How many eggs are needed to produce an assisted reproductive technology baby: is more always better?

Comparison of stimulation protocols for dose determination of gonadotropins: A systematic review and Bayesian network meta-analysis based on randomized controlled trials

BACKGROUND

To date, evidence regarding the effectiveness and safety of individualized controlled ovarian stimulation (COS) compared with standard dose COS has been inadequate.

OBJECTIVES

To evaluate the updated evidence from published randomized controlled trials (RCTs) about the efficacy and safety of individualized COS with different ovarian reserve test biomarkers or clinical experience versus standard dose COS.

SEARCH STRATEGY

Terms and descriptors related to COS, individualized or standard, and RCT were combined to search, and only English language studies were included. Conference abstracts and comments were excluded.

SELECTION CRITERIA

RCTs with comparison between different individualized COS strategies and standard starting dose strategy were included.

DATA COLLECTION AND ANALYSIS

Two reviews independently assessed the eligibility of retrieved citations in a predefined standardized manner. Relative risk (RRs) and the weighted mean difference (WMD) with 95% confidence intervals (CIs) were pooled using a random-effects model on R software version 4.2.2.

MAIN RESULTS

Compared with the standard dose COS strategy in pairwise meta-analysis, the individualized COS strategy was associated with a notable lower risk of ovarian hyperstimulation syndrome (OHSS; 174/2384 [7.30%] vs 114/2412 [4.73%], RR 0.66, 95% CI: 0.47-0.93, I2 = 46%), a significantly lower risk of hyperresponse to stimulation (hyperresponse; 476/2402 [19.82%] vs 331/2437 [13.58%], RR 0.71, 95% CI: 0.57-0.90, I2 = 61%), and a slightly longer ovarian stimulation days (duration of stimulation; WMD 0.20, 95% CI: 0.01-0.40, I2 = 66%). Bayesian network meta-analysis also found that biomarker-tailored strategy had a significantly lower risk of OHSS than standard dose strategy (OHSS; RR 0.63, 95% CI: 0.41-0.97, I2 = 47.5%).

CONCLUSION

Compared with standard dose COS strategy, individualized COS strategy could significantly reduce the risks of OHSS and hyperresponse to stimulation, but the duration of stimulation was slightly longer.

TRIAL REGISTRATION

PROSPERO: CRD42023358439.

Cut-off point of mature oocyte for routine clinical application of rescue IVM: a retrospective cohort study

BACKGROUND

The rescue in vitro mature(Rescue IVM) technique allows the use of immature oocytes collected in conventional COH to obtain more mature oocytes for fertilization through in vitro maturation. Some studies have shown that Rescue IVM could improve clinical outcomes in patients undergoing IVF/ICSI, but the effectiveness and the indications for the clinical application of this technique remain controversial. It remains to be studied whether Rescue IVM should be universally applied in all conventional IVF/ICSI cycles.

METHOD

This is a large retrospective cohort study that included a total of 22,135 female patients undergoing their first IVF treatment cycles. The effect of the number of mature oocytes(metaphaseII[MII]) on the cumulative live birth rate was investigated in a population with routine IVF/ICSI first. The receiver operating characteristic curve(ROC) analysis was used to explore the cut-off point of the number of MII affecting CLBR. Secondly, Patients undergoing ICSI with Rescue IVM were included in the analysis with those who underwent ICSI only during the same period, grouped according to the MII cut-off values. Multi-factor binary logistic regression and inverse probability weighting (IPW) were used to investigate whether Rescue IVM influenced the final cumulative live birth rate(CLBR).

RESULTS

The CLBR increased with the number of MIIoocytes (P < 0.001). The ROC analysis showed the cut-off point for the number of MIIoocytes to have a significant effect on CLBR was 9 (sensitivity 0.715, specificity 0.656). Furthermore, 912 patients who underwent ICSI with Rescue IVM were included and compared to those who underwent ICSI only during the same period, and found Rescue IVM significantly increased the number of available MIIoocytes. For patients with MII numbers < 9, Rescue IVM significantly improves their clinical pregnancy rate(55.6% vs. 46.7%, P = 0.001) and CLBR(65.4% vs. 48.1%, P < 0.001), but not for those patients with MII numbers ≥ 9.

