Is there a benefit from routine follicular flushing for oocyte retrieval?

Follicular flushing increases the number of oocytes retrieved: a randomized controlled trial

STUDY QUESTION

Does follicular flushing increase the number of cumulus-oocyte complexes (COCs) retrieved compared to single aspiration?

SUMMARY ANSWER

Follicular flushing significantly increases the number of COCs retrieved compared to single aspiration.

WHAT IS KNOWN ALREADY

On the basis of published meta-analyses, follicular flushing does not seem to increase the number of oocytes retrieved, the probability of clinical pregnancy, or that of live birth and has been associated with an increase in the duration of oocyte retrieval. It should be noted, however, that all the eligible randomized controlled trials (RCTs) in these meta-analyses have randomized patients into either single aspiration or follicular flushing. This study design might not allow the detection of the true effect of follicular flushing. Despite randomization, this might still be obscured, to an extent, by heterogeneity in patients, stimulation characteristics, and differences in the oocyte retrieval procedure.

STUDY DESIGN, SIZE, DURATION

A prospective, single centre, RCT, including 105 patients was performed between July and December 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible patients were those undergoing oocyte retrieval for ICSI, aged <43 years, with BMI 18-35 kg/m2. Patients with all types of ovarian response (low-normal-high), as assessed on the day of triggering final oocyte maturation, were included. Random allocation of the ovaries of each patient to either single aspiration or follicular flushing was performed on the day of oocyte retrieval, using a computer-generated randomization list. Patients could enter the study only once. All follicles from ovaries allocated to either follicular flushing or single aspiration, were aspirated by the same 16G double lumen needle, with a constant aspiration pressure of 190 mmHg, resulting in flow rate of 0.42 ml/s. In the ovaries allocated to the follicular flushing group, if a COC was not recovered in the initial aspirate of each follicle, follicular flushing was performed until a COC was retrieved, up to a maximum of five times. The primary outcome measure was the number of COCs retrieved. Secondary outcomes were oocyte recovery rate, oocyte maturation rate, fertilization rate, and rate of good quality embryos on Day 2. Values are expressed as a median (inter-quartile range).

MAIN RESULTS AND THE ROLE OF CHANCE

Significantly more COCs were retrieved in the follicular flushing as compared to the single aspiration group in all patients [5 (7) vs 2 (3), P < 0.001, respectively], as well as in patients with high [9 (3) vs 5 (4), P < 0.001, respectively], normal [5 (2) vs 2 (3), P < 0.001, respectively] and low [1 (1) vs 1 (1), P < 0.001, respectively] ovarian response. In patients with low ovarian response, no COCs were retrieved in 5.7% of the ovaries in the flushing group vs 42.8% of the ovaries in the single aspiration group (P < 0.001). The oocyte retrieval rate was significantly higher in the follicular flushing vs the single aspiration group, in all patients [88.9% (25.0) vs 45.5% (37.5), P < 0.001, respectively], as well as in patients with high [81.8% (15.9) vs 45.5% (22.2), P < 0.001, respectively], normal [85.7% (28.6) vs 40.0% (30.0), P < 0.001, respectively], and low [100% (0) vs 50.0% (100), P < 0.001, respectively] ovarian response. No significant difference was observed regarding maturation rate [85.2% (30.8) vs 100% (33.3), P = 0.78], fertilization rate [76.4% (50) vs 83.3% (50) P = 0.42], and the proportion of good quality embryos on Day 2 [83.3% (40) vs 100% (50), P = 0.62]. Similarly, no differences in the above variables were observed in patients with different types of ovarian response. Follicular flushing as compared to single aspiration was associated with a significant increase in the duration of oocyte retrieval in all patients [248 s (332) vs 135 s (164), respectively], as well as in patients with high [464 s (225) vs 237 s (89), P < 0.001, respectively], normal [248 s (108) vs 141 s (95), P < 0.001, respectively], and low [64 s (59) vs 48 s (10), P < 0.001, respectively] ovarian response.

LIMITATIONS, REASONS FOR CAUTION

Although the current study design allows for a more accurate evaluation of the true effect of follicular flushing on the number of COCs retrieved, it does not permit the evaluation of its role on the probability of pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first RCT to suggest that follicular flushing increases the number of COCs retrieved compared to single aspiration, independently of ovarian response. This implies that follicular flushing plays an important role in the optimization of oocyte retrieval. These results, however, need to be confirmed in future studies, in which an equal flow rate should be used during oocyte retrieval.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was obtained for this study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

NCT05473455.

