Prospective evaluation of the ultrasound appearance of the endometrium in a cohort of 1,186 infertile women

Objective: To investigate the effect of differences in endometrial thicknes s and pattern as visualized with present-day high-resolution transvaginal u ltrasound equipment on the outcome of assisted reproductive treatment. Design: Prospective cohort study. Setting: Two large infertility units in university hospitals. Patient(s): The endometrial characteristics of 981 patients during 1,600 as sisted reproductive treatment cycles were compared with those of 205 untrea ted women. In addition, abnormal echogenic patterns of the endometrium were characterized histologically in 44 patients. Intervention(s): None. Main Outcome Measure(s): Pregnancy rates. Result(s): The endometrium was significantly thinner in untreated women and women treated with IUI than in women treated with IVF or intracytoplasmic sperm injection. The exponential proliferation of the endometrium was simil ar in conception and nonconception cycles. The odds for a successful pregna ncy were significantly lower in the presence of a chin endometrium in women treated with IUI but not in women treated with the long stimulation protoc ol for NF or intracytoplasmic sperm injection. Singleton pregnancies were m ore common than multiple pregnancies in patients with thin endometria. Conclusion(s): The pregnancy rates of assisted reproductive procedures are influenced only marginally by the degree of endometrial proliferation, and treatment should not be canceled because of inadequate endometrial thicknes s. Fertil Sreril(R) 2000;73:106-13. (C) 1999 by American Society for Reprod uctive Medicine.