Low birthweight and preterm birth rates 1 year before and after the Irish workplace smoking ban.
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.


METHODS
A cross-sectional observational study analysing routinely collected data using the Euroking K2 maternity system.


METHODS
Coombe University Maternal Hospital.


METHODS
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.


METHODS
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.
Kabir
Z
Z
Tobacco Free Research Institute (RIFTFS), Dublin, Ireland. zkabir@tri.ie
Clarke
V
V
Conroy
R
R
McNamee
E
E
Daly
S
S
Clancy
L
L
D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007494:Ireland / Q000453:epidemiology; D008423:Maternal Age; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000209:etiology; D011297:Prenatal Exposure Delayed Effects; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology* / Q000331:legislation & jurisprudence; D016540:Smoking Cessation / Q000706:statistics & numerical data; D017132:Workplace / Q000331:legislation & jurisprudence; D055815:Young Adult