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IVF is an acronym for in vitro fertilization ('in vitro' meaning 'in glass'). Simply put IVF is adding a man's sperm to his female partners eggs in the laboratory to produce embryos. In vitro fertilization is an option for many couples who cannot conceive through conventional therapies. These embryos are put back into the female partner's uterus (womb) after 3 to 5 days of being in the incubator, hopefully they will then grow into a baby. The reasons IVF is done include - poor sperm quality and/or quantity, obstructions between the egg and sperm, ovulation problems, and [Read more.]

In short: The 2017 Vienna consensus, from ESHRE and Alpha Scientists in Reproductive Medicine, is the standard reference for IVF laboratory performance indicators. Covering fresh IVF and ICSI cycles, it defines 19 indicators: 12 key performance indicators (KPIs), five performance indicators (PIs) and two reference indicators (RIs). Each has a fixed formula, and most have a minimum "competency" and an aspirational "benchmark" value. The values are mainly expert opinion, so each laboratory should choose and adapt its own set. The 2021 Maribor consensus adds matching indicators for clinical work. [Read more.]

In short: Gametes and embryos in vitro depend entirely on the laboratory for temperature, pH, oxygen and osmolality. ESHRE good practice asks that temperature, pH and osmolality are kept appropriate, and that fluctuations are minimised. The evidence, though limited, favours culture at 37 °C and low oxygen, while pH targets should follow the medium manufacturer. Osmolality drifts through evaporation, so oil overlay, drop volume and incubator humidity matter. Independent, calibrated monitoring and alarms turn these principles into daily control. Why culture conditions matter Embryos in vitro f [Read more.]

In short: The sixth edition of the WHO semen manual was published in July 2021. It divides semen examination into basic, extended and advanced chapters, written as step-by-step procedures. Motility returns to four grades, separating rapid from slow progressive sperm. Total sperm number is emphasised over concentration. It gives 5th centile values from men whose partners conceived naturally within a year. It states that this is not a limit between fertile and infertile men. How the manual is organised The manual has three parts: semen examination (Chapters 2 to 4), sperm preparation and cryopr [Read more.]

In short: Denudation before ICSI is when the laboratory first sees each oocyte's nuclear maturity and morphology. The 2025 Istanbul consensus update found that most single dysmorphisms do not justify discarding an oocyte. Giant oocytes should be excluded, and oocytes with smooth endoplasmic reticulum aggregates (SER-a) may be considered case by case. A polar body alone does not prove maturity: only a visible metaphase II spindle confirms it. Gentle, brief denudation under stable temperature and pH protects the oocyte. Cumulus oocyte complex assessment From the embryologist's perspective, a go [Read more.]

In short: The fertilisation check confirms which oocytes have formed two pronuclei (2PN) and extruded the second polar body. The 2011 Istanbul consensus set the check at 17 ± 1 hpi. Its 2025 update moves it to 16 to 17 hpi for IVF and ICSI, to catch zygotes whose pronuclei break down early. It drops the term "0PN" for static checks and supports cautious use of selected 1PN zygotes, but not 3PN zygotes. Detailed pronuclear scoring has little proven predictive value. When to check, and why Pronuclei appear earlier after ICSI than after conventional IVF, because the injected sperm need not cros [Read more.]

In short: Cleavage-stage assessment rests on cell number, fragmentation, cell size and nucleation, recorded at set times after insemination. The expected picture is 4 cells on Day 2 and 8 on Day 3, with under 10% fragmentation and one nucleus per cell. The 2025 Istanbul consensus update keeps these anchors, adds time-lapse reference timings and proposes a ranking scheme. Most of the supporting evidence is observational and of low or very low certainty. When to look: timing in hpi The 2011 Istanbul consensus set static checks at 44 ± 1 hours post insemination (hpi) on Day 2 and 68 ± 1 hpi on [Read more.]

In short: Embryology essentials is a new IVF.net series of short, practical reference pages for clinical embryologists, andrologists and trainees. This first page previews the series and sets out an A to Z of the core terms used daily in the IVF laboratory. Definitions follow the published international consensus documents wherever possible.About this seriesEach page in this series is written by IVF.net from published consensus documents and guidance. The main sources are the International Glossary on Infertility and Fertility Care and the Istanbul consensus on embryo assessment, with its 2025 [Read more.]

In short: Most laboratories grade blastocysts with the Gardner system. It scores expansion from 1 to 6, and the inner cell mass (ICM) and trophectoderm (TE) as A, B or C. The 2011 Istanbul consensus set common terms and timings for embryo assessment. Its 2025 update now recommends the Gardner system outright, adds a grade D for non-viable blastocysts and accepts Day 7 blastocysts as potentially usable. In large studies of fresh Day 5 transfers, TE grade was the strongest morphological predictor of live birth, followed by expansion. The certainty of this evidence is low.What is assessedDavid Ga [Read more.]

From  1st September on a series of 39 wenibars designed to assist you in preparing your embryology exams and certifiaction are available  "ON DEMAND" You can view the records when you have time . Self-assessment questions are provided for nearly all webinars. REGISTER  HERE:  https://quartec.co/webinars Or contact us : [email protected] [Read more.]