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

Ovo Clinic

Status: Completed

Conditions: Fertility Disorders

Treatments: Other: Frozen embryo transfer

Study type: Observational

Funder types: Industry

Identifiers

NCT06053827

3356

Details and patient eligibility

About

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.

Enrollment: 1,207 patients

Sex: Female

Ages: Under 40 years old

Volunteers: No Healthy Volunteers

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

Trial design

1,207 participants in 2 patient groups

Frozen embryo transfer substituted cycle

Description:

In a substituted cycle, estrogen and progesterone are given and a transfer is planned when the endometrium is ready

Treatment:

Other: Frozen embryo transfer

Frozen embryo transfer natural cycle

Description:

In a natural cycle no hormones are given and a transfer is planned when there is a dominant follicle apparent at the ultrasound

Treatment:

Other: Frozen embryo transfer