Figure 3.

The association between number of pregnancies and age at progressive multiple sclerosis onset. Higher number of pregnancies was associated with older age at progressive multiple sclerosis onset (mean ± SD) with a dose-dependent effect: nulliparous females (para 0) had the youngest age at progressive multiple sclerosis onset, females with para 1–3 had an intermediate age at progressive multiple sclerosis onset and females with para ≥4 had the oldest age at progressive multiple sclerosis onset