Pregnancy and birth outcomes in women with multiple sclerosis: Comparison of the RESPONSE study to the general French population

Background: Retrospective studies did not show strong evidence of higher risk of adverse neonatal or pregnancy outcomes in women with multiple sclerosis (MS) compared to general population, but there are contradictory data on prematurity, cesarean section, and small birthweight for gestational age (SGA). Methods: We compared pregnancy and birth outcomes in MS women included in RESPONSE, a French prospective cohort, with a recent survey (Enquête Nationale Périnatale (ENP)) describing leading indicators in perinatal epidemiology in France. Results: On 7 April 2023, 476 pregnancies (461 MS women, 482 expected newborns) from RESPONSE were available. The ENP study reported 12,723 women and 12,939 expected newborns in March 2021. MS patients were older (mean age 32.6 ± 4.4 vs. 30.9 ± 5.3 years, p < 0.001), with similar rate of cesarean (23.8% vs. 21.4%, p = 0.115) and use of locoregional analgesia (86.6% vs. 85.1%, p = 0.51). Preterm birth was less frequent (4.0% vs. 7.0%, p = 0.001). Birthweight of children from MS mothers was similar to general population (3240 ± 477.2 vs. 3264.5 ± 552.9 g, p = 0.22), with slightly more children with SGA (13.4% vs. 9.8%, p = 0.04). Conclusion: This prospective and contemporary comparison of pregnancy in MS women and the French population provides reassuring results. In the future, we need to assess the impact of disease-modifying treatment exposure during conception.