Air pollution exposure in vitrified oocyte donors and male recipient partners in relation to fertilization and embryo quality.

Background: Studies on air pollution and outcomes of in vitro fertilization (IVF) have focused on couples undergoing autologous IVF, in which it is challenging to disentangle maternal and paternal exposures during gametogenesis. We sought to evaluate the independent associations between air pollution exposure during oogenesis and spermatogenesis on fertilization and embryo quality in non-identified donor oocyte IVF cycles.

Methods: Our study included 500 oocyte donors and 915 male recipient partners who contributed 1,095 oocyte thaw cycles (2008-2019).

Sperm penetration at the maturing metaphase I stage can trigger oocyte activation in a mouse model.

Research Question: Can spermatozoa penetrate maturing metaphase I (MI) oocytes, and render subsequent development following conventional IVF in a mouse model?

Design: ICR mice were used in this study. Metaphase II (MII) cumulus-oocyte complexes (COC) harvested 15 h after injection of human chorionic gonadotrophin (HCG) were used for IVF as the control group (Group 1). In the treatment group (Group 2), maturing MI COC harvested 7 h after HCG injection were used for IVF.

Neighborhood deprivation in relation to ovarian reserve and outcomes of ovarian stimulation among oocyte donors.

Objective: To study the relationship between neighborhood deprivation index (NDI) and markers of ovarian reserve and outcomes of controlled ovarian stimulation among young, healthy oocyte donors.

Design: Retrospective cohort study.

Patients: A total of 547 oocyte donors who underwent 905 oocyte retrieval cycles (2008-2020) at a private fertility center in Sandy Springs, Georgia, United States.

Ambient traffic related air pollution in relation to ovarian reserve and oocyte quality in young, healthy oocyte donors.

Studies in mice and older, subfertile women have found that air pollution exposure may compromise female reproduction. Our objective was to evaluate the effects of air pollution on ovarian reserve and outcomes of ovarian stimulation among young, healthy females. We included 472 oocyte donors who underwent 781 ovarian stimulation cycles at a fertility clinic in Atlanta, Georgia, USA (2008-2019).

The effects of vitrification on oocyte quality.

Vitrification, is an ultra-rapid, manual cooling process that produces glass-like (ice crystal-free) solidification. Water is prevented from forming intercellular and intracellular ice crystals during cooling as a result of oocyte dehydration and the use of highly concentrated cryoprotectant. Though oocytes can be cryopreserved without ice crystal formation through vitrification, it is still not clear whether the process of vitrification causes any negative impact (temperature change/chilling effect, osmotic stress, cryoprotectant toxicity, and/or phase transitions) on oocyte quality, which translates to diminished embryo developmental potential or subsequent clinical outcomes.

The effects of oocyte donor and recipient body mass index on live birth rates and pregnancy outcomes following assisted reproduction.

Objective: To investigate the effects of oocyte donor and recipient body mass index (BMI) on outcomes of vitrified donor oocyte assisted reproductive technology (ART).

Design: Retrospective cohort study.

Setting: Private fertility center.

When using donor oocytes, does embryo stage matter? An analysis of blastocyst versus cleavage stage embryo transfers using a cryopreserved donor oocyte bank.

Purpose: Oocyte donor in vitro fertilization (IVF) represents an ideal model to study the effects of embryo stage on reproductive success, as embryos come from young women with high-quality oocytes. Our study aimed to determine if embryo transfer stage affected outcomes in oocyte donor IVF, including the common scenario where only a limited number of quality embryos are available after culture.

Methods: This retrospective cohort analyzed anonymous vitrified donor oocyte cycles at a single clinic between 2008 and 2015.

The effect of donor and recipient race on outcomes of assisted reproduction.

Background: A growing literature suggests that minority races, particularly Black women, have a lower probability of live birth and higher risk of perinatal complications after autologous assisted reproductive technology. However, questions still remain as to whether these racial disparities have arisen because of associations between race and oocyte/embryo quality, the uterine environment, or a combination of the two. Oocyte donation assisted reproductive technology represents a unique approach to examine this question.

