Failure of oocyte retrieval during in vitro fertilization: a sporadic event rather than a syndrome

Comparative analysis of hCG and dual-trigger protocols in IVF for advanced maternal age women: a single‑center retrospective cohort study based on propensity score matching

PURPOSE

This study aimed to compare the efficacy of human chorionic gonadotropin (hCG) and dual-trigger (gonadotropin-releasing hormone agonist [GnRH-a] and hCG) protocols in terms of cumulative live birth rate (CLBR) and other pregnancy outcomes among advanced-age women.

METHODS

We enrolled 801 women aged ≥ 35 years who were experiencing infertility and beginning their first in vitro fertilization cycle at a tertiary academic medical institution between August 2015 and June 2023. Among these, 115 and 686 women used the dual-trigger and hCG methods. Propensity score matching was employed to account for confounding variables. The main outcomes evaluated were CLBR and time to live birth (TTLB).

RESULTS

The CLBR did not differ significantly between the hCG and dual-trigger groups (29.86% vs. 26.09%, P = 0.44), whereas the TTLBs of both groups were similar (9.60 vs. 10.14 months, P = 0.72). CLBR results were similar for both groups, according to a Kaplan-Meier analysis (hazard ratio [HR] = 0.95; 95% confidence interval [CI] 0.63-1.43; P = 0.82). After a multiple Cox proportional hazards model was established, the CLBR of the hCG group remained comparable with that of the dual-trigger group (HR = 0.83; 95% CI 0.53-4.11; P = 0.39). The subgroup analysis also showed similar findings.

CONCLUSION

Considering the higher fertilization rate and shorter TTLB, the dual-trigger protocol may be more suitable than the hCG trigger protocol.

Might retrigger with human chorionic gonadotropin be a solution for empty follicle syndrome after gonadotropin releasing hormone agonist trigger?

Objective

This study aimed to determine whether the use of human chorionic gonadotropin (hCG) as a trigger could offer a potential solution for addressing empty follicle syndrome following the administration of a trigger for gonadotropin-releasing hormone agonist.

Materials and Methods

A retrospective cohort analysis was conducted using data extracted from the hospital database pertaining to 415 patients who underwent in vitro fertilization (IVF) with an antagonist protocol triggered by a gonadotropin-releasing hormone (GnRH) agonist between December 2019 and January 2023 at the Acıbadem Maslak Hospital Assisted Reproductive Technologies Unit. All cases that failed to obtain oocytes and required rescue were analyzed.

Results

This study analyzed 415 women who underwent IVF using GnRH agonist-triggered antagonist protocols. Among them, 6 (1.4%) had empty folicle syndrome (EFS). Patients with EFS had lower luteinizing hormone levels and fewer oocytes, embryos, and blastocysts, resulting in lower oocyte utilization rate. However, pregnancy rates were similar, with no biochemical or ectopic pregnancies observed in the EFS group.

Conclusion

Use of an hCG retrigger in hyperresponders with no oocytes after GnRHa trigger may prevent cycle cancelation. Although the rates of egg utilization may decrease, oocyte maturity remains comparable. Frozen embryo transfer following hCG retrigger administration yields similar positive pregnancy test results and live birth rates.

Risk factors for empty follicle syndrome in diminished ovarian reserve patients undergoing intracytoplasmic sperm injection cycles: A retrospective observational analysis

The aim of this study is to evaluate the risk factors for empty follicle syndrome (EFS) in patients with diminished ovarian reserve (DOR) undergoing an intracytoplasmic sperm injection cycle. In this retrospective study, patients with DOR were divided into 2 groups according to the presence of empty follicles on the day of oocyte retrieval. Patient age, body mass index (BMI), anti-Müllerian hormone (AMH), baseline follicle stimulating hormone (FSH) and estradiol (E2) levels, basal antral follicle count (AFC), total gonadotropin dose, and day of stimulation were recorded as risk factors. The association between EFS and these variables was assessed using the logistic regression method and ROC curve analysis. Increased BMI, low AMH, higher baseline FSH, low baseline AFC, higher gonadotropin dose, and longer day of ovulation induction were independent risk factors for EFS in patients with DOR. ROC curve analysis showed that BMI, AMH, baseline FSH, baseline AFC, higher gonadotropin dose, and longer ovulation induction days were predictive parameters in this group. According to the current study, higher BMI, lower AMH, higher baseline FSH, lower baseline AFC, higher gonadotropin dose and longer ovulation induction days were independent risk factors for EFS in patients with reduced ovarian reserve.

Low LH level does not indicate poor IVF cycle outcomes with GnRh-a single trigger: a retrospective analysis

OBJECTIVE

To compare the in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycle outcomes between patients with low and normal serum luteinizing hormone (LH) levels on the day after a gonadotropin-releasing hormone agonist (GnRH-a) single trigger. We further investigated the efficacy of human chorionic gonadotropin (hCG) retrigger on IVF cycle outcomes in patients with low LH levels after GnRH-a single trigger.

METHODS

We retrospectively analyzed 957 infertile patients (tubal factor, ovulation disorders, male sperm factor, or unexplained infertility) who were treated with IVF/ICSI at the Chengdu Xinan Gynecology Hospital from July 2017 to December 2020. Patients received sufficient GnRH-a single trigger were divided into two groups based on the serum LH levels on the next day of trigger: normal serum LH levels (≥ 10 mIU/mL) group (control group, n = 906) and low LH levels (< 10 mIU/mL) group (experimental group, n = 51). And the efficacy of hCG retrigger on IVF/ICSI cycle outcomes in 10 patients with low LH levels after GnRH-a single trigger.

