The Clinical Pregnancy Rates in Fresh Embryo Transfer Cycles are in Good Direct Correlation with the Entire Range of Pre-hCG Endometrial Thickness Values

Introduction:

Endometrial thickness is an established predictor of endometrial receptivity, with a threshold of

Aim:

To assess the association between endometrial thickness above the 7mm threshold and clinical pregnancy rates (CPR).

Materials:

A retrospective cohort study including all fresh embryo transfer IVF cycles of patients younger than 42 years, performed in our IVF unit, between 2009-2014. Basic clinical characteristics and treatment results were recorded. In all cases, endometrial thickness was measured with trans-vaginal ultrasound on the day of HCG triggering. Patients were divided into 5 groups based on endometrial thickness: <7mm; 7-9 mm; 10-12mm, 13-15mm, >15mm. Clinical pregnancy was defined as an intrauterine gestation with fetal heart beat on trans-vaginal ultrasound 4 weeks after embryo transfer.

Results:

During the study period 3871 IVF cycles were conducted in patients 15mm group had a significantly higher CPR (n=83; 47%) compared to the 13-15mm group (p<0.001). A univariate logistic regression analysis showed a linear correlation between endometrial thickness and clinical pregnancy rates (p<0.001).

Conclusions:

Thicker endometrium on day of HCG triggering in IVF cycles was associated with higher CPRs for all the ranges of endometrial thickness. The thicker the endometrium was the higher the chances to conceive.