Pregnancy, Breast Feeding—and Risk of Relapse in Multiple Sclerosis

MS predominantly affects women of childbearing age. Research shows that pregnancy has observable effects on the frequency of relapse in patients with MS, and that breast feeding may also have an influence.

What is the effect of pregnancy on patients with MS?
Results from the seminal Pregnancy in Multiple Sclerosis (PRIMS) study published in 2004 showed an approximate 70% reduction in relapse rate during the third trimester of pregnancy.¹ However, that study also showed a 70% increase above background pre-pregnancy relapse rates for the first 3 months postpartum.

Does breast feeding have an impact on MS?
The impact of breast feeding on postpartum relapse risk has long been debated. Women with MS make a difficult choice between nursing and disease-modifying therapies (DMTs). However, a recent meta-analysis of all published studies showed that women with MS who decide to breast feed are almost half as likely to experience a postpartum relapse compared with women who do not.²

Are women with MS who intend to breast feed less likely to take medication?
Women who breast feed are significantly less likely to use DMTs before pregnancy. This suggests that the choice to nurse is associated with more benign pre-pregnancy disease activity. Further studies are needed to reach a robust conclusion as to whether breast feeding truly influences disease outcome for MS patients.

References:
1. Vukusic S, Hutchinson M, Hours M, et al. Pregnancy and multiple sclerosis (the PRIMS study): clinical predictors of post-partum relapse. [published correction appears in Brain. 2004;127(pt 8):1912]. Brain. 2004;127(pt 6):1353-1360.
2. Pakpoor J, Disanto G, Lacey MV, et al. Breastfeeding and multiple sclerosis relapses: a meta-analysis. J Neurol. 2012 May 23; [Epub ahead of print].