P–399 Temporal dynamics of an IVF/ICSI success prediction test based on the vaginal microbiome

Study question What is the influence of time on the vaginal microbiome-based prediction of IVF/ICSI success? Summary answer Time influences the vaginal microbiome-based prediction of IVF/ICSI success. What is known already The association between the microbiome of the lower female reproductive tract and subfertility is discussed extensively suggesting its importance for fertility and fertility treatment. Using a modified next generation sequencing technique, an assay of the vaginal microbiome that predicts the pregnancy chances before starting the IVF/ICSI procedure has been developed and validated (1) displaying profiles associated with a low, medium and high chance of implantation. The vaginal microbiome is already known to change over time (2). However, it remains unclear to what extent spontaneous improvement from a low score can occur and over what time period. Study design, size, duration To investigate the spontaneous reversal capacity and associated time period of a low score microbiome profile in IVF-ICSI patients, an observational prospective cohort study of 77 women was performed using the ReceptIVFity assay. Women with medium or high profiles were encouraged to proceed with their ART treatment, whereas women with a low profile were suggested to delay the treatment for 1 month until a subsequent swab was taken with a maximum of 4 repeats. Participants/materials, setting, methods The study was carried out in a University based single center setting. Ethical approval was obtained (6259R MPG§23b). Patients between 24 and 41 years of age were included when eligible for their first, second or third IVF or IVF-ICSI attempt. Exclusion criteria were: antibiotic treatment in the 3 months prior to the test, women who have started with hormone treatment in the last 2 months in the context of ovarian stimulation, or downregulation of endometriosis. Main results and the role of chance Of the 77 patients included, 53 had a high or medium profile and proceeded with their treatment. 24 had a low profile and were supposed to delay the treatment in favor of a subsequent test. The low profile patients were followed up as indicated in the study description. Unfortunately, 11 of the 24 low score patients dropped out of the study. This relatively high number can only in parts be explained by unswayable medical reasons as no fertilization or embryo arrest but a comparable number of patients dropped out most likely due to Corona restrictions or Corona-related anxiety reasons. In the low score group, 1 month after the initial test, 12 patients repeated the swab; 4 remained low (33,33%), whereas 8 shifted to the medium or high (66,67%) groups. After 2 months, 4 patients had another test; 1 remained low (25%), 3 shifted to medium and high (75%). Therewith, in two months’ time 91,7% shifted from low to a better (medium/high) profile. So far, only 1 patient of the initial lows remained low for 5 months. The 12 shifters had a clinical pregnancy rate of 40% after the first embryo transfer after changing the microbiome profile from low to medium/high. Limitations, reasons for caution The results described were generated from a smaller group than intended initially due to a relative high dropout rate for no medical reasons. Wider implications of the findings: Patients suffering from infertility have a clinical benefit from performing a ReceptIVFity test before ART treatment and to delay treatment, when the result is low, since the spontaneous conversion time to a better profile, and therewith a higher pregnancy chance, occurred within 2 month in almost all patients. Trial registration number 2018124928