Smoking while pregnant can cause a baby to be born too early or have a low birth weight. Smoking also makes it more likely for a baby to have birth defects that affect the face, such as a cleft lip or cleft palate. There is also a connection between smoking during and after pregnancy and SIDS (sudden infant death syndrome).
Medical review: Nathan Cobb, MD, November 06, 2017
Centers for Disease Control. Smoking and Pregnancy. Accessed 11/7/2017.