Failed endometrial metabolite synthesis contributes to subfertility in women with unexplained infertility

Aim: This study compares endometrial metabolite signal intensities of patients diagnosed with unexplained infertility (UEI) with those of fertile women. Material and Methods: A total of 20 patients diagnosed with UEI and 20 fertile women with at least two children were included in the study. UEI patients were matched with the fertile group in terms of age and BMI. UEI was defined as the absence of conception despite 12 months of unprotected intercourse, not explained by anovulation. Endometrial spectroscopy was applied to the women in both groups in the mid-luteal phase of the cycle. The endometrial signals of choline (Cho), creatine (Cr), lactate, and lipids were measured in units and denominated in parts per million. Results: All patients in both groups underwent successful spectroscopy and the main metabolites of Cho, Cr, lactate, and lipids were recorded. Cho (2.93 +/- 1.03 vs. 3.22 +/- 2.04, p<0.05) and Cr (2.33 +/- 1.30 vs. 2.76 +/- 1.43, p<0.01) metabolite signal intensities were found to be significantly lower in UEI patients compared to fertile controls. Lactate (0.56 +/- 0.11 vs. 0.62 +/- 0.30, p>0.66) and lipid (0.70 +/- 0.02 vs. 0.78 +/- 0.61, p>0.54) signal intensities were found to be similar between the groups. Discussion: Decreased Cho and Cr signals, which are physiological indicators of endometrial function, may be the possible cause of subfertility in UEI patients.