RESULTS

There were no significant differences in IVF/ICSI cycle outcomes, including egg yield, two pronuclei fertilization rate, excellent embryo rate, or live birth rate of frozen-thawed embryos between patients with low and normal LH levels after GnRH-a trigger. It showed significantly higher risk of ovarian hyperstimulation syndrome in the group of low LH levels [ 0.7%(1/137) vs. 8.5%(4/47), P = 0.016] compared with the group of normal LH levels who received GnRH-a single trigger. The hCG retrigger had no obvious efficacy on cycle outcomes in patients with low LH levels, including oocytes retrieved, fertilization rate, embryo conditions, and live birth rate of frozen-thawed cycles.

CONCLUSION

The IVF/ICSI cycle outcomes of patients with low LH levels on the day after GnRH-a administration were similar to those of patients with normal LH levels. Blood LH test might not be required on the day following the trigger. The hCG retrigger did not have any effect on the cycle outcomes, suggesting that immediate retriggering with hCG was unnecessary.

Severe Ovarian Hyperstimulation Syndrome in a Case of Nonmutated Recurrent Genuine Empty Follicle Syndrome

Empty follicle syndrome (EFS) is a rare event in which no oocytes are retrieved from apparently normal growing follicles with normal steroidogenesis despite meticulous follicular aspiration in assisted reproductive technology (ART) cycles. EFS is mainly of two types, genuine EFS and false EFS. Here, we report a case of a 24-year-old woman presenting with primary infertility with normal ovarian reserve and regular menstrual cycles, husband having severe “oligo-astheno-teratozoospermia,” and planned for ART treatment. We could not retrieve any oocytes in successive cycles despite optimum human chorionic gonadotropin (hCG) levels on the day of oocyte retrieval and using different management protocols mentioned until now in the literature. The whole genomic analysis was found to be normal (46, XX). Further, the patient had experienced severe ovarian hyperstimulation syndrome (OHSS) after the second cycle of ovarian stimulation despite no luteal hCG support. We were ineffectual to find the cause of recurrent EFS in this patient and therefore counseled the patient for donor oocytes. This case highlights the difficulty in treating genuine EFS patients and the need for monitoring serum estradiol levels during ovarian stimulation to prevent another serious complication of OHSS.

Genuine Empty Follicle Syndrome: Role of Double Trigger and Delayed Oocyte Retrieval (DTDO)

BACKGROUND

Empty follicle syndrome (EFS) is a condition of undetermined etiology where no oocytes are retrieved in an ART cycle despite adequate response to ovarian stimulation and diligent follicular aspiration. Because of the rarity of this condition, no much published strategies are available to tackle this.

AIM

The aim of this study was to evaluate whether sequential administration of gonadotropin-releasing hormone agonist (GnRHa) and human chorionic gonadotropin (hCG) as a trigger at 40 h and 36 h, respectively, before oocyte retrieval (OCR) could correct genuine empty follicle syndrome (GEFS).

STUDY SETTING AND DESIGN

This retrospective observational cohort study was conducted in a tertiary fertility center over a period of 6 years from January 2014 to December 2019. Patients with a history of GEFS were administered GnRHa and recombinant hCG subcutaneously at 40 h and 36 h, respectively, before OCR, i.e., double trigger and delayed oocyte retrieval (DTDO) (n = 13). The primary outcome measures studied were number of mature oocytes retrieved, oocyte maturation index (OMI), number of fertilized oocytes, and number of embryos available for embryo transfer. The secondary outcome measures were clinical pregnancy rate (CPR), miscarriage rate (MR) and live birth rate (LBR) per first frozen embryo transfer (FET) cycle, incidence of inadvertent premature ovulation, and ovarian hyperstimulation syndrome.

STATISTICAL ANALYSIS

Comparison between the groups was analysed by Fisher's exact test and paired t-test.

RESULTS

Patients in the DTDO group showed a significant improvement (P < 0.01) in the number of mature oocytes retrieved, OMI, number of fertilized oocytes, and number of embryos available for embryo transfer. In the first FET cycle, CPR (44.44%), LBR (44.44%), and MR (11.11%) were observed in the DTDO group.

CONCLUSION

Our findings implicate that double trigger and delayed OCR (DTDO) is a safe and efficacious treatment strategy for GEFS.

Characteristics of Empty Follicular Syndrome during In vitro Fertilization Embryo Transfer and its Association with Various Etiologies in Comparatively Young Patients

Background:

Nearly 0.6%–7% of patients undergoing in vitro fertilization embryo transfer (IVF ET) will not be able to yield any oocyte despite successful ovarian stimulation and this condition is called as empty follicular syndrome (EFS). EFS is a dreadful situation for clinicians as well as patients, seems to be an unavoidable clinical condition despite a proper ovarian stimulation.

Materials and Methods:

This was a retrospective observational study conducted at a tertiary hospital; 1103 patients who underwent IVF ET between January 2016 and May 2017 were included in the study.

Study Outcome:

To estimate the incidence of empty follicle syndrome (EFS) and to study the associated factors.

