Dynamics of endometrial thickness over time: a reappraisal to standardize ultrasonographic measurements in an infertility program.

OBJECTIVE: To assess changes in endometrial thickness during different phases of spontaneous uterine contractions in the menstrual cycle.

DESIGN: Prospective, longitudinal study.

SETTING: Infertility clinic.

PATIENT(S): Sixty-eight infertile patients seen for basic assessment between January 30 and July 1, 2002.

MAIN OUTCOME MEASURE(S): Endometrial thickness on two-dimensional transvaginal ultrasonography.

RESULT(S): Changes in endometrial thickness were seen on transvaginal ultrasonongraphy in 52 of 68 (76.47%) patients during spontaneous uterine contractions throughout the follicular phase of menstrual cycle. Changes involved the myometrium and subendometrium. Changes in thickness ranged from 1.3 mm to 2.8 mm, regardless of the day of study.

CONCLUSION(S): Multiple measurements must be made to calculate a mean endometrial thickness that takes into account alterations due to contractions.