BJOG. 2007 Jun;114(6):699-704.
The influence of maternal smoking habits on the risk of subsequent
stillbirth: is there a causal relation?
H?berg L, Cnattingius S.
Department of Medical Epidemiology and Biostatistics, Karolinska
Institutet, Stockholm, Sweden. lovisa.hogberg.055@student.ki.se
Objectives:
Maternal smoking has previously been associated with risk
of stillbirth. If women who quit smoking reduce their risk of
stillbirth, the hypothesis of a causal association would be
supported.
Design:
Prospective cohort study.
Setting:
Nationwide
study in Sweden. POPULATION: All primiparous women who delivered
their first and second consecutive single births between 1983 and
2001, giving a total number of 526,691 women. METHOD: A
population-based Swedish study with data from the Medical Birth
Registry, the Immigration Registry and the Education Registry.
Logistic regression analyses were used to estimate odds ratios,
using 95% confidence intervals. MAIN OUTCOME MEASURE: Stillbirth in
the second pregnancy.
Results:
Compared with nonsmokers in both
pregnancies, women who smoked during the first pregnancy but not
during the second do not have an increased risk of stillbirth (OR
1.02; 95% CI 0.79-1.30), while corresponding risk among women who
smoked during both pregnancies was 1.35 (95% CI 1.15-1.58).
Conclusion:
The result supports that maternal smoking during
pregnancy is causally associated with stillbirth risk. Smoking is a
preventable cause of stillbirth, and smoking interventions is an
important issue in antenatal care.
