The exact causes of orofacial clefts are unknown, but experts believe that both genetics and environmental factors contribute, according to the Centers for Disease Control and Prevention. Gene mutations and the mother's environment, diet and medications during pregnancy may combine to cause these defects.
Women who smoke or who suffer from diabetes are more likely to give birth to children with orofacial clefts, states the CDC. Medications used to treat epilepsy, such as topiramate or valproic acid, are also linked to these deformities when ingested during the first trimester. An ultrasound can diagnose most forms of cleft lip and cleft palate, although some forms, including submucous cleft palate and bifid uvula, may evade diagnosis for years.