Women with multiple sclerosis can be reassured that should they choose to become pregnant, they are generally not at any greater risk of adverse pregnancy or birth outcomes than are similar women without the disease, according to a retrospective cohort study.

The findings should have important clinical implications for this group of patients, because about three-quarters of people with MS are women and the clinical onset of the disease most often occurs in early adulthood, just when many are considering starting a family, Mia L. van der Kop and her coauthors wrote.

Studies have shown that one-fifth to one-third of women with MS bear children after disease onset.

Ms. van der Kop and her coinvestigators at the University of British Columbia, Vancouver, linked clinical data from the British Columbia (BC) MS clinics’ database with outcomes data from the BC Perinatal Database Registry (BCPDR) to examine whether maternal MS was associated with adverse neonatal and delivery outcomes and what factors, if any, were associated with risk (Ann. Neurol. 2011 June 27 [doi: 10.1002/ana.22483]).

Of 7,056 female patients who were registered at one of the four MS clinics in BC from 1980 through 2008, the investigators found links for 321 women (432 births) with laboratory-supported or clinically definite MS whose with births occurred between April 1998 and March 2009 in the BCPDR. These births were compared with 2,975 births from a random sample of 2,958 women in the general population who were frequency-matched for age, local health authority, and delivery year. The clinics’ database is estimated to capture 80% of the MS population in BC. Patients’ names and dates of birth were used to confirm the accuracy of linkage.

A greater proportion of births in the MS group were to women who were nulliparous, primigravid, hypertensive, or had smoked during pregnancy. A greater proportion of births in the comparison group were to mothers with diabetes during pregnancy and a history of multiple therapeutic abortions.

Maternal MS was not associated with assisted vaginal delivery (odds ratio, 0.78) or cesarean section (OR, 0.94). The proportion of elective cesarean sections was similar in both the MS and comparison groups (18.6% vs. 16.1%, respectively), and the indication for cesarean delivery did not differ between groups. Delivery outcomes were not associated with either an older age at MS onset or longer duration.

The degree of disability in MS mothers was not significantly associated with higher odds of a cesarean section or an assisted vaginal delivery, compared with women with a normal neurologic exam.

Among nulliparous women, there was no significant difference in the median duration of the second stage of labor between those with MS and those in the comparison group. Duration of the second stage of labor was not associated with age at MS onset.

This study was supported by the Canadian Institutes of Health Research. All of the authors reported having significant ties to disease advocacy- or government-based groups, research groups, or pharmaceutical companies.