TRIAL REGISTRATION DATE

15 July 2022.

DATE OF FIRST PATIENT’S ENROLMENT

27 July 2022.

A Monocentric Randomized Controlled Clinical Trial to Compare Single- and Double-Lumen Needles in Oocyte Retrieval Procedure in Assisted Reproductive Technologies

The purpose was to determine any difference in outcomes, primarily in terms of number of retrieved oocytes per procedure, between two different needles used for oocytes retrieval procedure in Assisted Reproductive Technologies: the single-lumen needle (SLN) versus the double-lumen needle (DLN) with follicle flushing after aspiration. This randomized controlled trial included oocyte retrieval (OR) cycles for IVF and ICSI performed in 18 to 42-year-old women between March 2019 and January 2021 at a tertiary-care Fertility Center. A total of 200 ORs were randomized, 100 in each group. The mean number of retrieved oocytes was not different between groups (10.2 ± 6.5 for DLNs vs. 10.7 ± 7.0 for SLNs, p = 0.810). No significant differences were observed also in terms of number of retrieved oocytes/punctured follicles (83.0% ± 27.0% vs. 81.0% ± 22.0%, p = 0.916), number of retrieved oocytes/follicles at trigger (78.0% ± 29.0% vs. 78.0% ± 27.0%, p = 0.881), number of mature oocytes (7.6 ± 5.3 vs. 8.0 ± 5.1, p = 0.519), and pregnancy rate (27% vs. 23%, p = 0.514). However, the time required to retrieve each oocyte was longer using the DLN (1.5 ± 1.3 vs. 1.1 ± 0.9 minutes, p = 0.002). The present study confirmed the new perspectives on the sole use of SLNs in terms of saving time, without affecting the number of retrieved oocytes. Trial registration number and date of registration NCT03611907; July 26, 2018.

The importance of follicular flushing in optimizing oocyte retrieval

PURPOSE OF REVIEW

To critically evaluate the use of follicular flushing during oocyte retrieval.

RECENT FINDINGS

The latest meta-analysis evaluating follicular flushing does not favour its use over single aspiration. The randomized controlled trials (RCTs) included, however, are characterized by significant heterogeneity regarding the population analysed, the needle type and lumen used, the aspiration pressure applied and the number of flushing attempts performed. More importantly, information regarding the flow rate used for aspiration is scarce. The only RCT employing a constant flow rate between single aspiration and follicular flushing in women with monofollicular development, suggests that a higher number of oocytes is retrieved after follicular flushing.

SUMMARY

In order to eliminate clinical heterogeneity that might obscure the detection of the true effect of follicular flushing, randomization to single aspiration and follicular flushing should occur within the same patient. This can be achieved by randomly allocating each patient's ovary to either single aspiration or follicular flushing, maintaining similar flow rates between the groups compared.Given the importance of maximizing the number of oocytes retrieved from a given number of follicles developed, the conduction of properly designed RCTs evaluating follicular flushing is certainly required.

Follicular flushing during oocyte retrieval in assisted reproductive techniques

BACKGROUND

Follicular aspiration under transvaginal ultrasound guidance is routinely performed as part of assisted reproductive technology (ART) to retrieve oocytes for in vitro fertilisation (IVF). The process involves aspiration of the follicular fluid followed by the introduction of flush, typically culture media, back into the follicle followed by re-aspiration. However, there is a degree of controversy as to whether this intervention yields a larger number of oocytes and is hence associated with greater potential for pregnancy than aspiration only.

OBJECTIVES

To assess the safety and efficacy of follicular flushing as compared with aspiration only performed in women undergoing ART.

