Do basal oestradiol and oestradiol:androgens and oestradiol:FSH ratios reflect pregnancy potential of women receiving intrauterine insemination during natural cycles?

The aim of this retrospective study was to evaluate whether basal hormone profiles could be related to the ability to achieve pregnancy in women receiving intrauterine insemination (IUI) treatment during their natural menstrual cycle. Serum hormone profiles on cycle day 3 of naturally menstruating women were assessed in a total of 163 treatment cycles (29 conceptional and 53 non-conceptional cycles of 27 women who became pregnant and 81 non-conceptional cycles of 33 women who did not become pregnant). Basal concentrations of LH, FSH and prolactin were similar between conceptional and non-conceptional cycles. In contrast, concentrations of oestradiol in conceptional cycles (38 +/- 26 pg/ml: mean +/- SD) were significantly higher than those in non-conceptional cycles (23 +/- 18 pg/ml) (P = 0.0003). Concentrations of androstenedione and testosterone were lower but not significantly so in conceptional cycles as compared with non-conceptional cycles. The ratios of oestradiol/androstenedione, oestradiol/testosterone and oestradiol/FSH were significantly higher in conceptional as compared with non-conceptional cycles (29, 2.3, 6.2 versus 17, 1.2, 3.6 respectively) (all P < 0.006). Thus, increased concentrations of oestradiol and increased oestradiol/androgens and oestradiol/FSH ratios already on day 3 of the natural menstrual cycle correlate with the likelihood of achieving conception during the following IUI treatment. Therefore, measurement of basal hormones, including androstenedione and testosterone, may be useful to assess the health status of the coming dominant follicle.