Selection of good embryos for transfer depends on embryo cohort size: implications for the 'mild ovarian stimulation' debate

Evaluating the heterogeneous effect of extended culture to blastocyst transfer on the implantation outcome via causal inference in fresh ICSI cycles

PURPOSE

In IVF treatments, extended culture to single blastocyst transfer is the recommended protocol over cleavage-stage transfer. However, evidence-based criteria for assessing the heterogeneous implications on implantation outcomes are lacking. The purpose of this work is to estimate the causal effect of blastocyst transfer on implantation outcome.

METHODS

We fit a causal forest model using a multicenter observational dataset that includes an exogenous source of variability in treatment assignment and has a strong claim for satisfying the assumptions needed for valid causal inference from observational data.

RESULTS

We quantified the probability difference in embryo implantation if transferred as a blastocyst versus cleavage stage. Blastocyst transfer increased the average implantation rate; however, we revealed a subpopulation of embryos whose implantation potential is predicted to increase via cleavage-stage transfer.

CONCLUSION

Relative to the current policy, the proposed embryo transfer policy retrospectively improves implantation rate from 0.2 to 0.27. Our work demonstrates the efficacy of implementing causal inference in reproductive medicine and motivates its utilization in medical disciplines that are dominated by retrospective datasets.

Using Unlabeled Information of Embryo Siblings from the Same Cohort Cycle to Enhance In Vitro Fertilization Implantation Prediction

High-content time-lapse embryo imaging assessed by machine learning is revolutionizing the field of in vitro fertilization (IVF). However, the vast majority of IVF embryos are not transferred to the uterus, and these masses of embryos with unknown implantation outcomes are ignored in current efforts that aim to predict implantation. Here, whether, and to what extent the information encoded within "sibling" embryos from the same IVF cohort contributes to the performance of machine learning-based implantation prediction is explored. First, it is shown that the implantation outcome is correlated with attributes derived from the cohort siblings. Second, it is demonstrated that this unlabeled data boosts implantation prediction performance. Third, the cohort properties driving embryo prediction, especially those that rescued erroneous predictions, are characterized. The results suggest that predictive models for embryo implantation can benefit from the overlooked, widely available unlabeled data of sibling embryos by reducing the inherent noise of the individual transferred embryo.

Cystic fibrosis transmembrane conductance regulator in follicular fluid and cumulus cells and its relationship with age

Oocyte quality deteriorates with female age and numerous indicators of oocyte quality exist. In the present study, the levels of cystic fibrosis transmembrane conductance regulator (CFTR) in the follicular fluid (FF) and cumulus cells (CCs) of infertile females in 3 different age groups were assessed to determine the relationship between CFTR and female age. The general features of the 3 groups, including age, body mass index, infertility duration, basal hormone levels and the number of retrieved oocytes were compared. The FF CFTR levels of the 3 groups were also compared and multiple age-related indicators of oocyte quality were analyzed, including the estradiol levels on the human chorionic gonadotropin injection day, the morphologically normal oocyte rate and the available or high-quality embryo rate. Immunofluorescence and PCR analyses were performed to examine CFTR expression in CCs around oocytes. The results indicated differences in general features and several indicators of oocyte quality among the 3 groups and significant differences in CFTR. The FF CFTR level was positively correlated with age, which was confirmed by immunofluorescence and PCR. Collectively, these results indicated that CFTR expression in FF and CCs may be associated with oocyte quality based on the age of individuals undergoing the assisted reproduction technique.

Immature oocyte incidence: Contributing factors and effects on mature sibling oocytes in intracytoplasmic sperm injection cycles

Objective

The aim of this study was to investigate which factors contribute to the incidence of immature oocytes (germinal vesicle -GV- and metaphase I -MI-) and how they impact the intracytoplasmic sperm injection (ICSI) outcomes of sibling mature oocytes.

Methods

Data from 3,920 cycles performed from June/2010 to August/2016 in a private university-affiliated IVF center were evaluated for the influence of controlled ovarian stimulation protocol (COS) on immature oocytes incidence and its effects on ICSI outcomes.

Results

MI (p=0.004) and GV (p=0.029) number were negatively correlated with gonadotropin dose. Patients stimulated by rFSH had increased GV/oocyte rate in both GnRH agonists (p<0.001) and antagonist (p=0.042) protocols, in comparison to rFSH associated with rLH protocol. MI and GV/oocyte rates were negatively correlated to fertilization (p<0.001), high-quality embryo on da p<0.001; GV/oocyte p=0.033) and pregnancy (MI/oocyte p=0.002; GV/oocyte p=0.013) rates. Cycles above a 10.5% MI/oocyte cut-off were correlated to higher response to ovarian stimulation, poor embryo development and almost two times lower pregnancy rate. Immature oocyte incidence is affected by COS and impacts on ICSI outcomes.

Conclusion

Our evidence suggests that oocytes derived from a cohort with high incidence of maturation fail may have detrimental clinical outcomes.

