New Insight of Lipiodol Flush on Pregnancy Outcomes in Women with Recurrent Implantation Failure Undergoing IVF/ICSI: a Prospective Study Based on Propensity Score Matching.

Pregnancy outcomes in women with recurrent implantation failure (RIF) undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI): does treatment with lipiodol flush matter? In this propensity score-matched study, we recruited 966 RIF patients who underwent IVF/ICSI from two tertiary hospitals. These patients were divided into groups based on whether they received lipiodol flush or not. Further stratification was applied to investigate the effect of lipiodol flush on pregnancy outcomes in RIF patients with different cycle type of embryo transferred. Then, patients subjected to lipiodol flush were categorized into three groups based on the duration of the interval: short interval (≤ 3 months), moderate interval (3-6 months), and long interval (≥ 6 months). The groups were well-matched at baseline. The lipiodol flush group exhibited a significantly lower incidence of biochemical pregnancy (46.27% vs. 56.22%, p = 0.046) and live birth (25.87% vs. 37.31%, p = 0.014). Subgroup analysis for fresh embryo transfer cycles revealed no significant differences in pregnancy outcomes. Among RIF patients underwent frozen-thawed embryo transfer cycle, a statistically significant difference in the live birth rate was observed in the lipiodol flush group when compared to the control group (26.40% vs. 37.21%, p = 0.030). Analysis of different lipiodol flush intervals demonstrated a significantly lower live birth rate in the lipiodol flush group. Our results challenge the value of lipiodol use in clinical practice for the treatment of RIF.Trial registration: Chinese Clinical Trial Registry, ChiCTR1900024273. Registered 4 July 2019.