CD in MS patients, compared to Portuguese women in general. Breastfeeding did not influence MS activity.