CONCLUSION

This study further clarifies the candidates for the application of Rescue IVM technique: patients with an MII oocytes < 9 in a conventional IVF/ICSI cycle. In contrast, it is not necessary for patients who already have sufficient mature oocytes(≥ 9), to avoid over-medication.

Development and validation of a conventional in vitro total fertilization failure prediction model

BACKGROUND

Conventional total fertilization failure (TFF) is a challenging problem for clinicians. The predictive model developed in this study aims to predict the individual probability of conventional in vitro total fertilization failure.

METHODS

The prediction model was developed based on 1635 patients who underwent first-attempt in vitro fertilization (IVF) cycles from January 2018 to January 2020. Total fertilization failure and normal fertilization occurred in 218 and 1417 cycles, respectively. Multivariate logistic regression analyses were used to develop the prediction model. Performance of our model was evaluated using calibration (Hosmer-Lemeshow test) and discrimination (area under the receiver operating characteristic curve [AUC]).

RESULTS

Thirteen risk factors for TFF were included in the prediction model, as follows: female age; female body mass index; infertility duration; number of oocytes retrieved; stimulation protocol; infertility etiology; infertility diagnosis; male age; sperm concentration; total sperm motility; normal sperm morphology percentage; swim-up sperm motility; and swim-up sperm concentration. The AUC of our model was 0.815 (95% CI: 0.783-0.846), indicating satisfactory discrimination performance.

CONCLUSION

Considering female and male factors (especially sperm parameters), we established a model that predicts the probability of TFF in conventional IVF procedures that will be helpful in the laboratory supporting IVF to facilitate physicians in determining optimal treatment.

The gonadotropins starting dose calculator, which can be adjusted the target number of oocytes and stimulation duration days to achieve individualized controlled ovarian stimulation in Japanese patients

Purpose

To create a gonadotropin starting dose calculator for controlled ovarian stimulation, which can adjust the target number of oocytes and stimulation duration for each facility to achieve individualized controlled ovarian stimulation among the Japanese patients.

Methods

The patients received controlled ovarian stimulation using the gonadotropin-releasing hormone antagonist protocol, and oocytes were retrieved. Using single regression analysis, we selected age, anti-Müllerian hormone (AMH), and initial serum follicle-stimulating hormone as variables to predict the number of oocytes retrieved per gonadotropin dose (oocyte sensitivity index). Each variable was then analyzed using backward stepwise multiple regression.

Results

Age and AMH were selected as predictive variables from the backward stepwise multiple regression, and we developed a multiple regression equation. We decomposed the equation as the number of oocytes retrieved/(gonadotropin starting dose × stimulation duration days) and created a calculation formula to predict the gonadotropin starting dose from the target number of oocytes and stimulation duration days.

Conclusions

This is the first study to develop an individualized dosing algorithm for gonadotropins among Japanese patients. Our calculator will improve controlled ovarian stimulation performance and enable national standardization by allowing all physicians, regardless of their years of experience, to determine the appropriate starting dose of gonadotropins equally.

Optimal Oocyte Number in Controlled Ovarian Stimulation with Gonadotropin-Releasing Hormone Agonist/Antagonist and Day 3 Fresh Embryo Transfer

