When you’re going through IVF – or any fertility treatment for that matter – it can be hard to know what all those abbreviations, acronyms and long, complicated medical words around in vitro procedures really mean ?


As if you don’t have enough going on without feeling the need to become a medical encyclopedia!

So, here they are, broken down into the essential, need-to-know definitions, so you can feel confident you know exactly what your GP or specialist is going on about.

(Sorry, we know some of them might seem a bit obvious…)

Here is A-Z the list of most common IVF treatment definitions:

AI (Artificial Insemination)

Inserting sperm into your uterus, without having sex, in order to try and get pregnant.

More like this

AMH (Anti-Mullerian Hormone)

You'll hear people talking a lot about this protein hormone, as you're often tested to check your levels of it during infertility investigations.

You can have the test at any stage in your cycle: how much of the hormone you have can show whether or not your body will react well to fertility drugs for IVF treatment – it also gives docs that all-important look into your ovarian egg reserve.

Ideally, you want an AMH Level of 6 - 24, but don't be disheartened if you have low (or high) levels, as MFM mum Kymbo rightly points out...

"Ithilwenn has a lower AMH level then me but had a really amazing response to [IVF] drugs. Everyone is different. Please do not give up hope, cos your time will come!"

(If in any doubt, speak to your fertility specialist or GP).


This is the small vial liquid fertility drugs you use to inject yourself may be packaged in.

ART (Assisted Reproductive Technologies)

Sadly, not a creative form of therapy, but the umbrella term used to describe infertility treatments like IVF, which require both the egg and the sperm to be handled.

ASH (Assisted Hatching)

A complex procedure to assist the IVF process, when previous attempts have been unsuccessful, or it's looking like there's a slim chance of it ever working.

It allows a fertilised embryo to ‘hatch’ from a layer of cells called the zona pellucida in the 4th day of its development, by creating a small hole in the layer – ‘hatching’ from these cells is how embryos attach to the uterus walls.


Azoospermia is the medical term for an infertility condition in men, when there's no sperm present in the semen.

BBT (Basal Body Temperature)

Your body’s natural temperature when you’re rested – tracking this can be used as a way of tracking when you’re at your most fertile, as ovulation can cause a slight increase in temp.

Biochemical Pregnancy

The medical term used to describe a very early miscarriage, which usually happens in the 1st couple weeks after you've had your embryo transferred to the womb ?


The term for the early stage of an embryo, 5 days after fertilisation. The inner cells will become the foetus, and the outer cells go on to form the placenta. Before this, it would usually be called a zygote.


Buserelin is a synthetic hormone drug, used to 'switch off' your ovaries at the start of the IVF procedure (before starting it up again with different drugs).

Usually, Buserelin will be given in either an injection form (which you learn to do yourself, from home), or you can take it in the form of a nasal spray.

Chemical Pregnancy

Another term to describe a very early miscarriage, which occurs 1 - 2 weeks after you've had your embryos transferred to your womb ?

Clinical Pregnancy

This sounds a bit scary, right? But actually it's just describing a pregnancy that’s been confirmed by 2 things: an ultrasound showing either a heartbeat or gestational sac, and high levels of the pregnancy hormone HCG.


A fertility drug that stimulates the ovaries – read more about what Clomid does.

COS (Controlled Ovarian Stimulation)

The process of stimulating ovulation using fertility drugs (such as Clomid, Metformin).


Freezing cells or tissue in order to keep it preserved for the future – so, the fancy term for ‘freezing' when you're talking about freezing your eggs or embryos.

DI (Donor Insemination)

Using sperm from a sperm donor in order to get pregnant. This can be used in IUI, but also IVF and other fertility treatment options. Read more about DI options here.

Donor Egg Cycle

A calendar for the IVF cycle which is taking place with donor eggs.

Down Regulation

This term's important when it comes to the process of IVF - as it describes one of the first things that'll happen.

Your specialist will 'switch off' your ovaries, so to speak, by using a drug. Of course, they'll start things back up again with a series of fertility drugs after.

You might hear this being called 'down regging', and you may also hear the phrase 'down regulation cycle'.

