# Analysis of the day 3 transfer strategy for POSEIDON patients

## TL;DR

This study compares embryo transfer strategies in POSEIDON and non-POSEIDON patients, finding day 3 transfers are most effective for POSEIDON patients, with group I having the best outcomes.

## Contribution

The study provides new insights into the effectiveness of day 3 embryo transfer for specific POSEIDON patient groups, highlighting group-specific outcomes.

## Key findings

- POSEIDON patients had 42% of cycles ending with day 3 embryo transfer, while non-POSEIDON patients mostly underwent frozen embryo transfer.
- POSEIDON group I had the highest rate of top-quality embryos and implantation potential at 28%.
- Patients aged ≥35 in all groups had the highest miscarriage rates.

## Abstract

The aim of the study was to analyze the effectiveness of the day 3 ET
strategy, and the morphology of the transferred embryos, in patients from
POSEIDON and non-POSEIDON groups.

600 cycles of patients meeting the POSEIDON criteria and 600 non-POSEIDON
cycles were analyzed to determine the proportion of cycles with an ET on
days 3 or 5, or FET. Then we reviewed 330 day 3 ETs to compared the
developmental stage, morphology, zona pellucida thickness and implantation
potential of embryos transferred on day 3 from POSEIDON and non-POSEIDON
patients.

Most cycles of POSEIDON patients end with ET on day 3 (42%) or without
transfer (37%). In contrast, most cycle of non-POSEIDON patients end with
FET (44%) and just 9% is canceled. The lowest percentage of embryos at the
morula stage was recorded in POSEIDON groups III (10%) and IV (9%). The
average number of cells in embryos was comparable in all groups. The largest
percentage of top-quality embryos (grade A) were in POSEIDON group I (47%)
.The highest implantation potential were observed in the non-POSEIDON group
<35Y (28%), and in POSEIDON groups I (28%) and III (26%). The highest
incidence of miscarriage was recorded in all POSEIDON and non-POSEIDON
groups that included patients who were ≥35 years of age.

The day 3 ET strategy still seems optimal for POSEIDON patients. The
prognosis depends on which Poseidon group the patient is in. The best
prognosis is for group I and the worst for group IV.