Human reproduction update
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Human reproduction update · Jan 2019
Meta AnalysisFresh versus elective frozen embryo transfer in IVF/ICSI cycles: a systematic review and meta-analysis of reproductive outcomes.
Elective freezing of all good quality embryos and transfer in subsequent cycles, i.e. elective frozen embryo transfer (eFET), has recently increased significantly with the introduction of the GnRH agonist trigger protocol and improvements in cryo-techniques. The ongoing discussion focuses on whether eFET should be offered to the overall IVF population or only to specific subsets of patients. Until recently, the clinical usage of eFET was supported by only a few randomized controlled trials (RCT) and meta-analyses, suggesting that the eFET not only reduced ovarian hyperstimulation syndrome (OHSS), but also improved reproductive outcomes. However, the evidence is not unequivocal, and recent RCTs challenge the use of eFET for the general IVF population. ⋯ Although the use of eFET has steadily increased in recent years, a significant increase in LBR with eFET was solely noted in hyper-responders and in patients undergoing PGT-A. Concerning safety, eFET significantly decreases the risk of moderate and severe OHSS, albeit at the expense of an increased risk of pre-eclampsia.
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Human reproduction update · Mar 2018
Testicular organoids: a new model to study the testicular microenvironment in vitro?
In recent decades, a broad range of strategies have been applied to model the testicular microenvironment in vitro. These models have been utilized to study testicular physiology and development. However, a system that allows investigations into testicular organogenesis and its impact in the spermatogonial stem-cell (SSC) niche in vitro has not been developed yet. Recently, the creation of tissue-specific organ-like structures called organoids has resurged, helping researchers to answer scientific questions that previous in vitro models could not help to elucidate. So far, a small number of publications have concerned the generation of testicular organoids and their application in the field of reproductive medicine and biology. ⋯ By way of appropriate research questions, we might use testicular organoids to deepen our basic understanding of testicular development and the SSC niche, leading to new methodologies for male infertility treatment.
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Human reproduction update · Jan 2018
Review Meta AnalysisIs frozen embryo transfer better for mothers and babies? Can cumulative meta-analysis provide a definitive answer?
Initial observational studies and a systematic review published 5 years ago have suggested that obstetric and perinatal outcomes are better in offspring conceived following frozen rather than fresh embryo transfers, with reduced risks of preterm birth, small for gestational age, low birth weight and pre-eclampsia. More recent primary studies are beginning to challenge some of these findings. We therefore conducted an updated systematic review and cumulative meta-analysis to examine if these results have remained consistent over time. ⋯ The results of this cumulative meta-analysis confirm that the decreased risks of small for gestational age, low birth weight and preterm delivery and increased risks of large for gestational age and high birth weight associated with pregnancies conceived from frozen embryos have been consistent in terms of direction and magnitude of effect over several years, with increasing precision around the point estimates. Replication in a number of different populations has provided external validity for the results, for outcomes of birth weight and preterm delivery. Meanwhile, caution should be exercised about embarking on a policy of electively freezing all embryos in IVF as there are increased risks for large for gestational age babies and hypertensive disorders of pregnancy. Therefore, elective freezing should ideally be undertaken in specific cases such as ovarian hyperstimulation syndrome, fertility preservation or in the context of randomised trials.