Clinical outcomes of a vitrified donor oocyte programme: A single UK centre experience

A comparative analysis of the clinical pregnancy and perinatal outcomes between oocyte vitrification and embryo vitrification based on the propensity score matching method

PURPOSE

This study investigated the safety and effectiveness of oocyte vitrification by comparing the clinical pregnancy and perinatal outcomes between transfer cycles of vitrified oocytes and those of vitrified embryos.

METHODS

A retrospective cohort study was conducted to analyze the clinical data of patients who underwent cleavage-stage embryo transfer at the Department of Reproductive Medicine between January 2011 and June 2021. Seventy-seven transfer cycles of fresh cleavage-stage embryos developed from vitrified-thawed oocytes (oocyte vitrification group) and 2170 transfer cycles of vitrified-thawed cleavage-stage embryos developed from fresh oocytes (embryo vitrification group) were included. Further, 293 cases were selected from the embryo vitrification group after applying propensity score matching at 1:4. The primary outcomes were miscarriage rate, live birth rate, and neonatal birth weight.

RESULTS

No statistically significant differences were observed in the baseline data, pregnancy, perinatal outcomes, or neonatal outcomes for either singleton or twin births between the two groups after matching. Backwards stepwise regression was used to analyze the length of gestation. The age of female participants (β =  - 0.410, 95% CI =  - 1.339 ~  - 0.620, P < 0.001) had a statistically significant effect.

CONCLUSION

Oocyte vitrification results in similar clinical pregnancy and perinatal outcomes as does embryo vitrification; hence, it is a relatively safe assisted reproductive technique.

Fertility preservation in pediatric healthcare: a review

Survival rates for children and adolescents diagnosed with malignancy have been steadily increasing due to advances in oncology treatments. These treatments can have a toxic effect on the gonads. Currently, oocyte and sperm cryopreservation are recognized as well-established and successful strategies for fertility preservation for pubertal patients, while the use of gonadotropin-releasing hormone agonists for ovarian protection is controversial. For prepubertal girls, ovarian tissue cryopreservation is the sole option. However, the endocrinological and reproductive outcomes after ovarian tissue transplantation are highly heterogeneous. On the other hand, immature testicular tissue cryopreservation remains the only alternative for prepubertal boys, yet it is still experimental. Although there are several published guidelines for navigating fertility preservation for pediatric and adolescent patients as well as transgender populations, it is still restricted in clinical practice. This review aims to discuss the indications and clinical outcomes of fertility preservation. We also discuss the probably effective and efficient workflow to facilitate fertility preservation.

The Impact of Metal Nanoparticles on Female Reproductive System: Risks and Opportunities

Humans have always been exposed to tiny particles via dust storms, volcanic ash, and other natural processes, and our bodily systems are well adapted to protect us from these potentially harmful external agents. However, technological advancement has dramatically increased the production of nanometer-sized particles or nanoparticles (NPs), and many epidemiological studies have confirmed a correlation between NP exposure and the onset of cardiovascular diseases and various cancers. Among the adverse effects on human health, in recent years, potential hazards of nanomaterials on female reproductive organs have received increasing concern. Several animal and human studies have shown that NPs can translocate to the ovary, uterus, and placenta, thus negatively impacting female reproductive potential and fetal health. However, NPs are increasingly being used for therapeutic purposes as tools capable of modifying the natural history of degenerative diseases. Here we briefly summarize the toxic effects of few but widely diffused NPs on female fertility and also the use of nanotechnologies as a new molecular approach for either specific pathological conditions, such as ovarian cancer and infertility, or the cryopreservation of gametes and embryos.

An Eight Year Experience of Autologous Oocyte Vitrification for Infertile Patients Owing to Unavailability of Sperm on Oocyte Retrieval Day