SEARCH METHODS

We searched the following electronic databases up to 13 July 2021: the Cochrane Gynaecology and Fertility Specialised Register of Controlled Trials, CENTRAL (containing output from two trial registries and CINAHL), MEDLINE, Embase, and PsycINFO. We also searched LILACS, Google Scholar, and Epistemonikos. We reviewed the reference lists of relevant papers and contacted experts in the field to identify further relevant studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared follicular aspiration and flushing with aspiration alone in women undergoing ART using their own gametes. Primary outcomes were live birth rate and miscarriage rate per woman randomised.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies identified by search against the inclusion criteria, extracted data, and assessed risk of bias. A third review author was consulted if required. We contacted study authors as needed. We analysed dichotomous outcomes using Mantel-Haenszel odds ratios (ORs), 95% confidence intervals (CIs), and a fixed-effect model, and we analysed continuous outcomes using mean differences (MDs) between groups presented with 95% CIs. We examined the heterogeneity of studies via the I2 statistic. We assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 15 studies with a total of 1643 women. Fourteen studies reported outcomes per woman randomised, and one study reported outcomes per ovary. No studies were at low risk of bias across all domains; the main limitation was lack of blinding. The certainty of the evidence ranged from moderate to very low, and was downgraded for risk of bias, imprecision, and inconsistency. We are uncertain of the effect of follicular flushing on live birth rate compared to aspiration alone (OR 0.93, 95% CI 0.59 to 1.46; 4 RCTs; n = 467; I2 = 0%; moderate-certainty evidence). This suggests that with a live birth rate of approximately 30% with aspiration alone, the equivalent live birth rate with follicular flushing lies between 20% and 39%.  We are uncertain of the effect of follicular flushing on miscarriage rate compared to aspiration alone (OR 1.98, 95% CI 0.18 to 22.22; 1 RCT; n = 164; low-certainty evidence). This suggests that with a miscarriage rate of approximately 1% with aspiration alone, the equivalent miscarriage rate with follicular flushing lies between 0% and 22%. We are uncertain of the effect of follicular flushing on oocyte yield (MD -0.47 oocytes, 95% CI -0.72 to -0.22; 9 RCTs; n = 1239; I2 = 61%; very low-certainty evidence); total number of embryos (MD -0.10 embryos, 95% CI -0.34 to 0.15; 2 RCTs; n = 160; I2 = 58%; low-certainty evidence); and clinical pregnancy rate (OR 1.12, 95% CI 0.85 to 1.51; 7 RCTs; n = 939; I2 = 46%; low-certainty evidence). The duration of the retrieval process may be longer with flushing (MD 175.44 seconds, 95% CI 152.57 to 198.30; 7 RCTs; n = 785; I2 = 87%; low-certainty evidence). It was not possible to perform a meta-analysis for adverse events, although individual studies reported on outcomes ranging from depression and anxiety to pain and pelvic organ injury.

AUTHORS' CONCLUSIONS

The effect of follicular flushing on both live birth and miscarriage rates compared with aspiration alone is uncertain. Although the evidence does not permit any firm conclusions on the impact of follicular flushing on oocyte yield, total number of embryos, number of cryopreserved embryos, or clinical pregnancy rate, it may be that the procedure itself takes longer than aspiration alone. The evidence was insufficient to permit any firm conclusions with respect to adverse events or safety.

Does Oocyte Retrieval Performance in Mono-follicular Cycles Differ by Physician Experience?

Oocyte pick-up (OPU) is considered as a minor surgical procedure and complications are very rare when performed by trained physicians. However, data on training standards are limited and assessment of proficiency is challenging. The aim of this study was to show the impact of physician experience on OPU performance in mono-follicular in vitro fertilization (IVF) cycles, using two measurable outcome parameters: successful oocyte retrieval and operative time. Senior physicians (n = 6) had over 15 years of experience and novice physicians (n = 4) had at least 30 procedures under supervision. The study population included 226 mono-follicular cycles. Oocyte retrieval was successful in 179 out 226 procedures (79.2%); seniors and novices achieved similar oocyte retrieval rates (74.1%, 43/58 vs 80.9%, 136/168, p = 0.270). The mean duration of the procedure was 513.4 ± 163.1 (126-769) s. It was significantly shorter with a mean difference of - 117.9 s (95% CI: - 164.4 to - 71.3, p = 0.0001, Hedges g = 1.3) for senior physicians when compared to novices (425.8 ± 146.2 versus 543.7 ± 157.9 s). Novices who start performing OPU independently after 30 supervised procedures perform well in collecting the single oocyte grown in mono-follicular cycles; however, the mean duration of the procedure is relatively longer compared to seniors. After initial training period, physicians have few opportunities to compare themselves with their seniors and peers; periodical reassessment of the technique-which should also cover managing the operation time-would help confirm their own practices.

What is the optimum number of follicular flushes in mono-follicular in-vitro fertilization cycles in a poor responder population?

