Iron deficiency is common in pregnant women. Both mother and baby need iron for developing blood supplies. A developing baby also stores iron for use after birth. This increases the mother's iron needs. It is practically impossible to get enough iron from food.
Doctors usually recommend supplements.
A good diet takes planning. No one can guarantee a baby will be born healthy and strong. Nothing offers greater benefits to mother and baby than good nutrition. Sources Brown, J.E. 1995. Christian, J.L. and J.L. Greger.