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Low birthweight and preterm birth rates 1 year before and after the Irish workplace smoking ban
Author(s) -
Kabir Z,
Clarke V,
Conroy R,
McNamee E,
Daly S,
Clancy L
Publication year - 2009
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.2009.02374.x
Subject(s) - medicine , odds ratio , pregnancy , logistic regression , obstetrics , low birth weight , premature birth , demography , population , gestational age , singleton , birth weight , environmental health , genetics , sociology , biology
Objective It is well‐established that maternal smoking has adverse birth outcomes (low birthweight, LBW, and preterm births). The comprehensive Irish workplace smoking ban was successfully introduced in March 2004. We examined LBW and preterm birth rates 1 year before and after the workplace smoking ban in Dublin. Design A cross‐sectional observational study analysing routinely collected data using the Euroking K2 maternity system. Setting Coombe University Maternal Hospital. Population Only singleton live births were included for analyses (7593 and 7648, in 2003 and 2005, respectively). Methods Detailed gestational and clinical characteristics were collected and analysed using multivariable logistic regression analyses and subgroup analyses. Main outcome measures Maternal smoking rates, mean birthweights, and adjusted odds ratios (ORs) of LBW and preterm births in 2005 versus 2003. Results There was a 25% decreased risk of preterm births (OR, 0.75; 95% CI, 0.59–0.96), a 43% increased risk of LBW (OR, 1.43; 95% CI, 1.10–1.85), and a 12% fall in maternal smoking rates (from 23.4 to 20.6%) in 2005 relative to 2003. Such patterns were significantly maintained when specific subgroups were also analysed. Mean birthweights decreased in 2005, but were not significant ( P = 0.99). There was a marginal increase in smoking cessation before pregnancy in 2005 ( P = 0.047). Conclusions Significant declines in preterm births and in maternal smoking rates after the smoking ban are welcome signs. However, the increased LBW birth risks might reflect a secular trend, as observed in many industrialised nations, and merits further investigations.