Influence of snuff and smoking habits in early pregnancy on risks for stillbirth and early neonatal mortality.
BACKGROUND
Prenatal exposure to Swedish snuff (including nicotine and other components in grinded tobacco) is reported to increase stillbirth risk, but the effect of snuff on early neonatal mortality is unknown. Prenatal smoking exposure is associated with risks for both stillbirth and early neonatal mortality. We aimed to study if women who quit using snuff or quit smoking before first antenatal visit reduce their risks.


METHODS
In a nationwide study of 851,371 singleton births in Sweden from 1999 to 2010, we used multiple logistic regression models to examine associations between cessation or continuation of snuff use or smoking and risks for stillbirth (at 28 weeks or later) and early neonatal mortality (death during the first week of life).


RESULTS
Compared with nontobacco users, snuff users and smokers in early pregnancy had increased risks for stillbirths, and adjusted odds ratios (ORs), with 95% confidence intervals (CI), were 1.43 (1.02-1.99) and 1.59 (1.40-1.80), respectively. Women who stopped using snuff or stopped smoking before first visit to antenatal care had no increased risks. Compared with nontobacco users, smokers had an increased risk for early neonatal mortality (adjusted OR = 1.37 [95% CI 1.11-1.71]). Women who stopped smoking and snuff users in early pregnancy had no increased risks of early neonatal mortality.


CONCLUSIONS
Both snuff and smoking influence risk for stillbirth, and women who stop using snuff or smoking have a similar stillbirth risk as nontobacco users. Smoking but not snuff use influences risk for early neonatal mortality.
Department of Medicine, Clinical Epidemiology Unit, Karolinska Institutet, Stockholm, Sweden;
Sachiko
S
Baba
Anna-Karin
AK
Wikström
Olof
O
Stephansson
Sven
S
Cnattingius
D005260:Female; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D016015:Logistic Models; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects*; D050497:Stillbirth / Q000453:epidemiology*; D013997:Time Factors; D014030:Tobacco, Smokeless / Q000009:adverse effects*