Efficacy of low-dose human chorionic gonadotropin alone to complete controlled ovarian stimulation

To prove that low-dose hCG alone can be clinically used to replace FSH-containing gonadotropins to complete controlled ovarian hyperstimulation (COH). Controlled, prospective, randomized study. Academic center. Infertile patients who are candidates for assisted reproduction. Patients received [1] recombinant FSH or hMG throughout COH (group A); [2] ovarian priming with recombinant FSH/hMG followed by low-dose hCG (200 IU/day) alone (group B). Medication consumption; daily serum and follicular fluid (FF) measurements of LH, FSH, hCG, E 2, P, T, and androstenedione (A); number and size of follicles; intracytoplasmic sperm injection (ICSI) outcome. In group B: [1] duration and dose of recombinant FSH/hMG administration were reduced; [2] preovulatory serum hCG, E 2, and T were higher, whereas FSH was lower; [3] FF hCG, E 2, T levels, and E 2/T, E 2/A, and E 2/P ratios were higher, whereas A was lower; [4] small but not large preovulatory follicles were reduced; [5] fertilization rates were higher; and [6] serum and FF P levels, and ICSI outcome did not differ. Low-dose hCG alone in the late COH stages: [1] reduced recombinant FSH/hMG consumption whereas ICSI outcome was comparable to traditional COH regimens; [2] stimulated follicle growth and maturation independent of FSH administration; [3] was associated with a reduced number of small preovulatory follicles; [4] did not cause premature luteinization; [5] resulted in a more estrogenic intrafollicular environment.