Luteal estradiol pretreatment of poor and normal responders during GnRH antagonist protocol

Luteal estradiol pretreatment (LEP) to IVF protocols designed to improve follicle synchronization and retrieval of mature oocytes. We conducted a retrospective study including women undergoing IVF program who were given a course of 4 mg oral estradiol-17β daily from day 20 of the same cycle until day 1 of their next cycle before starting an antagonist protocol, forming LEP-group but control-group started on day 3 a stimulation without pretreatment. A total is divided into 2 groups (poor (group 1, n = 148) and normal responders (group 2, n = 244)). Our findings show for group 1 a significant decrease in cancelation rate (3% vs 14%) and a significant improvement in clinical outcomes (clinical pregnancy per transfer and live birth rate respectively: 47% and 44% vs 12% and 11%). For group 2, this pretreatment could increase significantly the maturation rate (77% vs 68%). The rate of frozen embryos was improved in both groups: (group 1: 11% vs 2% and group 2: 53% vs 41%). LEP increases the frozen embryos rate whatever the nature of the ovarian response, but especially for normal responders it coordinates follicular recruitment increasing the maturation rate. In the case of poor responders, it affects positively clinical outcomes decreasing the canceled cycles.

Efficacy of luteal estrogen administration and an early follicular Gonadotropin-releasing hormone antagonist priming protocol in poor responders undergoing in vitro fertilization

Objectives

We investigated whether luteal estrogen administration and an early follicular Gonadotropin-releasing hormone antagonist (E/G-ant) priming protocol improves clinical outcomes in poor responders to controlled ovarian stimulation for in vitro fertilization (IVF)-embryo transfer, and identified underlying mechanisms.

Methods

This restrospective study consisted of 65 poor responders who underwent the E/G-ant priming protocol. Sixty-four other poor responders undergoing conventional protocols without pretreatment were included as the control group. Clinical outcomes were compared between 2 groups.

Results

The E/G-ant priming protocol group exhibited improvements over the control group in terms of the number of retrieved oocytes (3.58±2.24 vs. 1.70±1.45; P=0.000), mature oocytes (2.68±2.11 vs. 1.65±1.23; P=0.000), fertilized oocytes (2.25±1.74 vs. 1.32±1.26; P=0.001), good embryos (1.62±0.91 vs. 1.14±0.90, P=0.021). Day 3 follicle-stimulating hormone (FSH; 8.40±4.84 vs. 16.39±13.56; P=0.000) and pre-ovulation progesterone levels (0.67 vs. 1.28 ng/mL; P=0.016) were significantly higher in the control group than in the E/G-ant priming group. The overall rate of positive human chorionic gonadotropin tests was higher in the E/G-ant priming group than in the control group (32.3% vs.16.1%; P=0.039). Also, clinical pregnancy rate (26.2% vs. 12.5%; P=0.048) and the rate of live births (23.1% vs. 7.1%; P=0.023) were significantly higher in the E/G-ant priming group than in the control group.

Conclusion

The E/G-ant priming protocol would lead to promising results in poor responders to IVF by suppressing endogenous FSH and by preventing premature luteinization.

The effect of follicle size and homogeneity of follicular development on the morphokinetics of human embryos

Purpose

Our aim was to investigate follicular size (large, ≥17 mm and small, <17 mm) at the time of OPU and homogeneity of follicular development (homogenous development: follicles being present in a homogenous spread of all sizes; heterogeneous: a predominance of small and large follicles) by analysing the morphokinetics of embryo development.

Methods

In this prospective cohort study, 2526 COCs belonging to 187 patients were cultured to day 5. Embryos were evaluated morphokinetically. Four subgroups were defined: large follicles from heterogeneous cycles (LHet) and homogenous cycles (LHom) and small follicles from heterogeneous cycles (SHet) and homogenous cycles (SHom).

Results

Rates of fertilization, blastocyst formation and top and good quality blastocysts were found to be significantly higher in embryos from the LHom group (p < 0.001; p < 0.001; p < 0.001). Small follicles from both homogenous and heterogeneous cycles had significantly lower blastocyst formation and top and good quality blastocyst rates (p < 0.001; p < 0.001). Embryos from SHet had significantly more direct cleavages (p = 0.011). Time to reach blastocyst was shorter in SHom than LHet and LHom (p = 0.002; p = 0.027, respectively). However, once the blastocyst stage was achieved, implantation rates were not significantly different between subgroups, the highest rate being observed in the LHom group. Multivariable analysis revealed that homogeneity of follicular development and follicular size had a significant effect on blastocyst development and quality (p = 0.049; p < 0.001, respectively).

Conclusion

Follicular dynamics, illustrated by follicular size and homogeneity of follicular development, influence early human embryo development. Patterns of follicular growth have an impact on embryo quality and viability which is reflected in morphokinetic variables.

Electronic supplementary material

The online version of this article (doi:10.1007/s10815-017-0935-1) contains supplementary material, which is available to authorized users.

GnRH antagonist and letrozole co-treatment in diminished ovarian reserve patients: a proof-of-concept study

The current study aimed to investigate the effects of luteal gonadotropin-releasing hormone (GnRH) antagonist pretreatment on the outcomes of diminished ovarian reserve (DOR) patients who were treated using a FSH/letrozole/GnRH antagonist (FLA) protocol. Thus, patients who had luteal GnRH antagonist pretreatment (AFLA) prior to stimulation were compared to patients who had the FLA protocol, only. An electronic database was used to identify patients and stimulation characteristics. Women who had a total antral follicle count (AFC) of <7 were included in the analysis. A total of 45 cycles using luteal GnRH antagonist pretreatment in combination with a letrozole/GnRH antagonist (AFLA) protocol were compared to 76 cycles using a FLA protocol, only. The total gonadotropin dose, duration of stimulation, and peak estradiol levels were comparable between the groups (p>0.05). However, the AFLA group had significantly more metaphase-2 (MII) oocytes (p=0.009), a higher oocyte maturity rate (MII/total oocytes) (p=0.029), and a higher mature oocyte yield (MII/AFC) (p=0.020) with more cleaved embryos (p=0.036), and a significantly reduced number of canceled cycles (26.7% vs. 44.7%; p=0.048). The clinical pregnancy rate per cycle was 22.2% vs. 13.2% (p=0.195) in the AFLA and FLA groups, respectively. Interestingly, a subgroup analysis including ESHRE Bologna criteria poor responder patients showed that the luteal administration of GnRH antagonist resulted in better outcomes when compared with the FLA protocol alone. In conclusion, luteal GnRH antagonist pretreatment improves ovarian stimulation parameters and reproductive outcomes in poor ovarian reserve IVF patients.

