One of those reasons is meconium aspiration, a condition where babies inhale a substance called meconium in utero a bowel movement in the amniotic fluid.
Since then, review studies have found that overall rates of congenital malformations in infants exposed to lamotrigine "in utero" are relatively low (1-4%).
Babies exposed, in utero, can have deformities, delays in development, or seizures along with many other problems such as rash, fever, hepatosplenomegaly, anemia, and jaundice.