A retrospective cross-sectional study: fresh cycle endometrial thickness is a sensitive predictor of inadequate endometrial thickness in frozen embryo transfer cycles

Patricia T Jimenez,Randall R Odem,Valerie S Ratts,Samantha B Schon,Emily S Jungheim

doi:10.1186/1477-7827-11-35

Abstract

BackgroundThe purpose of this study is to assess predictors of inadequate endometrial cavity thickness (ECT), defined as < 8 mm, in frozen embryo transfer (FET) cycles.MethodsThis is a retrospective cross-sectional study at an academic fertility center including 274 women who underwent their first endometrial preparation with estradiol for autologous FET in our center from 2001-2009. Multivariable logistic regression was performed to determine predictors of inadequate endometrial development in FET cycles.ResultsNeither age nor duration of estrogen supplementation were associated with FET endometrial thickness. Lower body mass index, nulliparity, previous operative hysteroscopy and thinner fresh cycle endometrial lining were associated with inadequate endometrial thickness in FET cycles. A maximum thickness of 11.5 mm in a fresh cycle was 80% sensitive and 70% specific for inadequate frozen cycle thickness.ConclusionsPrevious fresh cycle endometrial cavity thickness is associated with subsequent FET cycle endometrial cavity thickness. Women with a fresh cycle thickness of 11.5 mm or less may require additional intervention to achieve adequate endometrial thickness in preparation for a frozen cycle.

Highlights

The purpose of this study is to assess predictors of inadequate endometrial cavity thickness (ECT), defined as < 8 mm, in frozen embryo transfer (FET) cycles
Cryopreservation of embryos created during fresh in vitro fertilization (IVF) cycles provides a less expensive and time-intensive opportunity for pregnancy
Subjects with inadequate endometrial development during FET had a lower body mass index (BMI) (22.7±3.51 vs. 25.62±5.54 kg/m2; p

Summary

Introduction

The purpose of this study is to assess predictors of inadequate endometrial cavity thickness (ECT), defined as < 8 mm, in frozen embryo transfer (FET) cycles. As in vitro fertilization (IVF) culture techniques continue to improve, the number of embryos transferred in each cycle decreases. Transferring fewer embryos is a key component in preventing multiple gestations and their associated complications. Fresh IVF cycles often lead to supernumerary embryos. Cryopreservation of embryos created during fresh IVF cycles provides a less expensive and time-intensive opportunity for pregnancy. Vitrification has proven to be a superior method for cryopreservation, further improving frozen embryo transfer (FET) pregnancy rates [1,2]. Optimization of the FET cycle is crucial

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