Results:

There were 53 (4.8%) cases of EFS out of 1103 cycles of IVF ET; 43 (3.9%) cases were false EFS and 10 (0.9%) cases were genuine EFS. Mean age of EFS group and oocyte retrieved group was 30.17 years and 29.12 years respectively. Recurrence rate of EFS during the next IVF cycle was 36.8%. Decreased ovarian reserve was associated with an increased chance of EFS (54.7%) with a recurrence rate as high as 57%.

Conclusion:

The incidence of EFS is not an uncommon clinical scenario; it depends upon ovarian reserve to a great extent. Young age is not immune for the occurrence of EFS as there is a similar incidence in comparatively younger age group in our study. EFS is seen in all etiological groups of infertility, but only respite is that there is a chance of about 63.2% oocyte retrieval during repeat IVF cycle.

The ESHRE Working Group on Ultrasound in ART, D’Angelo A, Panayotidis C, Amso N, Marci R, Matorras R, Onofriescu M, Turp AB, Vandekerckhove F, Veleva Z, Vermeulen N, Vlaisavljevic V. Recommendations for good practice in ultrasound: oocyte pick up†

STUDY QUESTION

What is good practice in ultrasound (US), and more specifically during the different stages of transvaginal oocyte retrieval, based on evidence in the literature and expert opinion on US practice in ART?

SUMMARY ANSWER

This document provides good practice recommendations covering technical aspects of US-guided transvaginal oocyte retrieval (oocyte pick up: OPU) formulated by a group of experts after considering the published data, and including the preparatory stage of OPU, the actual procedure and post-procedure care.

WHAT IS KNOWN ALREADY

US-guided transvaginal OPU is a widely performed procedure, but standards for best practice are not available.

STUDY DESIGN SIZE DURATION

A working group (WG) collaborated on writing recommendations on the practical aspects of transvaginal OPU. A literature search for evidence of the key aspects of the procedure was carried out. Selected papers (n = 190) relevant to the topic were analyzed by the WG.

PARTICIPANTS/MATERIALS SETTING METHODS

The WG members considered the following key points in the papers: whether US practice standards were explained; to what extent the OPU technique was described and whether complications or incidents and how to prevent such events were reported. In the end, only 108 papers could be used to support the recommendations in this document, which focused on transvaginal OPU. Laparoscopic OPU, transabdominal OPU and OPU for IVM were outside the scope of the study.

MAIN RESULTS AND THE ROLE OF CHANCE

There was a scarcity of studies on the actual procedural OPU technique. The document presents general recommendations for transvaginal OPU, and specific recommendations for its different stages, including prior to, during and after the procedure. Most evidence focussed on comparing different equipment (needles) and on complications and risks, including the risk of infection. For these topics, the recommendations were largely based on the results of the studies. Recommendations are provided on equipment and materials, possible risks and complications, audit and training. One of the major research gaps was training and competence. This paper has also outlined a list of research priorities (including clarification on the value or full blood count, antibiotic prophylaxis and flushing, and the need for training and proficiency).

LIMITATIONS REASONS FOR CAUTION

The recommendations of this paper were mostly based on clinical expertise, as at present, only a few clinical trials have focused on the oocyte retrieval techniques, and almost all available data are observational. In addition, studies focusing on OPU were heterogeneous with significant difference in techniques used, which made drafting conclusions and recommendations based on these studies even more challenging.

WIDER IMPLICATIONS OF THE FINDINGS

These recommendations complement previous guidelines on the management of good laboratory practice in ART. Some useful troubleshooting/checklist recommendations are given for easy implementation in clinical practice. These recommendations aim to contribute to the standardization of a rather common procedure that is still performed with great heterogeneity.

STUDY FUNDING/COMPETING INTERESTS

The meetings of the WG were funded by ESHRE. The other authors declare that they have no conflict of interest.

TRIAL REGISTRATION NUMBER

NA.ESHRE Pages content is not externally peer reviewed. The manuscript has been approved by the Executive Committee of ESHRE.

Empty follicle syndrome revisited: definition, incidence, aetiology, early diagnosis and treatment

In this review, the definition, incidence and possible causes of empty follicle syndrome (EFS), including molecular mechanisms that may underlie the syndrome, are discussed, along with prevention and treatment options. EFS is the complete failure to retrieve oocytes after ovarian stimulation, despite apparently normal follicle development and adequate follicular steroidogenesis. Two variants of EFS have been described: the 'genuine' form (gEFS), which occurs in the presence of adequate circulating HCG levels at the time of oocyte aspiration, and the 'false' form (f-EFS), which is associated with circulating HCG below a critical threshold. Heterogeneous HCG concentration thresholds, however, have been used to define gEFS, and to date no standardization exist. The situation is unclear when GnRH-analogues are used for ovulation trigger, as the threshold circulating LH and progesterone levels used to define EFS as 'genuine' are not established. The cause of fEFS has been clearly identified as an error in HCG administration at the time of ovulation trigger; in contrast, the cause of gEFS is still unclear, although some pathogenetic hypotheses have been proposed. Optimal treatment and prognosis of these patients are still poorly understood. Large, systematic multi-centre studies are needed to increase the understanding of EFS.

