This prospective study was designed to examine the feasibility of natural cycle in vitro fertilization (IVF) in poor responders, and the clinical factors that may predict successful outcome. Twenty-two poor responders underwent IVF treatment with 44 unstimulated cycles. The results of the natural cycles were compared with those of the 55 low-response stimulated cycles of these patients during the 12 months prior to the study. Eighteen (82%) patients had at least one oocyte retrieved, while nine (41%) had at least one cycle with embryo transfer. Two (9%) patients each gave birth to a healthy term baby. These results are comparable with those of the stimulated cycles. Serum early follicular follicle stimulating hormone (FSH) level was found to be the only reliable predictor of oocyte recovery and overall outcome in each specific natural cycle. However, because of great variability in basal FSH levels among different cycles of the same patient, this is not a reliable predictor of outcome in future cycles. We conclude that poor responders are a unique group of patients who may benefit from natural-cycle IVF treatment.

This prospective study was designed to examine the feasibility of natural cycle in vitro fertilization (IVF) in poor responders, and the clinical factors that may predict successful outcome. Twenty-two poor responders underwent IVF treatment with 44 unstimulated cycles. The results of the natural cycles were compared with those of the 55 low-response stimulated cycles of these patients during the 12 months prior to the study. Eighteen (82%) patients had at least one oocyte retrieved, while nine (41%) had at least one cycle with embryo transfer. Two (9%) patients each gave birth to a healthy term baby. These results are comparable with those of the stimulated cycles. Serum early follicular follicle stimulating hormone (FSH) level was found to be the only reliable predictor of oocyte recovery and overall outcome in each specific natural cycle. However, because of great variability in basal FSH levels among different cycles of the same patient, this is not a reliable predictor of outcome in future cycles. We conclude that poor responders are a unique group of patients who may benefit from natural-cycle IVF treatment.

The aim of this prospective randomized study was to compare the effects of two gonadotrophin-releasing hormone (GnRH) agonists, buserelin and triptorelin, on human ovarian follicular steroidogenesis, oocyte fertilization and IVF treatment outcome. Ovulatory, healthy women undergoing IVF were treated either with human menopausal gonadotrophin (HMG) alone or with HMG and one of the two GnRH agonists. Serum and follicular fluid hormonal concentrations and cultures of luteinizing granulosa cells obtained during follicular aspiration were analysed. GnRH agonist treatment significantly affected steroidogenesis both in serum and follicular fluid. In follicular fluid, progesterone and oestradiol concentrations were significantly elevated while testosterone concentrations were significantly lower in the triptorelin group. The ratios of testosterone/progesterone, oestradiol/progesterone but not oestradiol/testosterone concentrations were significantly affected by GnRH agonist administration. Similarly, the steroidogenic activity of luteinizing granulosa cells in vitro was significantly decreased in women treated with GnRH agonists. Women treated with GnRH agonists had significantly more fertilized oocytes and cleaving embryos. The results indicate a marked effect of GnRH agonists on the pattern of ovarian follicular steroidogenesis that cannot be explained solely by changes in gonadotrophin concentrations.

The study was undertaken to examine any differences existing in total cortisol concentrations in the follicular fluid (FF) of pre-ruptured follicles between 'low responder' patients (group 1, n = 20) and 'good responder' patients (group 2, n = 15). The groups were defined according to how many oocytes had been retrieved during the previous in-vitro fertilization procedure (group 1: three or fewer; group 2: more than three) and total oestradiol concentration at previous in-vitro fertilization (IVF) (group 1: < or = 500 pg/ml; group 2: > 500 pg/ml). All patients were aged 36-43 years (group 1 mean +/- SD: 38.2 +/- 4.7; group 2: 32.1 +/- 3.8 years) and were diagnosed with tubal or unexplained infertility. The total FF cortisol concentrations obtained in conjunction with an IVF procedure were assayed and related to oocyte fertilization. Follicular fluid was analysed for total cortisol content. Only follicles between 19 and 20 mm diameter were analysed in both groups. After aspiration of blood-free FF, total cortisol concentrations were measured by radioimmunoassay, designed for the quantitative measurement of cortisol, and related to oocyte fertilization. Total cortisol concentration in FF from fertilized oocytes was 9.7 +/- 0.6 microg/ml (mean +/- SD) in group 1 compared to 9.2 +/- 4.4 microg/ml in group 2 (not statistically significant). Total cortisol concentrations were not associated with oocyte fertilization and no difference between the groups was found in total cortisol concentrations in the FF of unfertilized oocytes or empty follicles.