Objective: The objective of this study was to provide a descriptive analysis of the clinical outcomes achieved in oocyte vitrification in cases where sperm was unavailable on oocyte retrieval day, and to identify predictors of oocyte survival. Methods: This retrospective cohort study used data from a university-affiliated reproductive medical center. There were 321 cycles in which some of, or all oocytes were vitrified owing to the unavailability of sperm between March 2009 and October 2017. A descriptive analysis of the clinical outcomes including both fresh embryo transfers and cryopreserved embryo transfers was provided. The ability of an individual parameter to forecast oocyte survival per thawing cycle was assessed by binary logistic regression analysis. The cumulative probability of live birth (CPLB) was estimated by using the Kaplan-Meier method according to the total number of oocytes thawed in consecutive procedures. Results: The average survival rate was 83.13%. High-quality embryo rate and blastocyst rate decreased significantly decreased significantly in vitrification oocyte group compared to fresh control oocytes. The comparison of sibling oocytes in part-oocyte-vitrified cycles shows fewer high-quality embryos developed in the vitrified group. The live birth rate per warmed-oocyte was 4.3%. Reasons for lack of sperm availability on oocyte retrieval day and serum cholesterol levels were found to be associated with oocyte survival rate in the present study. Kaplan-Meier analysis showed no significant difference in CPLB between patients ≤35 vs. >35 years. Conclusions: Oocyte vitrification is an indispensable and effective alternative when sperm are not available on oocyte retrieval day. The present study provided evidence that oocytes from infertile couples were more likely to suffer oocyte/embryo vitrification injury. Clinicians need to take this into account when advising patients in similar situations. Further studies will be necessary to clarify the correlation between serum metabolism parameters and human oocyte survival after vitrification.

Oocyte donation: not all oocyte cryobanks are the same

RESEARCH QUESTION

Is the efficacy of imported vitrified oocyte donation affected by the cryobank of origin?

DESIGN

Longitudinal cohort study, including 249 completed oocyte warming cycles from 200 recipients (January 2016-July 2020). No severe male factor was included. Vitrified oocytes were provided by three Spanish cryobanks. Primary outcome was cumulative live birth delivery rate (CLBR) per completed oocyte warming cycle.

RESULTS

After warming 1535 oocytes, 1244 survived (81.0%) and 945 fertilized (76.0%); embryo utilization rate was 65.3%. The overall CLBR per completed cycle was 47.0% but was lower in cryobank 1 (31.2%) versus cryobank 2 (56.0%, P = 0.0010) and cryobank 3 (50.8%, P = 0.0241). Multivariate logistic regression analysis identified survival of four or more oocytes as the strongest predictor for delivery (P = 0.0282). Only 202 out of 249 oocyte warming cycles had four or more survived oocytes in a proportion that was significantly lower in cryobank 1 versus cryobank 2 (70.1% versus 89.0%, P = 0.0020); comparison with cryobank 3 (81.0%) was not significant. In the 202 oocyte warming cycles, CLBR in cryobank 1 (37.0%) was lower versus cryobank 2 (58.8%, P = 0.0115) and cryobank 3 (60.8%, P = 0.0019), suggesting a reduced viability in oocytes from cryobank 1 that survived warming.

CONCLUSIONS

Differences were found in the efficacy of imported vitrified oocytes in relation to the cryobank of origin. Each centre needs to evaluate the results internally when starting a collaboration with an oocyte cryobank to establish the necessary measures to maximize treatment efficacy.

'Why have women not returned to use their frozen oocytes?': a 5-year follow-up of women after planned oocyte cryopreservation

RESEARCH QUESTION

What are the reproductive choices and retrospective reflections of women at least 4 years after planned oocyte cryopreservation (POC)?

DESIGN

This was an internet survey, using the REDCap application, of women who underwent POC, at a single-centre university-affiliated IVF unit, 4-8 years before the survey. The questionnaire addressed reproductive choices and outcomes following POC.

RESULTS

Seventy-nine women who underwent POC during 2011-2014 were invited to participate, and 70 (89%) responded. Mean age at cryopreservation was 37.1 ± 2.4 (range 30-41) years, mean age at study participation 42.6 ± 2.6 (range 35-48) years, and mean time from first cryopreservation cycle to study participation 5.5 ± 1.3 (range 4-8) years. The main retrospectively reported reason for POC was not wanting to become pregnant without a partner (59, 84%). During the follow-up period, 44 women (63%) attempted to conceive either naturally or by assisted reproductive technology using fresh or cryopreserved oocytes. Of those, 28 women achieved a live birth (64% of those who tried to conceive). Fourteen respondents (20% of all respondents) reported using their cryopreserved oocytes, and three (21%) achieved a birth using those oocytes. Fifteen women (34%) of those who tried to conceive used donor spermatozoa.

CONCLUSIONS

The most common reasons for not using frozen oocytes were achieving pregnancy without frozen oocytes or preferring not to have a child without a partner. A considerable proportion of women who had POC and were not interested in being a single parent by choice eventually try to conceive using donor spermatozoa several years later.

