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

NCT ID: NCT07088952

Last Updated: 2026-01-13

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

572 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-10-22

Study Completion Date

2028-05-30

Brief Summary

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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.

Detailed Description

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Conditions

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Embryo Transfer

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Prospective open randomized parallel group 1:1 ratio
Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

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Control

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

Group Type NO_INTERVENTION

No interventions assigned to this group

Early trigger

Trigger indicated at folicular diameter smaller than standard clinical practice

Group Type EXPERIMENTAL

Trigger at smaller folicular size

Intervention Type PROCEDURE

Trigger indicated at folicular diameter smaller than standard clinical practice, from 13mm to 16.9mm

Interventions

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Trigger at smaller folicular size

Trigger indicated at folicular diameter smaller than standard clinical practice, from 13mm to 16.9mm

Intervention Type PROCEDURE

Eligibility Criteria

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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
Minimum Eligible Age

18 Years

Maximum Eligible Age

50 Years

Eligible Sex

FEMALE

Accepts Healthy Volunteers

No

Sponsors

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Vida Recoletas Sevilla

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Vida Recoletas Sevilla

Seville, Sevilla, Spain

Site Status RECRUITING

Countries

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Spain

Central Contacts

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Manuel Fernández Sánchez, MD PhD

Role: CONTACT

+34954286274

Clara Palacio de Marco, MSc

Role: CONTACT

+34954286274

Facility Contacts

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Clara Palacio de Marco, MSc

Role: primary

+34954286274

Other Identifiers

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2310-SEV-02-MF

Identifier Type: -

Identifier Source: org_study_id

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