Triggering Ovulation at Follicle Size Smaller or Larger Than 17mm in a Modified Natural Cycle (17FET)

Vida Recoletas Sevilla

Status: Enrolling

Conditions: Embryo Transfer

Treatments: Procedure: Trigger at smaller folicular size

Study type: Interventional

Funder types: Other

Identifiers

NCT07088952

2310-SEV-02-MF

Details and patient eligibility

About

The rise in frozen embryo transfer (FET) cycles within assisted reproductive technology (ART) has sparked the need to refine endometrial preparation protocols. The switch from hormone replacement cycles (HRT) to natural cycles, poses scheduling challenges onto laboratories, doctors and patients. The modified natural cycle (mNC), offering more precision for scheduling, shows promise but lacks comprehensive data on the potential flexibility of triggering criteria that may allow to control timing in a wider range.

This prospective randomized study seeks to address this knowledge gap by evaluating the non-inferiority of triggering ovulation in mNC with follicle diameters of 13-16.9mm compared to the conventional 17-22mm.

The study aims to enhance the understanding of the impact of follicle size at ovulation in reproductive outcomes, optimize FET treatments providing a more flexible mNC protocol, and improve patient care in ART clinics.

Enrollment: 572 estimated patients

Sex: Female

Ages: 18 to 50 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• At least one expanded blastocyst (regardless of its quality)
• Spontaneous menstrual cycles
• Consent to undergo frozen embryo transfer in a modified natural cycle

Exclusion criteria

• Abnormal uterine cavity
• Fluid in endometrial cavity

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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572 participants in 2 patient groups

Control

No Intervention group

Description:

Trigger indicated as per standard clinical practice at folicular diameter of at least 17mm

Early trigger

Experimental group

Description:

Trigger indicated at folicular diameter smaller than standard clinical practice

Treatment:

Procedure: Trigger at smaller folicular size