Does a fall in serum estradiol levels after hCG administration correlate with lower pregnancy rates in patients undergoing fresh art cycles?

Abstract

Numerous factors have been proposed to correlate with (predict) the success of an ART cycle. One such factor is a rise in estradiol level following hCG. Our objective was to determine whether a fall in serum estradiol levels the day after hCG administration correlated with lower pregnancy rates in fresh, non-donor ART cycles. Retrospective cohort study. Patients undergoing fresh, non-donor embryo transfer cycles between January 1st, 2003 and January 31st, 2010 were included in the study. The primary outcome variable was a post-transfer positive serum hCG. Serum estradiol measurements were drawn the morning after hCG administration (6-11 hours post injection) and compared to the estradiol levels drawn 24 hours earlier. Pregnancy rates of women with falling serum estradiol levels were compared with patients with stable or rising estradiol levels using the chi-square test. Age, baseline FSH, type of pituitary down-regulation, number of days of ovarian stimulation, total ampules of gonadotropin administered, number of oocytes retrieved, and oocyte maturity rate were also compared between the two groups using t-test or chi-square, as appropriate. A total of 1970 cycles met inclusion criteria of which 1877 had the same or increasing serum estradiol levels and 93 had decreasing estradiol levels on the morning after hCG trigger administration. There were no statistically significant differences in demographics between the groups. The pregnancy rate in women with declining estradiol levels after hCG trigger administration did not differ from patients with the same or rising estradiol levels (54% vs 55%, P=0.89). This large cohort study demonstrated that patients with decreasing estradiol levels after hCG trigger administration had similar pregnancy rates as patients with the same or increasing estradiol levels. Obtaining estradiol levels after hCG trigger administration is not useful in predicting pregnancy rates.