ABSTRACT

Background: Depending on the physiological need, the uterine environment, especially the endometrium, has markedly changed during pregnancy.Also, in postpartum period, it was also shown significant changes in both uterine anterior-posterior diameter and endometrial thickness.

Aim: To evaluate the physiological changes of endometrial thickness during the postpartum period and to determine the underlying factors associated with it.

Methods: In this cross-sectional study,all pregnant women undergoing uncomplicated delivery at Yas Hospital Complex, an educational tertiary center, related to Tehran University of Medical sciences, Tehran, Iran., either by normal delivery or cesarean delivery was included into the study. Approximately 24 hours after delivery, subjects underwent abdominal and pelvic ultrasound at dorsolithotomy position. Midsagittal and axial planes were used to measure endometrial thickness.

Results: The mean endometrial thickness was 8.10±3.50 mm.There was a significant inverse correlation between endometrial thickness and gestational age (correlation coefficient -0.228, P value 0.021). The mean endometrial thickness in subjects with normal vaginal delivery and cesarean section was 8.65±2.65 mm and 7.62±3.61 mm respectively, which was significantly higher in subjects with normal vaginal delivery (P value = 0.012).

Conclusion: The mean endometrial thickness at 24 hours postpartum is estimated to be 8.10±3.50 mm in the selected Iranian population.This index is significantly influenced by the mood of delivery so that greater endometrial thickness in normal vaginal delivery is expected than cesarean section.