Fig. 4
From: The natural menstrual cycle revisited – can natural cycle be trusted
Relation between antral follicle count and FSH levels day 5. Blue dot represents a cycle with serum progesterone levels ≥ 30 nmol/L on cycle day 20 or 25. Red dot represents a cycle with serum progesterone levels < 30 nmol/L on cycle day 20 and 25