Aim: The study aimed to find out the fetal outcome (miscarriage, birth weight, prematurity, and stillbirth) and complications of pregnancy (hypertensive disorders, preterm birth, diabetes mellitus, and anemia) among teenage mothers in comparison to adult Saudi women. Methods: This was a retrospective comparative study, which includes 129 teenage primigravid mothers aged 19 years or younger and 740 adult primigravid mothers aged 20-29 years with fetal and maternal complications. Results: Higher incidence of miscarriage was found among teenage mothers p=0.0016, OR=5.25, 95% CI=1.87-14.74. The higher rate of low birth weight was recorded among adolescent mothers p=0.0033, OR=2.1129, 95% CI=1.28-3.48. A higher proportion of premature babies was reported among teenage mothers p=0.0001, OR=3.95, 95% CI=2.16-7.24. The teenage group showed a higher incidence of stillbirth in comparison to an adult group with statistically insignificant p=0.9, OR=1.15, 95% CI=0.133-9.91. Higher incidence of hypertensive disorders was found to be among the adult primigravid mothers p=0.45, OR=0.63, 95% CI=1.88-2.1. The higher proportion of preterm birth was reported among teenage mothers p=0.0001, OR=3.95, 95% CI=2.16- 7.24. One case of DM was reported among adult primigravid mothers and no any similar case among the study group was found, p=0.6939, OR=1.29, 95% CI=0.86-1.94. Higher incidence of anemia was found among teenage group p=0.2135, OR=1.29, 95% CI=0.86-1.94. Conclusion: Our study concluded that teenage pregnancy was associated with a high risk of miscarriage, low birth weight, premature babies and preterm birth. Proper antenatal care, health education and elevation of community awareness might reduce the number of teenage pregnancies and their complications.