Circulating progesterone levels and ongoing pregnancy rates in controlled ovarian stimulation cycles for in vitro fertilization: analysis of over 4000 cycles

Elevated serum progesterone levels on the day of hCG administration is associated with reduced ongoing pregnancy rates. In particular, serum progesterone levels of >1.5 ng/ml were associated with lower ongoing pregnancy rates following IVF/ICSI cycles irrespective of the GnRH analogue used for pituitary down-regulation.