Tavaniotou A, Albano C, Smitz J, Devroey P.
Centre for Reproductive Medicine, Dutch-Speaking Free University of Brussels, Brussels, Belgium

Fertil Steril. 2002 Apr;77(4):733-7.

Abstract
OBJECTIVE: To investigate the effect that clomiphene citrate exerts on luteinizing hormone (LH) concentrations in gonadotropin/gonadotropin-releasing hormone (GnRH) antagonist cycles.

DESIGN: Retrospective analysis.

SETTING: Tertiary referral center.

PATIENT(S): Two groups of patients undergoing in vitro fertilization (IVF) were compared. In group I, 20 patients were stimulated with clomiphene citrate (CC) in combination with gonadotropins and 0.25 mg of Cetrorelix (ASTA Medica AG; Frankfurt am Main, Germany) and in group II, 20 patients were stimulated with gonadotropins and 0.25 mg of Cetrorelix.

INTERVENTION(S): Blood sampling was performed in the late follicular, periovulatory, early, mid, and late luteal phases.

MAIN OUTCOME MEASURE(S): Luteinizing hormone (LH), estradiol, and progesterone.

RESULT(S): LH levels were significantly higher in group I than in group II on all the days studied. Progesterone serum concentrations were significantly higher in group II in the early luteal phase, but not in the follicular or the middle and late luteal phases.

CONCLUSION(S): LH concentrations are significantly higher in the follicular and luteal phases in cycles stimulated with CC, despite GnRH antagonist administration. This observation might have implications for the dose of GnRH antagonist needed to suppress LH in the follicular phase and questions the need for luteal-phase supplementation in cycles in which CC was used.