Early and midluteal phase blood estradiol levels after ovum pickup and pregnancy rates after ICSI cycles

To examine whether blood estradiol level tendencies during the late follicular and early luteal phases and the 11 days after embryo transfer have any association with the outcome of intracytoplasmic sperm injection-embryo transfer (ICSI-ET) cycles.This prospective study involved 38 assisted reproductive technology cycles in 35 infertile patients treated with assisted reproductive technologies in which blood samples taken on the 4th, 7th, 9th and 11th days following ET were tested for progesterone, estradiol and hCG levels using an enzyme-linked immunoassay. The estradiol blood levels were compared with the maximal follicular phase blood estradiol. The data were analyzed using Microsoft Excel (Redmond, Washington) and SPSS 10.0 (Chicago, Illinois). The chi2, Mann-Whitney U, Wilcoxon and Pearson tests were usedfor statistical analysis.Average maximum estradiol blood level, number of oocytes produced,fertilization rates and cleavage rates did not show any significant difference between pregnant and nonpregnant cycles. The lower the ratios of estradiol levels measured on posttransfer days 4, 7 and 9 to the maximumfollicular phase level, the lower the probability of pregnancy (P.01, P.01 and P.01, respectively).The steeper the decline in blood estradiol levels (affecting the periimplantation period) following ovum pickup relative to the maximum follicular phase estradiol levels, the lower the chance of pregnancy in ICSI-ET cycles.