Induction of preovulatory luteinizing hormone surge and prevention of ovarian hyperstimulation syndrome by gonadotropin-releasing hormone agonist.

OBJECTIVE

To use gonadotropin-releasing hormone agonist (GnRH-a) instead of human chorionic gonadotropin (hCG) to induce oocyte maturation for in vitro fertilization (IVF).

DESIGN

Pituitary and ovarian responses to GnRH-a and the outcome of IVF were studied prospectively. Data from patients injected with hCG were analyzed retrospectively.

SETTING

Program of IVF at the Rambam (Governmental) Hospital, Haifa, Israel.

PATIENTS AND INTERVENTIONS

One or two doses of buserelin acetate 250 to 500 micrograms were administered to six patients with moderate response (Estradiol [E2], 1,494 +/- 422 [+/- SD] pg/mL) and 8 patients with exaggerated response (E2, 7,673 +/- 3,028 pg/mL) to gonadotropin stimulation. Progesterone (P) and E2 were administered for luteal support.

MAIN OUTCOME MEASURES

Gonadotropin-releasing hormone agonist effectively triggered luteinizing hormone (LH)/follicle-stimulating hormone (FSH) surge. Mature oocytes were recovered in all patients. Luteal E2 and P were lower than in patients injected with hCG. No signs of ovarian hyperstimulation syndrome were observed.

RESULTS

Serum LH and FSH rose over 4 and 12 hours, respectively, and were significantly (P less than 0.05) elevated for 24 hours. Of all mature oocytes, 67% fertilized and 82% cleaved. Four pregnancies were obtained.

CONCLUSIONS

A bolus of GnRH-a is able to trigger an adequate midcycle LH/FSH surge, resulting in oocyte maturation and pregnancy. Our preliminary results also suggest that it allows a more accurate control of ovarian steroid levels during the luteal phase and may prevent the clinical manifestation of ovarian hyperstimulation syndrome.