GnRH agonist trigger for the induction of oocyte maturation in GnRH antagonist IVF cycles: a SWOT analysis

Gonadotrophin releasing hormone agonist (GnRHa) trigger is effective in the induction of oocyte maturation and prevention of ovarian hyperstimulation syndrome during IVF treatment. This trigger concept, however, results in early corpora lutea demise and consequently luteal phase dysfunction and impaired endometrial receptivity. The aim of this strenghths, weaknesses, opportunities and threats analysis was to summarize the progress made over the past 15 years to optimize ongoing pregnancy rates after GnRHa trigger. The advantages and potential drawbacks of this type of triggering are reviewed. The current approach to the management of GnRHa trigger in autologous cycles is based on the peak serum oestradiol level or follicle number and aims at a fresh embryo transfer or a segmentation approach with elective cryopreservation policy. We recommend intensive luteal support with transdermal oestradiol and intramuscular progesterone alone if peak serum oestradiol is 4000 or more pg/ml after GnRHa trigger or dual trigger with GnRHa and HCG 1000 IU if peak serum oestradiol is less than 4000 pg/mL. On the contrary, we recommend HCG 1500 IU 35 h after GnRHa trigger if there are less than 25 follicles, or freeze all oocytes or embryos if there are over 25 follicles.

Empty follicle syndrome: Successful pregnancy following dual trigger

Empty follicle syndrome (EFS) is an uncommon, but the frustrating complication of assisted reproductive technology with failure to obtain oocytes after an adequate ovarian response to stimulation. Most of the reported cases of EFS are drug-related problems which are actually avoidable and do not represent any potential pathology and that the risk of genuine EFS (GEFS) is much smaller than was once thought. Our case is the first report of a pregnancy obtained after management of GEFS with dual trigger in a gonadotropin-releasing hormone (GnRH) antagonist cycle. In this report, we present a patient who underwent two oocyte retrievals, in which no oocytes were obtained. In the third in-vitro fertilization cycle, a dual trigger with the combination of GnRH agonist and human chorionic gonadotropin yielded 11 oocytes, which led to the transfer of 2 blastocysts resulting in a live birth. Changing the treatment protocol with dual trigger brought about a successful outcome.

Is the time interval between HCG administration and oocyte retrieval associated with oocyte retrieval rate?

The aim of this study was to evaluate whether prolongation of the time interval between HCG administration and oocyte retrieval, from 36 h to 38 h, affects oocyte retrieval rate in women undergoing ovarian stimulation with gonadotrophins and GnRH antagonists for IVF. One hundred and fifty-six normo-ovulatory women were randomized to have oocyte retrieval performed 36 h (n = 78) or 38 h (n = 78) following HCG administration. Oocyte retrieval rate was defined as number of cumulus-oocyte-complex (COC) retrieved/follicle ≥ 11 mm present on day of HCG administration. No significant differences were observed between the groups regarding baseline characteristics. Moreover, no significant difference was observed between the groups regarding oocyte retrieval rate (difference: + 1.2%, 95% CI for difference between medians: -4.5 to +12.1). The median (95% CI for the median) was not significantly different between the groups regarding number of cumulus-oocyte-complexes (COCs) retrieved: 5.5 (5.0-7.0) versus 6.0 (5.0-6.2), respectively, and fertilization rates: 57.7% (50.0-66.7) versus 50.0% (44.8-65.5), respectively. Live birth rates were similar between the groups (20.5% versus 16.7%, RD: + 3.8%, 95% CI: -8.5 to +16.1, respectively). Prolongation of time interval between HCG administration and oocyte retrieval from 36 h to 38 h does not affect oocyte retrieval rate.

Luteal phase ovarian stimulation following oocyte retrieval: is it helpful for poor responders?

BACKGROUND

Poor ovarian response and retrieval of no oocytes following ovarian stimulation for in vitro fertilization (IVF) is a challenging problem for both the patient and the clinician.

FINDINGS

Recent evidence indicates that folliculogenesis occurs in a wave-like fashion indicating that there are multiple follicular recruitment waves in the same menstrual cycle. This relatively new scientific concept provides new opportunities for the utilization of ovarian stimulation in women with poor ovarian response. This communication reports on the social and scientific rationale for the use of luteal phase ovarian stimulation following oocyte retrieval in the same cycle (also called double stimulation).

CONCLUSIONS

Data to date showed that double ovarian stimulation in poor responders provides shorter time for retrieving mature oocytes with the potential formation of good quality embryos, and thus healthy pregnancies.

Failure of intrauterine insemination as rescue treatment in low responders with adequate HCG timing with no oocytes retrieved

In this retrospective study, the efficiency of carrying out rescue intrauterine insemination (IUI) in low-responder patients undergoing IVF when no oocytes were retrieved after follicular aspiration and when HCG timing was adequate was analysed. A historical control group was used. Over 13 years, women undergoing IVF with failure to obtain oocytes at follicular aspiration underwent rescue IUI if the following criteria were met: adequate HCG timing; one normal tube; motile sperm count after preparation over 3 million/ml; and ultrasound visualization of one to six follicles over 13 mm. The rescue IUI was carried out 1 h after follicular aspiration. Results were compared with those of a standard IUI population (5394 cycles) in the same period. Confidence intervals were calculated using Poisson 97.5% confidence upper tail limits when no event was observed in the study sample. No pregnancies were achieved among the 54 cases who underwent rescue IUI (confidence interval: 0 to 6.8%). This pregnancy rate was lower than that observed in the general IUI population (17.5%) (relative risk, 19.2). After adjusting for age and endometriosis, the relative risk was 11.7. The rescue IUI is an inefficient procedure. Its efficacy is unlikely to exceed 7% pregnancy rate per IUI.

