[Gonadotrophin dose and ovarian response: relations to the clinical outcome of in vitro fertilization and embryo transfer].

Objective: To investigate the association of gonadotrophin (Gn) dose and ovarian response with the clinical outcome of in vitro fertilization and embryo transfer (IVF-ET).

Methods: Patients undergoing IVF-ET with Gn stimulation for no more than 15 days were enrolled in this study. The patients were divided into 3 groups, namely group A (390 cycles) with total Gn dose :3375 IU and retrieved oocytes:4, group B (64 cycles) with total Gn dose :3375 IU and retrieved oocytes < or =3, and group C (97 cycles) with total Gn dose< or =3300 IU and retrieved oocytes< or =3. The clinical characteristics and outcomes of these 3 groups were comparatively analyzed.

Results: The clinical pregnancy rate and delivery rate were 38.8% and 32.5% in group A, 16.7% and 10.4% in group B, and 27.3% and 23.4% in group C, respectively. The follicle number, oocyte number, number of embryo transferred, peak serum E2 level, clinical pregnancy rate and delivery rate were significantly higher in group A than in groups B and C (P<0.05). Groups B and C had similar follicle number, oocyte number, and number of available embryos, but group C had significantly lower total Gn dose (P<0.05); the peak serum E2 level, clinical pregnancy rate and delivery rate were lower in group B than in group C, but the difference was not statistically significant (P>0.05).

Conclusions: In patients receiving a relatively low dose of Gn with smaller number of retrieved oocytes, Gn dose increment can improve the clinical pregnancy rate and delivery rate, suggesting a state of relatively poor ovarian response or mild ovarian reserve decrease; failure of increasing the number of oocytes retrieved with greater Gn dose suggests severely decreased ovarian responsiveness or ovarian reserve and also poor clinical prognosis.