Breastfeeding associated with a reduced risk of relapse in women with multiple sclerosis

Women with multiple sclerosis who breastfeed exclusively for at least two months appear less likely to experience a relapse within a year after their baby's birth, according to a report posted online today that will appear in the August print issue of Archives of Neurology, one of the JAMA/Archives journals.

"Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that predominantly affects women in their childbearing years," the authors write as background information in the article. "It is well known that women with MS have fewer relapses during pregnancy and a high risk of relapse in the postpartum period." Medications used to treat MS by modifying the immune system—including interferon beta and natalizumab—are not recommended for use during pregnancy or breastfeeding. Therefore, women with MS who give birth must choose between nursing and resuming MS treatment.

Annette Langer-Gould, M.D., Ph.D., then of Stanford University School of Medicine, Stanford, Calif., and now of Kaiser Permanente Southern California, Pasadena, and colleagues studied 32 pregnant women with MS and 29 pregnant women without MS who were the same age. The participants were interviewed about clinical, menstrual and breastfeeding history during each trimester and again two, four, six, nine and 12 months after they gave birth. In addition, neurological examination findings were collected from the physicians of women with MS.

More healthy women than women with MS breastfed (96 percent vs. 69 percent), and among those who did breastfeed, women with MS were more likely to begin daily formula feedings within two months after birth (30 percent compared with 18 percent). "Of the 52 percent of women with MS who did not breastfeed or began regular supplemental feedings within two months postpartum [15 women], 87 percent [13 women] had a postpartum relapse, compared with 36 percent [five women] of the women with MS who breastfed exclusively for at least two months postpartum [14 women]," the authors write. "Women with MS and healthy women who breastfed exclusively had significantly prolonged lactational amenorrhea [absence of menstruation], which was associated with a decreased risk of relapse in women with MS."

Most women with MS who did not breastfeed or supplemented with formula feedings (11 women, or 73 percent) reported that their primary reason for doing so was to take medications for MS. Eight of them (53 percent) resumed MS medications within two months after birth.

"Why breastfeeding might be beneficial in humans with an autoimmune disease like MS has not been studied," the authors write. "Studies of immunity and breastfeeding, while plentiful, are predominantly focused on breast milk content and health benefits to the infant. Little is known about maternal immunity during breastfeeding."

The results suggest that women with MS should be encouraged to breastfeed exclusively for at least the first two months after birth instead of resuming medications, the authors note. "Our findings call into question the benefit of foregoing breastfeeding to start MS therapies and should be confirmed in a larger study," they conclude.