Delivery at Term: Impact of University Education by Week of Gestation

Data on risk factors for early term delivery are scant despite greater complications in infants born at 37 and 38 weeks' gestation. We determined the probability of delivery by gestational week at term according to level of maternal education, an established risk factor for preterm birth.

We analyzed 2 319 697 live singleton births at term (≥37 weeks) in Quebec from 1981 to 2010. We estimated hazard ratios with 95% confidence intervals (CI) of delivery according to level of maternal education, adjusting for individual characteristics. The main outcome measure was the probability of delivery at term by week of gestation for women with university education versus high school education.

Early term birth at 37 and 38 weeks of gestation was less common for university-educated women (23.1%) than for high school-educated women (25.8%; P < 0.001). Compared with women with a high school education, university-educated women had a 15% lower probability of delivery at 37 to 38 weeks (95% CI: 0.84 to 0.86), a 4% lower probability of delivery at 39 weeks (95% CI: 0.96 to 0.97) and a 2% lower probability of delivery at 40 weeks (95% CI: 0.97 to 0.98). University-educated women were, however, more likely to deliver at 41 weeks.

A higher level of education was associated with longer duration of pregnancy at term. Women who were university-educated had a lower chance of delivery at 37, 38, 39, and even 40 weeks of gestation. Clinicians should be aware that women with lower levels of education are more likely to deliver earlier at term.