Ultrasound evaluation of the uterine size and endometrial changes in a normal menstrual cycle

Abstract

Background: The endometrium is one of the most dynamic structures in the body and during the reproductive years of a normal female, the uterus undergoes ultrasonographically detectable alterations characterised by cyclical changes in the echopattern of the endometrium. The aim of this study is to assess the changes in the uterus and endometrium during the menstrual cycle of females in South-East and South-South Nigeria by ultrasound assessment, and also to establish the mean and normal ranges for uterine size and endometrial thickness during the cycle.
Methods: A prospective ultrasonographic study of cyclical endometrial and uterine changes in 300 women in two Nigerian tertiary hospitals.
Results: There was progressive increase in uterine dimensions from menstrual phase (early cycle) to secretory phase (late cycle),
progressive increase in endometrial thickness from menstrual phase (early cycle) to secretory phase (late cycle), with a greater increase observed from menstrual phase to the proliferative phase than from proliferative phase to secretory phase. The menstrual phase endometrium was mostly hyperechoic; the proliferative phase mostly hypoechoic and the secretory phase mostly hyperechoic. The mean values for the endometrial thickness and the antero-posterior length and width of the uterus for this study were 3.2±1.1mm, 4.0±3.2cm, 7.0±0.7mm and 5.2±4.2cm respectively for menstrual phase, 7.5±1.9mm, 4.1±0.6cm, 7.4±2.7cm and 5.3±2.0cm
respectively for proliferative phase and 9.4±1.9mm, 4.2±0.4cm, 7.9±4.5cm and 5.9±3.4cm respectively for the secretory phase. The
normal sonographic appearances of the uterus study were a thin hyperechoic endometrium at the menstrual phase, a thicker triple
layer endometrium at the proliferative phase, and a very thick hyperechoic endometrium with no midline echo at the secretory phase.
Conclusion: This study established that the normal thickness of endometrium in our population group is 2–3mm during the menstrual
phase, 6– 9mm during the proliferative phase and 8–11mm during the secretory phase.

Key words: Uterine and endometrial changes, ultrasonography, Nigeria