Research suggests women who breastfeed may be protected from relapses of multiple sclerosis.
Scientists from Stanford University in California found just over half of the women studied with MS, the autoimmune condition, did not breastfeed after giving birth.
The study, which looked at 61 pregnant women, 32 of whom suffered from the disease, found that 87% of the women with MS who did not breastfeed had a relapse, compared with 36% of women with MS who breastfed for at least two months after their children were born.
The majority of women who chose not to breastfeed said they took the decision in order to re-start MS treatments.
Dr Annette Langer-Gould, the study's author, said: "Our findings call into question the benefit of choosing not to breastfeed or stopping breastfeeding early in order to start MS therapies.
"Larger studies need to be done on whether women should delay taking MS medications in order to breastfeed."
The findings will be presented at the annual meeting of the American Academy of Neurology in the spring.