Empty follicle syndrome

Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved after an apparently adequate ovarian response to stimulation and meticulous follicular aspiration. EFS can be classified into 'genuine' and 'false' types according to hCG levels. It is a rare condition of obscure etiology. The existence of genuine EFS has been questioned and is still controversial. The limitation around EFS is that the definition of EFS is obscure. Management of patients with EFS is a challenge to physicians. No single treatment is known to be universally effective. However, patients should be adequately informed regarding the importance of correct hCG administration because improper hCG administration is a common and preventable cause of EFS. EFS is a syndrome that deserves additional study because such investigation could lead to a further understanding of ovarian biology and infertility.

Human chorionic gonadotropin (hCG) plasma levels at oocyte retrieval and IVF outcomes

PURPOSE

The aim of our study was to ascertain the influence of hCG levels at oocyte pick-up on IVF outcomes, and their relationship with clinical parameters.

METHODS

A prospective study was performed including 473 women undergoing IVF, aged under 40 years. Blood samples to analyze hCG levels were obtained at the time of follicular aspiration, 36 h after the administration of 250 μg of recombinant hCG.

RESULTS

Neither the numbers of oocytes obtained or fertilized, nor the pregnancy rate, were correlated with hCG levels. Moreover, hCG values were very similar in women who did and did not become pregnant (123.3 ± 48.7 and 117.5 ± 44.7 mUI/mL). Cases in which no oocytes were recovered after follicular aspiration had similar hCG levels to those in which more than 1 oocyte was obtained. On the other hand, hCG levels were negatively related to body mass index, weight, and age.

CONCLUSIONS

These data indicate that after the administration of 250 μg of recombinant hCG, hCG levels are not responsible for failure to recover oocytes. Specifically, there was no correlation between plasma hCG levels and the number of oocytes obtained or other markers of IVF outcome. There was, however, an inverse relationship with BMI, body weight and age.

Recurrence of empty follicle syndrome with stimulated IVF cycles

AIM

To determine the incidence of recurrent empty follicle syndrome (EFS) and to analyse the factors associated with this phenomenon.

METHODS

Retrospective analysis comparing all EFS cycles with cycles in which oocytes were retrieved in our in vitro fertilization (IVF) unit between 1998 and 2006.

RESULTS

Of 8292 IVF cycles, 163 (2.0%) resulted in empty follicles. Risk factors for EFS included advanced age (37.7 ± 6.0 years vs. 34.2 ± 6.0 years, p < 0.001), longer infertility (8.8 ± 10.6 years vs. 6.3 ± 8.4 years, p < 0.05), higher baseline follicle-stimulating hormone levels (8.7 ± 4.7 IU/L vs. 6.7 ± 2.9 IU/L, p < 0.001) and lower E2 levels before the human chorionic gonadotropin injection (499.9 ± 480.9 pg/mL vs. 1516.3 ± 887.5 pg/mL, p < 0.001) compared with cases in which ova were retrieved. Among patients with EFS, recurrent EFSs occurred in 15.8% of subsequent cycles.

CONCLUSION

The EFS is a sporadic event in the majority of patients. However, in about 16% of the patients, EFS may recur. These cases may be a variant form of poor response and patients with repetitive EFS syndrome should be counseled concerning their chances to conceive.

Empty follicle syndrome: successful treatment in a recurrent case and review of the literature

Empty follicle syndrome is a condition in which no oocytes are retrieved after an apparently adequate ovarian response to stimulation and meticulous follicular aspiration. It is a rare condition of obscure etiology. A patient with primary infertility who underwent seven assisted reproductive technique cycles is described. In spite of a satisfactory ovarian response, aspiration yielded no oocytes in four cycles and 1-4 low quality oocytes in three cycles. In the index treatment cycle, ovulation was triggered using GnRH agonist 40 h prior to ovum pickup and hCG was added 6 h after the first trigger. Eighteen oocytes were recovered, of which 16 were mature and were inseminated by ICSI. Two embryos were transferred 48 h after aspiration and nine embryos were cryopreserved. The patient conceived and delivered a healthy boy at 38 weeks of gestation. The literature is reviewed and possible etiologies and treatment options of this enigmatic syndrome are suggested.

The prevalence of genuine empty follicle syndrome

OBJECTIVE

To describe the prevalence of "genuine" empty follicle syndrome (EFS) and "false" EFS at assisted reproductive technology (ART).

DESIGN

Retrospective cohort.

SETTING

Large private fertility center.

PATIENT(S)

A total of 12,359 patients who underwent ART between 2004 and 2009.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The failure to recover an oocyte during oocyte retrieval at ART, with and without a detectable serum β-hCG on the day of retrieval.

RESULT(S)

Two cases of genuine EFS and nine cases of false EFS were identified in the cohort examined. The prevalence of genuine EFS was 0.016%, and the prevalence of false EFS was 0.072%. Only two out of 11 cases of EFS were considered genuine.

CONCLUSION(S)

Genuine EFS is a rare occurrence. Because this syndrome tends to recur with dismal pregnancy rates at ART, continued identification and further investigation of the syndrome are needed.

Empty follicle syndrome after GnRHa triggering versus hCG triggering in COS

PURPOSE

This study aimed to explore the incidence of empty follicle syndrome (EFS) in oocyte donors who had final oocyte maturation triggered with GnRHa and to compare the incidence of EFS in this group of patients with IVF patients who had final oocyte maturation with hCG.

METHODS

Data including 2034 oocyte donation cycles and 1433 IVF cycles performed between years 2009 and 2010 was retrospectively analyzed to identify cases of EFS in each group.

