The value and role of plasma 17 beta-oestradiol measurements during ovarian hyperstimulation for in-vitro fertilization.

Follicular aspiration was performed in 464 hyperstimulated IVF treatment cycles in patients with severe tubal damage as the sole cause of their infertility. In 413 cycles, one to four embryos could be replaced, resulting in 102 clinical pregnancies. In 458 treatment cycles, data on plasma E2 levels were available on days -3 and -2, in 322 cycles also on days -1 and 0, day 0 being the day of follicular puncture. Although the distribution of cycles leading to clinical pregnancy within the 5-95th centile for plasma E2 levels differed from that observed outside this range, these differences were of no statistical significance. These results indicate that IVF pregnancies occur in the presence of a wide range of E2 levels, during the 3-day period preceding follicular aspiration. The importance of plasma E2 measurements for treatment policy must, therefore, be reconsidered.