Ovarian stimulation with pure follicle-stimulating hormone/human menopausal gonadotropin and improved laparoscopic aspiration needles influence the success of an in vitro fertilization program

Follicle flushing does not improve live birth and increases procedure time: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To determine whether follicle flushing during oocyte retrieval improves live birth or secondary outcomes in assisted reproductive technology (ART).

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women undergoing ART using autologous gametes.

INTERVENTION(S)

A systematic search of PubMed, EMBASE, Cochrane Database, and Web of Science for randomized controlled trials comparing follicle flushing to direct aspiration during oocyte retrieval published in English between 1989 to 2020.

MAIN OUTCOME MEASURE(S)

Live birth as primary outcome, and clinical and ongoing pregnancy, total and mature metaphase II (MII) oocytes retrieved, and operating time as secondary outcomes.

RESULT(S)

Eleven studies were included totaling 1,178 cases. No difference in live birth was demonstrated between follicle flushing and direct aspiration. Clinical pregnancy and ongoing pregnancy were not improved with flushing. Total oocyte and MII yield were lower with flushing compared with direct aspiration. Procedure time was increased with flushing by 2 minutes in poor responders and 9 minutes in normal responders. Other sensitivity analyses did not demonstrate any changes, except the difference in MII yield was no longer statistically significant.

CONCLUSION(S)

Follicle flushing during oocyte retrieval increases procedure time and does not improve live birth or secondary ART outcomes. Randomized data do not support the use of follicle flushing as an intervention in ART.

The use of follicle flushing during oocyte retrieval in assisted reproductive technologies: a systematic review and meta-analysis

STUDY QUESTION

Does follicular flushing during assisted reproductive technologies (ART) improve the number of oocytes retrieved?

SUMMARY ANSWER

Follicular flushing during ART does not result in a greater number of oocytes in normal responders.

WHAT IS KNOWN ALREADY

Despite limited evidence supporting the use of follicular flushing, it continues to be a common procedure in many ART clinics. Prior studies have provided conflicting results regarding the routine use of flushing during oocyte retrieval.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis of 518 patients who participated in 6 randomized trials over 20 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Literature searches were conducted to retrieve randomized controlled trials on follicle or ovarian flushing in ART. Databases searched included PubMed, EMBASE, Web of Science and the Cochrane Database of Clinical Trials (CENTRAL). Six trials that included 518 subjects matched the inclusion criteria. Studies included were limited to trials that were published, randomized trials comparing oocyte retrieval with a single-lumen pick-up needle versus follicle flushing after direct aspiration with a multi-channel oocyte pick-up needle in ART patients.

MAIN RESULTS AND THE ROLE OF CHANCE

In each of the trials, measures of the oocyte yield (oocytes retrieved divided by follicles aspirated), total oocytes retrieved, fertilization or pregnancy were not different when comparing direct aspiration with follicle flushing. Four trials reported a higher operative time with follicle flushing. Results of the meta-analysis indicated no significant differences in the oocytes retrieved [weighted mean difference: 0.07, 95% confidence interval (CI): -0.13 to 0.29] or the oocyte yield (odds ratio: 1.06, 95% CI: 0.95-1.18) between the non-flushing and flushing groups.

LIMITATIONS, REASONS FOR CAUTION

All trials featured an open label design and the majority of patients in this meta-analysis were normal responders. The applications of these results to poor responders, patients undergoing natural cycle ART or minimal stimulation ART should be made with caution.

WIDER IMPLICATIONS OF THE FINDINGS

Follicle flushing does not improve ART outcomes in normal-responding patients and should not be performed. This meta-analysis should solidify this recommendation as it includes the largest trial published on the subject and is consistent with a recently published Cochrane review.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported, in part, by the Program in Reproductive and Adult Endocrinology, NICHD, NIH, Bethesda, MD. The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Is there a benefit in follicular flushing in assisted reproductive technology?

