Why do babies have cleft lips and how are they detected?

A cleft lip is a birth defect that develops early on in the pregnancy. It happens when there is not enough tissue in the lip area to join together. Doctors don't know exactly what causes cleft lips. Most say it could be genetic since there's a great chance of a baby having a cleft lip if someone in the family has it. A cleft lip could also be potentially caused by environmental factors like viruses and chemicals, as well as medication that the mum took during pregnancy, like drugs used for athritis and psoriasis, and acne (if drug contains Accutane). A cleft lip can be detected during a prenatal ultrasound, when you're around 20 weeks. Hope this helps!