Rituximab, MS, and pregnancy

Depicted are the number of RTX infusions (blue bars) and MS relapses (orange line) that occurred during the study period among pregnancies ending in live births (n = 37) who received at least 1 RTX infusion before conception or during the first trimester (Tri). The study period encompasses the 12 months before conception, pregnancy, and the 12 months postpartum divided into 3-month intervals. Four women relapsed during the study period after initiating RTX. Only 2 women relapsed during pregnancy or the postpartum period, 1 during the 2nd trimester of pregnancy who received her most recent RTX infusion 3 months before conception (R1), and one between 6 and 9 months postpartum who received her most recent RTX infusion 3.9 months before conception (R2). Two additional women had relapses after RTX initiation in the 12 months before conception; 1 woman 10.3 months before conception who received her most recent RTX infusion 4.5 months before relapse, and another woman who relapsed 8.5 months before conception, 0.9 months after her first RTX infusion. Most pregnancies (n = 25, 68%) occurred within 6 months of their most recent RTX infusion. Increasing numbers of RTX infusions over the study period are denoted by increasingly lighter shades of blue. The darkest blue shading indicates the first RTX infusion during the study period of which most (n = 32) occurred during the 12 months before conception. The woman who is depicted with her first RTX infusion occurring 0–3 months postpartum had her last RTX infusion more than 12 months before conception. Two additional women received their last RTX infusion >12 months before conception; neither had resumed RTX before the end of the study period. Twenty-one women received their first ever infusion of RTX in the year before pregnancy and 2 shortly after their last menstrual period. Twelve women received 2 infusions, 6 received 3 infusions, 4 had 4 infusions, and 3 had 5 RTX infusions (lightest shade of blue) during the study period. The number of women at risk are those who had received at least 1 infusion of RTX before pregnancy (or shortly after conception). In the postpartum period, the number of women at risk also incorporates the duration of the follow-up. No women have been lost to follow-up, but 11 women are less than 12 months postpartum. RTX = rituximab.