A rapid decline in serum oestradiol concentrations around the mid-luteal phase had no adverse effect on outcome in 763 assisted reproduction cycles

Progesterone is essential in the luteal phase whereas luteal oestradiol may play only a permissive role on the endometrium, However, a rapid decline i n oestradiol concentrations around the mid-luteal period may compromise the endometrial integrity leading to poor IVF outcomes. A retrospective analys is of 763 women aged <40 years undergoing their first IVF cycle and having less than or equal to 3 embryos replaced was undertaken, In cycles receivin g human chorionic gonadotrophin (HCG) for luteal support, 25th, 50th and 75 th centiles of the ratio of day-of-HCG oestradiol to midluteal oestradiol ( oestradiol ratio) were 1.8, 2.8 and 5.0 respectively. Hormonal parameters w ere not different between pregnant and non-pregnant cycles, The outcomes we re similar irrespective of the oestradiol ratio. Progesterone supplementati on was used instead when the HCG oestradiol was >18 000 pmol/l or there wer e features of ovarian hyperstimulation syndrome. Pregnancy rates of these h yperstimulated cycles were 16.7 and 11.4% per cycle respectively when oestr adiol ratio was less than or equal to 5.0 and >5.0, This difference did not reach statistical significance. Our results could not find an adverse outc ome in cycles showing a rapid decline in oestradiol during the mid-luteal p hase.