Smoking during Pregnancy Linked to Birth Defects like Missing Limbs and Cleft Palate

After combing through data on 174 000 cases of birth malformations and data on 11.7 million control subjects (normal births) over the past 50 years, researchers at University College in London have finally completed the first ever major study on the specific birth defects associated with smoking during pregnancy.

According to the scientists, women who light up during pregnancy increase the risks for:

• Skull defects by 33%
• Children born missing one or more limbs by 26%
• Eye defects by 25%
• Cleft lip palate by 28%
• Gastrointestinal problems by 26%
• Clubfoot by 28%
• Gastroschisis by 50% (gastroschisis is a condition where parts of the stomach or intestines push through to the exterior of the skin)

And though smoking while pregnant is widely known to be harmful,  a surprising number of women continue to smoke through their pregnancy.

• In the UK, 17% of women smoke during pregnancy. Among mothers under 20 years of age, that percentage climbs to 45%
• In the US, 20% of women under the age of 25 smoke during pregnancy

Lead study author Professor Allan Hackshaw said that while literature on the harms of smoking during pregnancy have long focused on risks such as low birth weight or miscarriage, information on increased risks for  birth defects has been lacking - because no one really knew which birth defects were associated specifically with smoking.

With the publication of this study, he argues, "Now we have this evidence, advice should be more explicit about the kinds of serious defects such as deformed limbs, and facial and gastrointestinal malformations that babies of mothers who smoke during pregnancy could suffer from…There's still this idea among some women that if you smoke the baby will be small and that will make it easier when it comes to the delivery. But what is not appreciated is that smoking during pregnancy increases the risk of defects in the child that are life-long."

The full study results can be read in the today’s edition of the journal Human Reproduction Update.