Natural Frozen Embryo Transfer (FET) vs Substituted Frozen Embryo Transfer (FET)

Clinique Ovo1,207 enrolled

Overview

In frozen embryo transfer substituted cycles, patients are treated with progesterone and estrogen in an attempt to mimic the natural cycle and a transfer is planned whenever the endometrium is ready. In contrast, in frozen embryo transfer natural cycle patients are not taking any hormones, only triggered with hCG (human chorionic gonadotropin) when a dominant follicle is ready or they wait for the disappearance of the dominant follicle to plan the transfer date. Some doctors and centres shift towards using the substituted protocol in an attempt to make scheduling easier with less frequent ultrasounds. This study will aim to compare clinical and biochemical pregnancy rates in patients who underwent frozen embryo transfers in natural cycles vs substituted cycles at the centre.

Study Type

OBSERVATIONAL

Enrollment

1,207

Conditions

Fertility Disorders

Interventions

Frozen embryo transferOTHER

A frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy

Medical Language ↔ Plain English

Inclusion Criteria: * Age \< 40 years old * Women having undergone either a frozen embryo transfer in natural cycle or substituted cycle * IVF and FET cycles done at Clinique OVO Exclusion Criteria: * egg or embryo recipient * History of recurrent miscarriages, defined as ≥ 3 consecutive losses * Patients that needed Viagra, Plasma-Rich Platelet (PRP) or other modalities to improve their endometrial thickness * Uterine abnormalities * Abnormal hormonal profiles * FET Stimulated cycles * History of recurrent implantation failure defined as failed ≥ 2 euploid embryos transfer or ≥ 3 blastocysts

Outcomes

Primary Outcomes

Evaluate the clinical pregnancy rate of embryo transfer in natural vs substituted cycles

clinical pregnancy is the presence of fetal heartbeat at the viability ultrasound

Time frame: 6 to 8 weeks after Frozen Embryo Transfer