We aimed to investigate the optimal number of oocytes retrieved in normal responders with the gonadotropin-releasing hormone (GnRH) antagonist (GnRHant) protocol in comparison with the GnRH agonist (GnRHa) long protocol. This retrospective study is based on a single-center cohort including 657 fresh cycles with day 3 embryo transfer using the GnRHa long protocol and the GnRHant flexible protocol at the fertility clinic of a university hospital between 2005 and 2019. The rate ratios (RR) of clinical pregnancy were evaluated using log-binomial regression depending on the categories by the number of retrieved oocytes and pituitary suppression methods. After controlling for age, body mass index, and basal follicle-stimulating hormone, women with 10-11 oocytes retrieved demonstrated a significantly higher chance of clinical pregnancy compared to the reference group (4-5 oocytes) (RR 1.68, 95% CI 1.12-2.53). However, retrieval of more than 11 oocytes did not show a significant difference in pregnancy rates (PR) from the reference group. In women treated with GnRHant, a significantly higher clinical PR was also observed in women with 10-11 oocytes retrieved compared to the reference group (RR 1.90, 95% CI 1.05-3.42). In women treated with GnRHa long protocol, a higher probability of clinical pregnancy was observed (RR 1.30, 95% CI 0.98-1.73) in the group with 8-11 oocytes retrieved and it demonstrated borderline statistical significance (P = 0.07). In summary, the optimal number of oocytes for maximizing the rate of a clinical pregnancy is different according to the method of pituitary suppression. Too many oocytes do not seem to be beneficial for achieving better clinical outcomes.

Is there an optimal number of oocytes retrieved at which live birth rates or cumulative live birth rates per aspiration are maximized after ART? A systematic review

The association between the number of oocytes retrieved and fresh live birth rate (LBR) or cumulative LBR (CLBR), and whether an optimal number of oocytes are retrieved when LBR or CLBR are maximized, are highly relevant clinical questions; however published results are conflicting. A systematic review of all eligible studies (n = 16) published until January 2020 on MEDLINE, Embase, Scopus, CINAHL and Web of Science was conducted. Five studies evaluated only LBR from fresh cycles, five studies evaluated only CLBR from stimulated cycles and six evaluated both. A marked difference was observed between the oocyte yields at which LBR and CLBR were reportedly maximized in the individual studies. On the basis of nine studies, the optimal number of oocytes at which fresh LBR seems to be maximized is proposed to be between 12 and 18 oocytes (15 oocytes was the most common suggestion). On the other hand, CLBR continues to increase with the number of oocytes retrieved. This is the first systematic review on the topic, and it suggests that the retrieval of 12-18 oocytes is associated with maximal fresh LBR, whereas a continuing positive association is present between the number of oocytes retrieved and CLBR.

Computational prediction of implantation outcome after embryo transfer

The aim of this study is to develop a computational prediction model for implantation outcome after an embryo transfer cycle. In this study, information of 500 patients and 1360 transferred embryos, including cleavage and blastocyst stages and fresh or frozen embryos, from April 2016 to February 2018, were collected. The dataset containing 82 attributes and a target label (indicating positive and negative implantation outcomes) was constructed. Six dominant machine learning approaches were examined based on their performance to predict embryo transfer outcomes. Also, feature selection procedures were used to identify effective predictive factors and recruited to determine the optimum number of features based on classifiers performance. The results revealed that random forest was the best classifier (accuracy = 90.40% and area under the curve = 93.74%) with optimum features based on a 10-fold cross-validation test. According to the Support Vector Machine-Feature Selection algorithm, the ideal numbers of features are 78. Follicle stimulating hormone/human menopausal gonadotropin dosage for ovarian stimulation was the most important predictive factor across all examined embryo transfer features. The proposed machine learning-based prediction model could predict embryo transfer outcome and implantation of embryos with high accuracy, before the start of an embryo transfer cycle.

