Implantation: The correlation of placental protein 14 concentrations in uterine flushing and endometrial morphology in the peri-implantation period

Abstract

The relationship between the concentrations of placental protein 14 (PP14) in uterine flushing and the endometrial morphology in the mid-luteal phase was assessed in a prospectively designed study involving the precise timing of all samples by the luteinizing hormone (LH) surge. A total of 29 regularly cycling women with unexplained infertility or recurrent miscarriage were studied. To flush the uterine cavity, 10 ml of physiological saline solution was used immediately prior to sampling of an endometrial specimen for morphological study, in the mid-luteal phase. PP14 concentrations were measured by radioimmunoassay in uterine flushings and plasma samples; the endometrium was assessed by the use of histological dating criteria and morphometric techniques. PP14 levels in uterine flushings were correlated with endometrial dating and volume fraction measurement of the glands. They were consistently below the sensitivity of the assay with histological dating of < day LH +5, or when the glandular lumen occupied < 20% of the gland. In contrast, PP14 concentrations in plasma were not related to histological dating or morphometric analyses, and did not differ in patients with normal endometrial development (20.8 ng/ml) and in those with retarded endometrial development (22.5 ng/ml). The presence of detectable concentrations of PP14 in uterine flushing was significantly associated with normal histological dating. Uterine flushing may therefore provide a reliable, non-invasive alternative to endometrial biopsy in the evaluation of endometrial function in the peri-implantation period.