Obstetric implications for and identification of women with a normal clomiphene citrate challenge test result who have a poor response to gonadotropins

Objective

To determine the incidence and obstetric implications and to identify prospectively women with a poor response to hMG with a normal clomiphene citrate challenge test (CCCT) result.

Design

Retrospective chart review.

Setting

Tertiary fertility center.

Patient(s)

One hundred sixty-three women who underwent ovulation induction with hMG for IUI, and 266 women who underwent ovulation induction with GnRH analogue and hMG for IVF. All had a CCCT before stimulation. Seventy-five percent of IUI patients (123 of 163) and 89% of IVF patients (238 of 266) had normal CCCT results. A poor response to hMG was defined as a response less than the 90th percentile of women with an abnormal CCCT result (peak E₂ [pg/mL] level per ampule hMG used: 90th percentile ≤30).

Intervention(s)

Clomiphene citrate challenge test and ovulation induction for IUI or IVF.

Main outcome measure(s)

Response to gonadotropins and pregnancy outcome after treatment.

Result(s)

Thirty-five percent of IUI patients (43 of 123) and 52% of IVF patients (123 of 238) with a normal CCCT result had a poor response to hMG. Intrauterine insemination patients with a poor response to hMG had significantly lower delivery rates than IUI patients with a normal response (19% vs. 39%). In vitro fertilization patients with a poor response to hMG had similar delivery rates compared with IVF patients with a normal response (32% vs. 35%). For both groups of patients, an FSH >12 mIU/mL (IMx assay) on either day 3 or day 10 (normal ≤14.5 IMx) was highly predictive of a poor response to hMG, the elevated FSH level being a much better predictor than the woman's age.

Conclusion(s)

A poor response to hMG with a normal CCCT result (false negative) is a common event. A day-3 or day-10 FSH >12 mIU/mL (IMx assay) or 20 mIU/mL (converted to the original RIA) will identify approximately 80% (IUI) and approximately 94% (IVF) of the women who will experience a poor response to hMG. When identified, the data suggest that these patients will benefit significantly from the more aggressive IVF.

Key words:  Clomiphene citrate challenge test , poor response to hMG , pregnancy outcome in poor responders , ovulation induction , intrauterine insemination , IVF