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Fertility glossary

The 50 fertility terms that you need to know before starting your fertility journey

mother kissing her baby

Here at TFP, we know that whether you’re embarking on your first fertility journey or even just considering fertility treatments, it can be a daunting experience into the unknown. That’s why we are here to be your guide each and every step of the way.

TFP has over 30 years of experience working with patients just like you. So, believe us when we say we know how important it is for you to understand fertility treatments and terminology.

That’s why we have pulled together a list of the 50 fertility terms that you need to know, in one simple, easy to read fertility glossary.



A branch of medicine that specialises in men’s reproductive health.

Anti-mullerian hormone (AMH)

AMH is a blood test used for the assessment of ovarian reserve.

It can help to predict which patients may expect low or high egg numbers and identify patients at a higher risk of ovarian hyperstimulation syndrome (OHSS).

Antral follicle count (AFC)

AFC is an ultrasound scan study that measures ovarian reserve. The scan is performed on day 2-5 of your menstrual cycle. The number of antral follicles present in the ovaries will be counted. Antral follicles are the small sacs that contain the potential egg which develops in response to the drugs given during IVF treatment.

Assisted reproductive technology (ART)

Procedures that help fertilise an egg with sperm outside the body in the laboratory.


Slow-moving sperm (the male reproductive cell).


Absence of sperm in the ejaculate.


Balanced inversion

A chromosome abnormality where a piece of chromosome breaks off, turns over and re-attaches itself back to the same chromosome.

Balanced translocation

A chromosome abnormality where a piece of chromosome breaks off and re-attaches itself to a different chromosome.


A drug used in in vitro fertilisation (IVF) treatment that acts on the pituitary gland to down-regulate the body’s own reproductive hormones. These control the release of eggs from the ovaries and encourage favourable reaction to the other hormone drugs used in IVF treatment.


The early stage of an embryo that is five days old is referred to as a blastocyst. A blastocyst has a large number of cells and consists of two distinct cell types. Around 40% of embryos will reach the blastocyst stage and have a higher chance of implanting once transferred.

Blastocyst culture and transfer are usually recommended for patients with a good number of fertilised eggs, where it would be difficult to choose the best quality embryos at an earlier stage of development. Developing embryos to the blastocyst stage enables the best embryos to select themselves. This will be discussed with all patients on the day of egg collection and again on the day of fertilisation.


Cleaved embryo

A fertilised egg that has undergone cell division.

Corpus luteum

During ovulation, the follicle carrying the egg ruptures to release the egg, and the resulting structure is known as the corpus luteum. This is responsible for the production of progesterone, a vital hormone in pregnancy.

Culture medium

The fluid in which eggs and embryos are grown in the laboratory.


The jelly-like substance that surrounds the nucleus of a cell.


Donor treatment

A fertility treatment cycle using donated eggs, sperm or embryos.


Ectopic pregnancy

A pregnancy that develops outside a woman’s womb, commonly in the fallopian tubes.


When the woman’s egg is fertilised by the man’s sperm, an embryo is formed. The embryo then develops into the foetus.


The study of hormones.


A medical disorder where the type of cells that line the wall of the womb are also present outside the womb, either in the ovaries or elsewhere in the pelvis.


The lining of the womb.


A coiled tube at the back of the testicle that stores and carries the sperm.



A benign muscle growth in the wall of the womb.


The fluid-filled sac that contains the potential egg. These are counted and measured via an ultrasound scan during the stimulation phase of your IVF treatment cycle.

Follicle-stimulating hormone (FSH)

A hormone produced by the pituitary gland that stimulates the growth of egg follicles.



A hormone released by the pituitary gland which acts on the testes and ovaries to increase the production of sex hormones and to stimulate either the production of sperm or eggs. The two main gonadotropins are follicle-stimulating hormone (FSH) and luteinising hormone (LH).


Human chorionic gonadotrophin (HCG)

HCG is a hormone produced by the trophoblast cells that surround a growing embryo and eventually forms the placenta after implantation. The presence of HCG is detected as a positive test in some urine pregnancy tests (HCG pregnancy strip tests) and in the blood. During IVF treatment, HCG is injected to mature the egg follicles, usually 36 hours before egg collection.

