Do maternal characteristics and past pregnancy experiences predict preterm delivery among women aged 20 to 34?

To identify key demographic, lifestyle, and medical indicators for preterm births in women aged 20 to 34.

A population-based, case-control study consisting of 987 women aged 20 to 34, who delivered a liveborn singleton infant at <37 weeks' gestation in Alberta between May 1999 and August 2000. Controls delivered liveborn infant(s) at > or =37 weeks' gestation. Information was obtained from computer-assisted telephone interviews, and the provincial Physician Notice of Stillbirth/Birth database. Analysis included bivariate and logistic regression techniques.

Logistic regression modelling indicated that significant risk factors for preterm delivery included poor past pregnancy outcome (odds ratio [OR] 6.4), poor emotional health (OR 1.8), more than 3 years or less than 1 year between pregnancies (OR 1.4 and 1.9, respectively), polyhydramnios and oligohydramnios (OR 4.1), bleeding at greater than 20 weeks' gestation (OR 10.4), malpresentation (OR 2.9), gestational hyper- tension (OR 2.2), and gestational hypertension with proteinuria (OR 4.4). Women who had fewer than 10 prenatal visits, regardless of attending prenatal classes, were at highest risk of preterm delivery (OR 6.7).

In this population of women aged 20 to 34 years, few prenatal visits, poor emotional health prior to pregnancy, and conditions of the current pregnancy were strongly associated with preterm singleton birth.