RecruitingNCT06433518

BEst Size for Ovulation Triggering in Poseidon 4 Patients (BEST 4 Study)

What Should Be The Optimal Ovulation Triggering Size in Poseidon Group 4 Patients Undergoing Ovarian Stimulation?

Sponsor

Centrum Clinic IVF Center

Enrollment

200 participants

Start Date

Mar 15, 2026

Study Type

OBSERVATIONAL

Conditions

Fertilization in Vitro Fertilization

Summary

This observational clinical study aims to determine the optimal timing of ovulation triggering in women aged 35 and above with poor ovarian reserve. For this purpose, cases undergoing ovarian stimulation for assisted reproductive treatment and planned final oocyte triggering will be evaluated in two separate groups: 1. \*\*Experimental Group\*\*: Final oocyte triggering will be performed when the follicle or follicles measure between 13-16 mm. 2. \*\*Control Group\*\*: Final oocyte triggering will be performed when the follicle or follicles measure greater than 17 mm. All triggers will be administered uniformly with 6500 units of recombinant hCG and 0,2 mg triptorelin injections. The primary outcome of the study will be the number of mature oocytes. Secondary outcomes will include fertilization rates, embryo counts, and implantation rates. Primary and secondary outcomes will be compared between the two groups.

Eligibility

Sex: FEMALEMin Age: 35 YearsMax Age: 44 Years

Inclusion Criteria5

Women age equal to or greater than 35 years
Women with low serum AMH (\<1,2 ng/ml),
women with low AFC (\<5)
women Undergoing assisted reproduction with Short antagonist protocol or long -agonist protocol
women who used Max daily gonadotropin dose of 300 IU

Exclusion Criteria9

Age \<35 years.
Ovarian reserve parameters not meeting the POSEIDON group 4 definition.
Natural or modified natural cycles without controlled ovarian stimulation.
In vitro maturation (IVM) cycles.
Luteal-phase stimulation or DuoStim protocols.
Preimplantation genetic testing (PGT-A, PGT-M, or PGT-SR) cycles, unless prespecified for stratified analyses.
Major untreated uterine cavity pathology (e.g., submucosal fibroids, significant intrauterine adhesions, congenital uterine anomalies) or untreated hydrosalpinx.
Cycles with missing or incomplete follicular measurement data on the trigger day.
Cycles with non-standardized or undocumented trigger-to-oocyte retrieval intervals.

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Interventions

OTHEROvulation Trigger Timing Based on Leading Follicle Size in POSEIDON Group 4 IVF Patients

In this study, ovulation trigger timing is determined according to the diameter of the leading follicle measured by transvaginal ultrasound during ovarian stimulation in women classified as POSEIDON group 4. Patients undergoing controlled ovarian stimulation are monitored with serial ultrasound examinations and serum hormone measurements. Ovulation triggering is performed when the leading follicle reaches predefined size categories. The study evaluates the association between the diameter of the leading follicle at the time of trigger and reproductive outcomes. The primary outcome measure is the number of metaphase II (MII) oocytes retrieved, while secondary outcomes include blastocyst formation and pregnancy outcomes.