Better prognosis of multiple sclerosis in patients who experienced a full-term pregnancy

We conducted a longitudinal prospective study to evaluate the long-term effect of pregnancy on the progression of multiple sclerosis (MS).

Parous female MS patients were extracted from the database of Isfahan multiple sclerosis society (IMSS). Through comparing the annual relapsing rate during a mean of 4 years before pregnancy versus a mean of 6 years after delivery, MS progression influenced by the pregnancy was analyzed.

102 female patients were included in our study. The mean annual relapsing rate 4 years prior to pregnancy was significantly higher than at the subsequent 6 years after delivery (1.06 vs. 0.45, p < 0.001). In addition, the annual relapsing rate in years prior to pregnancy was significantly higher than each trimester of gestation (p < 0.001). Furthermore, there was a 2.2-fold increased risk of having a relapse in individuals who had experienced more relapses prior to pregnancy, and a 0.8-fold decreased in the risk of having more relapses with older age at the onset of MS.

Although the course of MS was deteriorated 3 months after delivery, it was not statistically significant comparing annual relapsing rates during the years prior to pregnancy. Moreover, the rate of disease progression slowed down in the 6-year period monitored after delivery.