Outcomes and Recommendations of an Indian Expert Panel for Improved Practice in Controlled Ovarian Stimulation for Assisted Reproductive Technology

Purpose. To improve success of in vitro fertilization (IVF), assisted reproductive technology (ART) experts addressed four questions. What is optimum oocytes number leading to highest live birth rate (LBR)? Are cohort size and embryo quality correlated? Does gonadotropin type affect oocyte yield? Should “freeze-all” policy be adopted in cycles with progesterone >1.5 ng/mL on day of human chorionic gonadotropin (hCG) administration? Methods. Electronic database search included ten studies on which panel gave opinions for improving current practice in controlled ovarian stimulation for ART. Results. Strong association existed between retrieved oocytes number (RON) and LBRs. RON impacted likelihood of ovarian hyperstimulation syndrome (OHSS). Embryo euploidy decreased with age, not with cohort size. Progesterone > 1.5 ng/dL did not impair cycle outcomes in patients with high cohorts and showed disparate results on day of hCG administration. Conclusions. Ovarian stimulation should be designed to retrieve 10–15 oocytes/treatment. Accurate dosage, gonadotropin type, should be selected as per prediction markers of ovarian response. Gonadotropin-releasing hormone (GnRH) antagonist based protocols are advised to avoid OHSS. Cumulative pregnancy rate was most relevant pregnancy endpoint in ART. Cycles with serum progesterone ≥1.5 ng/dL on day of hCG administration should not adopt “freeze-all” policy. Further research is needed due to lack of data availability on progesterone threshold or index.

A greater number of euploid blastocysts in a given cohort predicts excellent outcomes in single embryo transfer cycles

PURPOSE

This multicentered retrospective study analyzed whether the quantity of euploid blastocysts in a given cohort after comprehensive chromosomal screening can be used to identify candidates for single embryo transfer.

METHODS

Blastocysts from 437 patients underwent trophectoderm biopsy followed by array comparative genomic hybridization. Embryos were then selected for single or double embryo transfer. The number of euploid blastocysts produced and transferred for each patient was recorded, as was clinical pregnancy rate and multiple gestation rate.

RESULTS

In patients with ≤ 3 euploid blastocysts, clinical pregnancy rate was higher in double, compared to single embryo transfers. However, in patients with ≥ 4 euploid blastocysts, clinical pregnancy rate was not reduced with single embryo transfer was performed, whereas the multiple gestation rate was greatly reduced.

CONCLUSIONS

Size of the euploid embryo cohort is a marker for success in single embryo transfer cycles. Patients who produce at least four euploid blastocysts are outstanding candidates for single embryo transer.

A randomized controlled trial comparing two vitrification methods versus slow-freezing for cryopreservation of human cleavage stage embryos

Purpose

To compare two different vitrification methods to slow freezing method for cryopreservation of human cleavage stage embryos. Design: Prospective randomised trial. Setting: University assisted reproduction centre. Patient(s): 568 patients (mean age 33.4 ± 5.2) from April 2009 to April 2011.

Methods

1798 supernumerary good-quality cleavage stage embryos in 645 IVF cycles intended to be cryopreserved were randomly allocated to three groups: slow freezing, vitrification with the Irvine® method, vitrification with the Vitrolife® method. Main Outcome Measure(s): Embryo survival and cleavage rates, implantation rate.

Results

A total of 1055 embryos were warmed, 836 (79.2 %) survived and 676 were finally transferred (64.1 %). Post-warming embryos survival rate was significantly higher after vitrification (Irvine: 89.4 %; Vitrolife: 87.6 %) than after slow freezing (63.8 %) (p < 0.001). No differences in survival rates were observed between the two vitrification methods, but a significant higher cleavage rate was observed using Irvine compared to Vitrolife method (p < 0.05). Implantation rate (IR) per embryo replaced and per embryo warmed were respectively 15.8 % (41/259) and 12.4 % (41/330) for Irvine, 17.0 % (40/235) and 12.1 % (40/330) for Vitrolife, 21.4 % (39/182) and 9.9 % (39/395) for slow-freezing (NS).

Conclusions

Both vitrification methods (Irvine and Vitrolife) are more efficient than slow freezing for cryopreservation of human cleavage stage embryos in terms of post-warming survival rate. No significant difference in the implantation rate was observed between the three cryopreservation methods.

Mild ovarian stimulation for in vitro fertilization: are we ready to change? A meta-analysis

OBJECTIVE

To compare the efficacy of mild ovarian stimulation versus conventional stimulation in in vitro fertilization (IVF).

DESIGN

Meta-analysis.

SEARCH STRATEGY

A systemic literature search was carried out for prospective randomised clinical trials. We electronically searched using PubMed, Medline and Embase for all the studies published from 1990 to December 2011.

INTERVENTIONS

Mild ovarian stimulation IVF that uses lower doses and/or shorter duration of gonadotrophins in GnRH antagonist co-treated cycle compared with conventional stimulation IVF.