Objective:

Assessment of the optimal number of follicular flushes on retrieval rate and quality of oocytes in mono-follicular in-vitro fertilization (IVF) cycles.

Material and Methods:

A retrospective analysis of 246 oocyte pick-up procedures in mono-follicular IVF cycles of 226 poor responder women was performed. The primary endpoint was oocyte retrieval rate in the initial aspirate versus subsequent flushing episodes. The secondary endpoints were oocyte maturity, fertilization rates and embryo cleavage.

Results:

The procedure was successful in 187 cycles (76%), of which 160 metaphase-II oocytes were retrieved. Retrieval rates were similar for natural and modified natural cycles (p=0.595). The initial aspirate provided 54% of the total yield and the rest was obtained from up to four episodes of flushing. Follicular flushing increased oocyte recovery rate from 41.1% to 76%. None of the oocytes retrieved after three flushes fertilized. Oocyte maturity, fertilization and embryo cleavage rates were comparable for oocytes from the initial aspirate and one or two episodes of flushing. Oocytes obtained after the third flushing episode developed into poor quality embryos.

Conclusion:

Flushing confers a benefit for oocyte recover rates in mono-follicular IVF cycles in poor responder women. However, more than three attempts at flushing were not associated with good outcome.

Evaluation of follicular flushing with double lumen needle in patients undergoing assisted reproductive technology treatments

OBJECTIVE

The purpose of this study was to investigate the possible impact of follicular flushing on the number of oocytes retrieved and oocytes in metaphase II in patients with poor ovarian response (POR) compared to direct aspiration.

METHODS

This prospective, comparative, randomized single center study included 208 punctures of patients with POR, submitted to assisted reproduction technology (ART) treatments. Two groups were compared; one in which double lumen needles were used (Wallace DNS1733) for follicular flushing (n=105), and one in which single lumen needles were used (Wallace ONS1733) for direct aspiration (n=103), upon the observation of ≤ 5 follicles between 15-17 mm, ≤ 4 follicles with sizes greater than 18 mm on hCG day, and ≤ 7 recovered oocytes.

RESULTS

There were no differences in age (39.07±3.88 vs. 38.11±3.43); weight (61.73±17.53 vs. 65.96±15.44); AMH (0.63±0.59 vs. 0.94±0.97); stimulation days (9.57±1.87 vs. 10.29±2.82); estradiol levels (788.94±670.82 vs. 940.16±694.69); progesterone (617.29±319.76 vs. 561.18±486.78); or number of follicles with sizes ≥18 mm (1.84±0.95 vs. 2.07±1.09). Although gonadotropin totals (1678.28±798.52 vs. 2080.45±852.36; p=0.0008), number of aspirated oocytes (3.00±2.11 vs. 3.69±2.20; p=0.02), and number of metaphase II oocytes (2.20±1.64 vs. 2.99±1.88; p=0.02) were significantly different, oocyte / follicle ratio ≥15 mm (0.93 vs. 0.98) and metaphase II oocytes / follicles ≥15 mm (0.68 vs. 0.79) were similar in both groups. The failure to capture was 16% vs. 9.8%.

CONCLUSIONS

Considering that there was no difference in the oocyte per follicle ratio, follicular flushing did not increase the number of oocytes recovered from poor responders.

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.

Follicular flushing increases the number of oocytes retrieved in poor ovarian responders undergoing in vitro fertilization: a retrospective cohort study

Background

To investigate the impact of follicular flushing on the number of oocytes retrieved and embryo quality and to determine the optimal number of flushings for poor ovarian responders (PORs) undergoing in vitro fertilization (IVF).

Methods

This retrospective study included 291 IVF cycles in 224 patients who were PORs and had no more than three dominant follicles on retrieval day. During oocyte retrieval, follicular fluid was aspirated and examined for an oocyte. If no oocyte was identified, follicular flushing was repeated until an oocyte was retrieved or up to a maximum of nine times.

Results

The mean number of oocytes retrieved by aspiration and subsequent flushes was significantly higher than the number retrieved from the initial aspirate (1.73 ± 0.96 VS. 1.23 ± 1.00, P = 0.000). The total recovery rate was 83.7% (503/601), which was significantly higher than the 59.6% recovery rate for direct aspiration (P = 0.000). Before the 4th follicular flushing, the cumulative recovery rate increased significantly as flushing was repeated, but after the 4th flushing, the ascending trend was mitigated; and the risk ratio of recovering fewer oocytes after 4 flushes compared with after 9 flushes was 0.765 (95%CI, 0.570–1.026, P = 0.074). Significant differences were not observed in maturation rate, fertilization rate, cleavage rate or high-quality embryo rate (P > 0.05).

