Figure 4

Illustration of the heterogeneity in follicle size following controlled ovarian stimulation in rhesus macaques. The number and size of antral follicles that develop on the ovaries after daily treatment with exogenous gonadotropins can be estimated by transabdominal ultrasonography (left panel). The percent of the total follicle cohort at various sizes ≥ 2 mm diameter on day 7 of our standard COS protocol (6 days of r-hFSH, 30 IU 2× per day, then r-hFSH + r-hLH, 30 IU each 2× per day; plus daily GnRH antagonist treatment [15]) are illustrated in the right panel. Typically, in this and prior [39] protocols, follicles vary in size between 2 to 6–8 mm in diameter.