Health of 2-year-old children born after vitrified oocyte donation in comparison with peers born after fresh oocyte donation

STUDY QUESTION

Does oocyte vitrification adversely affect the health of 2-year-old children compared with peers born after use of fresh oocytes in a donation programme?

SUMMARY ANSWER

The growth and health of 2-year-old children born after oocyte vitrification are similar to those of peers born after use of fresh oocytes.

WHAT IS KNOWN ALREADY

Although oocyte vitrification is a well-established procedure in ART, the evidence on its safety for offspring is limited. Currently, no disadvantageous effects of oocyte vitrification have been shown in terms of obstetric and neonatal outcome. However, no data beyond the neonatal period are available to date.

STUDY DESIGN, SIZE, DURATION

A combined retrospective and prospective observational study was performed in a tertiary reproductive centre. The retrospective data were available in our extensive database of children born after ART. Donor cycles with an oocyte retrieval between January 2010 and March 2017 and a fresh embryo transfer resulting in the livebirth of a singleton were selected from the established oocyte donation programme. Fresh or vitrified oocytes were used in the donor cycles and all pregnancies in oocyte recipients were achieved after ICSI. Only children residing in Belgium were eligible for follow-up.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Biometric and health parameters of 72 children born after oocyte vitrification were compared with those of 41 children born after use of a fresh oocyte. Data were collected by means of questionnaires and physical examinations at the age of 21–30 months. The primary outcome measures were anthropometry and health at 2 years of age.

MAIN RESULTS AND THE ROLE OF CHANCE

Length, weight, BMI, head circumference, left arm circumference and waist circumference at the age of 2 years were comparable between the vitrification and fresh group, also after adjustment for treatment, and maternal and neonatal characteristics (all P > 0.05). Health of the children in terms of hospital admission and surgical intervention rates were comparable between the vitrification and fresh group (both P > 0.05).

LIMITATIONS, REASONS FOR CAUTION

Although the current study is the largest series describing health parameters beyond the neonatal period, the small numbers still preclude definite conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides the first evidence indicating that oocyte vitrification does not adversely affect the growth and health of offspring beyond the neonatal period.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Methusalem grants and by grants from Wetenschappelijk Fonds Willy Gepts, all issued by the Vrije Universiteit Brussel. All co-authors declared no conflict of interest in relation to this work. Both the Centre for Reproductive Medicine and the Centre for Medical Genetics from the UZ Brussel have received several educational grants from IBSA, Ferring, MSD and Merck for either research on oocyte vitrification or for establishing the database for follow-up research and organizing the data collection.

Planned oocyte cryopreservation (Planned OC): systematic review and meta-analysis of cost-efficiency and patients' perspective

BACKGROUND

Advances in vitrification techniques have enabled planned oocyte cryopreservation ('Planned OC').

OBJECTIVES

To explore the cost-efficiency and utilisation of planned OC, as well as patients' perspectives on the process.

SEARCH STRATEGY

A systematic search in PubMed/MEDLINE, Embase, Cochrane Database and PsychINFO, for all relevant studies published between January 2007 and December 2019.

SELECTION CRITERIA

The protocol followed PRISMA guidelines in PECO format, and was registered with PROSPERO.

DATA COLLECTION AND ANALYSIS

Two independent reviewers evaluated all manuscripts for inclusion eligibility. Authors were contacted for missing data. Included studies were assessed for risk of bias and for heterogeneity. Weighted effects were measured and plotted.

MAIN RESULTS

The search yielded 12 545 records, of which 43 were included. Planned OC is cost-efficient at 35, assuming 60% utilisation; and at 37 assuming utilising donor sperm when necessary. At 38 it is cost-efficient to defer planned OC in favour of undergoing 2 IVF cycles. Currently, utilisation of banked-oocytes within 22-58 months, is up to 15%. Nine percent of warmed banked oocytes result in life births. Online resources and treating physicians are equally important sources of information regarding planned OC. Most patients think planned OC is ideal before age 35 and are not fully aware of what the process entails and tend to overestimate the success rates. The main barrier to wider endorsement of planned OC is being wary of potential health implications or of limited success.

CONCLUSION

Planned OC is an adequate method for preserving fertility. However, knowledge gaps result in under-utilisation leading to reduced cost-efficiency.

TWEETABLE ABSTRACT

Identifying facilitators and barriers for wider adoption of banking oocytes can enhance the cost-efficiency of this modality.

