Pregnancy and fetal outcomes after interferon-β exposure in multiple sclerosis

Neurology. 2010 Nov 16;75(20):1794-802. doi: 10.1212/WNL.0b013e3181fd62bb.


Objective: To assess pregnancy and fetal outcomes after in utero exposure to interferon-β (IFNβ) in all pregnancies occurring in women with multiple sclerosis (MS) during the study period, with a specific focus on the risk of spontaneous abortion.

Methods: In this cohort study, data were gathered through a standardized, semi-structured interview. Patients who discontinued IFNβ less than 4 weeks from conception (exposed) were compared with those who had discontinued the drug at least 4 weeks from conception or who were never treated (not exposed). Possible confounders were handled through multivariate analyses adjusted for propensity score (PS).

Results: We collected data on 396 pregnancies in 388 women, 88 classified as exposed (mean exposure 4.6 ± 5.8 weeks). IFNβ exposure was not associated with an increased risk of spontaneous abortion (PS-adjusted odds ratio [OR] 1.08, 95% confidence interval [CI] 0.4 to 2.9, p = 0.88), although it was associated with both lower baby weight (PS-adjusted β -113.8, p < 0.0001) and length (PS-adjusted β -1.102, p < 0.0001). Proportion of spontaneous abortion in exposed patients fell within the range expected for the Italian population in the same period. IFNβ exposure (PS-adjusted OR 2.11, 95% CI 1.18 to 3.78, p = 0.012) and cesarean delivery were the only predictors of preterm delivery. In the exposed group, we did not observe any significant fetal complications, malformations, or developmental abnormalities over a median follow-up of 2.1 years.

Conclusions: Our findings point to the relative safety of IFNβ exposure times of up to 4 weeks and can assist neurologists facing therapeutic decisions in women with MS with a pregnancy plan.

Publication types

  • Comparative Study
  • Multicenter Study

MeSH terms

  • Abortion, Spontaneous / chemically induced*
  • Abortion, Spontaneous / etiology
  • Abortion, Spontaneous / physiopathology
  • Adult
  • Cohort Studies
  • Female
  • Fetal Diseases / chemically induced
  • Fetal Diseases / diagnosis
  • Fetal Diseases / physiopathology
  • Fetal Weight / drug effects
  • Follow-Up Studies
  • Humans
  • Infant, Newborn
  • Interferon-beta / adverse effects
  • Interferon-beta / therapeutic use*
  • Male
  • Multiple Sclerosis / complications
  • Multiple Sclerosis / drug therapy*
  • Pregnancy
  • Pregnancy Outcome / epidemiology
  • Prospective Studies


  • Interferon-beta