A

• Abandoned cycle: An IVF or ICSI treatment cycle which is cancelled after ovarian stimulation has begun but before egg collection.
• Abstinence: The number of days since last ejaculation.
• Adhesions: Scar tissue which forms following surgery, infection or trauma and which causes pelvic organs to stick together. 
• Anosmia: Inability to smell, may be associate with some azoospermic conditions
• Antisperm antibodies: The immune system of some patients may recognise sperm as ‘foreign’ cells and produce antibodies against them. If this happens the antibodies can coat the outside of the sperm which may prevent the sperm from attaching to the egg and therefore inhibit fertilisation.
• Assisted hatching: A technique used to help the embryo escape from its zona pellucida (shell). An embryo needs to hatch before implantation can occur.
• Asthenozoospermia: Terminology used to describe subfertility where sperm have reduced motility (movement): less than 50% motile sperm or with sperm showing slow progression.
• Azoospermia: The disorder where the ejaculated semen does not contain any sperm cells; this may be due to a blockage obstructive azoospermia or a failure in production of the sperm.

B

• Blastocyst: the stage at which the cells of the embryo differentiate into the trophectoderm cells and the inner cell mass and the formation of a blastocoelic cavity.  Blastocyst formation occurs at about day 5 of development. 

C

• Cervix: A narrow passage connecting the vagina to the womb (uterus)
• Chromosomes: Chromosomes are thread-like bodies of DNA which contain the genetic code in genes. Half of the chromosomes will be inherited from the mother and the other half from the father.
• Chlamydia: A sexually transmitted disease that may affect both males and females; there may be few symptoms and if left untreated the disease can often lead to infertility.
• Cleavage: Cell division in early embryos necessary for development
• Clomiphene: An anti-oestrogen drug that helps to stimulate the production of follicles, often used to treat anovulation and in DI and IUI cycles.
• Congenital malformations: Malformations seen at birth (birth defects) due to inherited or environmental causes.
• Counselling: Couples seeking fertility sometimes require emotional support to help them through what can be a difficult time. A counsellor will help couples to understand the implications of treatment and its consequences.
• Cryopreservation: Embryos, sperm and oocytes (only offered by some clinics) can be frozen and stored in liquid nitrogen at minus 196 degrees centigrade for use at a later date. They are passed through a series of specially designed solutions which help to protect the cells from damage during the freezing process.

D

• DI – Donor Insemination: Donor sperm is introduced into the cervix or uterus using a catheter. It may be used to treat couples where the male partner is unable to produce his own sperm, single sex couples, or single women.
• Donated embryos: Embryo donation provides a chance for couples for whom no treatment is available to help them. Fertility is an issue for both partners; hence the only chance of a pregnancy is through embryo donation.
• Donated oocytes: If a woman is unable to produce oocytes of her own, or is producing oocytes of poor quality, it may be possible to use oocytes that have been donated from another fertile woman.
• Donated sperm: Semen is donated by a sperm donor and frozen at a sperm banking facility.  It may then be used to treat couples when the male partner is unable to produce sperm. Donor sperm may also be used to treat single women or same-sex couples.
• Donor: A person or couple who chooses to provide their oocytes, sperm or embryos for use by others. All UK donors must be screened for known infectious diseases, and have no legal right or obligation to any child born as a result of treatment given in a UK licensed clinic.  Additionally UK donors do not have a legal right to anonymity and may potentially be contacted by offspring once they reach eighteen years of age.

E

• Ectopic pregnancy: Where a pregnancy occurs outside the uterus, usually in the fallopian tubes, and may occur both in natural pregnancies and those following assisted conception.
• Egg (oocyte): The gamete produced in the ovary of a woman, generally one egg is made each monthly cycle
• Egg donor: A woman who donates her eggs for the treatment of others.
• Ejaculation: The release of seminal fluid at orgasm, following sexual arousal.
• Embryo: An embryo is formed following successful fertilisation of an egg by a sperm, which then subsequently divides to form the individual cells which make up the embryo.
• Embryo grading: In the laboratory embryos can be ‘graded’ according to their appearance. The number, shape and symmetry of the cells and any fragmentation is assessed and compared to the expected stage of development; this may give an indication of embryo quality and the potential of an embryo to develop into a pregnancy.
• Embryo transfer: Procedure of replacing embryo(s) in the uterus
• Endometriosis: A condition in which small parts of endometrium, which usually provides the lining of the womb, grow in other places within the pelvic cavity. The severity of endometriosis varies depending upon the areas and amount of endometrial growth; it can cause bleeding, pelvic pain and problems with fertility.
• Endometrium: The lining of the womb which develops each month ready to receive the implanting embryo, but shed in a period if no implantation occurs.
• Epididymis: sperm storage and transport tube in the testis

F

• Fallopian tubes (Oviducts): The fallopian tubes connect together the ovaries and the uterus. In a natural cycle this is where the sperm and egg meet and fertilisation occurs.
• Fertilisation: Occurs when an egg and sperm meet successfully to form a zygote, the stage before an embryo. 
• Folic Acid: A dietary supplement that is advisable for women planning a pregnancy and those in the early stages of pregnancy that helps to reduce the chances of neural tube defects such as spina bifida.
• Follicles: The small fluid filled sacs that develop on the ovaries and usually contain eggs.
• FSH - Follicle Stimulating Hormone: A hormone produced by the Pituitary Gland in the brain that stimulates the production of follicles containing eggs on the ovaries. The drugs that are given during IVF and ICSI cycles to stimulate the production of lots of eggs contain FSH.

