Exclusive breastfeeding may be recommended after it was shown to reduce the risk of postpartum relapses.
Annette Langer-Gould, MD, PhD
Results from a prospective cohort of women with multiple sclerosis (MS) published in Neurology suggest that most women diagnosed with MS can have children without incurring an increased risk of relapses, and should be encouraged to breastfeed exclusively as this was found to reduce the risk of early postpartum relapses.1
The data showed that annualized relapse rates (ARRs) declined from 0.37 before pregnancy to between 0.14 and 0.07 (P <.0001) during pregnancy, and did not show disease activity rebound in the postpartum period. The researchers saw an ARR of 0.27 at 3 months postpartum and an ARR of 0.37 at 4 to 6 months, matching prepregnancy rates.
Patients included in the study who breastfed exclusively reduced the risk of early postpartum relapses (adjusted hazard ratio [HR] = 0.37, P = .0009).
“The findings from this study are consistent with our previously reported findings that exclusive breastfeeding seems to reduce the risk of postpartum relapse in the first but not second half of the postpartum year, acting like a treatment with a natural end date when the infant begins regular supplemental feedings, typically between 4 and 8 months of age,” Annette Langer-Gould, MD, PhD, lead investigator, regional lead for Clinical and Translational Neuroscience, Southern California Permanente Medical Group, and colleagues, concluded in a statement.
Langer-Gould and colleagues previously published data from this cohort involving the risk of postpartum relapse in patients with MS. In May 2019, she sat down with NeurologyLive to discuss the findings of that work, which she and her colleagues presented at the 2019 American Academy of Neurology Annual Meeting. Results from the study demonstrated that changes in MS diagnostic criteria and the availability of highly effective DMTs nearly nullified the risk of postpartum relapse for the majority of patients with MS.2
Electronic health records (EHRs) of 466 pregnancies among 375 women with MS and their infants at Kaiser Permanente Southern and Northern California between 2008 and 2016 were collected to assess whether the increased risk of postpartum relapses is modified by breastfeeding or DMTs. To account for disease severity, researchers used multivariate models.
Relapses were defined as the occurrence, reappearance, or worsening of symptoms of neurologic dysfunction lasting for 48 hours or more and needed to be documented by a treating physician. Symptoms that continued to occur within 1 month of each other were documented as the same relapse. Researchers calculated ARRs for the 2 years before pregnancy, each trimester during pregnancy, and each 3-month interval during the postpartum year to describe the natural history of MS.
Using survival analysis, investigators measured the association between breastfeeding and use of DMT in the postpartum period and the time to onset in the first postpartum relapse. Logistic regression models were used to model the predicted probability of exclusive breastfeeding or resuming DMTs within 2 months postpartum.
Of the 375 women included in the study, 83.5% (n = 389) had relapsing-remitting MS, 54.7% (n = 252) had at least 1 relapse within 2 years before pregnancy, 39.9% (n = 186) had MS-related disability, and 67.2% (n = 252) had suboptimally controlled disease at pregnancy onset. More specifically, 51.62% (n = 238) had been treated with a DMT within 1 year prior to pregnancy and 25.81% (n = 119) has used a DMT at the time of conception.
DMTs used within 1-year prior included interferon-beta, glatiramer acetate, dimethyl fumerate, natalizumab, rituximab, and fingolimod. The FDA recently approved updated prescribing information for interferon, including the removal of contraindications for pregnancy in early April 2020. Removal of the “Pregnancy Category C” classification came after the drug was shown to have no deleterious effect on pregnancy outcomes.
In addition to ARR returning back to normal prepregnancy rates at 4- to 6-months postpartum, women who breastfed exclusively and were excluded from the suboptimally controlled disease analysis demonstrated no rebound increase in the ARR in the first 3 months postpartum (0.56 and 0.47, 2 years before pregnancy and 0-3 months postpartum, respectively; P = .33).
Women who breastfed exclusively had fewer relapses (n = 15; 8.98%) in the first 6 months postpartum compared with those who breastfed nonexclusively (n = 41; 17.1%) or not at all (n = 15; 25.4%; P = .0054).
Resuming modestly effective DMTs had no effect on the risk of postpartum relapses during the first 6 months or the entire postpartum year (adjusted hazard ratio [HR], 0.89; 95% CI, 0.56—1.43; P = .63).
“Women who are considering foregoing breastfeeding to resume modestly effective DMTs should be informed that there is no evidence that these DMTs will reduce the risk of postpartum relapses and counseled about the general health benefits of breastfeeding,” Langer-Gould and colleagues concluded.
1. Langer-Gould A, Smith JB, Albers KB, et al. Pregnancy-related relapses in breastfeeding in a contemporary multiple sclerosis cohort. Neurology. 2020;94:1-e11. Doi: 10.1212/WNL.0000000000009374
2. 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