Aim. To determine pregnancy and delivery outcomes among teenagers. Materials and Methods. An 8-year retrospective comparative hospital-based cohort study is analysing singleton pregnancy comorbidities and delivery parameters of a teenage group under the age of 20 compared with a young adult group 20-24 years of age in a university hospital. Results. Teenage is a risk factor for preterm birth <37 weeks (1.21 [1.08-1.35]), foetal growth restriction (1.34 [1.21-1.48]), episiotomy (1.27 [1.21-1.34]), uterine revision (1.15 [1.06-1.25]), APGAR <7 at 1 min (2.42 [1.21-1.67]), cephalopelvic disproportion (1.26 [1.07-1.48]), and postpartum haemorrhage (1.42 [1.25-1.62]); however, caesarean delivery occurs less frequently in teenagers than in adults (0.75 [0.70-0.80]). The following comorbidities are risk factors for teenage pregnancy (risk ratio [CI 95%]): anaemia (1.13 [1.10-1.17]), low urinary tract infection (1.10 [1.03-1.18]), pediculosis (2.42 [1.90-3.00]), anogenital condyloma (1.50 [1.04-2.17]), and trichomoniasis (1.74 [1.12-2.68]). The risks for hepatitis B and hepatitis C, premature rupture of membranes, and placenta praevia were lower compared with those in the young adult group, respectively, 0.43 (0.26-0.71), 0.90 (0.85-0.96), and 0.29 (0.20-0.41), while the risk for gestational diabetes and preeclampsia were the same in both groups. Conclusion. Considering the high risks for teenage pregnancy, this information should be provided to pregnant adolescent women and their caregivers.