April 10, 2019— If you're a woman with multiple sclerosis (MS) and you're thinking about getting pregnant, you may have heard that your MS symptoms are likelier to worsen right after your baby is born. Now a preliminary study casts doubt on this decades-old theory. It suggests that the increased risk of a disease flare-up may not exist after all.
The study involved data on 375 women who had relapsing-remitting MS. That's the most common form of MS. In it, the symptoms of MS come and go. Each flare-up, or relapse, is followed by a period of remission.
MS is an autoimmune disease that attacks the central nervous system. It is most common in women of childbearing age. MS can be managed with medicines. Women in this study stopped taking their medicines during pregnancy.
Among the study's findings:
- A year after giving birth, 26 percent of the women had an MS relapse.
- The women's chances of having a relapse fell during pregnancy and didn't climb back up right after birth. Not only that, but in the first three months after having a baby, the risk of a relapse actually remained slightly lower than it was before the women were pregnant.
- By four to six months after giving birth, the women saw their risk of a relapse return to near their pre-pregnancy levels.
The researchers also looked at treatments for MS. In the year after giving birth, 41 percent of the women started taking their modestly effective disease-modifying medicines (such as interferon-betas and glatiramer acetate) again. Resuming these drugs did not appear to affect their risk of a relapse.
Breastfeeding: A protective effect?
The researchers also looked at the risk of having an MS relapse in relation to breastfeeding. They found that:
- Women who fed their babies only breast milk for at least two months were about 40 percent less likely to have a relapse than women who did not breastfeed their babies.
- Women who fed their babies breast milk plus formula were just as likely to have a relapse as those who did not breastfeed.
The high rate of exclusive breastfeeding is one of the factors that could help explain the low rate of relapse after giving birth, one of the researchers said.
One thing to note: Very few women in this study were taking drugs that treat more severe MS. These drugs include natalizumab and fingolimod. Women who stop taking these drugs to become pregnant may have severe relapses, the research team noted. For that reason, they said future studies should look at these women.
The researchers will present their study at the American Academy of Neurology's 71st annual meeting.