Vitrification of the human embryo: a more efficient and safer in vitro fertilization treatment.

Cryopreservation has become a central pillar in assisted reproduction, reflected in the exponential increase of "freeze all" cycles in the past few years. Vitrification makes it possible to cool and warm human eggs and embryos with far less cryo-damage than 'slow-freeze' and allows nearly intact survival of embryos with very high survival rates for eggs as well. This has resulted in a complete transformation how we manage treatment for in vitro fertilization patients.

Impact of male partner characteristics and semen parameters on in vitro fertilization and obstetric outcomes in a frozen oocyte donor model.

Objective: To examine the degree to which paternal variables of age, body mass index (BMI), and sperm parameters affect vitrified donor oocyte IVF outcomes. Previous studies examining the impact of male partner characteristics on in-vitro fertilization (IVF) have found conflicting results. Concerns are rising over the potential effects of paternal factors, such as age and obesity, on pregnancy and child health.

The Human Oocyte Preservation Experience (HOPE) Registry: evaluation of cryopreservation techniques and oocyte source on outcomes.

Background: This prospective, Phase IV, multicenter, observational registry of assisted reproductive technology clinics in the USA studied outcomes of first cycles using thawed/warmed cryopreserved (by slow-freezing/vitrification) oocytes (autologous or donor).

Methods: Patients were followed up through implantation, clinical pregnancy, and birth outcomes. The main outcome measure was live birth rate (LBR), defined as the ratio of live births to oocytes thawed/warmed minus the number of embryos cryopreserved for each cycle, averaged over all thawing cycles.

Production of Live Offspring from Vitrified-Warmed Oocytes Collected at Metaphase I Stage.

Vitrification of matured oocytes is widely adopted in human clinics and animal research laboratories. Cryopreservation of immature oocytes, particularly those at metaphase I (MI), remains a challenge. In the present work, mouse MI oocytes denuded of cumulus cells were vitrified and warmed (V/W) either prior to (V/W-BEFORE-IVM, n = 562) or after (V/W-AFTER-IVM, n = 664) in vitro maturation (IVM).

Progesterone replacement with vaginal gel versus i.m. injection: cycle and pregnancy outcomes in IVF patients receiving vitrified blastocysts.

Study Question: Does the type of luteal support affect pregnancy outcomes in recipients of vitrified blastocysts?

Summary Answer: Luteal support with vaginal progesterone gel or i.m. progesterone (IMP) results in comparable implantation and pregnancy rates in IVF patients receiving vitrified blastocysts.

Cryopreservation of eggs.

Oocyte cryopreservation is playing an increasingly important role in the field of human infertility treatment. The ability to store viable oocytes for later use has given many women the option to delay childbearing in order to pursue other ventures in life, without the concern of losing the opportunity to have a family. Furthermore, oocyte cryopreservation is very valuable for diseased patients who have to undergo treatments that may compromise fertility.

Correlation between standard blastocyst morphology, euploidy and implantation: an observational study in two centers involving 956 screened blastocysts.

Study Question: Does conventional blastocyst morphological evaluation correlate with euploidy (as assessed by comprehensive chromosome screening (CCS) of trophectoderm (TE) biopsies) and implantation potential?

Summary Answer: A moderate relation between blastocyst morphology and CCS data was observed but the ability to implant seems to be mainly determined by the chromosomal complement of preimplantation embryos rather than developmental and morphological parameters conventionally used for blastocyst evaluation.

What Is Known Already: Combined with improving methods for cryopreservation and blastocyst culture, TE biopsy and CCS is considered to be a promising approach to select euploid embryos for transfer. Understanding the role of morphology in blastocyst stage preimplantation genetic screening (PGS) cycles may help in further optimizing the cycle management and clinical outcomes.

FISH reanalysis of inner cell mass and trophectoderm samples of previously array-CGH screened blastocysts shows high accuracy of diagnosis and no major diagnostic impact of mosaicism at the blastocyst stage.