PURPOSE OF REVIEW

Follicular flushing utilizing double-lumen retrieval needles attempts to increase oocyte yield during transvaginal retrieval. The original work on this topic, now more than 2 decades old, examined its utility in normal-responding assisted reproductive technologies (ART) patients. Newer studies examining its utility have focused on special populations expected to demonstrate benefit: poor responders, natural cycle and minimal stimulation ART, and in-vitro maturation cycles. This review assesses the current evidence regarding the effectiveness of ovarian follicular flushing in improving oocyte yield.

RECENT FINDINGS

Follicular flushing offers no substantive benefit in oocyte yield, fertilization rates, or pregnancy outcomes for normal and poor-responding ART patients. Patients undergoing natural cycle or minimal stimulation ART may benefit from follicular flushing resulting in more mature embryos but unclear effects on cycle outcome.

SUMMARY

Randomized controlled trials consistently demonstrate no benefit and increased procedural time with follicular flushing in both normal and poor-responding ART patients. Nonrandomized data suggest a possible role for follicular flushing in natural cycle or minimal stimulation ART and in those undergoing in-vitro maturation IVF cycles; however, randomized controlled trials are needed to verify this finding. Presently, there is insufficient evidence to recommend the routine use of follicular flushing.

The effects of IVF aspiration on the temperature, dissolved oxygen levels, and pH of follicular fluid

PURPOSE

To investigate the effects of IVF aspiration on the temperature, pH, and dissolved oxygen of bovine follicular fluid.

METHODS

The temperature was monitored at various positions in an aspiration kit. Dissolved oxygen and pH were measured before and after aspiration.

RESULTS

The temperature of follicular fluid dropped by 7.7 +/- 1.3 degrees C upon aspiration. Dissolved oxygen levels rose by 5 +/- 2 vol.%. The pH increased by 0.04 +/- 0.01.

CONCLUSIONS

The temperature change was attributed mainly to evaporation of fluid in the collection tube. Changes in dissolved oxygen levels and pH were due to contact with air. Standard vacuum-based aspiration may induce changes in follicular fluid, which could be detrimental to oocyte health and affect attempts to correlate chemical characteristics with oocyte quality.

A new follicle aspiration needle set is equally effective and as well tolerated as the standard needle when used in a prospective randomized trial in a large in vitro fertilization program

OBJECTIVE

To compare the effectiveness and tolerability of two different 17-gauge follicle aspiration needles used in a large in vitro fertilization (IVF) program.

DESIGN

Prospective, randomized single blinded study.

SETTING

Private IVF center.

PATIENT(S)

Three hundred women undergoing IVF were randomly allocated at the time of oocyte retrieval to either the study needle (n = 151; follicle aspiration set [FAS] set) or the standard needle (n = 149; Echotip) used in the practice. Patients were blinded to the needle used.

INTERVENTION(S)

Transvaginal ultrasound-guided oocyte aspiration.

MAIN OUTCOME MEASURE(S)

Number of eggs retrieved/follicles visualized, retrieval time, mean amount of blood in the aspirate, egg damage, patient tolerance, physician acceptability, implantation, and pregnancy rate.

RESULT(S)

No differences were found in the number of eggs retrieved normalized to follicles visualized. Egg damage (4% vs. 4.2%), average blood in the aspirate (2.2 vs. 2.2), and retrieval time per egg (38 vs. 36 seconds) were similar with both needles. There were also no differences in pain or cramping scores (at 30 minutes and 24 hours after retrieval) or in the physicians' ratings of the two needles. The percentage of patients receiving an embryo transfer (ET), the implantation rate per embryo transfer, and the clinical pregnancy rate per embryo transfer were comparable for both needles.

CONCLUSION(S)

The FASs are equivalent.

Controlled ovarian hyperstimulation regimens in assisted reproductive technologies

The goal of assisted reproductive technologies (ART) is to influence the recruitment of multiple, mature ovarian follicles. Several methods, including spontaneous cycle ART, clomiphene-based ART regimens, and gonadotropin regimens with and without adjuncts, are used. The controversies surrounding these techniques and their relative advantages and drawbacks are reviewed.