A review of 101 studies concludes that smoking during pregnancy increases the risk of certain types of severe birth defects, including defects of the heart, face, limbs, feet and eyes. CNN reports that the study is the first comprehensive, systematic review to look at which birth defects are associated with smoking.

The researchers write in the journal Human Reproduction Update that these specific defects should be included in public health educational information to encourage more women to quit smoking before or early on in pregnancy.

They note that maternal smoking during pregnancy is an established risk factor for miscarriage, stillbirth, low birthweight, premature births and small fetuses. Yet despite the risks, an estimated 14 percent of women smoke during pregnancy in the United States.