Taylor D R, Anthony F W, Dennis K J
Contraception. 1986 May;33(5):463-71. doi: 10.1016/s0010-7824(86)80005-1.
The suppression of ovulation during the first treatment cycle with Microgynon 30 (150 micrograms levonorgestrel and 30 micrograms ethinyl oestradiol) for nine subjects starting the "pill" on day 1 of their cycle and five subjects on day 5 was investigated. Serum oestradiol and progesterone levels throughout the cycle and midcycle urinary LH levels were reliably suppressed in all day 1 "starters". Serum progesterone levels and urinary LH levels were also suppressed in day 5 "starters" but one subject produced oestradiol levels within the normal range of ovulatory cycles. Mean oestradiol levels of day 5 "starters" were found to be significantly higher than those of day 1 "starters" (p less than 0.05).
对9名在月经周期第1天开始服用“短效口服避孕药”米非司酮30（150微克左炔诺孕酮和30微克炔雌醇）的受试者以及5名在第5天开始服用的受试者，在首个治疗周期中排卵抑制情况进行了研究。所有在第1天开始服用的受试者整个周期的血清雌二醇和孕酮水平以及周期中期尿促黄体生成素水平均得到可靠抑制。在第5天开始服用的受试者中，血清孕酮水平和尿促黄体生成素水平也受到抑制，但有一名受试者的雌二醇水平处于排卵周期的正常范围内。发现第5天开始服用的受试者的平均雌二醇水平显著高于第1天开始服用的受试者（p<0.05）。
