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

Recruiting now

Conditions studied: Fertilization, Fertilization in Vitro

In brief

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.

Key facts

Study ID

NCT06433518

Run by

Centrum Clinic IVF Center

People needed

200

Starts

2026-03-15

Expected to finish

2026-12-30

Last updated by the study team

2026-03-19

Who can join

Age: 35 and older, up to 44. Sex: female. Healthy volunteers: not accepted.

You may qualify if…

• 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

You may not qualify if…

• 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.

Where it is running

• Centrum Clinic IVF Center — Ankara, Ankara, Turkey (Türkiye) (enrolling)

Full record on ClinicalTrials.gov

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