What is a clinical embryologist?

By Rachel Cutting MBE, Principal Embryologist


The fascinating and complex science of reproductive biology forms the basics of a career in embryology. With at least one in six women needing assisted reproductive technology this area of medicine has grown rapidly since the birth of the world’s first IVF baby 40 years ago.

In Vitro Fertilisation (IVF) is a treatment option for those with a wide range of fertility issues, which may lead to an inability to conceive. The basis of the treatment involves placing eggs and sperm together in the laboratory, monitoring embryo development and selecting the healthiest embryo to be replaced into the women. Sperm, eggs and embryos can also be cryopreserved and stored for a variety of reasons.

Clinical embryologists work as part of a multidisciplinary team to help define appropriate treatment options, analyse diagnostic tests, and interpret embryological aspects of an IVF cycle. The role is very much patient facing and embryologists will give patients daily updates on their embryos, discuss sperm and embryo quality and help patients make decisions about their treatment. Communication and interpersonal skills are, therefore, very important as patients require much support through a cycle of treatment.

Good laboratory skills including meticulous attention to detail are required as the laboratory activities play a key part in a centres success rates. Embryologists require good hand eye coordination, have the ability to work under pressure, be able to concentrate, focus and have patience!



Sperm, oocytes and embryos require specific conditions to be able to survive outside the human body. Embryologists set up dishes, which contain culture media to support embryo development. The nutritional requirements of the pre-implantation embryo changes through development so a good understanding of which media is suitable for each stage is required.


Semen samples are analysed for their concentration and motility prior to centrifugation. Once prepared motility and concentration are reanalysed to assess which method of insemination is the most appropriate.


Oocytes (eggs) are collected by a clinician by aspirating fluid from the follicles. The fluid is observed under a microscope; oocytes are located and placed, after washing, in culture media.


Eggs are inseminated either by placing millions of motile sperm around the egg or when the sperm sample quality is sub-optimal sperm can be injected directly into the centre of the oocyte.
This method of insemination is called Intra-Cytoplasmic Sperm Injection (ICSI).


The following day from oocyte collection, eggs are assessed under a microscope to check for signs of fertilisation. A fertilised oocyte, a zygote, contains two pronuclei. Once fertilised the zygote will undergo successive cell divisions to form an embryo and a blastocyst (on day five). The embryologist will monitor the embryos development assessing daily the quality by noting cell number, cell shape and degree of fragmentation. Anomalies in embryo development are also recorded. Advances in technology now enable embryo development to be monitored in greater detail. Use of time-lapse incubators allows images for embryos to be taken every 10 minutes allowing in-depth analysis of embryo quality. This technology allows embryologists to understand the health and quality of an embryo, which aids selection of the best embryo for transfer.


Once the embryo with the highest chance of implanting is selected the embryologist will load the embryo into a catheter, which is passed to an operator who will feed the catheter through the cervix to the uterus where the embryo is deposited.


Sperm, oocytes and embryos can be cryopreserved and stored for future use either as part of an IVF cycle or for fertility preservation. Cryopreservation of oocytes and embryos is usually done by a process called vitrification and involves dehydration of the cells followed by rapid cooling. Timing is critical and the process is very technical to undertake. Cryobanks are carefully monitored and annual audits conducted to ensure samples are kept within the statutory consent period (currently 10 years).


If a cycle is unsuccessful or a patient wishes to try for a sibling, stored embryos can be rewarmed and transferred. The process involves placing the embryos in solutions to rehydrate the cells. Embryo quality is then monitored and assessed.


Some centres will carry out genetic testing of embryos. To do this an embryologist will perform a biopsy, usually at the blastocyst stage and send the biopsied cells to a genetic lab for testing. Genetic testing of embryo is called Pre-implantation Genetic Diagnosis (PGD) and is important in the prevention of disease. Couples who have or are carriers of a proven genetic disorder and wish to avoid the birth of an affected child undertake a cycle of IVF with genetic testing. An embryo which has no risk of the genetic disease is then selected for embryo transfer. Without PGD couples would have to decide whether to remain childless, conceive naturally and accept the risk or conceive naturally and undergo post-conception testing. If the fetus is found to have the genetic condition the difficult decision of whether to have a termination of pregnancy has to be made.


Maintaining high standards within the laboratory is a priority of an embryologist and a proportion of the role is dedicated to quality management. Quality Assurance (QA) and Quality Control (QC) are a fundamental part of everyday working in the laboratory. All critical equipment is monitored, audits are conducted and key performance indicators adhered to. Embryologists participate in quality assurance by undertaking external and internal QA.

An example of external QA is the NEQAS scheme where every quarter concentration, motility and morphology counts are submitted to compare performance on a national level. Maintaining accurate and detailed patient records is essential especially with respect to witnessing procedures.


Alongside quality management is compliance with respect to regulation. The UK sector is regulated by the Human Fertilisation and Embryology Authority (HFEA). The HFEA licences, monitors and inspects centres. Embryologists must adhere to the HFEA Code of Practice and ensure data required is submitted in a timely manner. As most centres have an electronic patient management system good IT skills are required.


With a strong interest in biology embryologists will need a science degree in biology or biomedicine and to gain registration as a clinical scientist with the Health and Care Professions Council (HCPC) will have to undergo the three years Scientific Training Programme (STP) to gain a masters degree in Reproductive Science. The STP is a full time salaried workplace-based training programme and involves short rotations through other departments such as genetics in the first year and occasional attendance at a university for the masters element.

Embryologists participate in Continual Professional Development (CPD) to ensure registration is maintained and current best practice is adhered to. CDP often involves attending and presenting at conferences or self-directed learning.


Many embryologists will have specific areas of responsibility such as involvement in a research project, data analysis, managing donor sperm recruitment or managing the cryopreserved material. Roles can be varied and embryologist are encouraged to develop their roles. In a more senior role embryologists are responsible for training, defining budgets and strategic planning. Analysis of data to assess performance is frequently undertaken as is problem solving and troubleshooting when required.

Embryologists are employed in either the independent or public sector. Working patterns often need to be flexible as weekend work and on call for alarms is required. The role and responsibilities of an embryologist can be immensely challenging, but it is also a hugely rewarding field of medicine to be involved in.


Rachel Cutting MBE, Principal Embryologist, www.jessopfertility.org.uk

Juliana Kassianos