Patients with multiple sclerosis who underwent assisted reproduction experienced more than double the risk of relapse in the postpartum period, regardless of disease-modifying therapy during pregnancy, according to new research.

The study analyzed relapse rates among patients with multiple sclerosis (MS) who received assisted reproductive technology (ART) compared with those who conceived spontaneously. Findings indicated that the elevated risk persisted even when patients continued or discontinued disease-modifying therapy during pregnancy. These results underscore the importance of careful monitoring of patients with MS following assisted reproduction.

Before pregnancy, the annualized relapse rate (ARR) was 0.14; during pregnancy, the ARR was 0.13; and at 3 months postpartum, the ARR rose to 0.33. These rates represented rate ratios of 2.42 between before pregnancy and postpartum, and 2.46 between during pregnancy and postpartum. At 12 months postpartum, the ARR declined to 0.27. Compared with before pregnancy, the rate ratio was 2.02, and compared with during pregnancy, it was 2.06. “Relapse activity was more than two times higher 3 months postpartum than before and during pregnancy,” the authors summarized.

Of the cohort of 111 women, 77 (69%) were not exposed to disease-modifying therapy (DMT) during pregnancy, whereas 34 (31%) received DMT. In the treated group, 26 (77%) received injectable therapies and 8 (24%) received infusion therapies. ARRs before and during pregnancy in women who were not exposed to DMT during pregnancy were 0.09 and 0.21, respectively, at 3 months postpartum. In those who were exposed to DMT, the ARR was 0.24 before and during pregnancy. It increased to 0.59 at 3 months postpartum.

The increase in relapse rates postpartum did not reach statistical significance when stratified by treatment exposure. Across the full cohort, 99 women (89%) were relapse-free before pregnancy, 101 (91%) were relapse-free during pregnancy, and 88 (79%) were relapse-free in the year after birth. "The relapse data showed that the number of women experiencing no relapses decreased by approximately 10%...which means that 23 (21%) women showed at least 1 relapse postpartum," the authors wrote. They noted that this rate differed from a recent study in which "only 9.5% women reported an attack or a relapse within 12 months of receiving ART treatment."

After delivery, DMT use increased to 57% and more women initiated higher-efficacy therapies. The authors explained, "it is most likely that this reflects the perceived higher risk of relapse postpartum; accordingly, these patients are advised to start/switch to a higher-efficacy DMT." The median time to resume DMT after birth was 75 days.

Maternal age of at least 35 years and no DMT exposure before pregnancy were associated with higher odds of being relapse-free at 12 months postpartum (odds ratio [OR] age at least 35 years = 3.09; OR for no DMT exposure before pregnancy = 4.05).

Lead author Lene von Kappelgaard, of the Department of Neurology at Copenhagen University Hospital – Rigshospitalet in Denmark and fellow researchers followed the cohort of 111 women with MS who underwent ART treatment between 1995 and 2018 and gave birth. Using data from national health registries, they assessed ARR before pregnancy, during pregnancy, and postpartum at 3 and 12 months. The most common DMT used before and during pregnancy was interferon beta-1a.

The authors wrote that their "study can help with family planning decisions for women with MS undergoing ART treatment, such as the use of DMTs during pregnancy."

Disclosures can be found in the study.

Source: BMJ Neurology Open