Annette Langer-Gould, MD, PhDAnnette Langer-Gould, MD, PhD
Trends in earlier diagnosis of multiple sclerosis (MS), rates of exclusive breastfeeding, and a plethora of readily available and effective disease-modifying therapies (DMTs) are likely behind a reduced risk for MS relapse in the postpartum period.

Results of the population-based study, led by Annette Langer-Gould, MD, PhD, of Kaiser Permanente Southern California, are scheduled to be presented at the 2019 American Academy of Neurology Annual Meeting, May 4-10, 2019 in Philadelphia.

Women with MS have long been cautioned to carefully plan their pregnancies, as study results collected nearly 20 years ago suggested that women faced a greater risk for relapse in the postpartum period.

In an effort to refresh the data with a contemporary cohort of patients, Langer-Gould and colleagues prospectively collected complete EHR data for 375 women with MS with 466 documented pregnancies from 2008 through 2016.

“The women in our population-based study had milder MS than in studies conducted 20-plus years ago, which is best explained by the multiple revisions of the MS diagnostic criteria,” Langer-Gould told NeurologyLive. “Today’s MS diagnostic criteria allow not only for an earlier diagnosis of MS, but also an increase in the diagnosis of milder forms of MS. For most women diagnosed with MS today who want to have children, the availability of DMTs appears to have no particular influence on their risk of relapse during pregnancy or the postpartum period.”

Among the cohort, 38% of patients had not received any treatment in the year prior to conception; 14.6% had clinically isolated syndrome; and 8.4% relapsed during pregnancy. During the postpartum year, 26.4% of patients experienced a relapse, 87% breastfed, 35% breastfed exclusively, and 41.2% resumed DMTs.

As expected, the investigators observed a decline in annualized relapse rates from pre-pregnancy (0.39) to during pregnancy (0.14-0.07; P <.0001); however, they did not observe any rebound disease activity in the postpartum period. Overall, annualized relapse rates were down slightly in the first 3 months of the postpartum period (0.27, P =.02), and returned to pre-pregnancy rates at 4 to 6 months postpartum (0.37).

Notably, patients who exclusively breastfed saw a reduced risk for postpartum relapse (adjusted hazard ratio 0.58; P =.01), yet those who resumed modestly effective DMTs saw no effect on relapse risk (P =86).

In an interview with NeurologyLive, Langer-Gould further explained the significance of their findings.

NeurologyLive: Do you feel that the availability and quality of contemporary DMTs has had a hand in altering disease course in this population? 

Annette Langer-Gould, MD, PhD: For the small number of women who have highly active disease prior to pregnancy and would have met MS diagnostic criteria 20 years ago, the availability of highly effective DMTs, including natalizumab, fingolimod, rituximab, alemtuzumab, and most recently ocrelizumab has made it possible for their disease to become really well-controlled, allowing them the opportunity to choose to have children as per their wishes; something they may not have considered possible otherwise.

Your study accounted for a high rate of breastfeeding; based on the results, should breastfeeding (exclusive or for a minimum amount of time) be encouraged among women with MS in the postpartum period? 

Yes, women with MS should be encouraged and supported to breastfeed exclusively for at least 2 months, possibly longer. Previous studies—including our own previously published studies—left some doubt about this as women with more active disease were much less likely to choose to breastfeed exclusively. However, in this very large, population-based study, this was no longer the case; disease activity prior to delivery did not significantly influence breastfeeding choices and even those women with more active MS prior to or during pregnancy had a lower risk of postpartum relapses if they breastfed exclusively for at least 2 months compared to those women who did not breastfeed at all.

As there seems to be a lot of misinformation and fear circulating among pregnant women or women planning to become pregnant with MS, what advice would you give to clinicians to share with their patients? 

Having MS should not factor into family planning decisions for most women diagnosed with MS today. They have a lower risk of relapse during pregnancy and their risk of relapse in the postpartum year is the same as if they had not gotten pregnant regardless of whether they are on MS DMTs or not. Breastfeeding exclusively appears to be the best way to minimize their risk of a postpartum relapse in addition to providing many additional health benefits for the child and mother. 
 
For those women who require treatment with natalizumab or fingolimod, they too can get pregnant but this will take some advanced planning as their disease can return, sometimes with a vengeance even during pregnancy, when these drugs are stopped. We did not specifically address this question in this study as most women with MS today have milder disease, but other studies have.  

For more coverage of AAN 2019, click here. 
REFERENCE
Langer-Gould A, Smith J, Albers K, et al. Pregnancy-related relapses in a large, contemporary multiple sclerosis cohort: no increased risk in the postpartum period. Presented at: 2019 American Academy of Neurology Annual Meeting. May 4-10, 2019; Philadelphia, PA. Abstract S6.007