Influence of body mass index on the relationship between endometrial thickness and pregnancy outcome in single blastocyst frozen embryo transfer cycles.

To date there is limited published data assessing whether body mass index (BMI) influences endometrial thickness (ET) and whether this impacts on pregnancy outcomes in single blastocyst FET cycles. The objective of this study, therefore, was to examine the relationship between BMI and ET on the outcome of single blastocyst FET cycles over a five-year period from 2012 until 2016. Patient age, BMI, endometrial pattern and ET prior to FET were recorded. Pregnancy outcomes included: implantation rate, clinical pregnancy rate and live birth rate. A total of 464 cycles met the inclusion criteria and the female age was 36.0 ± 3.0 years (mean ± SD). The mean ± SD BMI was 23.3 ± 3.1 kg/m