RESULTS

The incidence of EFS in the two groups did not differ significantly, 3.5% versus 3.1%, (n.s.).

CONCLUSIONS

This large retrospective analysis indicates that the incidence of EFS is not increased after GnRHa triggering as compared to hCG triggering.

Empty follicle syndrome-Still an enigma

Empty follicle syndrome (EFS), although rare with an incidence of 0.2-7%, is a frustrating condition where no oocytes are retrieved in in vitro fertilization (IVF), even though ultrasound and estradiol measurements show the presence of many potential follicles. It is a complex phenomenon that cannot be explained by low bioavailability of human chorionic gonadotrophin alone; neither can it be reliably diagnosed by the measurement of serum beta-human chorionic gonadotrophin (bhCG) on the day of oocyte retrieval (OR), except possibly when the bhCG concentration is very low. Here we report a case who underwent intracytoplasmic sperm injection (ICSI) for her partner's severe oligoasthenozoospermia. Controlled ovarian hyperstimulation (COH) was done in her first cycle of ICSI, using a gonadotrophin-releasing hormone (GnRH) agonist long protocol with follicle-stimulating hormone (FSH) and human menopausal gonadotrophin (HMG). However, as we were unable to retrieve any oocytes, her COH protocol was changed in the subsequent cycle with a successful outcome.

Immature oocytes in "apparent empty follicle syndrome": a case report

Empty follicle syndrome (EFS) is a condition in which no oocytes are obtained after an apparently successful ovarian stimulation. Genuine EFS (GEFS) is differentiated from false EFS by an optimal level of human chorionic gonadotropin on the day of oocyte retrieval. Some believe that GEFS does not exist and that it is only a reflection of the margin of error attendant upon the procedure of oocyte aspiration. Others believe that GEFS is caused by dysfunctional folliculogenesis, resulting in early atresia of oocytes. In this report, we present a case of apparent GEFS, in which immature oocytes were identified after filtration of follicular aspirates. Our findings suggest that delayed maturation of oocyte cumulus complexes in response to HCG might be an etiologic mechanism in some cases of GEFS. This creates a situation similar to the aspiration of immature follicles, where germinal vesicle-stage oocytes with dense scanty cumulus cells are often difficult to identify under a dissecting microscope.

Empty follicle syndrome: the reality of a controversial syndrome, a systematic review

OBJECTIVES

To examine all case reports and studies of empty follicle syndrome (EFS) that have been published since the condition was first reported, in an attempt to identify trends or common features that may expose possible risk or causative factors.

DESIGN

Systematic review of all available literature obtained from PubMed, Ovid, and Embase.

SETTING

Academic unit.

PATIENT(S)

Review of all published case reports and case studies.

INTERVENTION(S)

All original work was assessed and labeled as "genuine" or "false" EFS according to set definitions.

MAIN OUTCOME MEASURE(S)

Genuine and false EFS. We defined genuine EFS as a failure to retrieve oocytes from mature ovarian follicles after ovarian stimulation for IVF after apparently normal follicular development and steroidogenesis in the presence of optimal beta-hCG levels on the day of oocyte retrieval. False EFS included all cases in which this definition cannot apply and often in which human error or a pharmaceutical inaccuracy has occurred.

RESULT(S)

By classifying all cases of EFS as "genuine" or "false" according to stated definitions, it was evident that a much greater proportion of cases of reported EFS, 67%, occurred as a result of human error and that "genuine empty follicle syndrome" is an even rarer event than previously presumed.

CONCLUSION(S)

Our report highlights the value of classifying cases of EFS as "genuine" or "false" and shows that more epidemiological data are required of "genuine" EFS cases to develop a clearer picture of the possible etiology.

Transcriptional profiling of granulosa cells from a patient with recurrent empty follicle syndrome

Empty follicle syndrome (EFS) is characterized by the absence of oocytes after apparently normal follicular development and the pathogenesis of this syndrome is not well characterized. The aim of this study was to analyse whole gene expression of granulosa cells (GC) from a patient with recurrent EFS by using Affymetrix GeneChip. A total of 160 genes were identified as being differentially expressed (by at least two-fold) between EFS GC and the control GC. Most of the differentially expressed genes were involved in cell growth and death. Among these were MAPK3, which plays an important role in the inhibition of apoptosis, was down-regulated 2.3-fold in EFS GC. Moreover, secretory phospholipase A2 and transforming growth factor receptor II, key regulators of cell death pathway, were down-regulated 3.54- and 2.82-fold respectively in EFS. Gene expression of granulosa cells from the EFS patient was significantly altered. The absence of the oocytes might be due to the increased apoptotic gene expression and the reduction of transcripts whose products are responsible for healthy follicular growth. Gene expression analyses might be a useful technique in identifying markers to follow a healthy follicular maturation and understanding the events that lead to EFS.

Oocytes in the empty follicle: a controversial syndrome

OBJECTIVE

To assess the prevalence and etiology of the empty follicle syndrome (EFS).

DESIGN

Observational longitudinal study.

SETTING

Tertiary fertility centers.

PATIENT(S)

All patients beginning in vitro fertilization (IVF) treatment from December 2002 to November 2004 were included. Couples undergoing IVF with donor oocytes or participating in an experimental IVF study were excluded from analysis.

INTERVENTION(S)

Identification of EFS cycles. Comparing ovarian hyperstimulation strategy, follicle count, and timing of human chorionic gonadotropin (hCG) for final oocyte maturation of the EFS cycles with normal IVF cycles.

