Progesterone rise on the day of HCG administration (premature luteinization) in IVF: An overdue update

The pathogenesis of PL in COH is still poorly understood, and several hypotheses may be considered to explain this phenomenon: elevation of follicular LH levels, serum accumulation of HCG from HMG, increased LH receptor sensitivity of the granulosa cells to FSH, or poor ovarian response with increased LH sensitivity.