Breast-feeding Linked to Low Relapse Risk in MS

Pauline Anderson

September 01, 2015

Women with multiple sclerosis (MS) who breast-feed their baby exclusively for at least 2 months have a significantly lower risk for relapse during the first 6 months postpartum compared with those who breast-feed only sometimes or not at all, results of a large prospective study suggest.

When these women introduce supplemental feeding after 6 months and resume menstruation, disease activity returns, researchers report.

Taken together, the findings suggest that exclusive breast-feeding "acts like a modestly effective treatment with a natural end date," the authors conclude.

"Women with MS who want to breastfeed should be supported to do so," lead author Kerstin Hellwig, MD, Department of Neurology, St Josef Hospital, Ruhr-University, Bochum, Germany, told Medscape Medical News.

Their findings were published online August 31 in JAMA Neurology.

Detailed Data

The study included women with relapsing-remitting MS enrolled in the nationwide German MS and pregnancy registry. Data on relapses during the first 6 months postpartum for 72 patients were included in a recently published meta-analysis and presented at the 2013 American Academy of Neurology meeting. The current analysis included 201 women.

For each participant, researchers obtained a detailed breast-feeding history with the exact date of introduction of supplemental feedings, defined as formula, or other liquid or solids, and the date of return to menses. They defined relapses as the appearance, reappearance, or worsening of symptoms of MS neurologic dysfunction lasting for at least 24 hours that could not be explained by an infection, fever, or other cause.

About 90% of the women in the study received disease-modifying therapy (DMT) before pregnancy. Their prepregnancy relapse rate was relatively low.

The investigators divided the women into three groups based on their breast-feeding and DMT use: exclusive breast-feeding without resumption of DMT within 30 days of delivery (the reference group); breast-feeding with some supplemental feeding or no breast-feeding and not resuming DMT within 30 days; and breast-feeding with some supplemental feeding or no breast-feeding and resuming DMT within 30 days.

The researchers applied standard multivariable adjustment and propensity score matching to account for the fact that women with more severe disease might be more likely to choose not to exclusively breast-feed. These are two well-recognized statistical models, said Dr Hellwig.

Of the 201 women, 59.7% intended to breast-feed exclusively for 2 or more months, and of these 3.3% stopped exclusive breast-feeding owing to a relapse. Another 19.4% did not breast-feed and 20.9% combined breast-feeding with supplemental feedings.

Women who breast-fed exclusively were older and less likely to have received DMT before or at the time of conception. They were also less likely to have had a relapse during pregnancy and had a later return of menses compared with women who did not breast-feed exclusively. And they were significantly less likely to restart DMT during the first 30 days postpartum.

Compared with 24.2% of exclusive breast-feeders, 38.3% of nonexclusive breast-feeders had a relapse within 6 months. They had a significantly increased risk for relapse during this period (hazard ratio [HR], 1.80; 95% confidence interval [CI], 1.09 - 2.99; P = .02).

After adjustment for age, pre-pregnancy relapse frequency and relapse during pregnancy or using the propensity score method to account for additional factors associated with breast-feeding exclusively, the magnitude of the effect was similar and still statistically significant (HR, 1.70; 95% CI, 1.02 - 2.85; P = .04).

Supplemental Feeding

Most exclusive breast-feeders introduced supplemental feedings in the second half of the postpartum year. After that, 39.2% had a relapse compared with 46.9% of the nonexclusive breast-feeders. And during the second half of the postpartum year, 22.5% of the exclusive breast-feeders had their first postpartum relapse compared with 8.6% of those who did not breast-feed exclusively.

"Thus, during the entire postpartum year, the risk of having at least 1 relapse was almost identical between those 2 groups" (exclusive breast-feeding, 46.6%; nonexclusive breast-feeding, 46.9%), the authors write.

Earlier return of menses was also associated with a higher risk for relapse in the first 6 months. This, said Dr Hellwig, "confirms" the results of supplemental feedings on relapses. "Return of menses is quite a good proxy for the duration of exclusive breast-feeding."

Dr Hellwig pointed out that hormonal changes leading to anovulation might play a key role in reduced risk for relapse.

"Exclusive breast-feeding is hormonally totally different from not breast-feeding at all and from some breast-feeding. Only exclusive breast-feeding is introducing anovulation and lactational amenorrhea, but as soon as you introduce one or two supplemental feedings, the menses returns and the ovarian cycle starts again."

A "real strength" of the study was the detailed collection of data — directly after the birth of the baby and then every 3 months — on the exact date when the first meal was introduced to the infant, and the exact day when menses returned, said Dr Hellwig.

Some women are advised to resume MS medication very soon after the birth of their baby and some are afraid that not doing so might bring on a relapse, said Dr Hellwig.

"And that's okay; not everyone can breast-feed exclusively," she said. "I wouldn't recommend breast-feeding to someone who doesn't want to breast-feed because it's something which needs a little work and perhaps a little help from a midwife."

Researchers would like to see if the relapse rate stays relatively low for women with MS who continue to breast-feed. Dr Hellwig notes that the World Health Organization (WHO) recommends breast-feeding exclusively for 6 months.

And Dr Hellwig and her colleagues would like to compare breast-feeding with highly active drugs in terms of postpartum relapses. She noted that even first-line MS therapies reduce relapses by only 30%.

Reached for a comment, Lily Jung Henson, MD, chief of neurology, Piedmont Healthcare, Atlanta, Georgia, said the paper is consistent with what MS experts have come to believe over the past decade about the safety and benefit of breast-feeding in women with MS.

"But in addition, the study suggests that there is a difference between exclusive breast-feeding versus adding supplements, which is something that most people would not think about differentiating," said Dr Jung Henson.

"Although further study would be helpful, this finding would certainly influence a lot of women who are on the fence about whether to breastfeed and if so, for how long."

Dr Hellwig is supported by the German Research Council (Deutsche Forschungsgemeinschaft) and has received speaker honoraria from Biogen Idec, Teva Pharma, sanofi-aventis, Novartis Pharma, Bayer Healthcare, Genzyme, and Merck Serono. Dr Jung Henson has disclosed no relevant financial relationships.

JAMA Neurology. Published online August 31, 2015. Abstract


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