MAIN OUTCOME MEASURES

Live birth rates per started cycle and ongoing pregnancy rates per started cycle of IVF.

RESULTS

On live birth rate, there was a significant difference in favour of the conventional stimulation [70/444 (15.7%) mild vs. 78/325 (24%) conventional] (OR 0.59, CI 0.41-0.85, p = 0.004). Similar findings were observed in the ongoing pregnancy data [140/696 (20%) mild vs. 144/547 (26%) in favour of conventional stimulation] (OR 0.72, CI 0.55-0.93, p = 0.01). The sub-analysis of two studies showed a statistically significant reduction of hyperstimulation syndrome in favour of the mild stimulation (OR 0.27, CI 0.11-0.66).

CONCLUSION

This analysis presents strong evidence in favour of conventional stimulation IVF, which therefore should currently be considered a treatment of choice for patients requiring IVF treatment.

In-vitro maturation of human oocytes: before or after vitrification?

PURPOSE

This study aims to determine if in-vitro maturation (IVM) of human immature oocytes should be performed before or after vitrification.

METHODS

A total of 184 immature oocytes were randomly divided into two different groups: 100 were vitrified at metaphase II (MII) stage 24 h-48 h after IVM (group 1) and 84 were immediately vitrified at germinal vesicle (GV) or metaphase I (MI) stages and in vitro matured after warming (group 2).

RESULTS

Survival rate after warming was similar in both groups (86.9% versus 84.5%). However, oocyte maturation rate per collected oocyte was significantly higher for oocytes matured before vitrification (group 1, 46%) than for oocytes vitrified before IVM (group 2, 23.8%) (p < 0.01). Consequently, the number of MII oocytes inseminated per oocyte collected was significantly higher for group 1 (40%) than for group 2 (23.8%) (p < 0.05).

CONCLUSION

IVM procedure is more efficient when it is performed before oocyte vitrification.

A systematic review of randomized trials for the treatment of poor ovarian responders: is there any light at the end of the tunnel?

OBJECTIVE

To assess the definitions for "poor ovarian responders" used among randomized trials for the treatment of women with impaired response to stimulation.

DESIGN

Systematic review.

SETTING

None.

PATIENT(S)

Poor ovarian responders.

INTERVENTION(S)

Treatment modalities for the management of poor ovarian responders.

MAIN OUTCOME MEASURE(S)

Number and nature of the criteria used to define poor ovarian response to stimulation and threshold values used.

RESULT(S)

Among 47 randomized trials, 41 different definitions for the patients with poor ovarian response have been used. No more than 3 trials used the same definition, whereas even trials from the same research groups used different definitions across different trials. None of the criteria used was adopted in more than 50% of the trials. Age and antral follicle count were adopted only in 9% of the definitions, whereas the criteria of number of follicles on the final stimulation day and number of oocytes retrieved were used in more than 40% of the trials; nonetheless, even for these criteria, the threshold values were consistently different.

CONCLUSION(S)

The variability regarding the definition of poor ovarian responders appears to be striking. Although the Bologna criteria developed by European Society for Human Reproduction and Embryology consensus in 2011 aim to define a consistent group of patients, their applicability needs to be tested through clinical trials. Meanwhile, meta-analyses of the currently available trials should be strongly discouraged because they may lead to the adoption of interventions of ambiguous value.

Follicular dominance on the fifth day of controlled ovarian stimulation reduces implantation in long down-regulated ICSI cycles

OBJECTIVE

To determine if follicular dominance on the fifth day of controlled ovarian stimulation (COS) predicts implantation rates in down-regulated intracytoplasmic sperm injection (ICSI) cycles.

STUDY DESIGN

One hundred and sixty-two consecutive women undergoing ICSI treatment with long down-regulation and recombinant follicle-stimulating hormone injections were included in a prospective cohort analysis. The clinical pregnancy and implantation rates per transfer were compared between two groups, one with and the other without follicular dominance detected by ultrasound on the fifth day of COS.

RESULTS

There was no significant difference between the groups regarding the number of good quality embryos transferred, but clinical pregnancy and implantation rate per transfer were higher in group with follicular synchrony.

CONCLUSIONS

Follicular dominance on COS day 5 results in reduced implantation rates after ICSI.

Cryopreservation of human failed maturation oocytes shows that vitrification gives superior outcomes to slow cooling

This study investigated whether failed maturation oocytes could be used to evaluate different cryopreservation procedures. A total of 289 failed maturation oocytes (GV and MI stages), obtained from 169 patients undergoing IVF treatment (mean age 33.84±5.0) were divided into two different slow-cooling groups (1.5 mol/l 1,2-propanediol+0.2 mol/l sucrose in either NaCl (group A) or choline chloride (ChCl) (group B) based cryopreservation solutions) and one vitrification group (15% ethylene glycol+15% dimethyl sulphoxide). Survival rate, in vitro maturation (IVM) rate, fertilization and developmental rate of cryopreserved oocytes were assessed. Regardless of the stage at which cryopreservation was performed (GV+MI), the slow cooling with ChCl based medium always gave significantly lower survival rate than the slow cooling in NaCl based medium (p=0.01) and vitrification (p<0.001). An extended study also showed statistically reduced survival rate between slow-cooling NaCl based medium and vitrification (p<0.05). Global results of in vitro maturation and fertilization showed worse results between both slow-cooling NaCl and ChCl based media versus vitrification. In conclusion, for oocytes that had failed to mature, vitrification gave better survival, maturation, fertilization and also cleavage rates than the slow-cooling protocols. Four cells embryos were obtained only from vitrified in vitro matured MI oocytes.

