To report pregnancy and infant outcomes among females with multiple sclerosis (MS) receiving ocrelizumab (OCR).

The US prescribing information advises contraception with OCR and for 6 months after the last infusion; however, pregnancies may occur in this interval.

Pregnancies from the Roche safety database were analyzed. Maternal OCR exposure was defined as ≥1 infusion; potential in utero exposure was defined as ≤3 months prior to the last menstrual period or during pregnancy. Fetal death was termed spontaneous abortion (SA) if <22 complete gestational weeks (GW), or stillbirth (SB) if later. Live births (LB) were preterm if <37 complete GW. Major congenital anomalies (MCAs) were classified via EUROCAT 1.5.

As of July 12, 2023, 3,253 cumulative MS pregnancies were received; 2,446 were reported prospectively, 800 retrospectively, seven unspecified. Of the 2,446 prospective pregnancies, 855 (35.0%) had in utero exposure, 575 (23.5%) had no in utero exposure and 1,016 (41.5%) had unknown exposure. Outcomes were known for 1,145 prospective pregnancies: 957 (83.6%) were LB (586 [61.4%] full-term, 81 [8.5%] preterm, 288 [30.2%] unknown GW); 14 (1.2%) ectopic pregnancies (EP); 58 (5.1%) elective terminations (ET); 115 (10.0%) SA; 1 (<0.1%) SB. Of 855 prospective pregnancies exposed in utero, 512 had known outcomes: 431 (84.2%) LB; 4 (0.8%) EP; 38 (7.4%) ET; 38 (7.4%) SA; 1 (0.2%) SB. Twelve (1.3%) MCAs occurred in prospective LB; seven had in utero exposure. Infant outcomes, including 1-year outcomes (n=226), effect of potential breastmilk exposure (n=126) and known B cell levels (n=68) will also be presented.

This is the largest dataset of pregnancy outcomes for an anti-CD20 therapy in MS. In utero exposure to ocrelizumab did not increase the risk of adverse pregnancy or infant outcomes compared with previous reports as well as epidemiological background of both MS and general population.