Whoever assaults a pregnant woman and inflicts substantial bodily harm on an unborn child who is subsequently born alive may be sentenced to imprisonment for not more than five years or to payment of a fine of not more than $10,000, or both.
As used in this section, "substantial bodily harm" includes the birth of the unborn child prior to 37 weeks gestation if the child weighs 2,500 grams or less at the time of birth. "Substantial bodily harm" does not include the inducement of the unborn child's birth when done for bona fide medical purposes.