G

• Gamete: A Gamete is the generic term used to describe the male and female sex cells i.e. the sperm and the egg.

H

• HFEA - Human Fertilisation and Embryology Authority: The HFEA is a body that was set up in 1991 following the 1990 Act of Parliament to regulate all assisted conception procedures in the United Kingdom. All clinics providing assisted conception treatments in UK are inspected and licensed by the HFEA and must work within the HFEA Code of Practice.
• Hormone profile: A blood test used to measure the levels of certain hormones in the blood that are related to reproductive function.
• Hysterosalpingogram: A diagnostic procedure used to assess whether the fallopian tubes are blocked or open. A dye is injected into the tubes, this dye can then be picked up on an x-ray and will show whether the tubes are patent (open).

I

• ICSI – Intra-Cytoplasmic Sperm Injection: An individual sperm is injected directly into the middle of an egg using a sophisticated microscope and micromanipulation tools. This procedure may increase the chances of fertilisation occurring in cases of male factor infertility.   It may also be used in cases which have had a previous failure to fertilise with conventional IVF, without any previous apparent sperm problem.
• Implantation: occurs when an embryo attaches to the endometrium, or lining of the womb.
• Inner cell mass: The area of cells inside a blastocyst that will go on to form the foetus.
• Insemination: the introduction of sperm in the proximity of the oocyte/s (eggs)
• IUI – Intra-Uterine Insemination: A small volume of sperm sample that has been prepared in the laboratory is introduced into the uterus through the cervix using a fine catheter (tube)
• In vitro: Literally meaning ‘In-Glass’ or in the laboratory.
• In vivo: Meaning inside the body.
• IVF – In Vitro Fertilisation: Mixing of eggs and sperm to achieve fertilisation outside the body.

J

K

• Karyotype: microscopic image of a set of chromosomes so their number and size can be checked.

L

• Laparoscopy: A surgical procedure in which a telescopic camera (laparoscope) is passed through a small incision in the navel to look at the pelvic organs; may be used to investigate causes of infertility.
• LH – Luteinising Hormone: LH is involved both in egg and sperm production. In women it helps the developing egg to ripen and reach the right stage of maturity for fertilisation to occur and be released. In men it stimulates the testicles to produce testosterone. A sharp rise in LH is detected in ovulation prediction tests.
• Live birth rates: The number of live births per 100 treatment cycles.

M

• Male factor: Impaired fertility of the male partner due to abnormalities of the semen or sperm, or a physical problem that interferes with delivery of the sperm to the female reproductive tract.  Problems associated with sperm may include the absence of sperm or low sperm concentration, high levels of abnormal sperm, poor motility or progression, anti-sperm antibodies.  Physical problems may be caused by a variety reasons including, Cystic Fibrosis (congenital absence of the Vas Deferens), impotence, obstructions (blockages) present in the testes, post-vasectomy or failed vasectomy reversal, psychosexual, retrograde ejaculation, spinal cord injury leading to ejaculation failure.
• Morphology: Most often used to describe the shape of sperm but can also be used to describe the appearance of the cells within an embryo.
• Motility: A term used in semen analysis to describe the movement of sperm. The percentage of sperm swimming is assessed and the speed with which they are progressing is measured.
• Multiple pregnancy: A pregnancy in which there is more than one foetus developing. Fertility treatment may result in a multiple pregnancy if more than one embryo is transferred or if more than one follicle develops during ovulation induction.

N

• Nucleus: Part of a cell which contains the chromosomes and which controls most of the activities of the cell.

O

• Oestradiol (Oetrogen): The female sex hormone that is produced by the ovaries.
• OHSS – Ovarian Hyperstimulation Syndrome: The drugs that are given to stimulate the production of eggs for a treatment cycle, although carefully prescribed, may occasionally cause the complication of OHSS. This is where too many follicles and eggs are produced and may mean that a cycle has to be abandoned until symptoms subside, or if the egg collection proceeds, the embryos may all be frozen until the ovaries have recovered and it is safe to continue treatment.
• Oligozoospermia: Terminology for a condition when the semen sample has a reduced concentration of sperm; the count is less than 20 million sperm per milliliter of ejaculate.
• Ongoing pregnancy: Refers to those pregnancies confirmed by ultrasound scan
• Oocyte (egg): The gamete produced in a woman’s ovaries; generally one egg is made each monthly cycle
• Oocyte collection (retrieval): Minor surgical procedure to collect the oocytes produced by the ovaries (usually after ovarian stimulation). Mostly done using ultrasound to visualise the ovaries and follicles containing the oocytes, but may be done using a laparoscope. The fluid-filled follicles are drained with a needle and the fluid examined for oocytes.
• Ovary: female reproductive organ where eggs are produced in follicles
• Ovulation: This is where a ripe egg is released by the ovary and begins it journey down the fallopian tube towards the uterus.
• OI – Ovulation Induction: Drugs are used to stimulate the ovaries to produce and release one or more eggs prior to insemination or timed intercourse to maximise the chance of conception.