Patient and in vitro fertilization (IVF) cycle characteristics associated with variable blastulation rates: a retrospective study from the Duke Fertility Center (2013–2017)

Background

To evaluate the association of patient and IVF cycle characteristics with blastulation rate and formation of high-quality blastocysts

Results

We analyzed autologous blastocyst cycles from 2013 to 2017. Cycles were subdivided into low (< 33%), intermediate (33–66%), and high (> 66%) blastulation rates. Embryo quality was assigned by embryologists using Gardner Criteria. R statistical package was used, and the blastulation groups were compared using analysis of variance (ANOVA) for continuous variables and chi-squared tests for categorical variables. The Bonferroni correction was used to adjust for multiple comparisons. One hundred seventeen IVF cycles met our inclusion criteria. Of these, 20 (17.1%) had low, 74 (63.2%) had intermediate, and 23 (19.7%) had high blastulation rates. Low blastulation rate was associated with a lower number of blastocysts, including fewer high-quality blastocysts. The mean number of oocytes retrieved was highest (18.1) in the group with the lowest blastulation rate, and lowest (13.4) in those with the highest blastulation rate, although this did not reach statistical significance. There were no significant differences between blastulation rates and age, gravidity, prior live birth, anti-mullerian hormone, estradiol and progesterone levels on the day of ovulation trigger, follicle-stimulating hormone dose, or fertility diagnosis.

Conclusions

High blastulation rate is associated with a greater number of blastocysts, including a greater number of high-quality blastocysts. Higher oocyte yield, however, is not associated with improved blastulation rates. Blastulation rates, blastocyst number, and quality remain difficult to predict based on cycle characteristics alone, and oocyte yield may not be an accurate predictor of either outcome.

The addition of anti-Müllerian hormone in an algorithm for individualized hormone dosage did not improve the prediction of ovarian response-a randomized, controlled trial

Study question

Does the addition of anti-Müllerian hormone (AMH) to a conventional dosage regimen, including age, antral follicle count (AFC) and BMI, improve the rate of targeted ovarian response, defined as 5-12 oocytes after IVF?

Summary answer

The addition of AMH did not alter the rate of targeted ovarian response, 5-12 oocytes, or decreased the rate of ovarian hyperstimulation syndrome (OHSS) or cancelled cycles due to poor ovarian response.

What is known already

Controlled ovarian hyperstimulation (COH) in connection with IVF is sometimes associated with poor ovarian response resulting in low pregnancy and live birth rates or leading to cycle cancellations, but also associated with excessive ovarian response, causing an increased risk of OHSS. Even though it is well-established that both AMH and AFC are strong predictors of ovarian response in IVF, few randomized trials have investigated their impact on achieving an optimal number of oocytes.

Study design, size and duration

Between January 2013 and May 2016, 308 patients starting their first IVF treatment were randomly assigned, using a computerized randomization program with concealed allocation of patients and in the proportions of 1:1, to one of two dosage algorithms for decisions on hormone starting dose, an algorithm, including AMH, AFC, age and BMI (intervention group), or an algorithm, including only AFC, age and BMI (control group). The study was blinded to patients and treating physicians.

Participants/materials, setting, methods

Women aged >18 and <40 years, with a BMI above 18.0 and below 35.0 kg/m2 starting their first IVF cycle where standard IVF was planned, were eligible. All patients were treated with a GnRH agonist protocol and recombinant FSH was used for stimulation. The study was performed as a single-centre study at a large IVF unit at a university hospital.

Main results and the role of chance

The rate of patients having the targeted number of oocytes retrieved was 81/152 (53.3%) in the intervention group versus 96/155 (61.9%) in the control group (P = 0.16, difference: -8.6, 95% CI: -20.3; 3.0). Cycles with poor response (<5 oocytes) were more frequent in the AMH group, 39/152 (25.7%) versus the non-AMH group, 17/155 (11.0%) (P < 0.01), while the number of cancelled cycles due to poor ovarian response did not differ 7/152 (4.6%) and 4/155 (2.6%) (P = 0.52). An excessive response (>12 oocytes) was seen in 32/152 (21.1%) and 42/155 (27.1%) patients, respectively (P = 0.27). Moderate or severe OHSS was observed among 5/152 (3.3%) and 6/155 (3.9%) patients, respectively (P = 1.0). Live birth rates were 48/152 (31.6%) and 42/155 (27.1%) per started cycle.

