Correlation between endometrial biopsy and luteal phase plasma progesterone in women complaining for couple infertility.

One hundred forty-three women complaining for couple infertility (more than 2 yr), were investigated for luteal phase deficiency (i.e. insufficient endometrial luteinization) by endometrial biopsy and serial determinations (in days -10, -7 and -4 respect the onset of the next menses) of plasma progesterone during luteal phase. One hundred-three women had the first endometrial biopsy in phase (IP), 36 had the biopsy "out of phase" (OOP). Among them 13 did not repeat endometrial biopsy, 12 had the second biopsy out of phase (and then classified as Luteal Phase Deficiency) and 11 had the second biopsy "in phase". Only the women affected by luteal phase deficiency had the plasma progesterone (mean of 3 samples) significantly lower than that of infertile women with normal endometrial luteinization. However the majority of the individual progesterone values of these two groups overlapped. The endometrial biopsy seems to be the most practicable method for investigating luteal phase deficiency in women complaining for couple infertility.