MAIN OUTCOME MEASURE(S)

Number of follicles punctured, number of oocytes recovered, previous and future IVF attempts, and serum hormone levels.

RESULT(S)

Twenty-five of a total of 1,849 patients were identified with an EFS cycle. Reasons for occurrence of EFS cycles were mistiming of hCG for final oocyte maturation, premature ovulation, and poor ovarian response. None of the affected patients had experienced EFS cycles in earlier IVF attempts nor were there any recurrence in subsequent treatments.

CONCLUSION(S)

Accurate timing of induction of final oocyte maturation, properly scheduled ovarian hyperstimulation, instruction of patients and doctors, and full workup for IVF are essential for the successful recovery of oocytes. Occurrence of EFS in IVF can normally be attributed to a failure of at least one of these factors and probably rarely or never occurs otherwise.

Pericentric inversion of chromosome 2 in a patient with the empty follicle syndrome: Case report

The empty follicle syndrome (EFS) is defined as a lack of retrieved oocytes from follicles, at the time of repeated aspiration and flushing, following ovulation induction. The actual mechanism responsible for the EFS is still unknown. The aim of this study was to offer more information regarding the possible connection of this syndrome with pericentric inversion of chromosome 2. We give a case report of a patient who had multiple failed IVF attempts, due to the absence of oocyte and granulosa cells in the follicular fluid, following oocyte retrieval in both stimulated and natural cycles. Chromosomal analysis showed the presence of a pericentric inversion of chromosome 2: 46,XX,inv(2)(p11q21) in the female partner karyotype, while the male partner had a normal karyotype. Our case showed possible genetic factor influence in the aetiology of EFS.

Poor oocyte retrieval is a manifestation of low ovarian reserve

Women with complete absence of oocytes during retrieval, as well as those with less than the 10th percentile of the expected number of oocytes retrieved, have clear manifestations of low ovarian reserve. It seems that this occurrence is a gradual biological phenomenon related to the basic pathophysiology of ovarian aging.

Is the occurrence of the empty follicle syndrome a predictor that a subsequent stimulated cycle will be an unfavourable one?

Several hypotheses have been advanced to explain empty follicle syndrome (EFS) but it remains a controversial topic. This paper reports experience with three IVF cycles in which no oocytes were collected. In all cases, an additional IVF cycle was performed. The ovarian stimulation protocol, ultrasound and hormonal surveillance methods, human chorionic gonadotrophin timing and oocyte retrieval technique were similar in all patients. The assessment of additional cycles demonstrated a poor response in terms of oocyte quality, since the number of mature oocytes was low despite the high number of oocytes collected. Thus, the data suggest that in these patients, EFS should be considered as a borderline form of poor response to ovarian stimulation. If this is confirmed, EFS should be a recurrent event and an empty cycle could be a good predictor that a subsequent stimulated cycle will be an unfavourable.

Recurrent empty follicle syndrome

We report a case of a recurrent empty follicle syndrome. The patient was admitted to our intracytoplasmic injection program because of her partner's azoospermia. Ovarian stimulation was accomplished using gonadotrophin therapy after treatment with oral contraceptive pills followed by gonadotrophin-releasing hormone agonist. Thirty-six hours after the administration of HCG (human chorionic gonadotrophins), transvaginal oocyte retrieval yielded no oocytes despite the aspiration and flushing of all available follicles. Two years later, a second treatment cycle was started using the same pituitary desensitisation and ovarian stimulation regimens. HCG from a different batch with respect to that used in the first treatment cycle was administered. Aspiration and repeated flushing of all follicles of one ovary failed to yield any identifiable oocyte. The beta-HCG and progesterone serum concentrations on the day of retrieval were 181 mIU/mL and 3.79 ng/mL, respectively. New oocyte retrieval was planned 6 h after the first attempt for aspiration of follicles. Again, no ova were obtained at this second trial despite the aspiration of the all follicles. As to our knowledge this is the first report of recurrent EFS (empty follicle syndrome) and managed without repeating the HCG injection on the day of unsuccessful oocyte retrieval.

Unsuccessful oocyte retrieval: technical artefact or genuine 'empty follicle syndrome'?

Unsuccessful oocyte retrieval after apparently successful ovarian stimulation (also referred to as 'empty follicle syndrome') occurs in 1-7% of women undergoing assisted reproductive techniques. A literature review was performed, as individual studies have reached differing conclusions on the aetiology and treatment or management of the phenomenon. The aetiology is not clear, but probably multifactorial, and occurs in natural and stimulated cycles. In many cases, technical problems such as errors in human chorionic gonadotrophin (HCG) administration or defects in HCG batches can be identified, but this is not sufficient to account for all reported cases. The term empty follicle syndrome is inappropriate in cases in which such procedural factors can be identified. In many patients, however, unsuccessful oocyte retrieval appears to be due to an underlying ovarian dysfunction, and some may have a genuine empty follicle syndrome. Appropriate measures, such as monitoring of serum beta-HCG, should be taken to minimize the risk of unsuccessful oocyte retrieval. This review discusses the potential causes of unsuccessful oocyte retrieval, its clinical implications, and potential solutions to this clinical problem.