The effect of retrieved oocyte count on pregnancy outcomes in an assisted reproduction program

OBJECTIVE

To determine if women with less than five eggs retrieved do as well as women with more eggs retrieved in terms of pregnancy outcomes in our assisted reproduction program.

METHOD

Two hundred one women undergoing in vitro fertilization treatment at Fertility Unit in Royal Prince Alfred Hospital, University of Sydney, Australia were selected for retrospective evaluation. The women were grouped according to the number of oocytes retrieved at ovum pick-up. Group A consisted of women with less than 5 oocytes, group B with 5 to 10 oocytes and group C with 11 to 15 oocytes collected. Clinical and ongoing pregnancy rates were compared.

RESULTS

There was no difference between the groups in terms of clinical and ongoing pregnancy rates.

CONCLUSION

With good IVF lab conditions, if a patient reaches embryo transfer, the number of eggs retrieved should not affect the likelihood of pregnancy outcome in an assisted reproductive technology treatment.

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.

The clinical significance of the retrieval of a low number of oocytes following mild ovarian stimulation for IVF: a meta-analysis

BACKGROUND

Milder ovarian stimulation protocols for in vitro fertilization (IVF) are being developed to minimize adverse effects. Mild stimulation regimens result in a decreased number of oocytes at retrieval. After conventional ovarian stimulation for IVF, a low number of oocytes are believed to represent poor ovarian reserve resulting in reduced success rates. Recent studies suggest that a similar response following mild stimulation is associated with better outcomes.

METHODS

This review investigates whether the retrieval of a low number of oocytes following mild ovarian stimulation is associated with impaired implantation rates. Three randomized controlled trials comparing the efficacy of the mild ovarian stimulation regimen (involving midfollicular phase initiation of FSH and GnRH co-treatment) for IVF with a conventional long GnRH agonist co-treatment stimulation protocol could be identified by means of a systematic literature search.

RESULTS

These studies comprised a total of 592 first treatment cycles. Individual patient data analysis showed that the mild stimulation protocol results in a significant reduction of retrieved oocytes compared with conventional ovarian stimulation (median 6 versus 9, respectively, P < 0.001). Optimal embryo implantation rates were observed with 5 oocytes retrieved following mild stimulation (31%) versus 10 oocytes following conventional stimulation (29%) (P = 0.045).

CONCLUSIONS

The optimal number of retrieved oocytes depends on the ovarian stimulation regimen. After mild ovarian stimulation, a modest number of oocytes is associated with optimal implantation rates and does not reflect a poor ovarian response. Therefore, the fear of reducing the number of oocytes retrieved following mild ovarian stimulation appears to be unjustified.

IVF/ICSI outcomes between cycles with luteal estradiol (E2) pre-treatment before GnRH antagonist protocol and standard long GnRH agonist protocol: a prospective and randomized study

OBJECTIVE

To study if luteal E(2) pre-treatment before GnRH antagonist protocol improves IVF/ICSI outcomes compared with standard long GnRH agonist protocol.

DESIGN

A prospective, randomized and controlled study.

SETTING

ART center of a state public hospital

PATIENT(S)

Two hundred twenty infertile women underwent IVF/ICSI treatments.

INTERVENTION(S)

Participants received oral Estradiol Valerate 4 mg/day preceding the IVF cycle from day 21 until day 2 of next cycle before GnRH antagonist protocol (E(2) pre-treatment group n=109) or received standard long GnRH agonist protocol as control group (n=111).

MAIN OUTCOME MEASURE(S)

Number of oocytes collected, MII oocytes, fertilization, implantation, live birth and early pregnancy rate, and hormone profiles.

RESULT(S)

E(2) pre-treatment exerted a significant suppressive effect on FSH but not LH secretion compared with basal FSH and LH levels. In E(2) pre-treatment group serum LH level was significantly higher during COH and serum P was also significantly higher on the day of HCG injection compared with control group. Five patients from E(2) pre-treatment group had elevated LH at all time (>or= 10 IU/L) and also a concomitantly high P (>1 ng/mL). Two of the five women achieved pregnancy but had early pregnancy loss. Overall, IVF/ICSI outcomes such as implantation, clinical pregnancy and live birth rates were similar between E(2) pre-treatment and control groups.

CONCLUSION(S)

Luteal E(2) pre-treatment before GnRH antagonist protocol significantly increases serum LH level and incidence rate of premature LH but no significant effect is observed on implantation, clinical pregnancy, live birth and early pregnancy loss rates compared with long GnRH agonist protocol. However, more studies in large numbers of cycles are needed to confirm that increased serum LH level by E(2) pre-treatment during COH has no negative effect on the IVF/ICSI outcomes.

Effect of aspiration vacuum on the developmental competence of immature human oocytes retrieved using a 20-gauge needle

In-vitro maturation (IVM) of immature oocytes has been proposed as a potential alternative to conventional IVF treatment following ovarian stimulation. However, the effects of the oocyte retrieval conditions on subsequent development have not been well understood. This study assessed the effects of different aspiration vacuums during oocyte retrieval on the developmental competence of immature oocytes following IVM, IVF and embryo transfer, retrospectively. Immature oocytes were aspirated with 20-gauge needles with a vacuum of 180 or 300 mmHg. Immature oocytes were cultured in IVM medium for 26 h. All mature oocytes were inseminated by intracytoplasmic sperm injection (ICSI). Embryo transfer was carried out 2 or 3 days after ICSI. The percentage of cumulus-cell enclosed oocytes and of transferable embryos per retrieved oocytes in 180 mmHg (69.7% and 23.8%, respectively) were significantly higher (P < 0.01) than those in 300 mmHg (46.2% and 12.8%, respectively). The ongoing pregnancy rate per retrieval cycle in 180 mmHg (30%) was higher (P < 0.01) than that in 300 mmHg (4.3%). The data indicate that lower pressure of vacuum aspiration with a 20-gauge needle improves the developmental competence of immature oocytes following IVM, IVF and embryo transfer.

