An interventional study of follicular flushing and follicular aspiration in Low Ovarian Reserve, Poor Response to Ovulation Induction Poseidon Type IV and Poor Response to Ovulation Induction, sponsored by Instituto Bernabeu. Completed at 1 site in Spain. Open to female participants aged Up to 43 Years. Per ClinicalTrials.gov, last updated 2026-04-14.
Sponsored by Instituto Bernabeu · Not applicable, Interventional, and Treatment
This is a prospective, randomized, controlled clinical trial designed to evaluate whether follicular flushing increases the number of cumulus-oocyte complexes (COCs) retrieved compared to single aspiration in patients with poor ovarian response belonging to Poseidon groups 3 and 4.
A total of 40 patients with poor ovarian response belonging to Poseidon groups 3 and 4 will be included. In each patient, one ovary will be randomized to the study technique (follicular flushing), and the other ovary will be randomized to the control technique (single aspiration).
This is a prospective, randomized, controlled clinical study designed to evaluate the effect of follicular flushing on the number of cumulus-oocyte complexes (COCs) retrieved, compared to single aspiration, in patients with poor ovarian response classified as Poseidon groups 3 and 4.
A total of 40 patients will be included. All participants will receive a standardized stimulation protocol consistent with current practice for patients diagnosed with low ovarian reserve. After meeting all inclusion criteria, controlled ovarian stimulation will begin within the first four days of the menstrual cycle, using an antagonist protocol in all cases.
Starting on the 6th day of ovarian stimulation, daily administration of a GnRH antagonist at a dose of 0.25 mg (Ganirelix® or Cetrorelix®) will be initiated. Final oocyte maturation will be triggered once at least one follicle reaches a diameter of ≥17 mm, using either 250 μg of recombinant hCG (Ovitrelle®; Merck Serono) or 0.2 mg of triptorelin acetate (Decapeptyl®), or a double trigger. Oocyte retrieval will be performed 36 hours after triggering final oocyte maturation.
On the day of oocyte retrieval, randomization will be performed using a computer-generated randomization list. In each patient, one ovary will be randomly assigned to the control group (single aspiration), and the contralateral ovary will be assigned to the study group (follicular flushing). Simple random allocation will be used. Each patient will be allowed to participate in the study only once.
Oocyte retrieval procedures will be performed by four trained physicians to evaluate the reproducibility and generalizability of the technique. Follicles will be aspirated using 17G needles in both groups. For follicular flushing, the same needle model used for single aspiration (Cook) will be employed. To eliminate dead space, the needle will be prefilled with flushing medium before beginning the procedure. Aspiration pressure will be maintained at 190 mmHg during oocyte retrieval.
In the single aspiration group, after aspirating all follicles, the needle will be rinsed with flushing medium to minimize the risk of oocyte retention inside the needle.
In the follicular flushing group, if no cumulus-oocyte complex (COC) is recovered during the initial aspiration, follicular flushing will be repeated until a COC is obtained, up to a maximum of three flushes. After three flushes, if no COC is retrieved, the procedure will be completed by rinsing with flushing medium to prevent possible oocyte retention within the needle.
The embryologist will immediately inform the physician performing the oocyte retrieval whether a COC has been recovered, in order to determine whether to continue flushing or proceed to the next follicle (open flushing technique).
The duration of the procedure will be recorded from needle insertion to its withdrawal for each ovary in both groups.
Instituto Bernabeu is the lead sponsor of 18 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Pacientes con baja respuesta ovárica grupos POSEIDON 3 y 4 (\< 35 años y RFA \<5 y/o AMH \< 1.2 ng/ml o > 35 años≥ 35 años y RFA \<5 o AMH \<1.2 ng/mL respectivamente)
Exclusion Criteria:
Presence of ovarian pathology.
Use of conventional IVF as the fertilization method.
Oocytes will be retrieved from one ovary using single follicular aspiration
Procedure: follicular aspiration
Oocytes will be retrieved from the contralateral ovary using follicular flushing, with up to three flushes per follicle if no cumulus-oocyte complex is obtained initially
Procedure: follicular flushing
Follicles will be aspirated using 17G needles of the same gauge in both groups. For follicular flushing, the same type of needle used for single aspiration (Cook) will be employed. To eliminate dead space, the needle will be prefilled with flushing medium before starting the procedure. Aspiration pressure will be maintained at 190 mmHg during oocyte retrieval. In the follicular flushing group, if no cumulus-oocyte complex (COC) is recovered during the initial aspiration, follicular flushing will be performed until a COC is obtained, up to a maximum of three times. After three flushes, if no COC is retrieved, the procedure will be completed by rinsing with flushing medium to minimize the possibility of oocyte retention within the needle.
In the single aspiration group, after aspirating all follicles, the needle will be rinsed with flushing medium to prevent the possibility of oocyte retention within the needle.
number of cumulus-oocyte complexes
number of cumulus-oocyte complexes (COCs) retrieved after each aspiration
Time frame: During the egg retrieval
Oocyte recovery rate
number of oocytes retrieved / number of follicles ≥11 mm on the day of final oocyte maturation trigger
Time frame: day of the egg retrieval
Fertilization rate
number of 2PNs / number of MII oocytes
Time frame: 1 day after the egg retrieval
Empty follicle rate
zero oocytes retrieved / follicles punctured
Time frame: day of the egg retrieval
Procedure time
calculated from needle insertion to its withdrawal for each ovary
Time frame: In seconds from needle insertion to its withdrawal for each ovary
Plan to share: Undecided
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This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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Instituto Bernabeu