BackgroundAdolescent pregnancy is an important issue in terms of reproductive health. Adolescent mothers have to overcome two crises at the same time: motherhood and maturity. Childbirth experience and posttraumatic stress disorder may influence the mother’s perception of her infant and postpartum care behaviors.MethodsThis cross-sectional study was conducted on 202 adolescent mothers referring to health centers in Tabriz and its suburbs between May and December, 2022. Data were collected by PTSD Symptom Scale, Childbirth Experience Questionnaire 2.0, and Barkin Index of Maternal Functioning. The association between childbirth experience, posttraumatic stress disorder and maternal functioning was assessed by multivariate analysis.ResultsAfter adjusting the effect of socio-demographic and obstetric characteristics, the score of maternal functioning among mothers without posttraumatic stress disorder was statistically significantly higher than mothers with posttraumatic stress disorder diagnosis [β (95% CI)=2.30 (0.39 to 4.20); p = 0.031]. The score of maternal functioning increased with the increase in the childbirth experience score [β (95% CI)=7.34 (3.87 to 10.81); p < 0.001]. The score of maternal functioning among mothers with wanted sex of baby was statistically significantly higher than unwanted sex of baby [β (95% CI)=2.70 (0.37 to 5.02); p = 0.023].ConclusionHealthcare professionals should pay special attention to improving maternal functioning among adolescent mothers. One of the important actions can be to create a positive experience of childbirth for avoiding of posttraumatic stress disorder following birth and counseling with mothers who stated sex of fetus is undesired.