Conclusions

Follicular flushing may increase the number of oocytes retrieved and does not have adverse effects on oocyte or embryo quality in PORs undergoing IVF. Four times may be an optimal number of follicular flushings.

Follicular flushing during oocyte retrieval in assisted reproductive techniques

BACKGROUND

Follicular aspiration under transvaginal ultrasound guidance is routinely performed as part of assisted reproductive technology (ART) to retrieve oocytes for in vitro fertilisation (IVF). However, controversy as to whether follicular flushing following aspiration yields a larger number of oocytes and hence is associated with greater potential for pregnancy than aspiration only is ongoing.

OBJECTIVES

To assess the safety and efficacy of follicular flushing as compared with aspiration only performed in women undergoing ART.

SEARCH METHODS

We searched the following electronic databases up to 18 July 2017: Cochrane Gynaecology and Fertility Group (CGF) Specialised Register of Controlled Trials, the CENTRAL Register of Studies Online (CRSO), MEDLINE, Embase, PsycINFO, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We also searched the trial registries ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform to identify ongoing and registered trials up to 4 July 2017. We reviewed the reference lists of reviews and retrieved studies to identify further potentially relevant studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared follicular aspiration and flushing with aspiration alone in women undergoing ART using their own gametes. Primary outcomes were live birth rate and miscarriage rate per woman randomised.

DATA COLLECTION AND ANALYSIS

Two independent review authors assessed studies against the inclusion criteria, extracted data, and assessed risk of bias. A third review author was consulted if required. We contacted study authors as required. We analysed dichotomous outcomes using Mantel-Haenszel odds ratios (ORs), 95% confidence intervals (CIs), and a fixed-effect model, and we analysed continuous outcomes using mean differences (MDs) between groups presented with 95% CIs. We examined the heterogeneity of studies via the I2 statistic. We assessed the quality of evidence by using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria.

MAIN RESULTS

We included ten studies, with a total of 928 women. All included studies reported outcomes per woman randomised. We assessed no studies as being at low risk of bias across all domains and found that the main limitation was lack of blinding. Using the GRADE method, we determined that the quality of the evidence ranged from moderate to very low, and we identified issues arising from risk of bias, imprecision, and inconsistency.Comparing follicular flushing to aspiration alone revealed probably little or no difference in the live birth rate (OR 0.95, 95% CI 0.58 to 1.56; three RCTs; n = 303; I2 = 30%; moderate-quality evidence). This suggests that with a live birth rate of approximately 41% with aspiration alone, the equivalent live birth rate with follicular flushing is likely to lie between 29% and 52%. None of the included studies reported on the primary outcome of miscarriage rate.Data show probably little or no difference in oocyte yield (MD -0.28 oocytes, 95% CI -0.64 to 0.09; six RCTs; n = 708; I2 = 0%; moderate-quality evidence). Very low-quality evidence suggests that the duration of oocyte retrieval was longer in the follicular flushing group than in the aspiration only group (MD 166.01 seconds, 95% CI 141.96 to 190.06; six RCTs; n = 714; I2 = 88%). We found no evidence of a difference in the total number of embryos per woman randomised (MD -0.10 embryos, 95% CI -0.34 to 0.15; two RCTs; n = 160; I2 = 58%; low-quality evidence) and no evidence of a difference in the number of embryos cryopreserved (meta-analysis not possible). Data show probably little or no difference in the clinical pregnancy rate (OR 1.07, 95% CI 0.78 to 1.46; five RCTs; n = 704; I2 = 49%; moderate-quality evidence). Only two studies reported on adverse outcomes: One reported no differences in patient-reported adverse outcomes (depression, anxiety, and stress), and the other reported no differences in needle blockage, vomiting, and hypotension. No studies reported on safety.

AUTHORS' CONCLUSIONS

This review suggests that follicular flushing probably has little or no effect on live birth rates compared with aspiration alone. None of the included trials reported on effects of follicular aspiration and flushing on the miscarriage rate. Data suggest little or no difference between follicular flushing and aspiration alone with respect to oocyte yield, total embryo number, or number of cryopreserved embryos. In addition, follicular flushing probably makes little or no difference in the clinical pregnancy rate. Evidence was insufficient to allow any firm conclusions with respect to adverse events or safety.

