Ultrasound characteristics and histological dating of the endometrium in a natural cycle in infertile women compared with fertile controls.

OBJECTIVE: To compare endometrial dating and ultrasound texture in a natural cycle before IVF and relate these to outcome and to fertile references.
DESIGN: Prospective study with a fertile reference group.
SETTING: Four university IVF clinics. PATIENT(S): Seventy-five IVF patients and 21 fertile women. INTERVENTION(S): Ultrasound, biopsy, blood sampling. In vitro fertilization-ET in the following cycle. MAIN OUTCOME MEASURE(S): Endometrial evaluation, P, IVF outcome. RESULT(S): At day LH+7, 42% infertile vs. 67% fertile women demonstrated endometria that were in phase (statistically nonsignificant difference). Nine percent had an accelerated endometrium, and 47% (infertile) vs. 24% (fertile) had a delayed endometrium (statistically nonsignificant difference). Statistically significantly fewer women with tubal factor and no hydrosalpinges had an endometrium in phase (20%) than was the case in fertile women (67%). Dating could not predict outcome. Statistically significantly more women in the hydrosalpinx group had a visible midline at day LH+7 compared with the case in other infertile groups. Forty-three percent conceived after IVF-ET. Plasma P was statistically significantly lower in nonpregnant women compared with in women with ongoing pregnancies and with fertile controls. A periovulatory hyperechogenic endometrium resulted in no ongoing pregnancies. CONCLUSION(S): In a natural cycle preceding IVF, a low midluteal P level predicts a low implantation rate. A periovulatory hyperechogenic endometrium or hydrosalpinges visible at ultrasound may have some predictive value. Endometrial dating was of no help.