Fig. 1

Fluctuating serum estrogen (E2), FSH and LH levels of the patient with PCOS during a controlled ovarian hyperstimulation (COH) regime in the IVF cycle. A prolong- acting agonist protocol was selected. Before the initiation of therapy, the baseline serum E2, FSH and LH levels were tested on the third day of menstruation (0). Twenty-eight days after pituitary downregulation with GnRHa (3.75 mg), the patient received 31-day Gn administration and exhibited slowly increasing and fluctuating levels of serum E2 in the cycle