Ectopic Pregnancy

The medical term for when your baby grows outside of the womb, instead of inside. Most ectopic pregnancies occur in the fallopian tubes, but can also take place outside of the reproductive system altogether.

It's truly gut-wrenching, heart-breaking stuff, but it's important to know that it's also a life-threatening condition. Please do read more about ectopic pregnancy here.

Egg Collection/Retrieval

A simple, surgical procedure to gather your eggs for treatment. It can either be called a 'collection' or a 'retrieval' - it's still the same thing ?


Your baby in the very early stages of its development – 2 - 8 weeks after fertilisation takes place. Prior to this, the embryo is called a blastocyst, and before that, a zygote.

Embryo Transfer

The final stage of IVF treatment, and the last op, where your embryos are placed back into your uterus, after an assisted reproduction technique (ART) has taken place.


This is a medical condition which can affect women, where tissue meant to grow inside the womb can grow elsewhere – often in the ovaries or fallopian tubes. As a result, you'll often hear the illness being linked to infertility issues.

Fallopian Tubes

The bit of the female body where the egg travels from the ovaries, to the uterus.


The joining of your egg and your partner's sperm, where the combination of both of your different genes takes place.

FET (Frozen Embryo Transfer)

Embryos are placed into your uterus, just like during the Embryo Transfer. Though in this case, the embryos will be thawed, after previously being frozen.


Follicles are small sacs with fluid inside that sit on your ovaries. There's an immature egg inside each follicle, which grows and reaches it's peak growth around the time of ovulation.

Your follicle count may be checked during the TTC/IVF process.


A slang term for follicles, which you'll often see in online forums.

FSH (Follicle-Stimulating Hormone)

A hormone produced by your Pituitary Gland, which regulates your menstrual cycle. For men, FSH helps manage sperm production.

Just like the AMH levels, your FSH will often be tested during initial infertility tests – as it can determine whether or not egg reserves or sperm count is low, giving you an indicator of how your treatment will progress.


A cell that fuses with another cell during fertilisation. These two cells carry the genetic info that makes up a person – including chromosomal info.

GIFT (Gamete IntraFallopian Transfer)

An infertility treatment where your eggs are removed from the ovaries, and placed inside the fallopian tubes, along with male sperm, in order to get pregnant.

You can learn more about GIFT, its success rates and NHS availability here.

GS (Gestational Surrogacy)

Surrogacy describes the process of another woman carrying your baby. It’s a really sensitive and complicated subject – one we've covered in more detail here.

HCG (Human Chorionic Gonadotropin)

HCG is a hormone created by the placenta – this is the hormone detected by some pregnancy tests.

You'll hear a lot about this hormone on your IVF journey, and will be given an injection of it before your egg collection procedure.


An op that allows your doctor to see inside your uterus, mostly in cases of abnormal bleeding. You may need this test if you're having infertility problems investigated.

ICSI (Intracytoplasmic Sperm Injection)

When a lone, high-quality sperm is injected straight into your egg during IVF, rather than allowing the sperm and egg to find one another in the dish.


A very early stage in pregnancy, where the blastocyst (early embryo) is attaching to the wall of your uterus. You may experience implantation bleeding 1 – 2 weeks after conception. You can learn more about implantation bleeding here.

In Vitro

This Latin term refers to any medical process that takes place outside of a human body, for example in a test tube or petri dish.

In Vivo

In Vivo means the opposite. It refers to any process taking place inside the organism.

IVF (In Vitro Fertilisation)

An egg being fertilised by sperm outside the body.

IVM (In Vitro Maturation)

This is the same process as IVF, though the eggs that are collected to be fertilised outside of the body are not fully matured – they will be matured in a lab before IVF takes place.

You can learn more about IVM, success rates and NHS availability here.


A surgical op which allows doctors to look at the organs in the abdomen and pelvic region – including the ovaries, uterus and fallopian tubes.

It's also performed during infertility treatments like GIFT and ZIFT, when eggs are placed back into the fallopian tubes.

LH (Luteinising Hormone)

Similar to FSH, this is a hormone produced by the Pituitary Gland, that monitors your ovaries, and for men, monitors their testes.

