This link might help explain numbness in Multiple Sclerosis:
http://www.mymsaa.org/about-ms/symptoms/numbness/

What I felt as numbness (altered sensation) was confirmed by a Neurological exam. I also experienced Paresthesia (pins/needles, buzzing/vibrations) from the waist down, including the girlie parts. I was unable to tell when I needed to urinate and had trouble leaking urine due to this.

Pregnancy and Multiple Sclerosis:

It is not uncommon to have a relapse (attack, flare-up, exacerbation) post-partum. Many women have relapses during pregnancy as well as post-partum, some women have no problems with their MS during or after pregnancy.