Yikes. Pretty important. A lot of the weakness is probably directly related to low iron!
Osteoporosis also... so much more prevalent in women because of childbirth and not having enough calcium. So... yeah. She should probably keep taking whatever pre-natal vitamin she was taking (assuming she WAS taking a pre-natal with folic acid?!) and add in Omega vitamins too.
But that's just my opinion I guess. But my opinion is regurgitated from my family doctor and daughter's pediatrician... for whatever that's worth.