Abstract
Background
Few studies, and none in Canada, have examined the relation between maternal smoking, alcohol consumption and drug dependence during pregnancy and early neonatal morbidity.
Methods
We analyzed records of singleton live births in Alberta, Canada. Markers of neonatal morbidity were Apgar scores (<7 at 5 minutes postpartum) and resuscitation measures (2001-2005, N=191,686), and neonatal intensive care unit (NICU) admissions (2002-2005, N=154,924). Logistic regression was used to estimate odds ratios (ORs) for self-reported substance use and maternal health before conception, adjusting for maternal age, parity, year and fetal gender. Univariate ORs and population-attributable fractions were computed with and without correction for under-reporting of substance use.
Results
Maternal smoking during pregnancy was the most prevalent risk factor, affecting 20% of mothers by self-report, with the figure being possibly twice as high once corrected for under-reporting. Smoking (ORs 1.2), alcohol consumption (ORs 1.2-1.5) and drug dependence (ORs 1.7-2) by the mother during pregnancy were associated with increased risk for each of the markers of early neonatal morbidity (p<0.05, after correcting for covariates). Eliminating the most common among these risk factors, maternal smoking, would prevent 10-15% of each of the three neonatal morbidity markers. Other recorded factors related to mother’s pre-conception health, despite some strong associations, were responsible for only a small proportion of cases.
Discussion
We conclude that in preventing early neonatal morbidity among singleton births in Alberta, control of maternal smoking, the most common of the potentially modifiable risk factors, remains an important goal.
Key words: Pregnancy, epidemiology, neonatology, substance-related disorders, smoking
Résumé
Contexte
Il y a peu d’études (et il n’y en a eu aucune au Canada) sur le lien entre le tabagisme maternel, la consommation d’alcool et la toxicomanie durant la grossesse et la morbidité néonatale précoce.
Méthode
Nous avons analysé les dossiers des naissances vivantes uniques en Alberta, au Canada. Les marqueurs de la morbidité néonatale étaient le score d’Apgar (<7 à 5 minutes post-partum) et les mesures de réanimation (2001-2005, N=191 686), ainsi que les admissions dans les unités de soins néonatals intensifs (2002-2005, N=154 924). Par analyse de régression logistique, nous avons estimé les rapports de cotes (RC) pour la consommation autodéclarée d’alcool ou de drogue et la santé maternelle avant la conception, en rajustant les données selon l’âge de la mère, la parité, l’année et le sexe du fœtus. Les RC univariés et les fractions étiologiques du risque ont été calculés avec et sans rajustements pour la sous-notification de la consommation d’alcool et de drogue.
Résultats
Le facteur de risque le plus courant était le tabagisme maternel durant la grossesse; il concernait 20 % des mères selon leurs propres déclarations, et ce chiffre pourrait être deux fois plus élevé si l’on tient compte de la sous-notification. Le tabagisme (RC 1,2), la consommation d’alcool (RC 1,2-1,5) et la toxicomanie (RC 1,7-2) de la mère durant la grossesse étaient associés à des risques accrus pour chacun des marqueurs de la morbidité néonatale précoce (p<0,05, compte tenu des covariables). En éliminant le plus courant de ces facteurs de risque (le tabagisme maternel), on préviendrait entre 10 et 15 % des trois marqueurs de morbidité néonatale. Les autres facteurs en dossier liés à la santé de la mère avant la conception, malgré certaines associations importantes, n’étaient responsables que d’une petite proportion des cas.
Discussion
Nous en concluons que pour prévenir la morbidité néonatale précoce parmi les naissances uniques en Alberta, le contrôle du tabagisme maternel (le plus courant des facteurs de risque potentiellement modifiables) demeure un objectif important.
Mots clés: grossesse, épidémiologie, néonatologie, troubles liés à une substance, tabagisme
Footnotes
Acknowledgements: Igor Burstyn drew salary support from the Alberta Heritage Foundation for Medical Research as a Population Health Investigator. During early design and data acquisition for this project, Nitin Kapur was the recipient of a Commonwealth Scholarship from The Canadian Bureau for International Education. Staff of the Alberta Perinatal Health Program provided indispensable advice during data acquisition; the project was enabled by data supplied by the Alberta Perinatal Health Program.
Conflict of Interest: None to declare.
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