Use of a luteal estradiol patch and a gonadotropin-releasing hormone antagonist suppression protocol before gonadotropin stimulation for in vitro fertilization in poor responders

The administration of a luteal E2 patch/GnRH antagonist protocol before gonadotropins in poor responders may improve ovarian stimulation and result in greater uniformity in follicular development and improved pregnancy rates.

Outcome of in vitro fertilization treatment in patients who electively inseminate a limited number of oocytes to avoid creating surplus human embryos for cryopreservation

OBJECTIVE

To determine whether the outcome of IVF treatment in patients who electively inseminate a limited number of oocytes is comparable to that in a group of good-prognostic or poor-prognostic patients.

DESIGN

Retrospective clinical study.

SETTING

University-based tertiary fertility center.

PATIENT(S)

Two hundred three women under the age of 40 years.

INTERVENTION(S)

Patients undergoing their first cycle of IVF who elected to have no more than four oocytes inseminated (study group) or who produced only four or fewer oocytes (poor-prognostic group) or who had excess embryos cryopreserved (good-prognostic group).

MAIN OUTCOME MEASURE(S)

Implantation rate, clinical pregnancy rate, and ongoing pregnancy rate.

RESULT(S)

There were no significant differences in the implantation rate for the study group when compared with the good-prognostic group or the poor-prognostic group. The clinical pregnancy rate (62.5% vs. 64%) and ongoing-pregnancy or birth rate (56.3% vs. 60.7%) were similar between the study group and the good-prognostic group. However, the clinical pregnancy rate (62.5% vs. 29.7%) and ongoing-pregnancy rate (56.3% vs. 24.3%) were higher in the study group compared with the poor-prognostic group.

CONCLUSION(S)

Inseminating fewer oocytes in patients who elect not to cryopreserve excess embryos does not adversely affect their probability of conception.

Hormonal manipulations in the luteal phase to coordinate subsequent antral follicle growth during ovarian stimulation

During the early follicular phase in the menstrual cycle, antral follicle sizes are often markedly heterogeneous. These follicular size discrepancies may, at least in part, result from the early exposure of FSH-sensitive follicles to gradient FSH concentrations during the preceding luteal phase. In addition, they potentially affect the results of ovarian stimulation. Indeed, pre-existing follicle size discrepancies may encumber coordinated follicular growth during ovarian stimulation, thereby reducing the number of follicles that reach maturation at once. To investigate this issue, three clinical studies were conducted to test the hypothesis that luteal FSH suppression could coordinate follicular growth. First, luteal FSH concentrations were artificially lowered by administering physiological oestradiol doses and measured follicular characteristics on the subsequent day 3. Second, it was verified whether luteal oestradiol administration could promote the coordination of follicular growth during ovarian stimulation and improve its results. Third, the effects of premenstrual gonadotrophin-releasing hormone (GnRH) antagonist administration on follicular characteristics were assessed during the early follicular phase. The results showed that luteal FSH suppression by either oestradiol or GnRH antagonist administration reduces the size and improves the homogeneity of early antral follicles during the early follicular phase, an effect that persists during ovarian stimulation. Coordination of follicular development may optimize ovarian response to short GnRH agonist and antagonist protocols, and constitutes an attractive approach to improving their outcome.

Oocyte number per live birth in IVF: were Steptoe and Edwards less wasteful?

As part of a learning exercise to assess the efficiency of oocyte utilization after controlled ovarian stimulation, we compared historical data from the publications of Steptoe and Edwards describing their early experiences in Oldham and at Bourn Hall with retrospective data from IVF and ICSI cycles carried out at Bourn Hall Clinic during the year 2000. For the purpose of analysing the more recent data, patients were subdivided into groups by age (< or = 37 years and > or = 38 years) and by oocyte yield (low, intermediate and high). In patients less than 38 years of age, live birth rates were equivalent in each group, irrespective of the number of oocytes retrieved. Patients who yielded low numbers of oocytes (1-5) utilized an average of 9.6 oocytes per live birth, compared with 25.1 and 51.5 in those who yielded intermediate (6-16) and high (16+) numbers of oocytes. The comparison with historical data suggests that the 'efficiency' of oocyte utilization has not improved significantly since the early 1980s, despite 25 years' experience of controlled ovarian stimulation for IVF treatment.

Multiple gestation and infertility treatment: registration, reflection and reaction—the Belgian project

Multiple pregnancies associated with infertility treatment are recognized as an adverse outcome and are responsible for morbidity and mortality related to prematurity and very low birthweight population. Due to the epidemic of iatrogenic multiple births, the incidence of maternal, perinatal and childhood morbidity and mortality has increased. This results in a hidden healthcare cost of infertility therapy and this may lead to social and political concern. Reducing the number of embryos transferred and the use of natural cycle IVF will surely decrease the number of multiple gestations. Consequently, optimized cryopreservation programmes will be essential. For non-IVF hormonal stimulation, responsible for more than one-third of all multiple pregnancies after infertility treatment, a strict ovarian stimulation protocol aiming at mono-ovulation is crucial. Multifetal pregnancy reduction is an effective method to reduce high order multiplets but carries its own risk of medical and emotional complications. Excellent data collection of all infertility treatments is needed in our discussion with policy makers. The Belgian project, in which reimbursement of assisted reproduction technology-related laboratory activities is linked to a transfer policy aiming at substantial multiple pregnancy reduction, is a good example of cost-efficient health care through responsible, well considered clinical practice.

