Maternal smoking tied to oral birth defects

California, United States, November 6: A recent study found that pregnant women who smoke during pregnancy double the risk of giving birth to babies with a cleft lip and/or palate birth defect as compared to mothers who do not smoke. This risk increases with the amount of cigarettes that the woman smokes.

The scientists measured exposure to smoke in 500 mums-to-be during pregnancy (between 2003 and 2005) and found that children born to mothers who smoked while pregnant were nearly 2.5 times more likely to have oral cleft defects, clefts that occur in the lip and palate (roof of the mouth).

This is the first ever study which measured the cotinine level, a metabolite of nicotine, in the blood of expecting moms while various past studies relied solely on pregnant women reporting their smoking habits which were not so reliable.

'Cleft palate' and 'Cleft lip' are birth defects, which mean during the development of the baby in the womb between the sixth and 11th week, the parts of the lip and/or palate fail to join together properly. This can affect the way the child's face looks.

The word cleft means ‘split’ between two things, hence cleft lip means ‘split in the upper lip’ and cleft palate means ‘split in the roof of the mouth.’ One or 2 in every 700 to 800 babies are affected by a condition known as cleft lip or cleft palate. Approximately 6,800 babies in the US alone are born with oral-facial clefts each year, clefts that are not accompanied by other birth defects.

Gary M Shaw, PhD, research director at the March of Dimes (a U.S. health charity) California in Oakland, U.S., said, "This research is the first time we've been able to measure something – in this case cotinine – and determine the risk of smoking during pregnancy for oral-facial birth defects."

Babies with oral cleft palate have more feeding difficulties, ear infections, hearing loss, dental problems (small teeth, missing teeth, extra teeth, or crooked teeth) and speech difficulties than normal infants. Surgery often can repair these birth defects.

Dr Jennifer L Howse, president of the March of Dimes, said, "The message to women is simple and clear: Don't smoke during pregnancy or even if you are considering becoming pregnant."

Dr Howse added if expecting women can be helped to stop smoking, more babies will be given a healthy start in life. According to the March of Dimes, state and federal officials must include smoking cessation programs in the maternity care.

The study "Mid-Pregnancy Cotinine and Risks of Orofacial Clefts and Neural Tube Defects" was conducted by Shaw's California group along with colleagues from Norway, The Netherlands, and Texas, USA.

The findings of the study appear in the Wednesday's online issue of the Journal of Paediatrics.

Apart from birth defects, children of mothers who smoke during pregnancy can have cardiovascular or urogenital abnormalities and in general one can say babies of mothers who smoke are not as healthy as babies of non smokers.

If a mother smokes during pregnancy, her child’s risk for Sudden Infant Death Syndrome, also known as SIDS or cot death also increases. A report found that babies of mothers who smoked cigarette both during and after pregnancy had two to three times higher risk of dying from SIDS than that of infants born to mothers who did not smoke.