What are the risks of multiple sclerosis relapse during the postpartum period?

Updated: Aug 20, 2019
  • Author: Carmel Armon, MD, MSc, MHS; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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In the first 3 months after delivery, MS relapses appear to increase in frequency and severity, though they return to their prepregnancy level afterward. Because this increase is offset by the decrease in MS activity during pregnancy, pregnancy does not seem to change the overall course of the disease from the perspective of disability.

Patients with relatively severe disease before and during pregnancy appear to be at greatest risk for relapses in the postpartum period. No other single predictor was identified. In these patients, therapies that may reduce the likelihood of relapses should be considered.

In an early study, Millar et al evaluated 45 pregnancy-associated relapses in 170 pregnancies and reported that 39 women experienced relapses in the postpartum period. [46]

Worthington et al observed that relapses were most frequent during the first 6 months after pregnancy and that fewer relapses than expected occurred in postpartum months 6-24. [40] The investigators conducted a 3-year prospective study of the level of disability, severity, and distribution of relapses in 15 women with MS diagnosed before pregnancy, using 22 nulliparous women with the disease as control subjects.

Salemi et al retrospectively determined that the relapse rate increased in the first 3 months after delivery, though the change was not statistically significant. [42]

In a study of 338 women, Korn-Lubetzki et al found that postpartum exacerbations of MS were 3 times more common in patients than in control subjects. [41]

In the Pregnancy in Multiple Sclerosis (PRIMS) study, the postpartum relapse rate increased by approximately 70% and then returned to the prepregnancy rate. [43] Neither breastfeeding nor epidural analgesia affected the rate of relapse or progression of disability.

In a study of 227 women enrolled in the PRIMS study for an additional 2 years after delivery, Vukusic et al reported that women with increased disease activity in the year before pregnancy and those who had additional relapses during pregnancy were most likely to have postpartum relapses. [47] The investigators did not find a single predictor (including breastfeeding or epidural anesthesia) that helped in accurately identifying women with MS who would have relapses in the first 3 months after delivery.

In the second postpartum year, the relapse rate was similar to that of the year before pregnancy. [47] In addition, pregnancy, delivery, and the postpartum period did not ultimately increase overall disability from MS.

Roullet et al also found that relapses were most severe during the postpartum period, as reflected by a change of more than 1 point in the Expanded Disability Status Scale (EDSS) score. [44] Worthington et al confirmed this result, finding that relapses were most severe during the first 6 months after pregnancy. [40] No overall significant differences in the severity of relapses were found between patients and control subjects, as measured by using the median EDSS score after the pregnant and postpartum periods.

Epidural anesthesia did not appear to affect the rate of relapse or progression of disability in either the PRIMS trial [43] or its 2-year extension. [47] This finding suggests that despite anecdotal reports suggesting otherwise, epidural analgesia is safe and does not carry a significant risk when it is used for deliveries in patients with MS.

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