Premenstrual administration of gonadotropin-releasing hormone antagonist coordinates early antral follicle sizes and sets up the basis for an innovative concept of controlled ovarian hyperstimulation

OBJECTIVE

To investigate whether premenstrual administration of a GnRH antagonist coordinates early antral follicle sizes during the subsequent follicular phase.

DESIGN

Prospective, longitudinal study.

SETTING

University Hospital in France

PATIENT(S)

Twenty-five women, 50 cycles.

INTERVENTION(S)

On cycle day 2 (control/day 2), women underwent measurements of early antral follicles by ultrasound and serum FSH and ovarian hormones. On day 25, they received a single cetrorelix acetate administration, 3 mg. On the subsequent day 2 (premenstrual GnRH antagonist/day 2), participants were re-evaluated as on control/day 2.

MAIN OUTCOME MEASURE(S)

Magnitude of follicular size discrepancies.

RESULT(S)

Follicular diameters (4.1 +/- 0.9 vs. 5.5 +/- 1.0 mm) and follicle-to-follicle size differences decreased on premenstrual GnRH antagonist/day 2 as compared with control/day 2. Consistently, FSH (4.5 +/- 1.9 vs. 6.7 +/- 2.4 mIU/mL), E(2) (23 +/- 13 vs. 46 +/- 26 pg/mL), and inhibin B (52 +/- 30 vs. 76 +/- 33 pg/mL) were lower on GnRH antagonist/day 2 than on control/day 2.

CONCLUSION(S)

Premenstrual GnRH antagonist administration reduces diameters and size disparities of early antral follicles on day 2, likely through the prevention of luteal FSH elevation and early follicular development. This simple, original approach may be used to coordinate multifollicular development in controlled ovarian hyperstimulation.

Transfer of nonselected transferable day 3 embryos in low embryo producers

OBJECTIVE

To examine the implantation potential of embryos from assisted reproductive technology cycles with low embryo production and to assess the effects of clinical variables and embryo scores (ES) on pregnancy outcome.

DESIGN

Prospective clinical study.

SETTING

Assisted reproductive technology unit in a tertiary medical center.

PATIENT(S)

From July 1998 to December 2001, 280 cycles in 229 infertile couples produced a limited number of one, two, or three embryos 3 days after oocyte retrieval and underwent fresh embryo transfer (ET).

INTERVENTION(S)

Embryos with two or more blastomeres were scored and transferred.

MAIN OUTCOME MEASURE(S)

ES and implantation rate per ET.

RESULT(S)

Of 863 fresh ET cycles during the study period, 32.4% (280) were low embryo producers. Among them, there were no significant differences in average ES of individual embryos in single, dual, or triple ET or in embryos obtained from patients with low or high E2 responses, or young or old age. Embryos derived from conventional IVF had a better ES than those derived from intracytoplasmic sperm injection. The clinical pregnancy rate was strongly correlated with the cumulative ES. Implantation rates were similar among and between groups, with an average rate of 15.9%.

CONCLUSION(S)

Embryos of low embryo producers had an inherently low implantation potential that appeared to be unrelated to the number of embryos transferred, female age, ovarian E2 genesis, or fertilization method. The cumulative ES can serve as a predictor of pregnancy.

Implantation Rates after Two, Three, or Five Days of Embryo Culture

Extended embryo culture together with amelioration of embryo selection methods and embryo culture conditions have allowed a substantial increase on both pregnancy and implantation rates. However, uterine embryo transfers are still performed after 2 to 6 days of egg retrieval. In this paper, we show the results of two studies, one prospective study comparing IVF outcome of day 2 and day 3 embryo transfers, and a retrospective study looking at blastocyst transfers versus day 3 embryo transfers in our egg donation program. Also, we test the predictive value of the presence of three or more seven cell-stage embryos on day 3 of development on blastocyst formation and pregnancy rates. No significant differences were found between day 2 and day 3 embryo transfers in terms of pregnancy, ongoing pregnancy, and implantation rates, as well as in multiple and in high order pregnancy. In general, day 6 embryo transfers resulted in significantly higher ongoing pregnancy and implantation rates compared with day 3 embryo transfers (41.1 per cent and 23.6 per cent versus 50.1 per cent and 38.1 per cent, respectively). No differences were found in terms of multiple gestations despite transferring significantly more embryos on day 3 compared with day 6 transfers. When less than three 7-cell embryos were present in the embryo cohort, day 6 embryo transfers did not improve the rates of ongoing pregnancy with regards to day 3 embryo transfer, although significant high implantation rates were obtained on the group of blastocyst transfer. The presence of three or more 7 cell-stage embryos improved significantly both ongoing pregnancy and rates on blastocyst transfers compared to day 3 embryo transfers (65.6 per cent versus 50.6 per cent and 37.4 per cent vs 24.7 per cent, respectively). In conclusion, at least in egg donation, day 3 embryo transfers do not improve either pregnancy or implantation rates when compared to day 2 transfers. Generally speaking blastocyst transfers give significantly higher chance of pregnancy and implantation rates per cycle and per transfer than early cleavage stage transfers. However, the absence of a good embryo cohort, that is having less than three 7 cell-stage embryos on day 3, blastocyst transfers will improve implantation rates but not ongoing pregnancy rates.

