(21 May 2010)
Serum Estradiol (E2) concentration is influenced by a number of factors that include but are not limited to stimulation protocol and dose, reproductive age and initial number of antral follicles present in the ovaries. In this retrospective study, data were obtained from patients undergoing IVF/ICSI and analysed to test the hypothesis that increased follicular fluid volume ratio, and that a higher ratio would result in a healther endometrium and higher positive pregnancy rates. For each patient (n=38) the follicular volume(µl) was calculated for 1) all follicles, 2) all follicles greater than 10mm, and 3) all follicles greater than 15mm. Each value was divided by the serum E2 concentration (pmol/L, Abbott Axsym® E2 assay) recorded 2 or 3 days prior to oocyte recovery.
The pregnancy group (n=12) had a score of 0.43+0.04, (E2 5970+931pmol/L) and an endometrium thickness of 11+0.4mm. The non pregnant group (n=26) had a score of 0.64+0.7. (5442+622pmol/L) and an endometrium thickness of 11.5+0.4mm. Data were also analysed in relation to number of oocytes recovered. Patients with 6 or less (n=10), 7 to 12 (n=14) or greater than 12 oocytes (n=14) recovered had ratios of 0.53+0.09, 0.68+0.1, 0.48+0.5 and E2 concentrations of 2925+352pmol/L, 5075+429pmol/L and 8059+946pmol/L respectively. When analysed according to pregnancy status, patients with 7 to 12 oocytes recovered had values of 0.50+0.4 for the pregnant group (endometrium 10.9+0.5mm) versus 0.81+0.18 for the non-pregnant group (endometrium 12.2+1mm). Patients with mroe than 12 oocytes recovered recorded values of 0.31+0.06 for the pregnant group (endometrium 11.2+0.7mm) and 0.58+0.08 for the non-pregnant group (endometrium 11.0+0.7mm).
While the numbers of patients used in this preliminary study are too low to draw any firm statistical conclusions, they do demonstrate that a lower follicular volume to E2 ratio may be of benefit to patients. This ratio may be a good indicator of oocyte quality and the possible efficiency of the treatment protocol. E2 serum concentration and endometrium thickness alone may not be the best indicator of a successful stimulation.