Human menopausal gonadotrophin (HMG)

This is the general name for the drug used in IVF treatment to stimulate the growth of egg follicles. There are many different trade names (e.g. Puregon, Menopur, Gonal-F). They contain FSH alone or FSH and LH together.


Hysteroscopy is an operation in which a thin telescope is inserted through the neck of the womb and then into the cavity of the womb. Small polyps and fibroids can be removed by hysteroscopic surgery.


Intracytoplasmic sperm injection (ICSI)

A procedure to overcome low sperm count, motility or antisperm antibodies by injecting a single sperm into the egg.

In vitro

A Latin phrase, meaning “in glass”, referring to the test tube in which fertility treatments originally took place.



An investigation of the woman’s reproductive system using a thin telescope inserted through the navel while the patient is under general anaesthesia. Although no wider than a fountain pen, the telescope magnifies the surgeon’s view of the fallopian tubes, the ovaries and the uterus. This procedure is vital in diagnosing certain causes of infertility, such as blocked tubes, endometriosis or adhesions.

Lutenising hormone (LH)

Luteinising hormone is a hormone produced by the pituitary gland that controls ovulation. The ‘LH surge’ indicates that ovulation will occur in about 36 hours. The LH surge is stimulated by the increase in oestrogen in the blood created by the growing egg follicle.

Luteal phase support

These are the supportive drugs that you start taking after egg collection and continue with until after embryo transfer.



A drug that contains FSH and LH that stimulates the growth of follicles containing eggs.


Motility is how well sperm move. Low sperm motility can be the reason why some couples need help to conceive.


Nuchal test

A prenatal scan that can identify chromosomal abnormalities, such as Down Syndrome.



Low sperm count, with a high percentage of slow-moving and abnormal sperm.


Low sperm count.




A drug used to suppress ovulation.

Ovarian hyperstimulation syndrome (OHSS)

A potentially serious complication when fertility drugs are used and too many follicles develop in the ovaries. The symptoms include lower abdominal pain, swelling of the abdomen, nausea, vomiting and sometimes shortness of breath. Treatment involves bed rest with increased fluid intake. In rare cases, hospitalisation and intravenous fluids are required.

Ovarian reserve

Women are born with their lifetime supply of eggs in their ovaries. The ovarian reserve is a woman’s ‘store’ of eggs. Women’s eggs are gradually used up as they menstruate and age until very few eggs are left. Menopause then begins and periods will stop. The reserve of eggs falls particularly fast in women over the age of 40, reducing their fertility.


Polycystic ovarian syndrome (PCOS)

PCOS is a common condition that affects ovarian function. PCOS affects millions of women in the UK. Symptoms include irregular periods, facial hair and difficulty getting pregnant.

The three main features of the condition are:

1. Your ovaries do not regularly release eggs (ovulate), and you have irregular periods.

2. Having high levels of “male hormones” called androgens in your body, which may cause an excess facial or body hair

3. Your ovaries become enlarged and contain several fluid-filled sacs (follicles) that contain the potential eggs.

You will usually be diagnosed with PCOS if you have at least two of these features.


A benign growth of the lining of the womb (endometrium). If large, it could potentially affect the chances of implantation of the embryo.


Progesterone is a hormone secreted in the body that helps to prepare the uterus for the implantation of the embryo. Progesterone levels can be measured in the bloodstream and show a marked increase after ovulation has occurred.



The release of several eggs from the ovary as a result of fertility treatment.



High levels of sperm of abnormal shape and structure.



Ultrasound is modern diagnostic equipment that works by aiming ultrasonic sound waves and displaying visual interpretation of the echoes on a screen. Vaginal ultrasound is an internal use of this equipment to provide a clear view of the womb and ovaries including follicles. Ultrasound is also used in pregnancy to provide a diagnostic picture of the foetus.


Vas deferens

The tube in the male reproductive system that transports sperm from the epididymis to the ejaculatory duct in anticipation of ejaculation.


The rapid freezing and storage of eggs and embryos at -196 degrees celsius.

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