Coordination of early antral follicles by luteal estradiol administration provides a basis for alternative controlled ovarian hyperstimulation regimens

OBJECTIVE

To investigate whether luteal E(2) administration reduces size discrepancies of early antral follicles.

DESIGN

Prospective, crossover study.

SETTING

ART unit, Clamart, France.

PATIENT(S)

Sixty women and 120 cycles.

INTERVENTION(S)

On cycle day 3 (baseline day 3), all women underwent measurements of early antral follicles by ultrasound and serum FSH and ovarian hormones. From day 20 until the next cycle day 2, 30 of them received oral 17beta-E(2), whereas the remaining women served as controls. The day after E(2) discontinuation (E(2) day 3) or on subsequent cycle day 3 (control day 3), participants were reevaluated as on baseline day 3.

MAIN OUTCOME MEASURE(S)

Magnitude of follicular size discrepancies.

RESULT(S)

Follicular size discrepancies and follicular diameters were significantly attenuated on E(2) day 3 (3.7 +/- 0.5 mm) as compared with baseline day 3 (4.9 +/- 1.0 mm), but not in controls (5.0 +/- 0.8 vs. 4.9 +/- 0.8 mm). FSH (4.3 +/- 1.9 vs. 7.3 +/- 3.3 mIU/mL) and inhibin B (34 +/- 28 vs. 71 +/- 32 pg/mL) levels were consistently lower on E(2) day 3 than on baseline day 3 but remained unchanged in controls.

CONCLUSION(S)

Luteal E(2) administration reduces the size and improves the homogeneity of early antral follicles on day 3. This approach may be instrumental in synchronizing follicular development during controlled ovarian hyperstimulation.

Trends in the incidence of births and multiple births and the factors that determine the probability of multiple birth after IVF treatment

BACKGROUND

We aimed to review trends in the probability of birth and multiple birth before and after the legal restriction limiting the maximum allowable number of embryos transferred, and to examine factors that determine the probability of multiple birth following IVF treatment.

METHODS

We analysed data relating to 7170 IVF and 530 intracytoplasmic sperm injection cycles reaching embryo transfer undertaken by 4417 women at a single tertiary referral assisted conception centre in the UK between 1984 and 1997. Probability of birth, and of proportion of multiple births among those who gave birth, was explored using logistic regression analysis.

RESULTS

Between 1984 and 1997 there was a significant increase in probability of birth but no change in the probability of multiple birth. The trend in probability of birth was almost wholly explained by the significant increase in number of embryos created per cycle. Pooling all the data, risk factors for increased chance of birth and multiple birth were: younger age (<35 years), diagnoses other than tubal infertility, fewer than three previous unsuccessful cycles, previous IVF live birth and a large number of embryos created. Given these factors, increasing the number of embryos transferred did not increase the chance of a birth, but did increase the chance of a multiple birth.

CONCLUSIONS

The probability of birth has increased and the probability of multiple birth has remained unchanged, despite legislation limiting the number of embryos transferred in the UK. Efforts should be made to reduce the incidence of multiple births by transferring fewer embryos, especially in the presence of good prognostic factors for birth.

Value of the hamster oocyte test and computerised measurements of sperm motility in predicting if four or more viable embryos will be obtained in an IVF cycle

The experimental group consisted of men from 81 couples waiting for in vitro fertilization (IVF), about half of whom had sperm dysfunction defined by a negative post-coital test. A diagnostic semen sample was subjected to a hamster oocyte penetration test (HOPT) after stimulation of the acrosome reaction with A23187 +/- pentoxifylline and to computerized sperm motility measurements (CASA) as well as conventional semen analysis according to the WHO protocol. Logistic regression was used to identify parameters that predicted the probability of achieving four or more viable embryos at IVF among the 65 couples from whom four or more oocytes were collected. The number of oocytes available and whether the woman had previously been pregnant (ever pregnant) were important factors but once these had been taken into account a number of sperm parameters had additional predictive power. The most useful of these were the percentage sperm static (CASA) or the percent sperm progressively motile (conventional semen analysis) in the Percoll preparation. A model incorporating the number of oocytes collected, ever pregnant and percentage sperm static achieved 85% correct prediction of outcome in the experimental dataset but only 62% correct prediction in an independent set of 280 IVF cycles. The percentage of hamster oocytes penetrated was a significant predictor but had no advantage over simple motility measurements. The results illustrate the difficulty of basing a prognosis for achieving satisfactory fertilization in IVF on the properties of spermatozoa.

Zygote evaluation: an efficient tool for embryo selection

One of the main problems concerning IVF units is the need to decrease the occurrence of multiple pregnancies in their practice without affecting the overall success rate. Different embryological parameters concerning every step of the early embryo development are known to have some predictive value for implantation potential. In this prospective study, a pronuclear scoring system was used to classify zygotes into six patterns from 0 to 5. Cleaved, day 3 embryos developed from pattern 0 zygotes, which was described as the normal pattern, were transferred when available. For each zygote pattern, the subsequent embryological development was analysed. Pattern 0 zygotes led to significantly more 'good quality' embryos with higher implantation potential than embryos developing from the other zygote patterns (P < 0.01). Embryo transfers including at least one pattern 0 resulted in significantly more pregnancies than transfers without any pattern 0 zygotes (39.3 versus 19.7%, P < 0. 01). No relationship between clinical parameters (age of female partner, infertility cause) and zygote pattern distribution was demonstrated.