Insulin-like growth factor binding protein-1 and ovarian stimulation

Serum concentrations of insulin-like growth factor binding protein-1 (IGFBP-1) were measured in 42 patients with tubal infertility undergoing two different regimens of ovarian stimulation for in-vitro fertilization. The first group comprised 24 women given a luteinizing hormone-releasing hormone agonist analogue (buserelin, LHRHa) on cycle days 1-4 followed by follicle-stimulating hormone and human menopausal gonadotrophin (LHRHa group). The second group of 18 women received clomiphene citrate and gonadotrophins (CC group). On the day of human chorionic gonadotrophin administration, the sum of follicular diameters (P less than 0.05) and the number of follicles punctured in the LHRHa group (P less than 0.01) were significantly higher than in the CC group. In spite of the greater number of follicles, the oestrogen levels were similar in both groups, but women in the LHRHa group had significantly higher serum IGFBP-1 concentrations during the last 5 days of stimulation. These results suggest that the stimulated preovulatory follicles may contribute to the elevation of serum IGFBP-1.