Limitations, reasons for caution

The categorization of AMH values in predicted low, normal and high responders was originally established using the Diagnostic Systems Laboratories assay and was translated to more recently released assays, lacking international standards and well-established reference intervals. The interpretation of AMH values between different assays should therefore be made with some caution.

Wider implications of the findings

An individualised dosage regimen including AMH compared with a non-AMH dosage regimen in an unselected patient population did not alter the number of women achieving the targeted number of oocytes, or the cancellation rate due to poor response or the occurrence of moderate/severe OHSS. However, this study cannot answer the question if using an algorithm for dose decision of FSH is superior to a standard dose and neither which ovarian reserve test is the most effective.

Study funding/competing interest

Financial support was received through Sahlgrenska University Hospital (ALFGBG-70 940) and unrestricted grants from Ferring Pharmaceuticals and the Hjalmar Svensson Research Foundation. None of the authors declares any conflict of interest.

Trial registration

The study was registered at www.clinicaltrials.gov NCT02013973.

Trial registration date

6 December 2013.

DATE OF FIRST PATIENT RANDOMIZED

14 January 2013.

Can ovarian double-stimulation in the same menstrual cycle improve IVF outcomes?

OBJECTIVE

To evaluate the double-stimulation protocol efficacy over conventional ovarian stimulation in recovering a more adequate number of oocytes and increase the number of embryos to be transferred or to be genetically analyzed.

METHODS

A retrospective and comparative study with 13 patients who underwent unsuccessful in vitro fertilization (IVF) cycles with a conventional antagonist ovarian stimulation protocol and repeat the attempt with a double stimulation protocol. The following variables were analyzed: number of oocytes collected, mature oocytes collected, fertilization rate, blastocyst rate, biopsied blastocyst rate and euploidy rate.

RESULTS

The double stimulation protocol had a significant higher number of oocytes collected (p=0.007) and mature oocytes to be injected (p=0.01). There was no statistically significant difference in fertilization (p=0.78) and blastocyst (p=0.59) rates.

CONCLUSION

Double stimulation favors patients who are at risk of incurring several attempts of IVF to achieve pregnancy.

Total number of oocytes and zygotes are predictive of live birth pregnancy in fresh donor oocyte in vitro fertilization cycles

OBJECTIVE

To evaluate the association of oocyte donor-recipient characteristics, oocyte donor response, and live birth pregnancy rate following fresh donor oocyte IVF-ET.

DESIGN

Retrospective cohort study.

SETTING

Academic reproductive medicine practice.

PATIENT(S)

Two hundred thirty-seven consecutive fresh donor oocyte IVF-ET cycles from January 1, 2007 to December 31, 2013 at the Massachusetts General Hospital Fertility Center.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Live birth rate per cycle initiated.

RESULT(S)

The mean (±SD) age of oocyte donors and recipients was 27.0 ± 3.7 and 41.4 ± 4.6 years, respectively. Oocyte donor demographic/reproductive characteristics, ovarian reserve testing, and peak serum E₂ during ovarian stimulation were similar among cycles which did and did not result in live birth, respectively. Overall implantation, clinical pregnancy, and live birth pregnancy rates per cycle initiated were 40.5%, 60.8%, and 54.9%, respectively. The greatest probability of live birth was observed in cycles with >10 oocytes retrieved, mature oocytes, oocytes with normal fertilization (zygote-two pronuclear stage), and cleaved embryos.

CONCLUSION(S)

The number of oocytes (total and mature), zygotes, and cleaved embryos are associated with live birth following donor oocyte IVF cycles. These findings suggest that specific peri-fertilization factors may be predictive of pregnancy outcomes following donor oocyte IVF cycles.

Embryo density may affect embryo quality during in vitro culture in a microwell group culture dish

PURPOSE

Culturing embryos in groups is a common practice in mammalian embryology. Since the introduction of different microwell dishes, it is possible to identify oocytes or embryos individually. As embryo density (embryo-to-volume ratio) may affect the development and viability of the embryos, the purpose of this study was to assess the effect of different embryo densities on embryo quality.