Comparison of costs associated with substituting culture medium with saline solution for follicular flushing during oocyte retrieval

OBJECTIVES

To compare culture medium and saline solution for follicular flushing during oocyte retrieval with assisted reproductive technologies.

METHODS

The present retrospective study analyzed data collected at Galway Fertility Clinic, Galway, Ireland, between January 1, 2015 and August 31, 2016; all patients attending the clinic for in vitro fertilization/intracytoplasmic sperm injection during this period were included. Data were stratified by whether follicular flushing was performed with culture medium or saline, and the oocyte yield rate, fertilization rate, embryo utilization rate, and biochemical and clinical pregnancy rates were compared between the groups.

RESULTS

In total, 422 oocyte retrieval procedures with culture medium and 277 with normal saline were analyzed. The fertilization (P=0.676) and clinical pregnancy rates (P=0.593) did not differ between the groups. Using normal saline resulted in an approximately 41-fold per-patient cost saving compared with culture medium.

CONCLUSION

Switching from culture medium to normal saline for follicular flushing significantly reduced oocyte-retrieval costs without adversely affecting reproductive outcomes.

Oocyte retrieval at 140-mmHg negative aspiration pressure: A promising alternative to flushing and aspiration in assisted reproduction in women with low ovarian reserve

BACKGROUND:

Oocyte retrieval in women with low ovarian reserve is challenging and often results in poor pregnancy outcomes.

AIM:

The aim was to compare outcomes of oocyte retrieval using three aspiration methods in women with normal and low antral follicle counts (AFCs).

STUDY DESIGN:

Retrospective cohort study.

SETTING:

Tertiary care hospital.

MATERIALS AND METHODS:

Data from 172 women who underwent in-vitro fertilization/intracytoplasmic sperm injection over 3 years was studied after dividing into three groups: Group A (96) - normal AFC (≥10), direct oocyte retrieval at 120 mmHg, Group B (41) - low AFC (<10), direct retrieval at 140-mmHg, Group C (35) - low AFC, follicular flushing, and aspiration at 120-mmHg. In each group, oocyte yield, embryo quality, and pregnancy out comes were assessed.

RESULTS:

The oocyte and embryo yield in Groups A and B were comparable (P > 0.05) but were significantly less in Group C (P < 0.05). The pregnancy rates in Groups A and B were similar (35.4%, 39%) but were significantly less (17.1%) in Group C (P < 0.05). The live birth rate was 76% in Group A, 69% in Group B, and 50% in Group C. The miscarriage rates in the three groups were 21%, 31%, and 50%, respectively.

CONCLUSION:

Direct oocyte retrieval with 140-mmHg showed significantly better oocyte yield and pregnancy outcomes compared to flushing and aspiration in women with low AFC.

Correlation between follicular diameters and flushing versus no flushing on oocyte maturity, fertilization rate and embryo quality

OBJECTIVE

To determine (a) the correlation between follicular sizes, oocyte maturity, normal fertilization rate, cleavage and embryo quality; and (b) to establish whether oocytes recovered with or without follicular flushing have different developmental competence.

DESIGN

Prospective observational study.

SETTING

Academic medical center.

PATIENTS

Forty nine cycles (37 ICSI and 12 IVF).

INTERVENTIONS

Measurement of 360 follicular diameters on the day of egg retrieval and classification into three groups Group A (mean diameter 12-14.5 mm.), group B (mean diameter 15-18 mm.) and group C (diameter >18.5 mm.).

MAIN OUTCOME MEASURE

Correlation between follicular size at the time of retrieval and oocyte maturity, fertilization and cleavage rate in 226 oocytes (163 ICSI and 63 IVF). Developmental competence of oocytes retrieved with flushing versus non flushing.

RESULTS

Almost all (99 %) of the oocytes recovered from follicles of group C were in metaphase II as opposed to 80 % in group A and 81 % in group B (p < 0.01). Overall there was a progressive and significant increase in fertilization rates from group A follicles to group C (47 % vs. 67 %, p 0.05). Overall 53 % of oocytes retrieved from group A follicles showed either no fertilization or abnormal fertilization versus 27 % in group C (p 0.05). The oocyte recovery rate with follicular flushing improved from group A to group B and to group C follicles (65 % vs. 49 % vs.37 % respectively p < 0.01). There were no differences in rates of immature oocyte, fertilization, abnormal or not fertilization and cleavage.

