Women who breastfeed have a lower rate of multiple sclerosis (MS) relapses in the postpartum period compared to those who do not breastfeed or supplement it with regular formula, an analysis of published studies shows.
The findings suggest that breastfeeding protects women from postpartum relapses, but due to the observational nature of the studies included, a randomized clinical trial will be necessary to confirm this link.
The study, “Association Between Breastfeeding and Postpartum Multiple Sclerosis Relapses,” was published in the journal JAMA Neurology.
While many treatments reduce MS relapses, none is recommended for pregnant or breastfeeding women. As a result, relapse rates in the postpartum period increase, with up to 30% of women experiencing a relapse in the first three months after giving birth.
The findings effectively make women choose between breastfeeding or forgoing breastfeeding to resume their medications. But some studies actually suggest that breastfeeding may protect them from relapsing.
To find out how breastfeeding affects postpartum relapses, researchers at the the University of California reviewed data from 24 studies, published from 1980 to 2018, and encompassing a total of 2,974 women. All studies included a comparator group and were rated as having either moderate or serious risk of bias.
The definition of breastfeeding varied somewhat between studies. Nine studies required the breastfeeding group to do so exclusively without supplementing formula, generally for at least two months. Other studies included women with any history of breastfeeding in the breastfeeding group.
Overall, breastfeeding was associated with a 37% lower risk of postpartum relapse compared to women who did not breastfeed. This was similar to what was found when researchers restricted the analysis to studies with only a moderate risk of bias — 50% reduction in relapse risk among women who breastfed.
Despite the significant variance among the studies, likely because studies followed women for different periods of time (three to 12 months), had different pre-pregnancy relapse rates, and had different publication years, the consensus was there is benefit associated with breastfeeding.
The benefit of breastfeeding was stronger in studies that required exclusive breastfeeding (no supplementation by formula) for at least two months, although the benefit appeared to be present even in studies where the breastfeeding groups included any breastfeeding.
Researchers expressed concern regarding confounders (an “extra” variable that was not accounted for) in individual studies, as many did not adjust for common confounders such as prior MS disease activity. This is important because women with higher disease activity are more likely to defer breastfeeding and also are more likely to experience postpartum relapses.
However, the seven studies that accounted for such confounders still showed a protective effect of breastfeeding.
“This systematic review and meta-analysis suggests that breastfeeding is protective against postpartum relapses in women with MS,” researchers wrote, suggesting that the reduced relapse rate may be due to hormonal changes associated with breastfeeding.
Despite reduction in postpartum relapses with breastfeeding, the chance of relapses remains fairly high, highlighting the need to identify additional strategies to prevent relapses postpartum.
“We believe further study is required to evaluate the duration of benefit associated with breastfeeding and the safety of breastfeeding during treatment with DMTs, because treatment appears to be a key barrier to breastfeeding for women with MS,” researchers concluded.