Objective: To present the reference range of fetal thymus gland according to gestational age groups. Methods: In this prospective study, size was assessed in singleton, uncomplicated pregnancies between 19 and 38 weeks gestation our outpatient clinic 2019 2020. Based on their monthly pregnancy follow-ups, measurement divided into 5 groups (Group 1: 19–22 weeks, Group 2: 23–26 3: 27–30 4: 31–34 ...