CONCLUSIONS

The results of this study shows that: a) Follicles larger than 18 mm at retrieval have consistently mature oocytes with a higher rate of fertilization; b) Small size follicles are still capable of containing mature oocytes, but their rate of abnormal or no fertilization is high; c) Oocytes recovered with flushing are still able to produce embryos with full developmental competence.

Follicular flushing and in vitro fertilization outcomes in the poorest responders: a randomized controlled trial

STUDY QUESTION

Does follicular flushing during oocyte retrieval improve the number of oocytes retrieved in the poorest responders?

SUMMARY ANSWER

Follicular flushing in the poorest responders does not increase the number of oocytes retrieved and may result in lower implantation and clinical pregnancy rates.

WHAT IS KNOWN ALREADY

Although previous studies have shown no beneficial effect of follicular flushing in normal responders, no study has demonstrated a detrimental effect and many IVF centers continue to perform this technique in poor responders. Data on follicular flushing in this patient group are limited, with no randomized trial to date assessing its utility in the poorest responders.

STUDY DESIGN, SIZE, DURATION

This randomized controlled trial compared the effects of follicular flushing and direct aspiration on IVF outcomes in the poorest responders, defined as having four or fewer follicles ≥12 mm on the day of hCG administration. Fifty patients were randomized during the 12-month enrollment period.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The patients were treated at an academic fertility center at Weill Cornell Medical College, New York.

MAIN RESULTS AND THE ROLE OF CHANCE

Fifty women were randomized to follicular flushing (n = 25) or direct aspiration (n = 25). One patient in the direct aspiration group was canceled prior to oocyte retrieval for premature ovulation and was included in the intent-to-treat analysis. There was no difference in the number of oocytes retrieved with a median (IQR) of 4 (2-6) in the aspiration group versus 3 (2-5) in the flushing group (95% CI: -0.78, 1.98; P = 0.41). Patients who underwent follicular flushing had significantly fewer embryos transferred {1.7 [standard deviation (SD) 0.6] versus 2.5 (SD 1.2), P = 0.03}, a lower implantation rate (5.3 versus 34.2%, P = 0.006) and a lower clinical pregnancy rate (4 versus 36%, P = 0.01). The difference in pregnancy rates remained significant after adjusting for embryos transferred.

LIMITATIONS, REASONS FOR CAUTION

Findings, including results for secondary outcome measures, may not be generalizable to natural IVF cycles as these were excluded from the study.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first randomized trial to evaluate the utility of follicular flushing in the poorest responders, and the first to demonstrate a potentially detrimental effect of flushing on IVF outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

NCT 01558141.

Follicular flushing during oocyte retrieval: a systematic review and meta-analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to examine the literature and identify randomized controlled trials (RCTs), in order to answer if performing follicular flushing during the oocyte retrieval may improve the assisted reproductive technologies (ART) outcomes.

METHODS

An exhaustive electronic search was performed using MEDLINE and EMBASE databases. Only RCTs comparing follicular flushing to aspiration only during ART, were included. We included 5 trials, with a total of 482 patients randomized, with median ages ranging from 30.5 to 37.1.

RESULTS

The data analyses did not show significant differences regarding live birth rate, clinical pregnancies rates, and the number of oocytes retrieved. The duration of oocyte retrieval was significantly increased in the follicular flushing group.

CONCLUSIONS

The results from this systematic review and meta-analysis suggest that there is no advantage to use of routine follicular flushing during OR in an unselected group of patients.

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.

Follicular flushing during oocyte retrieval in assisted reproductive techniques

BACKGROUND

Ultrasound guided transvaginal aspiration of oocytes has replaced other methods of oocyte retrieval for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). However, there is controversy over whether flushing yields a larger number of oocytes and a higher potential for pregnancy than aspiration only.

OBJECTIVES

To determine whether follicular aspiration and flushing increases live birth or ongoing pregnancy rates and the number of oocytes over aspiration alone in women undergoing IVF and ICSI.

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group Specialised Register of controlled trials, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO and the citation lists of relevant publications (to April 2010).

SELECTION CRITERIA

Randomised controlled trials that compared follicular aspiration and flushing with aspiration alone were included. Trials were excluded if the flushing method comparison was confounded by comparisons of other methods.

