Background: To determine if adolescent pregnancies are at increased risk of poor obstetrical outcome compared with a general obstetrical population.Methods: A five-year retrospective review of the Toronto Hospital for Sick Children's Teenage Pregnancy Unit was carried out. Information was available on 209 patients < 19 years age between January 1994 and December 1998. This was compared to information available from a database of all women delivering at the same hospital, The Toronto Hospital General Division, during the same time period (n = 13,557). The Chi-square test of independence was used to compare the data and is reported as adolescent group vs. hospital group.Results: Labour was induced in 25.5% vs. 21.8% (p = 0.20). Epidural anaesthesia was received by 63.5% vs. 53% (p < 0.05). The incidence of preterm delivery (<37 wks) was 13.5% vs. 8.1% (p < 0.05), low-birth-weight babies (< 2500 g) 13.4% vs. 8.6% (p < 0.05) and small-for-gestational-age babies (<2 SD) 1.9%. The incidence of post-term delivery (>41 wks) was 12.5% vs. 4.3% (p < 0.001), macrosomia (>4000 g) 1.9% vs. 9.2% (p < 0.001) and large-for-gestational-age babies (>2 SD) 0.5%. Operative delivery (forceps or vacuum) occurred in 19.7% vs. 19.9% (p = 0.94) and caesarian section in 6.2% vs. 20.1% (p < 0.001). APGARs <7 at five minutes were found in 2.4% vs. 3.1% (p = 0.60). 12.0% of infants were admitted to the neonatal nursery. There were no stillbirths.Conclusions: Both preterm deliveries and low-birth-weight babies were more frequent in the adolescent group although the incidence of SGA babies was low. The low caesarian section rate also likely reflects these findings. Postterm delivery was also more common, yet macrosomia occurred less frequently.