Vaginal versus oral E(2) administration: effects on endometrial thickness, uterine perfusion, and contractility.

ABSTRACT

OBJECTIVE: To compare the effects of vaginal or oral E(2) administration on endometrial thickness, uterine perfusion, and contractility. DESIGN: Prospective, randomized, crossover study. SETTING: Assisted Reproduction Unit, Clamart, France. PATIENT(S) Thirty-nine infertile women undergoing 78 E(2)/P cycles. INTERVENTION(S) Women received micronized 17beta-E(2), 2 mg/day orally (cycle days 1 to 28) and P, 300 mg/day vaginally (cycle days 15 to 28). After a menstrual cycle washout interval, women received a similar treatment except that 17beta-E(2) was administered vaginally. MAIN OUTCOME MEASURE(S) Endometrial thickness, mean uterine artery pulsatility index, endometrial blood flow, and uterine contraction frequency assessed in ultrasound scans on cycle days 14 and 18. RESULT(S) On day 14, the endometrium was thicker (8.7 +/- 0.6 vs. 7.1 +/- 0.3 mm, P< .0001), pulsatility index values were lower (2.4 +/- 0.1 vs. 3.0 +/- 0.2, P< .0002), and endometrial blood flow tended to be increased in the vaginal E(2) cycles as compared to the oral E(2) cycles. On day 18, similar differences remained. However, P-induced decrease in contraction frequency was slighter in vaginal E(2) cycles (33% vs. 18%, P< .0003). CONCLUSION(S) Vaginal E(2) administration improves endometrial proliferation and uterine perfusion, presumably because of combined local and systemic effects, but may interfere with P-induced uterine relaxation.