Endometrial growth and uterine blood flow: a pilot study for improving endometrial thickness in the patients with a thin endometrium

ObjectiveTo examine whether thin endometria can be improved by increasing uterine radial artery (uRA) blood flow.DesignA prospective observational study.SettingUniversity hospital and city general hospital.Patient(s)Sixty-one patients with a thin endometrium (endometrial thickness [EM] <8 mm) and high radial artery-resistance index of uRA (RA-RI ≥0.81).Intervention(s)Vitamin E (600 mg/day, n = 25), l-arginine (6 g/day, n = 9), or sildenafil citrate (100 mg/day, intravaginally, n = 12) was given.Main Outcome Measure(s)EM and RA-RI were assessed by transvaginal color-pulsed Doppler ultrasound.Result(s)Vitamin E improved RA-RI in 18 (72%) out of 25 patients and EM in 13 (52%) out of 25 patients. L-arginine improved RA-RI in eight (89%) out of nine patients and EM in six (67%) patients. Sildenafil citrate improved RA-RI and EM in 11 (92%) out of 12 patients. In the control group (n = 10), who received no medication to increase uRA-blood flow, only one (10%) patient improved in RA-RI and EM. The effect of vitamin E was histologically examined in the endometrium (n = 5). Vitamin E improved the glandular epithelial growth, development of blood vessels, and vascular endothelial growth factor protein expression in the endometrium.Conclusion(s)Vitamin E, l-arginine, or sildenafil citrate treatment improves RA-RI and EM and may be useful for the patients with a thin endometrium.