Effects of oocyte vitrification on the behaviors and physiological indexes of aged first filial generation mice

To evaluate the long-term effects of oocyte cryopreservation on the health of the first filial generation (F1), we used B6D2F1 mice for oocyte collection, in vitro fertilization, and breeding. The female F1 mice born from the offspring of fresh mature oocytes (control group) and from the offspring of vitrified oocytes with traditional vitrification medium (VM group) and new improved vitrification medium (2P10E7D group) were maintained until 14-15 months of age for behavioral tests and 16-17 months of age for physiological analyses. Behavioral indexes, including anxiety-like status, discrimination ability, learning and memory ability, were investigated. Physiological indexes including body weight, body fat, heart rate, blood pressure, and blood lipids were also analyzed. In our results, the behavioral indexes, body weight, body fat, heart rate, blood pressure, total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) did not show significant differences among the three groups. However, the triglyceride (TG) level of the VM group was higher than that of the 2P10E7D group. Moreover, compared with the control group, both the VM group and the 2P10E7D group showed greatly increased diastolic blood pressure. This study is the first to report that oocyte vitrification might affect metabolic physiological indexes via transgenerational inheritance rather than behaviors related to anxiety-like status and cognitive ability. Furthermore, different vitrification media might have differential transgenerational effects.

ANZSREI consensus statement on elective oocyte cryopreservation

BACKGROUND

One in six Australian women and couples suffer infertility. A rising proportion relates to advanced maternal age, associated with poorer oocyte quality and in vitro fertilisation (IVF) outcomes. Internationally, oocyte cryopreservation technology applied to oocytes vitrified before 35 years provides similar live-birth statistics compared to IVF treatment using fresh oocytes. Oocyte cryopreservation is accessible in Australasian settings and elective uptake is increasing. For women accessing treatment, oocyte cryopreservation may expand future family building options.

AIMS

To develop the first Australasian Certification in Reproductive Endocrinology and Infertility (CREI) subspecialist-led consensus guideline on oocyte cryopreservation.

METHODS

The ANZSREI ACCEPT (Australasian CREI Consensus Expert Panel on Trial evidence group) met in 2017 and 2018 and identified clinical aspects of care for inclusion and review. Review of the available evidence was conducted and consensus statements prepared. Areas of dissent of expert opinion and for further research were noted.

RESULTS

Consensus was reached on definition and best practice in oocyte cryopreservation for freeze method, controlled ovarian stimulation, medical risk reduction and treatment and outcomes counselling. The term 'social egg freezing' may marginalise, stigmatise or attribute social blame to women, and there is a need to revise this to a neutral and non-judgemental term such as elective or planned oocyte cryopreservation.

CONCLUSION

Oocyte cryopreservation has the potential to improve cumulative live birth outcomes for women. Implementation of this guideline should facilitate an optimal approach for providing care.

Egg freezing and late motherhood

Egg freezing was initially used as an intervention for iatrogenic ovarian insufficiency. Nowadays, it is not considered an experimental procedure, and it is increasingly popular among healthy women who wish to maintain their reproductive potential (fertility preservation). This review summarises the evidence on egg freezing technology, reproductive outcomes and long-term effects, as well as its psychological and socioeconomic implications. Egg freezing technology is advancing, with vitrification being the current method of choice, due to its effectiveness. The reproductive outcomes following egg freezing appear to be promising, though the strong negative association with maternal age has to be taken into consideration. Unfortunately, data on long-term outcomes are missing, raising safety issues. Egg freezing has several socioeconomic implications involving health risks, as well as financial and psychological factors.

Child Health: Is It Really Assisted Reproductive Technology that We Need to Be Concerned About?

Concerns remain about the health of children conceived by infertility treatment. Studies to date have predominantly not identified substantial long-term health effects after accounting for plurality, which is reassuring given the increasing numbers of children conceived by infertility treatment worldwide. However, as technological advances in treatment arise, ongoing studies remain critical for monitoring health effects. To study whether the techniques used in infertility treatment cause health differences, however, remains challenging due to identification of an appropriate comparison group, heterogeneous treatment, and confounding by the underlying causes of infertility. In fact, the factors that are associated with underlying infertility, including parental obesity and other specific male and female factors, may be important independent factors to consider. This review will summarize key methodological considerations in studying children conceived by infertility treatment including the evidence of associations between underlying infertility factors and child health.