Glossary of Terms


Abstinence the required time frame where a man should refrain from ejaculation before having a semen analysis
Andropause the male equivalent of the female menopause – caused by a possible reduction of the production of the testosterone and other hormones in a man
Anti-Müllerian Hormone (AMH) a hormone used to measure a woman’s ovarian reserve, which is both a useful guide to a woman’s spontaneous fertility potential and a predictor of ovarian response to stimulation with hormones during fertility treatment
Antral follicle count a measurement of the number of follicles of less than 10mm in the early follicular phase.  Gives an indication of the number of follicles that may be recruited in any planned treatment cycle
Assisted hatching mechanical, chemical or laser breaching of the shell (zona pellucida) around the embryo
Azoospermia the complete absence of sperm in male ejaculate
Baselines a series of tests for both women and men that are carried out before treatment takes place.  The results of the tests form the basis of a patients’ treatment protocol.
Blastocyst a day five or day six embryo that has developed to have a layer of outer cells that eventually become the placenta and a small number of inner cells that will form the fetus
Chromosome small structures within the nucleus of every cell in the body which contain the genes
Clinical pregnancy evidence of a heartbeat of a developing fetus, in the uterus
Clinical pregnancy rate the proportion of on-going pregnancies for every 100 treatment cycles started
CMV cytomegalovirus: a member of the herpes groups of viruses which can cause risks to unborn children of women who contract it for the first time during pregnancy
Conceptual twins/triplets Conceptual twins or triplets are babies born following separate pregnancies from embryos that were ‘made’ at the same time as part of IVF treatment.  Conceptual twins/triplets are never identical as they come from separate embryos.  One or more of the babies will have been stored as an embryo in ‘deep freeze’ at the fertility clinic for months or even years after the IVF treatment and, following the birth of the first baby, the embryo will have been thawed and transferred back into the mother’s uterus to try for another baby
Congenital malformations or diseases which are present at birth and which are genetic in origin
Congenital abnormalities disabilities or diseases which are either present at birth or show themselves soon after birth
Consent permission: in fertility treatment, ‘informed consent’ is the written permission in full knowledge of the consequences of a procedure and must be given before a clinic can store gametes, create embryos or store embryos
Counselling all licensed clinics are required to offer patients counselling, to enable the patient to understand the implications of treatment, to give emotional support and to help the patient cope with the consequences of treatment
Cryopreservation the freezing of sperm, eggs or embryos and the storage of them in liquid nitrogen
Cycle treatment cycle – usually from the start of taking fertility drugs and including the egg collection, embryo transfer for IVF or ICSI –  or IUI insemination procedure – and the outcome of any pregnancy test.  Women going through treatment at the same time sometimes refer to each other as ‘cycle buddies’
Cystic fibrosis a disorder of the mucus-secreting glands of the lungs, the pancreas, the mouth and the gastro-intestinal tract and is the commonest serious genetic disease in Caucasian children
Cyst aspiration a procedure that drains the fluid from an ovarian cyst before starting a fertility treatment cycle
‘Day 21’ the name of a treatment planning appointment booked on or around day 21 of a woman’s menstrual cycle
Donor a woman who gives eggs , or a man who gives sperm, or a couple who give embryos to help a woman become pregnant
Donor Insemination the placing of donor sperm into the cervix (ICI) or the uterus (IUI)
Down regulation (DR) drugs that ‘switch-off’ a woman’s hormones and put her into a temporary menopausal state before she takes follicle-stimulating drugs as part of IVF or ICSI treatment
Drug protocol the type, quantity, method and length of time of taking the drugs required for any treatment cycle
Ectopic pregnancy a pregnancy that develops outside of the uterus, usually in one of the Fallopian tubes, but possibly also in the cervix, ovaries or abdomen.  An ectopic pregnancy is not viable and should be treated as a medical emergency.