LP (Luteal Phase)

This is the part of your menstrual cycle where your uterus lining thickens in order to prepare for pregnancy, which happens after your ovaries have already released an egg.

MAR (Medically Assisted Reproduction)

Another term for Assisted Reproductive Technologies (ART). Basically, where science steps in to help you get pregnant.


A similar drug to Clomid and Metformin, given that they all do the same thing - stimulate the ovaries to help produce eggs. The drug contains HCG.


A common fertility drug designed to stimulate the ovaries for egg production and regular periods – you can read more about what Metformin does here.

Mild Stimulation IVF

The IVF procedure - but with a smaller dose of fertility-boosting drugs. Literally, it means your body is only being mildly stimulated, rather than going the full whack.


The general name for the drug Synarel, which is often used to treatm endometriosis. Usually, you take it via a nasal spray.

Natural Cycle IVF

Again, the IVF procedure – but without use of fertility drugs to stop the natural production of eggs. It's all done to your natural menstrual cycle.


The female hormone you have that’s responsible for looking after your reproductive system. It's closely linked to how we feel emotionally, too, and can play a part in causing PMS symptoms ? Sometimes, you'll see it spelled as 'estrogen'.

OHSS (Ovarian Hyperstimulation Syndrome)

This is a potential complication of fertility drugs which affects the ovaries, that can occasionally become quite serious.

It's not majorly common, and you don't need to panic. Especially since your specialist will be aware of the risks - if you need more info, speak to your medical professional.


An egg cell – which after undergoing meiotic division (think back to your school biology lessons ?) can become a fully-fledged ovum.


Another term for one of your eggs.


To keep this one brief, it's a small device (that can come in several different forms) which is placed in your you-know-where as a support system to your uterus. Again, your doc will fully explain how it works if you're in need of one.


The brand name for one of the injections you receive during IVF treatment - the HCG shot.


A pregnancy hormone which assists in stimulating the uterus.


The hormone responsible for you producing milk after giving birth, which comes from the Pituitary Gland.


Many women who undergo IVF or similarly IUI treatments may be asked to 'sniff', i.e. inhale through the nostrils into the nasal passages, certain fertility drugs, such as Synarel.


This surprisingly amusing word is the full name for ‘sperm’ – the male sex cell which fertilises the egg.

Sperm Washing

The official term for separating individual sperm from semen. This usually takes place after the woman has had her eggs collected during IVF/ICSI treatment.


Brand name for Nafarelin, an endometriosis-treating drug often taken as a nasal spray.

TESA (Testicular Epididymal Sperm Aspiration)

A simple procedure where sperm is aspirated from the testicles using a needle. Your partner may have this done to them when their sperm doesn’t come out during ejaculation, or they've previously had a vasectomy.

TESE (Testicular Epididymal Sperm Extraction)

A surgical procedure where sperm is extracted from the testicles – unlike with aspiration, this involves a small incision in the testicles and is done in a hospital. The reasons for this procedure are the same as TESA.

Tubal Patency Test

Also known as HyCoSy, or Fallopian Tube Patency Test, this infertility test uses an x-ray examination to determine if your fallopian tubes are blocked or damaged in any way, and are the cause of your fertility issues.


The sex organ where your baby will be carried. ‘Uterus’ and ‘womb’ both refer to the same organ.


In IVF, vitrification refers to a type of cryopreservation (freezing) of embryos. Vitrification is 'ultra-rapid freezing' (so, in plain speak, very quick freezing), which differs to the traditionally-used process of slow-freezing.

It's thought this method provides higher chance of your pregnancy taking, once the embryos have been thawed.

ZIFT (Zygote Intrafallopian Transfer)

A similar procedure to GIFT. Your are removed from the ovaries, but they are fertilised in a lab (via IVF) before being placed inside your fallopian tubes via a laparoscopy procedure.


The cell created by the joining of the sperm and the ovum. It’s the result of fertilisation, and will eventually become a fully-fledged embryo.

Are we missing anything?

Let us know which words and abbreviations you’d like us to include for women and men on the TTC journey by reaching out in the comments below, or on Facebook.

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