Maternal smoking and causes of very preterm birth

Abstract

Background.Smoking increases the risk of preterm birth. The present study was made to elucidate the relation of smoking to causes of very preterm birth. Methods. In a case-control study on all very preterm births in two regions of Stockholm 1988-1992, prospectively collected data were extracted from antenatal and delivery records on smoking, other maternal characteristics, pregnancy complications, and causes of preterm birth. Cases were live single births with a gestational age of 32 weeks and 0 days, and controls were live singletons delivered at 37 weeks or later (n ¼ 295, respectively). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with logistic regression.Results. Compared with non-smokers, adjusted ORs of very preterm birth among moderate smokers (1-9 cigarettes per day) and heavy smokers (!10 cigarettes per day) were 1.4 (95% CI 0.8-2.4) and 2.9 (95% CI 1.5-5.7), respectively. Compared with non-smokers, risk of preterm labor was increased among moderate and heavy smokers [ORs 1.9 (95% CI 1.0-3.6) and 2.6 (95% CI 1.1-1.6), respectively]. These risks remained essentially unchanged in women without an identifiable cause of preterm labor ('idiopathic preterm labor'). Smoking was also associated with dose-dependent increases in risks of preterm birth due to preterm premature rupture of membranes and late pregnancy bleedings. There was no association between smoking and risk of very preterm birth caused by hypertensive diseases. Conclusions.Smoking increases the risk of very preterm birth caused by preterm labor (including idiopathic preterm labor), preterm premature rupture of membranes, and late pregnancy bleedings.

Maternal tobacco use and extremely premature birth – a population‐based cohort study

“…In 2002, maternal smoking was attributable to 5–8% of very and moderately preterm births in the US . There is a dose‐response relationship between smoking and risk of preterm birth, and the risk seems to increase with decreasing gestational age . However, few studies have investigated the association between smoking and extremely preterm birth …”

Biological determinants of spontaneous late preterm and early term birth: a retrospective cohort study

“…In line with this model and others similar to it, 8,9 the focus of most previous aetiological studies has been on very preterm birth (<34 weeks) or preterm birth in general (<37 weeks). [10][11][12] Therefore, the extent to which spontaneous births closer to full term are associated with these pathological processes is currently unknown.…”

The effects of maternal smoking during pregnancy on offspring outcomes

“…There is considerable evidence supporting the hypothesis that offspring of mothers who smoke during their pregnancies have impaired fetal growth, pre-term birth and lower birth weight infants (Conter et al, 1995; D'Onofrio et al, 2003; Knopik et al, 2005; Bada et al, 2005; Salihu et al, 2005; Kyrklund-Blomberg et al, 2005; Stroud et al, 2009; McCowan et al, 2009; Thiriez et al, 2009), which, in turn, are correlated with a host of neuropsychological developmental delays. Of these, the association between MSDP and low birth weight appears to account for many of the associated outcomes, replicating consistently in prospective and retrospective studies.…”