Maternal snuff use and smoking and the risk of oral cleft malformations--a population-based cohort study.
OBJECTIVE
To determine if maternal use of snuff (containing high levels of nicotine, low levels of nitrosamines and no combustion products) is associated with an increased risk of oral cleft malformations in the infant and whether cessation of snuff use or smoking before the antenatal booking influences the risk.


METHODS
A population-based cohort study was conducted on all live born infants, recorded in the Swedish Medical Birth Register from 1999 through 2009 (n = 1 086 213). Risks of oral clefts were evaluated by multivariate logistic regression analyses (using adjusted odds ratios, with 95% confidence intervals [CI]).


RESULTS
Among 975 866 infants that had information on maternal tobacco use, 1761 cases of oral clefts were diagnosed. More than 50% of the mothers who used snuff or smoked three months prior pregnancy stopped using before the antenatal booking. Almost 8% of the mothers were smoking at the antenatal booking and 1,1% of the mothers used snuff. Compared with infants of non-tobacco users, the adjusted odds ratios (95% CI) of any oral cleft for infants of mothers who continued to use snuff or to smoke were 1.48 [1.00-2.21] and 1.19 [1.01-1.41], respectively. In contrast, in infants of mothers who stopped using snuff or stopped smoking before the antenatal booking, the corresponding risks were not increased (adjusted odds ratios [95% CI] were 0.71 [0.44-1.14] and 0.88 [0.73-1.05], respectively).


CONCLUSIONS
Maternal snuff use or smoking in early pregnancy is associated with an increased risk of oral clefts. Infants of mothers who stopped using snuff or stopped smoking before the antenatal booking had no increased risk of oral cleft malformations. Oral snuff or other sources of nicotine should not be recommended as an alternative for smoke-cessation during pregnancy.
Department of Women's and Children's Health at Karolinska Institutet, Neonatal Research Unit, Karolinska University Hospital Solna, Stockholm, Sweden.
Anna
A
Gunnerbeck
Department of Women's and Children's Health at Karolinska Institutet, Neonatal Research Unit, Karolinska University Hospital Solna, Stockholm, Sweden ; Department of Medicine, Clinical Epidemiology Unit at Karolinska Institutet, Stockholm, Sweden.
Anna-Karin
AK
Edstedt Bonamy
Department of Medicine, Clinical Epidemiology Unit at Karolinska Institutet, Stockholm, Sweden ; Department of Women's and Children's Health at Uppsala University, Uppsala, Sweden.
Anna-Karin
AK
Wikström
Department of Medicine, Clinical Epidemiology Unit at Karolinska Institutet, Stockholm, Sweden.
Fredrik
F
Granath
Department of Women's and Children's Health at Karolinska Institutet, Neonatal Research Unit, Karolinska University Hospital Solna, Stockholm, Sweden.
Ronny
R
Wickström
Department of Medicine, Clinical Epidemiology Unit at Karolinska Institutet, Stockholm, Sweden.
Sven
S
Cnattingius
D002971:Cleft Lip / Q000209:etiology*; D002972:Cleft Palate / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014030:Tobacco, Smokeless / Q000009:adverse effects*