Transvaginal sonographic evaluation of endometrial growth and texture in spontaneous ovulatory cycles--a descriptive study.

Repeated transvaginal ultrasonographic examinations were performed during spontaneous ovulatory cycles to follow the texture and growth pattern of the endometrium in 23 healthy volunteers. The serum concentrations of oestradiol, progesterone and luteinizing hormone (LH) were measured regularly. The day of the LH peak was designated as day 0. On ultrasound only one thin echogenic line was seen from menstruation to day -7. From days -6 to -1 a change from one to three thin lines was observed together with an increasing hypoechogenic texture between the lines. These changes corresponded to the increasing serum concentration of oestradiol and increasing thickness of the endometrium. At ovulation there was maximum hypoechogenic texture between the lines which had become thicker. At ovulation the endometrium had a mean thickness (both layers) of 12 mm. From days +1 to +6 an increasing blurring of the three lines became apparent and the previously hypoechogenic layers gradually displayed a more echogenic texture. From day +7 to menstruation the lines were indistinguishable due to the appearance of a general hyperechogenic texture of the endometrium. In the luteal phase the growth of the endometrium plateaued. The results indicate that ultrasound assessment of endometrial growth and texture may be an important tool to evaluate normal ovulatory endometrial development. It can also be useful in monitoring stimulated cycles in different treatment modalities of assisted reproduction.