P

• PID – Pelvic Inflammatory Disease: Sexually transmitted infections may cause inflammation and damage to the reproductive organs and lead to difficulties with fertility.
• PESA – Percutaneous Sperm Aspiration: A fine needle is passed into the epididymis (the tubes in the testes which store sperm); the fluid is aspirated and examined in the laboratory for the presence of sperm.
• PCOS – Polycystic Ovarian Syndrome: A complex condition in which the ovaries produce many small cysts or follicles which can cause a hormone imbalance, problems with ovulation and consequently with fertility.
• Placenta: The placenta provides the connection between the mother and the developing foetus
• Pregnancy rate: number of pregnancies for every 100 treatment cycles started.
• Progesterone: Female hormone responsible for preparing the lining of the womb for pregnancy. If pregnancy does not occur, progesterone levels fall and the lining of the womb is shed (a ‘period’).
• Progression: Refers to the direction and speed with which the sperm are swimming.

Q

• Quality control: System to ensure safe and effective delivery of all processes used in treatment of patients.

R

• Retrograde ejaculation: At the time of ejaculation, semen passes into the bladder and is not released as normal.  This condition may occur in males with diabetes, post certain surgical procedures etc. It maybe possible to isolate the sperm cells from the urine in the laboratory.

S

• Semen analysis: Used to assess the parameters in seminal fluid produced at the time of ejaculation. The number of sperm, how many of the sperm are swimming (and how quickly) and the shape of the sperm are assessed. Other values such as the volume, the pH, viscosity and the presence of anti-sperm antibodies are measured.
• Sex selection: technique offered by some clinics to determine the sex of an embryo before replacement. Used to avoid transferring embryos which may carry sex-linked diseases.
• Spermatozoa (sperm): the male gamete produced in the testes.
• Sperm concentration: The number of sperm is counted under the microscope; according to the World Health Organisation a normal sperm concentration should be greater than or equal to 20 million/ml.
• Sperm donor: A man who donates his sperm for use in treatment by others.
• Stimulation/superovulation: Process of using drugs to induce the ovaries to produce multiple follicles.
• Surgical Sperm Retrieval: If there is a blockage in the sperm transport ducts that prevents sperm from being released during ejaculation it may be possible to extract the sperm directly from the testes using PESA or TESE during a minor procedure.
• Surrogacy: The act of getting pregnant and carrying a child on behalf of someone who for medical reasons cannot carry a pregnancy themselves.

T

• Take home baby rate: The number of cycles that result in a live birth per 100 treatment cycles.
• Teratozoospermia: During semen analysis the shape of the sperm head, midpiece (neck) and tail is compared to a ‘normal’ sperm model and the sperm classed as abnormal or normal. Teratozoospermia is a term used to describe subfertility linked to semen with raised levels of abnormally shaped sperm (greater than 95%).
• TESE – Testicular Sperm Extraction: A small sample of testicular tissue is taken using a needle during a minor operation. This tissue is then processed in the laboratory to extract any sperm that maybe present.
• Testis (testicle): male reproductive organ where sperm are produced.
• Testosterone: The male sex hormone that is produced by the testicles.
• Trophectoderm: The outer layer of cells of the blastocyst. When the blastocyst has hatched from the zona pellucida (shell), the trophectoderm cells make the initial contact with the endometrium, leading to implantation.  These cells eventually form the placenta.

U

• Ultrasound scan: High frequency waves are used to see inside the body and allow doctors and nurses to visualise structures such as the uterus and the ovaries. Used to monitor development of follicles during ovarian stimulation, and to ‘see’ the follicles during egg collection, as well as to confirm the presence of an early pregnancy.
• Uterine receptivity: This refers to the readiness of the lining of the womb (the endometrium) for an embryo to implant and pregnancy to begin. It is only in peak condition for implantation for a short time in each monthly cycle.
• Uterus: The uterus or womb is the female organ which supports the growth of an embryo and eventually a baby.

V

• Vas deferens: Sperm transport duct in the testis.

W

• Welfare of the Child: social and ethical aspects used in assessing the well-being of any child (new or existing) under 18 who may be affected by fertility treatment

X

• X chromosome: The X chromosome contains female genes. A maternal X chromosome is always passed on by the egg, and the fertilising sperm may pass on another X chromosome, or a Y chromosome.

Y

• Y chromosome: The Y chromosome contains male-specific genes from the father. As sperm carry an X or a Y chromosome, the sex of the potential child is determined by the fertilising sperm, an X chromosome giving rise to female and the Y chromosome leading to male.

Z

• Zona pellucida: The zona pellucida is the protective shell which encloses the egg.
• Zygote: Name for the fertilised oocyte.  A normally fertilised oocyte will have two pronuclei, one arising from each the sperm and the oocyte.  The zygote is the first stage in development of the embryo before cleavage occurs.