P-522 Embryo transfer procedural parameters do not predict IVF cycle outcome
Authors: Sfakianoudis K , Maziotis E , Tzonis P , Vaxevanoglou T , Grigoriadis S , Rapani A , Kotsifaki A , Pistola K , Pantou A , Simopoulou M , Pantos K 
Published: June 2023

Abstract

Study question
Do embryo transfer (ET) procedural parameters affect the clinical outcome, in terms of positive human chorionic gonadotropin (hCG), clinical pregnancy and live-birth?

Summary answer
Observation of ET procedural parameters, either as single parameters or combined in a model, does not seem to have a predictive value on cycle outcome.

What is known already
It has been reported that several ET procedural parameters of technical nature may influence IVF outcome. Observational studies on variables during and post ET from mucus presence to catheter reload, have been published and data hitherto is conflicting leaving practitioners confounded. It is essential to evaluate the effect of the reported ET performance parameters, clarifying the degree of effect on a singular or combinatorial level. This will assist practitioners in recording and analysing strictly factors that hold high-significance predictive value, instead of redundantly recording moot parameters that may be unfit to serve as key performance indicators post ET.

Study design, size, duration
A prospective observational study was performed between 3/2018 and 9/2022 in a single IVF center. ET procedures for a total of 1417 women were assessed. The performance parameters studied and associated with clinical outcomes were the following: time of ET, presence of cervical mucus in the catheter, presence of blood, catheter reload, employment of tenaculum and stylet, resistance during transfer, ease of transfer according to the practitioner and discomfort as experienced by the patient.

Participants/materials, setting, methods
Only women of normal endometrial and uterine anatomy and function were included. Genetic and endocrine abnormalities, azoospermia and PGT cycles were excluded. Embryo grading was performed according to Veeck’s and Gardner’s system depending on developmental stage. All ETs were performed employing the same type of soft catheter. The clinical outcomes evaluated were positive hCG, clinical pregnancy, and live-birth. Associations were evaluated on a singular or combinatorial level between the ET performance parameters and clinical outcomes.

Main results and the role of chance
A univariate logistic regression was employed to evaluate the possible effect of each of the ET procedural parameters. None of the ET parameters presented with statistical significance. The employment of ultrasound, the number, and the quality of transferred embryos, maternal age as well as the physician and embryologist performing the transfer were evaluated as covariates in a univariate regression model. Number (p = 0.01) and quality of transferred embryos (p = 0.003), as well as maternal age (p = 0.004) presented with statistical significance. The multivariate approach yielded similar results. To evaluate the possibility that interactions between the ET procedural parameters could affect cycle outcome a model was created evaluating all possible interactions and combination of the ET parameters. To adjust for possible multiple comparison bias, the Bonferroni correction was employed. Only the presence of mucus along with significant resistance seemed to present with statistical significance (p &lt; 0.0001). However, when adjusting for the covariates the combination of cervical mucus and significant resistance did not provide a statistically significant effect on clinical outcomes and thus cannot be considered as an independent predictor. When subgrouping only for women below the age of 35 with at least one top quality embryo, no statistically significant association was observed.

Limitations, reasons for caution
The sample size could be a reason for caution when interpreting the results of the present study as a larger number of women presenting with each combination may be required to reach the threshold of statistical significance. The single-center nature of the study may present as another limitation.

Wider implications of the findings
Data indicates that ET procedural parameters hold no predictive value singularly or combinatorially. The only robust predictive factors are embryo quality, number, and maternal age. While further studies are required to cement this finding, it may be the case that the time-consuming recording and analysis of such parameters is redundant.

Trial registration number
Not applicable