Study Question: Does comprehensive chromosome screening (CCS) of cells sampled from the blastocyst trophectoderm (TE) accurately predict the chromosome complement of the inner cell mass (ICM)?

Summary Answer: Comprehensive chromosome screening of a TE sample is unlikely to be confounded by mosaicism and has the potential for high diagnostic accuracy.

What Is Known Already: The effectiveness of chromosome aneuploidy screening is limited by the technologies available and chromosome mosaicism in the embryo. Combined with improving methods for cryopreservation and blastocyst culture, TE biopsy and CCS is considered to be a promising approach to select diploid embryos for transfer.

Laboratory processing and intracytoplasmic sperm injection using epididymal and testicular spermatozoa: what can be done to improve outcomes?

There are two main reasons why sperm may be absent from semen. Obstructive azoospermia is the result of a blockage in the male reproductive tract; in this case, sperm are produced in the testicle but are trapped in the epididymis. Non-obstructive azoospermia is the result of severely impaired or non-existent sperm production.

Prospective controlled study to evaluate laboratory and clinical outcomes of oocyte vitrification obtained in in vitro fertilization patients aged 30 to 39 years.

Objective: To determine whether the process of oocyte vitrification affects oocyte viability in in vitro fertilization (IVF) patients between 30 and 39 years of age.

Design: Prospective controlled study.

Setting: Private IVF practice.

Oocyte cryopreservation for donor egg banking.

Oocyte donation is an efficient alternative to using own oocytes in IVF treatment for different indications. Unfortunately, 'traditional' (fresh) egg donations are challenged with inefficiency, difficulties of synchronization, very long waiting periods and lack of quarantine measures. Given the recent improvements in the efficiency of oocyte cryopreservation, it is reasonable to examine if egg donation through oocyte cryopreservation has merits.

Preimplantation genetic screening: does it help or hinder IVF treatment and what is the role of the embryo?

Despite an ongoing debate over its efficacy, preimplantation genetic screening (PGS) is increasingly being used to detect numerical chromosomal abnormalities in embryos to improve implantation rates after IVF. The main indications for the use of PGS in IVF treatments include advanced maternal age, repeated implantation failure, and recurrent pregnancy loss. The success of PGS is highly dependent on technical competence, embryo culture quality, and the presence of mosaicism in preimplantation embryos.

Cryopreservation of oocytes in experimental models.

Until recently, success in oocyte cryopreservation has been very limited mainly due to poor understanding of the complex physiological processes that lead to cell damage during cryopreservation. In the past three decades, however, a wealth of information has been collected using various different animal models, which has led to development of new technologies and optimization of existing ones. The use of these models has provided the opportunity for research that may not have been possible with human material.

Impact of phase transition on the mouse oocyte spindle during vitrification.

During vitrification, the glass-like solidification is the phase-transition process from liquid to solid. Phase transition is one of the major factors suspected to affect the physiology of the oocyte, such as the structure of the meiotic spindle. Therefore, it is very important to investigate the systematic and morphological alterations of the metaphase-II spindle and chromosome arrangement during complete course of a vitrification and warming process.

Efficient derivation of embryonic stem cells from nuclear transfer and parthenogenetic embryos derived from cryopreserved oocytes.

Deriving histocompatible embryonic stem (ES) cells by somatic cell nuclear transfer (SCNT) and parthenogenetic activation (PA) requires fresh oocytes, which prevents their applications in humans. Here, we evaluated the efficiency of deriving ES cells from mature metaphase II (MII) and immature metaphase I (MI) vitrified oocytes, by PA or SCNT, in a mouse model. We successfully generated ES cell lines from PA (MII and MI) and SCNT (MII and MI) blastocysts.

Oocyte cryopreservation: is it time to remove its experimental label?

As more reproductive-age women survive cancer at the expense of gonadotoxic therapy, the need for viable fertility preservation options has become paramount. Embryo cryopreservation, often using donor sperm, has been the standard offered these women over the past 20 years. Preservation of unfertilized oocytes now represents an acceptable and often equally viable alternative, particularly for single women, due to technologic advances made in the past decade.