This prospective cohort study aims to compare three ultrasound based methods Applebaum score Modified Applebaum score and External Layer Thickness ELT to determine which best predicts endometrial receptivity and clinical pregnancy after frozen embryo transfer FET

The study evaluates women aged 22 to 42 undergoing single or double embryo transfer with at least one good quality embryo 

Applebaum and Modified Applebaum scores assess multiple endometrial parameters while ELT is a simpler quantitative measure describing the outer hyperechoic layer

Although widely used comparative prospective data on these scoring systems are limited

The primary objective is to identify which scoring system most accurately predicts clinical pregnancy

Secondary analyses include diagnostic accuracy sensitivity specificity positive predictive value negative predictive value association with early pregnancy loss and odds of pregnancy across high and low score groups. Ultrasound assessments are performed on the day of progesterone start and outcomes are measured through beta hCG and clinical pregnancy confirmation

Statistical analysis will involve ROC curve comparison regression models and appropriate inferential tests. Ethical approval informed consent and secure data handling will be ensured

This study may help determine whether a complex score a modified system or a single ELT measurement provides the most reliable tool for clinical decision making and improving FET outcomes.