METHODS

Data of 1337 embryos from 228 in vitro fertilization treatment cycles were retrospectively analyzed. Embryos were cultured in a 25 μl microdrop in a microwell group culture dish containing 9 microwells. Three density groups were defined: Group 1 with 2-4 (6.3-12.5 μl/embryo), Group 2 with 5-6 (4.2-5.0 μl/embryo), and Group 3 with 7-9 (2.8-3.6 μl/embryo) embryos.

RESULTS

Proportion of good quality embryos was higher in Group 2 on both days (D2: 18.9 vs. 31.5 vs. 24.7%; p < 0.001; D3: 19.7 vs. 27.1 vs. 21.2%; p = 0.029; Group 1. vs. Group 2. vs. Group 3). Cell number on Day 3 differed between Groups 1 and 2 (6.8 ± 2.2; 7.3 ± 2.1; p = 0.004) and Groups 2 and 3 (7.3 ± 2.1 vs. 7.0 ± 2.0; p = 0.014).

CONCLUSIONS

Culturing 5-6 embryos together in a culture volume of 25 μl may benefit embryo quality. As low egg number, position, and distance of the embryos may influence embryo quality, results should be interpreted with caution.

The total pregnancy potential per oocyte aspiration after assisted reproduction-in how many cycles are biologically competent oocytes available?

PURPOSE

While stimulation of women prior to assisted reproduction is associated with increased success rates, the total biological pregnancy potential per stimulation cycle is rarely assessed.

METHODS

Retrospective sequential cohort study of the cumulative live birth rate in 1148 first IVF/ICSI-cycles and 5-year follow up of frozen embryo replacement (FER) cycles were used. Oocyte number, number of embryos transferred, and cryopreserved/thawed and transferred embryos in a FER cycle were registered for all patients. Children per oocyte and per transferred embryo and percentage of cycles with births were calculated.

RESULTS

We obtained 9529 oocytes. Embryos (2507) were transferred in either fresh or FER cycles, resulting in 422 births and 474 live born children. Median age of the women was 32.5 years (range 20-41.5 years). In total, 34.3 % of all cycles ended with a live birth while in 65.7 % of the cycles, no oocytes were capable of developing into a child. The average number of oocytes needed per live born child after transfer of fresh and thawed embryos was 20 as only 5.0 % of oocytes aspirated in the first IVF/ICSI cycle had the competence to develop into a child.

CONCLUSIONS

In our setting, overall 5.0 % of the oocytes in a first cycle were biologically competent and in around 2/3 of all cycles, none of the oocytes had the potential to result in the birth of a child.

What number of oocytes is appropriate for defining poor ovarian response?

PURPOSE

This study attempted to derive an objective and sophisticated definition of poor ovarian response (POR).

MATERIALS AND METHODS

A total of 176 consecutive in vitro fertilization (IVF) cycles (137 patients) with conventional ovarian stimulation during 2009 to 2012 were studied by retrospective analysis. Optimal oocyte number (total or mature) was determined by statistics-based (distribution of oocyte number) and prognosis-based approaches (prediction for IVF outcome). Receiver operating characteristics curve analysis was used to show what number of oocytes could predict IVF pregnancy and whether clinical and laboratory variables could predict newly defined POR.

RESULTS

The 25th percentile of the distribution corresponded to total oocytes ≤2 and mature oocyte ≤1. The cut-off values for the prediction of IVF outcomes were total oocytes >5 and mature oocyte >1. Considering the incidence of POR (34.1%), a reasonable definition of POR was decided as total oocytes ≤2 or mature oocyte ≤1. For the prediction of this new definition, the extreme cut-off value (by setting a false positive rate of 5%) of serum anti-Mullerian hormone (AMH) was ≤0.76 ng/mL, which was better than serum follicle stimulating hormone or age. A new simple definition of POR was derived as total oocytes ≤2 or mature oocyte ≤1 in a previous cycle or a serum AMH level of ≤0.76 ng/mL. When this simple criterion was re-applied to our data, the predictive performance was similar to the Bologna criteria.

