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Smoking during pregnancy has been linked with orofacial clefts (OFCs)
in many studies. However, most studies have not been able to assess
the link between maternal smoking and specific cleft
characteristics, such as bilateral clefts.
Orofacial clefts include conditions such as cleft lip and cleft
palate.
CDC studied the link between maternal smoking, exposure to
environmental tobacco smoke, and cleft lip with or without cleft
palate (CLP) and cleft palate only (CPO).
- Researchers looked at data from the National Birth Defects
Prevention Study (NBDPS) for infants born during the period
October 1997–December 2001 and their mothers. . The NBDPS is an
ongoing, CDC-funded study in nine states of environmental and
genetic risk factors for major birth defects.
- Maternal smoking from 1 month before conception through the
third month of pregnancy (periconceptional period) was linked
with CLP. It was more strongly linked with bilateral CLP. A
weaker link was found for CPO.
- Mothers who smoked heavily during the periconceptual period
were about twice as likely to have an infant with an OFC than
were women who did not smoke. The link with heavy smoking was
strongest for bilateral CLP and CLP that occurred with other
birth defects. CPO with Pierre Robin sequence was also linked
with heavy maternal smoking.
- Among mothers who did not take folic acid during the
periconceptional period, the link with smoking was stronger than
among mothers who did take folic acid.
- There was no link between CLP or CPO and exposure to
environmental tobacco smoke alone.
- This study confirmed the modest link between smoking and
OFCs that has been reported many times, and it identified the
phenotypes most strongly affected. These results give health
professionals and researchers an opportunity to prevent some
clefts by reducing the number of women who smoke during
pregnancy.
Honein MA, Rasmussen SA, Reefhuis J, Romitti P, Lammer EJ, Sun L,
et al. Maternal smoking, environmental tobacco smoke, and the risk
of oral clefts. Epidemiology. 2007;18(2):226–33.
Date:
January 14, 2008
Content source: National Center on Birth Defects and Developmental
Disabilities
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