Study author Dr. Emilio Portaccio and colleagues conducted a prospective study of 298 women recruited from 21 Italian MS centers and followed up their pregnancies from 2002 to 2008. During this time, 302 out of 423 pregnancies resulted in full-term delivery, and follow ups continued for at least one year after delivery. About 34 percent of the mothers breastfed for at least two months after delivery, while the remaining mothers breastfed for less than this or not at all and were considered as not breastfeeding. During the 12 months following delivery, 37 percent of the mothers had one relapse and 6.6 percent had two or more.
Using a statistical tool to look at several measures at once to see which have the strongest influence on relapse rate after pregnancy, they found that "the only significant predictors of postpartum relapses were relapses in the year before pregnancy ... and during pregnancy."
The data indicated women who had relapses in the 12 months leading up to their pregnancy were 50 percent more likely to have a relapse after delivery than women who did not have a relapse in the year before pregnancy. And women who had relapses during pregnancy were more than twice as likely to have a relapse after delivery as the women who did not experience relapses during pregnancy.
This was after taking into account influencing factors like age at onset of MS, age at pregnancy, duration of the disease, level of disability, and exposure to drugs, including any MS drugs. There was nothing to suggest breastfeeding worsened the relapse rate.
The researchers also suggested the link between breastfeeding and lower risk of relapses after pregnancy that previous studies have reported may "simply reflect different patient behavior, biased by the disease activity."
Sourcing: MS Foundation