Sampling
intrauterine death
PREMATURE BIRTH
Based on the self-efficacy variable that was the primary outcome of this study, taking into account the alpha = 0.050, power = 0.90, m1 = 46.7, m2 = 52.9, sd1 = 6.5, sd2 = 7.0 and attrition rate of 25%, using the Sampsi module in Stata-13 software, the number of samples was determined to be 32 people in each group [The sampling setting was all comprehensive health centers of Hamedan City (36 centers). All pregnant women in the city are covered by these 36 centers. Using the Integrated Health Software (Sib), the researcher identified adolescent pregnant mothers (between 0–5 cases were identified in each center). A total of 119 mothers were identified, and after checking the inclusion criteria, 64 mothers were included in the study. The participants were then randomly assigned to either the intervention or control group using numbered envelopes. Four individuals were excluded from the study, leaving a sample size of 60 for analysis (3 people due to premature birth and one person due to intrauterine death). Notably, the statistical analyst was blinded to the group allocation (Fig. CONSORT flow diagram