Risk factors associated with preterm birth according to gestational age at birth.
OBJECTIVE
To identify and quantify risk factors associated with preterm birth, stratified by gestational age at birth.


METHODS
Three case-control analyses were done. Controls were pregnancies of > or =37 weeks of gestational age at birth. Cases were defined as: <28, 28-32, 33- <37 weeks of gestational age at birth respectively in the three case-control analyses. Women were categorized according to whether they carried single or multiple infants.


RESULTS
Obstetrical conditions (placenta previa, placental abruption), and maternal hypertension were significantly associated with preterm delivery in all case-control analyses (adjusted OR between 1.34-19.56, p < 0.05). Leading risk factors for preterm delivery in singleton pregnancies were placental abruption and placenta previa (adjusted ORs 4.85 and 4.13, p < 0.05). For multiple pregnancies they were polyhydramnios and maternal hypertension (adjusted ORs 4.39 and 2.45, p < 0.05).


CONCLUSIONS
Obstetrical conditions during the pregnancy and maternal hypertension are important risk factors for preterm birth.
Ofori
Benjamin D
BD
Faculty of Pharmacy, University of Montreal, Montreal, Quebec, Canada.
Le Tiec
Magali
M
Bérard
Anick
A
D000037:Abruptio Placentae / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D016208:Databases, Factual; D005260:Female; D005865:Gestational Age; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology; D016017:Odds Ratio; D010923:Placenta Previa / Q000453:epidemiology; D006831:Polyhydramnios / Q000453:epidemiology; D011247:Pregnancy; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology*; D011792:Quebec / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors