Triggering of ovulation using a gonadotrophin-releasing hormone agonist does not prevent ovarian hyperstimulation syndrome.

A total of 24 women with primary or secondary infertility due to oligo- or anovulation, were treated with human menopausal gonadotrophin (HMG). In 48 cycles, we used a gonadotrophin-releasing hormone agonist (GnRHa) nasal spray (buserelin) to induce a pre-ovulatory endogenous luteinizing hormone (LH) surge. In 44 cycles, there was a rapid rise of the serum LH concentration within 8 h from the first administration of GnRHa. One patient with pituitary hypogonadotrophic amenorrhoea showed a weak or no response in four treatment cycles. Conception occurred in 10 cycles (pregnancy/cycle (P/C) index = 22.7%), four of which ended in a spontaneous abortion and six of which are ongoing pregnancies. In 27 cycles, there was an increased risk for ovarian hyperstimulation syndrome (OHSS), defined as more than three follicles > or = 18 mm in diameter and/or serum oestradiol > 1200 pg/ml. Three of these treatment cycles gave rise to the development of moderate OHSS in the absence of exogenously administered human chorionic gonadotrophin, two being conception cycles.