DATA COLLECTION AND ANALYSIS

Eligible studies were assessed for methodological quality. For dichotomous data, odds ratios (OR) and 95% confidence intervals (CI) were calculated. For continuous data, mean differences were reported. The heterogeneity of the studies was examined by using statistical tests of homogeneity and the I(2) statistic.

MAIN RESULTS

No studies reported on the primary outcome of live birth. There was no evidence (3 studies, 164 patients) to suggest an association between follicular aspiration and flushing and ongoing or clinical pregnancy per woman randomised (OR 1.17, 95% CI 0.57 to 2.38). There was no evidence of a difference in adverse events reported between follicular aspiration and flushing and aspiration only. There was no evidence of significant differences in increased oocyte yield per woman randomised (1 study, 44 patients). Without flushing the operative time was significantly shorter, by 3 to 15 minutes (3 studies, P < 0.001) and the dose of pethidine required was significantly less (50 mg versus 100 mg, P < 0.00001).

AUTHORS' CONCLUSIONS

There is no evidence that follicular aspiration and flushing is associated with improved clinical or ongoing pregnancy rates, nor an increase in oocyte yield. The operative time is significantly longer and more opiate analgesia is required for pain relief during oocyte retrieval. There is a lack of evidence regarding the effect of follicular aspiration and flushing on live birth rates in the identified data.

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.

Mild ovarian stimulation for IVF

BACKGROUND

Mild ovarian stimulation for in vitro fertilization (IVF) aims to achieve cost-effective, patient-friendly regimens which optimize the balance between outcomes and risks of treatment.

METHODS

Pubmed and Medline were searched up to end of January 2008 for papers on ovarian stimulation protocols for IVF. Additionally, references to related studies were selected wherever possible.

RESULTS

Studies show that mild interference with the decrease in follicle-stimulating hormone levels in the mid-follicular phase was sufficient to override the selection of a single dominant follicle. Gonadotrophin-releasing hormone antagonists compared with agonists reduce length and dosage of gonadotrophin treatment without a significant reduction in the probability of live birth (OR 0.86, 95% CI 0.72-1.02). Mild ovarian stimulation may be achieved with limited gonadotrophins or with alternatives such as anti-estrogens or aromatase inhibitors. Another option is luteinizing hormone or human chorionic gonadotrophin administration during the late follicular phase. Studies regarding these approaches are discussed individually; small sample size of single studies along with heterogeneity in patient inclusion criteria as well as outcomes analysed does not allow a meta-analysis to be performed. Additionally, the implications of mild ovarian stimulation for embryo quality, endometrial receptivity, cost and the psychological impact of IVF treatment are discussed.

CONCLUSIONS

Evidence in favour of mild ovarian stimulation for IVF is accumulating in recent literature. However, further, sufficiently powered prospective studies applying novel mild treatment regimens are required and structured reporting of the incidence and severity of complications, the number of treatment days, medication used, cost, patient discomfort and number of patient drop-outs in studies on IVF is encouraged.

Ovarian follicular flushing among low-responding patients undergoing assisted reproductive technology

A randomized comparison trial was performed to evaluate whether follicular reaspiration with use of a double-lumen retrieval needle improves oocyte recovery when compared with direct follicular aspiration among low-responding patients undergoing ART. There were no differences observed in the number of oocytes retrieved (single lumen: 6.5 +/- 2.2 oocytes, double lumen: 7.2 +/- 2.3 oocytes) whereas follicular reaspiration with the double-lumen retrieval needle resulted in a twofold increase in procedure time.

[The follicular flushing duplicate the pregnancy rate on semi natural cycle IVF]

OBJECTIVE

To evaluate the importance of follicular flushing on semi natural cycle IVF.

MATERIAL AND METHODS

We have compared prospectively the reproductive potential of oocytes obtained from follicular fluid (LF, N = 79) to those obtained from follicular flushing (R, N = 47) in 146 oocyte pick ups.

RESULTS

The group LF and R were similar with regard to fertilization rate (79.7 versus 88.1%, respectively), percentage of superior grade embryos (28.8 versus 37.8%) and implantation rate (24.1 versus 44.1%).

CONCLUSION

The practice of follicular flushing on semi natural IVF cycle improves the pregnancy rate. The oocytes obtained by follicular flushing had the same reproductive potential than those obtained on follicular fluid.