The empty follicle syndrome

The empty follicle syndrome (EFS) is characterized by the lack of retrieved oocytes from follicles after ovulation induction and apparently normal follicular development for in vitro fertilization, despite repeated aspiration and flushing. The underlying mechanism of the EFS remains hypothetical. Some Authors have suggested that it is related to the "cause" leading to female infertility, whereas others have pointed to the alternative suggestion that it might reflect dysfunctional folliculogenesis, with early oocyte atresia and apparently normal hormonal response. Moreover, some Authors believe that the EFS does not exist, and that the oocyte retrieval failure is a pharmacological fault. The risk of recurrence is higher as the age of the patients increases. The EFS cannot be predicted by the pattern of ovarian response to stimulation either sonographically or hormonally. Consequently, the diagnosis of EFS is retrospective. Whatever the underlying cause of an EFS cycle, patients with an EFS cycle should be counselled regarding the possibility of recurrence of such an event in future cycles.

Recurrent empty follicle syndrome successfully treated with recombinant human chorionic gonadotrophin

We report a case of a patient with polycystic ovary syndrome and primary infertility who was admitted to our in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programme because of her partner's severe oligozoospermia and asthenozoospermia. Ovarian stimulation was accomplished in the three treatment cycles using gonadotrophin therapy after a dual approach with ovarian suppression using oral contraceptive pills followed by gonadotrophin-releasing hormone agonist therapy. Oocyte retrieval was unsuccessful in the first two treated cycles despite the fact that human chorionic gonadotrophin (HCG) from three different batches was used. In the third treatment cycle, recombinant HCG was used and five oocytes were retrieved. This is the first report of recurrent empty follicle syndrome despite the use of different batches of commercially available urinary HCG, and of its successful treatment using recombinant HCG.

Double oocyte aspiration may be a solution for empty follicle syndrome: case report

OBJECTIVE

To assess the possibility of salvaging the cycle in a case of empty follicle syndrome by scheduling a second retrieval.

SETTING

Miami IVF/Intracytoplasmic Sperm Injection Center, Alexandria, Egypt. It is a private center.

PATIENT(S)

A 24-year-old female with a 6-year history of primary infertility. Intracytoplasmic sperm injection was performed because of her partner's obstructive azoospermia. No oocytes could be retrieved despite normal ultrasonic and hormonal responses and the presence of 25 mature follicles.

INTERVENTION(S)

Serum hCG on the day of the first retrieval. A second dose of hCG was given after the first retrieval, and a second retrieval was scheduled 24 hours later.

MAIN OUTCOME MEASURE(S)

Number of oocytes retrieved, fertilization and cleavage rates, and pregnancy outcome.

RESULT(S)

Serum beta-hCG level on the day of the first retrieval was 300 IU/mL. Eleven oocytes were retrieved, (7 were metaphase II, 3 fertilized, and 2 cleaved) and two embryos were transferred. No pregnancy resulted.

CONCLUSION(S)

In a variant of empty follicle syndrome, the cycle could be salvaged by giving another dose of hCG and scheduling another retrieval 24 hours later.

Estradiol, progesterone and androstenedione content of follicular fluids in 'empty follicles'

In an in vitro fertilization (IVF) and embryo transfer program with human menopausal gonadotropin/human chorionic gonadotropin treatment no oocytes were recovered in 18 out of 788 cycles. Estradiol (E2), progesterone (P) and androstenedione contents of 27 follicles obtained from five of the 18 patients were radioimmunologically measured and P:E2 ratio calculated. Control values of 20 follicles were obtained from four of these five patients in subsequent IVF cycles. A total of 17 oocytes were harvested. Estradiol, progesterone and androstenedione mean +/- SEM values (nmol/l) were, respectively, 4246 +/- 1484, 3751 +/- 1768 and 1920 +/- 641 in the failed cycles and 2504 +/- 908, 13,678 +/- 4749 and 509 +/- 87 in the successful ones. P:E2 ratios were 0.88 +/- 1.03 and 5.67 +/- 1.70, respectively. The differences in these levels of progesterone, androstenedione and the ratios of P:E2 were significant (p < 0.01). It is concluded that the probable cause of 'empty follicles' is inappropriate luteinization and they are not characteristic for a given patient or for stimulation with human menopausal gonadotropin/human chorionic gonadotropin.

Failed oocyte retrieval after lack of human chorionic gonadotropin administration in assisted reproductive technology

OBJECTIVE

To document the absence of oocytes in follicular aspirates in women who, during controlled ovarian stimulation with gonadotropin-releasing hormone agonist (GnRH-a) and menotropins, fail to receive human chorionic gonadotropin (hCG) administration.

DESIGN

Retrospective analysis of clinical laboratory data.

SETTING

Multicentric.

PATIENTS

Five women undergoing controlled ovarian hyperstimulation with GnRH-a and menotropins for programs of assisted reproductive technologies.

RESULTS

The documented absence of an hCG injection produced "empty follicles" at transvaginal guided aspiration, despite numerous follicular lavages and aspiration of peritoneal fluid. The lack of oocytes and granulosa-cumulus complex in the follicular fluid was reverted in other cycles in the same patients when hCG was properly administered.

CONCLUSIONS

(1) This study emphasizes the importance of proper patients' and nurses' instructions for preparation of hCG injections and proper mixture of vehicle and powder before follicular aspiration. (2) In the absence of cumulus-corona-oocyte complex at aspiration, measure serum beta-hCG to ascertain whether hCG injection was administered or not. (3) Routine preoperative beta-hCG levels may be helpful to avoid unnecessary surgeries.