Study protocol: E-freeze - freezing of embryos in assisted conception: a randomised controlled trial evaluating the clinical and cost effectiveness of a policy of freezing embryos followed by thawed frozen embryo transfer compared with a policy of fresh embryo transfer, in women undergoing in vitro fertilisation.

BACKGROUND: Infertility affects one in seven couples; many of these need in vitro fertilisation (IVF). IVF involves external hormones to stimulate a woman's ovaries to produce eggs which are harvested surgically. Embryos, created in the laboratory by mixing eggs with sperm, are grown in culture for a few days before being replaced within the uterus (fresh embryo transfer). Spare embryos are usually frozen with a view to transfer at a later point in time - especially if the initial fresh transfer does not result in a pregnancy. Despite improvements in technology, IVF success rates remain low with an overall live birth rate of 25-30% per treatment. Additionally, there are concerns about health outcomes for mothers and babies conceived through IVF, particularly after fresh embryo transfer, including maternal ovarian hyperstimulation syndrome (OHSS) and preterm delivery. It is believed that high levels of hormones during ovarian stimulation could create a relatively hostile environment for embryo implantation whilst increasing the risk of OHSS. It has been suggested that freezing all embryos with the intention of thawing and replacing them within the uterus at a later stage (thawed frozen embryo transfer) instead of fresh embryo transfer, may lead to improved pregnancy rates and fewer complications. We aim to compare the clinical and cost effectiveness of fresh and thawed frozen embryo transfer, with the primary aim of identifying any difference in the chance of having a healthy baby. METHODS: E-Freeze is a pragmatic, multicentre two-arm parallel group randomised controlled trial where women aged ≥18 and < 42 years, with at least three good quality embryos are randomly allocated to receive either a fresh or thawed frozen embryo transfer. The primary outcome is a healthy baby, defined as a term, singleton, live birth with appropriate weight for gestation. Cost effectiveness will be calculated from a healthcare and societal perspective. DISCUSSION: E-Freeze will determine the relative benefits of fresh and thawed frozen embryo transfer in terms of improving the chance of having a healthy baby. The results of this pragmatic study have the potential to be directly transferred to clinical practice. TRIAL REGISTRATION: ISRCTN registry: ISRCTN61225414 . Date assigned 29/12/2015.

Adjuncts in the IVF laboratory: where is the evidence for 'add-on' interventions?

Globally, IVF patients are routinely offered and charged for a selection of adjunct treatments and tests or 'add-ons' that they are told may improve their chance of a live birth, despite there being no clinical evidence supporting the efficacy of the add-on. Any new IVF technology claiming to improve live birth rates (LBR) should, in most cases, first be tested in an appropriate animal model, then in clinical trials, to ensure safety, and finally in a randomized controlled trial (RCT) to provide high-quality evidence that the procedure is safe and effective. Only then should the technique be considered as 'routine' and only when applied to the similar patient population as those studied in the RCT. Even then, further pediatric and long-term follow-up studies will need to be undertaken to examine the long-term safety of the procedure. Alarmingly, there are currently numerous examples where adjunct treatments are used in the absence of evidence-based medicine and often at an additional fee. In some cases, when RCTs have shown the technique to be ineffective, it is eventually withdrawn from the clinic. In this paper, we discuss some of the adjunct treatments currently being offered globally in IVF laboratories, including embryo glue and adherence compounds, sperm DNA fragmentation, time-lapse imaging, preimplantation genetic screening, mitochondria DNA load measurement and assisted hatching. We examine the evidence for their safety and efficacy in increasing LBRs. We conclude that robust studies are needed to confirm the safety and efficacy of any adjunct treatment or test before they are offered routinely to IVF patients.

Pronuclear transfer in human embryos to prevent transmission of mitochondrial DNA disease.

Mutations in mitochondrial DNA (mtDNA) are a common cause of genetic disease. Pathogenic mutations in mtDNA are detected in approximately 1 in 250 live births and at least 1 in 10,000 adults in the UK are affected by mtDNA disease. Treatment options for patients with mtDNA disease are extremely limited and are predominantly supportive in nature. Mitochondrial DNA is transmitted maternally and it has been proposed that nuclear transfer techniques may be an approach for the prevention of transmission of human mtDNA disease. Here we show that transfer of pronuclei between abnormally fertilized human zygotes results in minimal carry-over of donor zygote mtDNA and is compatible with onward development to the blastocyst stage in vitro. By optimizing the procedure we found the average level of carry-over after transfer of two pronuclei is less than 2.0%, with many of the embryos containing no detectable donor mtDNA. We believe that pronuclear transfer between zygotes, as well as the recently described metaphase II spindle transfer, has the potential to prevent the transmission of mtDNA disease in humans.

Elective Single Embryo Transfer: an update to UK Best Practice Guidelines.

A significant number of multiple pregnancies and births worldwide continue to occur following treatment with Assisted Reproductive Technologies (ARTs). Whilst efforts have been made to increase the proportion of elective single embryo transfer (eSET) cycles, the multiple pregnancy rate or MPR remains at a level that most consider unacceptable given the associated clinical risks to mothers and babies, and the additional costs associated with neonatal care of premature and low birth weight babies. Northern Europe, Australia and Japan have continued to lead the way in the adoption of eSET. Randomised controlled trials or RCTs, meta-analyses and economic analyses support the implementation of an eSET policy, particularly in light of recent advances in ARTs. This paper provides a review of current evidence and an update to the eSET guidelines first published by Cutting et al. (2008) intended to assist ART clinics in the implementation of an effective eSET policy.

How should we choose the 'best' embryo? A commentary on behalf of the British Fertility Society and the Association of Clinical Embryologists.

Embryo selection to improve pregnancy rates remains a significant challenge in IVF. Non-invasive and invasive methods of embryo selection include morphological assessment, metabolomics, time-lapse imaging and preimplantation genetic screening. To date, none has been shown conclusively to yield improved implantation and live birth rates. This review summarises current understanding of methods for embryo selection.