CONCLUSION

We here propose a new definition of POR, which is simple and supported by statistical and prognostic analyses.

Pregnancy rates in donor oocyte cycles compared to similar autologous in vitro fertilization cycles: an analysis of 26,457 fresh cycles from the Society for Assisted Reproductive Technology

OBJECTIVE

To use a large US IVF database and compare pregnancy outcomes in fresh donor oocyte versus autologous IVF cycles in women age 20-30 years.

DESIGN

Retrospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Women undergoing fresh autologous ovarian stimulation, and oocyte donors and recipients in the United States between 2008 and 2010.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Implantation, clinical pregnancy (CP), and live birth (LB) rates.

RESULT(S)

Despite similar demographics, stimulation, and embryo parameters, donor oocyte recipients had significantly higher rates of implantation, CP, and LB compared to those undergoing fresh autologous cycles. Odds ratios for implantation, CP, and LB significantly favored the donor oocyte group in all comparisons, including those limited to intracytoplasmic sperm injection cycles, intracytoplasmic sperm injection with male factor, unexplained infertility, cleavage stage embryo transfer, blastocyst transfer, elective single blastocyst transfer, and autologous patients with prior tubal ligation.

CONCLUSION(S)

Recent US data suggest that the hormonal environment resulting from autologous ovarian stimulation lowers IVF success rates. Further research is needed to determine when to avoid fresh embryo transfer in autologous patients.

Oocyte number as a predictor for ovarian hyperstimulation syndrome and live birth: an analysis of 256,381 in vitro fertilization cycles

OBJECTIVE

To investigate the association between oocyte number and the rates of ovarian hyperstimulation syndrome (OHSS) and live birth (LB) in fresh autologous in vitro fertilization (IVF) cycles.

DESIGN

Retrospective cohort study.

SETTING

An academic reproductive medicine practice.

PATIENT(S)

We analyzed data from 256,381 IVF cycles using the 2008-2010 Society for Assisted Reproductive Technology national registry. Patients were divided into five groups based on retrieved oocyte number.

MAIN OUTCOME MEASURE(S)

Rates of OHSS and LB were calculated for each group. A generalized estimating equation (GEE) was used to assess differences in OHSS and LB between groups. Receiver operating characteristic (ROC) curves were used to evaluate oocyte number as a predictor of OHSS and LB.

INTERVENTION(S)

None.

RESULT(S)

The LB rate increased up to 15 oocytes, then plateaued (0-5: 17%, 6-10: 31.7%; 11-15: 39.3%; 16-20: 42.7%; 21-25: 43.8%; and >25 oocytes: 41.8%). However, the rate of OHSS became much more clinically significant after 15 oocytes (0-5: 0.09%; 6-10: 0.37%; 11-15: 0.93%; 16-20: 1.67%; 21-25: 3.03%; and >25 oocytes: 6.34%). These trends remained after adjustment with the use of GEE. ROC curves revealed that although oocyte number is not useful in the prediction of LB, 15 retrieved oocytes is the number that best predicts OHSS risk.

CONCLUSION(S)

Retrieval of >15 oocytes significantly increases OHSS risk without improving LB rate in fresh autologous IVF cycles. In general, less aggressive stimulation protocols should be considered, especially in high-responders, to optimize outcomes.

Accumulation of oocytes from a few modified natural cycles to improve IVF results: a pilot study

PURPOSE

To evaluate the role of co-transfer of embryos derived from vitrified oocytes accumulated during the previous modified natural cycles and an embryo developed from the last one as an alternative to repetitive single embryo transfer ina fresh modified natural cycle.

