This study was performed to assess the usefulness of basal follicle stimulating hormone(FSH) levels measured by immunoradiometric assay(IRMA) as a prognostic indicator of ovarian reserve and to determine the discriminatory level of basal FSH that
predicts the ovarian response and the probability of pregnancy in patients with controlled ovarian hyperstimulation(COH). From May 1994 to March 1995, ninety-three infertile women who had undergone intrauterine insemination(IUI) during COH cycles
were
allocated to the study group.
COH was performed using ultrashort protocol of gonadotropin-releasing hormone(GnRH) agonist(n=38), long protocol of GnRH agonist(n=35) and exogenous gonadotropin only(n=20). All patients included in this study had blood samples drawn on cycle day
2
or 3
prior to COH for IRMA of basal FSH. There was a distinct negative correlation between rising FSH values and numbers of follicles(≥14mm) on the day of human chorionic gonadotropin(hCG) administration. The values of estradiol(E2) on the day of hCG
administration showed distinct negative correlation with rising FSH values. There were no correlation between basal FSH values and total ampules(75IU) of gonadotropin administered, and the duration of gonadotropin administration. With a cut-off
level of
8.5%mIU/ml for the basal FSH concentration measured by IRMA, the false positivity rate for prediction of pregnancy were the lowest value. The false positivity increased as the cut-off level was decreased or increased, and therefore we selected
8.5mIU/ml
as the cut-off to optimize sensitivity and minimize false positivity. There was a significantly higher pregnancy rate in in the low group(<8.5mIU/ml), with 39.2% compared with 21.4% in the high group(≥8.5mIU/ml).
In the group using ultrashort protocol of GnRH agonist, patients with low basal FSH levels (<8.5mIU/ml) yielded a higher mean number of follicles (≥14mm) on the day of hCG administration than those with high levels (≥8.5mIU/ml)(11.52vs 7.28).
Mean
peak E2 level of low group, 2,378±1,034pg/ml was significantly higher than that of high group, 983±554pg/ml. In the group using long protocol of GnRH agonist, patients low basal FSH levels(<8.5mIU/ml) yielded a higher mean number of
follicles(≥14) on
the day of hCG administration than those with high levels (≥8.5mIU/ml)(17.05 vs 10.68). The amounts of gonadotropins administered was significantly reduced in low basal FSH group. Mean peak E2 level of low group, 1,897±1,137pg/ml was
significantly
higher than that of high group, 1,241±981pg/ml. In the group using gonadotropin only protocol, patients with low basal FSH levels (<8.5%mIU/ml) yielded a higher mean number of follicles(≥14mm) on the day of hCG administration than those with
high
levels(≥8.5mIU/ml) without statistical significance. Mean peak E2 level of low group, 2,334±1,812 pg/ml was significantly higher than that of high group, 1,375±645pg/ml.
Basal FSH levels are predictive of the ovarian response and probability of pregnancy in stimulated cycles and may be useful in patient selection and counseling of patients regarding their appropriateness for assisted reproduction.
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