Prediction of pregnancy after frozen‐thawed embryo transfer via in vivo intrauterine oxidation‐reduction potential measurements: a pilot study

PURPOSE: During the implantation period, the uterus goes through many complex, orchestrated changes, including alterations of the glycocalyx that are due to sialylation, sulfation, and fucosylation. A previous mouse study showed that the in vivo intrauterine oxidation‐reduction potential (ORP) aided in determining the alterations in the uterine endometrium that are suitable for implantation and for evaluating prospective uterine receptivity, while the in vivo intrauterine pH did not. It was assessed if the in vivo intrauterine ORP could be a useful parameter to predict pregnancy in women. METHODS: A prospective cohort study was conducted for patients who had received a frozen‐thawed single embryo transfer in a programmed, hormonally controlled cycle. The in vivo intrauterine ORP was measured 3 times during the treatment cycle, at cycle days 9‐10, 1 day before progesterone administration and immediately before the embryo transfer. RESULTS: The amount of in vivo intrauterine ORP at 9‐10 days after the start of menstrual bleeding was significantly lower in the pregnant group than in the non‐pregnant group. A receiver‐operator characteristic curve analysis of the intrauterine ORP as a predictor of non‐conception showed an area under the curve of 0.80. CONCLUSION: The in vivo intrauterine ORP could be a useful parameter to predict pregnancy for the frozen‐thawed embryo transfer treatment cycle.