METHODS

Thirty-six patients underwent ICSI procedure with three frozen natural oocytes supplemented by a fresh one obtained from the fourth modified natural cycle. Thirty-one controls received at least three consecutive single embryo transfer in a fresh modified natural cycle.

RESULTS

In the study group the oocyte retrieval, survival and total fertilization rate were 73.0 %, 78.1 %, and 64.5 %, respectively. Fifty-two embryos were transferred in 29 transfers. In the control group the oocyte retrieval and fertilization rate was 77.4 % and 83.7 %, respectively. Fifty single embryo transfers were performed. Of a total 14 pregnancies obtained in the study group 10 were defined as clinical and 4 as abortions. In the control group a total of 8 single clinical pregnancies and 2 miscarriages were encountered. The overall (20.0 % vs 48.2 %) and the clinical (16.0 % vs 34.4 %) pregnancy rate were significantly higher in the study group having cumulative embryo transfer following the oocyte accumulation.

CONCLUSIONS

These data demonstrate that the co-transfer of embryos derived from vitrified oocytes accumulated during the previous modified natural cycles and an embryo developed from the last fresh modified natural cycle assure an excellent clinical outcome with the overall and clinical pregnancy rate significantly higher compared to the repetitive single embryo transfer in a fresh modified natural cycle.

Developmental potential of in vitro or in vivo matured oocytes

This study compared the embryological features of mature and immature oocytes (different stages) collected from stimulated cycles of in vitro fertilization (IVF). Immature oocytes were identified, classified as PI (prophase I – germinal vesicle, GV) or MI (metaphase I), were matured in vitro and fertilized using the intra-cytoplasmic sperm injection (ICSI) technique. Fertilization potential, cleavage, and subsequent transfer/cryopreservation of the embryos derived from these in vitro matured oocytes were compared with those of in vivo matured oocytes (collected at the MII stage). The characteristics of embryos derived from gametes recovered in the MI and MII stages were similar. The fertilization rate of immature oocytes recovered in PI was significantly lower than that of MII oocytes (P = 0.031), and the cleavage rate of the PI group was also lower than that of the MI (P = 0.004) and MII (P < 0.001) groups. In vitro maturation of MI oocytes is a suitable alternative when immature oocytes are recovered, as their characteristics and development are similar to those of in vivo matured oocytes. Optimization of outcomes for PI oocytes will require development of techniques that can distinguish which of these gametes will mature and fertilize.

The effect of immature oocytes quantity on the rates of oocytes maturity and morphology, fertilization, and embryo development in ICSI cycles

PURPOSE

The goal was to evaluate the role of the number of retrieved immature oocytes on mature oocyte counts and morphology, and also the rates of fertilization and embryo development in ICSI cycles.

METHODS

101 ICSI cycles were included in this prospective evaluation. Patients were divided into 2 groups of A (≤ 2 immature oocytes) and B (> 2 immature oocytes). In sub-analysis, the impacts of the number of GV and MI oocytes were assessed on the rates of fertilization and embryo development. Also, correlations between the numbers of immature and mature oocytes, as well as maternal age between two groups were analyzed. Assessments of oocyte morphology, fertilization, embryo quality and development were done accordingly.

RESULTS

There was no correlation between the immature oocytes quantity with the number of mature ones. There were insignificant differences for embryo development between two groups, but fertilization rate was higher in group A (P = 0.03). In sub-analysis, insignificant differences were observed between two groups of ≤ and >2 GV and MI oocytes for rates of fertilization and embryo development. Also, the rates of clinical pregnancy and delivery were insignificant between groups. The rate of morphologically abnormal oocytes had no significant difference between two groups, except for wide perivitelline space (PVS) which was higher in group A (P = 0.03). There was no significant difference for maternal age between two groups.

CONCLUSIONS

In cases with few retrieved immature oocytes, rates of fertilization and incidence of wide PVS may increase, although immature oocytes may not have any negative impacts on early embryo development, or the rates on number of mature oocytes.