OBJECTIVE: The aim of this study was to evaluate an individualised gonadotrophin starting dose regimen for women with anovulatory infertility.

STUDY DESIGN: We included 71 normogonadotrophic anovulatory infertile women in a prospective, observational study. All underwent one ovulation induction cycle in a flexible, low-dose step-up protocol. The gonadotrophin starting dose (75-150IU/day) was individualised according to a nomogram incorporating menstrual cycle pattern (oligo- or amenorrhoea), BMI, and mean ovarian volume. The number of women who fulfilled the criteria for human chorionic gonadotrophin (hCG) administration (one follicle ≥17mm or 2-3 follicles ≥15mm) was assessed.

RESULTS: Of the 50 women (70.4%) who fulfilled the hCG criteria and underwent intrauterine insemination, 34 (47.9%) achieved monofollicular growth and 16 (22.5%) developed 2-3 mature follicles. Seventeen (23.9%) cycles were converted to in vitro fertilisation (IVF) due to the development of >3 mature follicles, and one (1.4%) cycle was cancelled due to risk of ovarian hyperstimulation syndrome. Baseline total antral follicle count was found to be significantly associated with fulfillment of the hCG criteria (OR 0.96, 95% CI: 0.92-0.99, P=0.01).

CONCLUSIONS: The nomogram-based dose regimen was not considered suitable for ovulation induction due to a tendency to overestimate the gonadotrophin starting dose. However, the model may serve as a mild IVF regimen, especially in women prone to excessive follicle growth.