The investigators aim to evaluate the width of the endometrial myometrial zone in participants during natural menstrual cycle by using specific computerized application on 3 dimensions sonographic images of their uteri.

The uterine endometrium and the uterine myometrium have different acoustic characterization in transvaginal ultrasound(TVS).TVS can also demonstrate the interface between these tissues - the endometrial myometrial zone(EMJ) .This is optimally achieved in 3 dimensions images in a coronal section of the uterus.A specific computerized algorithm was developed in our unit by using MATLAB software for the quantitative measurements of the EMJ width in different uterine planes.The investigators aim to evaluate changes in the width of the EMJ in different uterine planes in participants during natural menstrual cycle .

Inclusion Criteria:patients with regular menstrual cycles -

Exclusion Criteria:patients on contraceptive pills.patients after uterine surgery

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patients referred for transvaginal sonography