Recurrent implantation failure refers to failure to achieve a clinical pregnancy after transfer of at least four good-quality embryos in a minimum of three fresh or frozen cycles in a woman under the age of 40 years. The failure to implant may be a consequence of embryo or uterine factors. Thorough investigations should be carried out to ascertain whether there is any underlying cause of the condition. Ovarian function should be assessed by measurement of antral follicle count, FSH and anti-Mu¨llerian hormone. Increased sperm DNA fragmentation may be a contributory cause. Various uterine pathology including fibroids, endometrial polyps, congenital anomalies and intrauterine adhesions should be excluded by ultrasonography and hysteroscopy. Hydrosalpinges are a recognized cause of implantation failure and should be excluded by hysterosalpingogram; if necessary, laparoscopy should be performed to confirm or refute the diagnosis. Treatment offered should be evidence based, aimed at improving embryo quality or endometrial receptivity. Gamete donation or surrogacy may be necessary if there is no realistic chance of success with further IVF attempts.

Obesity may have an adverse effect on the outcome of IVF/intracytoplasmic sperm injection (ICSI) treatment. In this study, the effects of increased body mass index (BMI) on oocyte and embryo quality during IVF cycles were studied. A retrospective analysis of 426 IVF/ICSI cycles was performed. Cycles were classified according to the BMI: normal BMI (19-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)) and obese (> or = 30 kg/m(2)). Cycles were further stratified based on age (group 1, < 35 years; group 2, > or = 35 years). Markers of oocyte quality (number of oocytes inseminated and fertilization rate) and embryo quality (utilization rate, number of embryos discarded and cryopreserved, and mean embryo grade) were examined. In group 1, obesity had a significant adverse effect on the mean embryo grade (P = 0.02), the embryo utilization rate (P = 0.01), number of embryos discarded (P = 0.007) and cryopreserved (P < 0.05). In group 2, there was no difference in markers of embryo quality between the three BMI ranks. Obesity did not have any significant effect on markers of oocyte quality or clinical pregnancy rates. In conclusion, obesity may adversely affect embryo quality in young women (<35 years) undergoing IVF/ICSI, while the oocyte quality is not affected.

Assisted conception treatment is the single most important cause in the increase in multiple pregnancy and births over the last 25 years. Multiple births are associated with significant peri natal morbidity and mortality. Europe has led the way in reducing multiple births by widespread adoption of an elective single embryo policy, which in Belgium is linked to an increase in state funding. Randomized controlled trials suggest that an eSET policy must include the ability to cryopreserve and transfer any remaining quality embryos to obtain parity with a double embryo transfer. This document provides a review of the available evidence with guidelines for practice, to help facilitate the introduction of an eSET policy in the UK.

Summary Background Sperm selection strategies aimed at improving success rates of intracytoplasmic sperm injection (ICSI) include binding to hyaluronic acid (herein termed hyaluronan). Hyaluronan-selected sperm have reduced levels of DNA damage and aneuploidy. Use of hyaluronan-based sperm selection for ICSI (so-called physiological ICSI [PICSI]) is reported to reduce the proportion of pregnancies that end in miscarriage. However, the effect of PICSI on livebirth rates is uncertain. We aimed to investigate the efficacy of PICSI versus standard ICSI for improving livebirth rates among couples undergoing fertility treatment. Methods This parallel, two-group, randomised trial included couples undergoing an ICSI procedure with fresh embryo transfer at 16 assisted conception units in the UK. Eligible women (aged 18–43 years) had a body-mass index of 19–35 kg/m 2 and a follicle-stimulating hormone (FSH) concentration of 3·0–20·0 mIU/mL or, if no FSH measurement was available, an anti-müllerian hormone concentration of at least 1·5 pmol/L. Eligible men (aged 18–55 years) had not had a vasovasostomy or been treated for cancer in the 24 months before recruitment and were able, after at least 3 days of sexual abstinence, to produce freshly ejaculated sperm for the treatment cycle. Couples were randomly assigned (1:1) with an online system to receive either PICSI or a standard ICSI procedure. The primary outcome was full-term (≥37 weeks' gestational age) livebirth, which was assessed in all eligible couples who completed follow-up. This trial is registered, number ISRCTN99214271. Findings Between Feb 1, 2014, and Aug 31, 2016, 2772 couples were randomly assigned to receive PICSI (n=1387) or ICSI (n=1385), of whom 2752 (1381 in the PICSI group and 1371 in the ICSI group) were included in the primary analysis. The term livebirth rate did not differ significantly between PICSI (27·4% [379/1381]) and ICSI (25·2% [346/1371]) groups (odds ratio 1·12, 95% CI 0·95–1·34; p=0·18). There were 56 serious adverse events in total, including 31 in the PICSI group and 25 in the ICSI group; most were congenital abnormalities and none were attributed to treatment. Interpretation Compared with ICSI, PICSI does not significantly improve term livebirth rates. The wider use of PICSI, therefore, is not recommended at present. Funding National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

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