What is your goal ferritin level in pregnancy?  

The goal is really to avoid iron deficiency and <30 best defines this state. Need to be wary of circumstances such as inflammation where the ferritin level may be falsely high even in the setting of reduced body iron. 

Agree with Dr. @Phatak. Because of the mother's need to expand red blood cell mass and the iron needs of the fetus as the pregnancy progresses (these combine for a need of about 4 mg absorbed daily), would try to stay well ahead of 30.