Egg collection (EC) the procedure by which eggs are collected from the woman’s ovaries by using an ultrasound guided needle. Also known as egg retrieval
Ejaculation the squirting out of semen from the penis during orgasm (sexual climax) either by masturbation or during sexual intercourse
Embryo a fertilised egg
Embryo freezing /storage embryos not required for treatment in a cycle can be frozen and stored for future use. Freezing is also known as cryopreservation
Embryoscope an instrument for examining embryos at different stages of development using time lapse photography.  This is done without having to remove the embryos from incubation
Embryo transfer (ET) the transfer of one or more embryos to the uterus via an ultrasound guided catheter
Embryologist a scientist who cultures and studies embryos in a clinical or research laboratory
Endometriosis a female condition in which endometrial cells, which normally line the uterus, implant around the outside of the uterus and/or ovaries, causing internal bleeding, pain and reduced fertility
Endometrium the lining of the uterus which supports a fetus if a pregnancy occurs or which is shed during a normal menstrual period
Endometrial ‘scratching’ a technique where a fine plastic catheter is used to gently disrupt the endometrium with the aim of assisting the embryo to implant in a fertility treatment cycle
Epididymis coiled tubing outside the testicles which store sperm
Fallopian tube(s) the tubes between the ovaries and the uterus. After release of the egg from one of the ovaries, the tube transports the egg to the uterus
Female factor any reason why a woman is infertile, such as ovulation failure or damage to the Fallopian tubes
Fetus the term used for an embryo after the eighth week of development until birth
Fertilisation the entry of a sperm into an egg to create an embryo
Fertility drugs which may be used in IVF treatment, include the following:
•  buserelin used in down regulation, buserelin suppresses the activity of the pituitary gland which normally stimulates the ovaries to produce eggs. The ovaries can then be stimulated with gonadotrophins to produce many follicles
•  FSH Follicle Stimulating Hormone (may be called Metrodin or Puregon or GonalF) can be given also to stimulate follicles
•  hCG Human Chorionic Gonadotrophin is given by injection about 34-36 hours before egg collection. It helps to ripen the eggs within the follicles
•  hMG Human Menopausal Gonadotrophin (may be called Merional or Menopur) stimulates the development of follicles within the ovaries
Follicle(s) a small sac in the ovary in which the egg develops
Frozen Embryo Transfer (FET) after egg collection and fertilisation, good quality surplus embryos can be frozen in liquid nitrogen at -196°C and stored for future use. Once thawed, most embryos can be replaced in the womb in a natural cycle, although patients may sometimes require hormones to improve the womb lining
Gamete the male sperm or the female egg
Genetic abnormalities physical or mental differences caused by absent, extra or rearranged chromosomes
Genetic counselling a process by which information is imparted to those affected by. or at risk of a genetic disorder. It includes information on the nature of the disorder, the size and extent of genetic risks, the options, including genetic testing, that may help clarify the risks, and the available preventative, supportive and therapeutic measures
Genetic testing testing to detect the presence or absence of, or change in, a particular gene or chromosome
Gonadotrophins drugs used to stimulate the ovaries similar in composition to natural follicle stimulating hormone (FSH) and luteinising hormone (LH) produced in the pituitary gland
Hepatitis infection with one of the hepatitis viruses (A,B or C) which causes acute or chronic inflammation of the liver
Hormone hormones are natural chemical substances produced by the body some of which control the development and release of the egg from the ovary during each menstrual cycle. Natural and synthetic preparations of those hormones are used to increase the number of eggs produced in a cycle
HRT Hormone Replacement Therapy: oestrogen and progesterone drugs taken by a women to mimic a natural menstrual cycle
Implantation where an embryo becomes embedded in the uterine lining
Implantation failure the failure of an embryo to implant successfully or normally into the endometrium after transfer in a fertility treatment cycle
Incubator a sealed unit which replicates human body temperature and CO2 levels for the storage and of sperm, eggs and embryos at key stages of fertility treatment
Infection screening blood tests to check for transmissible diseases (including HIV, Hepatitis B and Hepatitis C)
In Vitro Fertilisation (IVF) eggs and sperm are collected and put together to achieve fertilisation outside the body. Resulting embryos can be transferred into the woman’s womb and a pregnancy may occur
Inhibin B a hormone measured to assess a woman’s ovarian reserve
Intra Cytoplasmic Sperm Injection (ICSI) a micromanipulation technique. A variation of IVF treatment where a single sperm is injected into the inner cellular structure of the egg. This technique is used for couples in which the male partner has severe sperm dysfunction
Intrauterine Insemination (IUI) placing of sperm into the uterus of a woman
Livebirth the delivery of one or more babies. Twins, triplets or more are considered to be a single livebirth event
Livebirth rate (LBR) the number of live births achieved from every 100 treatment cycles started
Long protocol a form of fertility treatment that involves a down regulation phase
Luteal Phase part of a woman’s menstrual cycle.  The end of the follicular phase is marked by ovulation, when the pituitary gland produces luteinising hormone (LH) which triggers ovulation. The egg is released into the Fallopian tube where it is ready to be fertilised by sperm.  As ovulation marks the end of the follicular phase, it also marks the start of the luteal phase when the corpus luteum (the now empty dominant follicle that released the egg) releases the hormone progesterone, which prepares the uterus for possible fertilisation of the egg and implantation of an embryo.
Karyotype the ‘map’ of the whole chromosomes within a cell, including their number, shape and size
Male factor a term which covers any reason why a man’s sperm may be less effective or incapable of fertilisation, including the absence of viable sperm and a failed reversal of a vasectomy
Menopause the ceasing of the menstrual cycle and the end of reproductive life
Menstrual cycle a cycle of approximately one month in the female during which the egg is released from an ovary, the uterus is prepared to receive the fertilised egg and blood and tissue are lost via the vagina if a pregnancy does not occur
Micromanipulation this term covers any technique used in IVF to bypass the zona pellucida (protein shell) which surrounds the egg, as this frequently prevents sperm which has poor motility or morphology from penetrating and fertilising the egg. ICSI is the most commonly used method of micromanipulation
Miscarriage spontaneous complete loss of a pregnancy before 24 weeks
Multiple birth the birth of more than one baby from a pregnancy (these are counted as single live births irrespective of the number of babies born).
Multiple birth rate the percentage of all births in which more than one baby was born
Multiple pregnancy a pregnancy in which two or more fetal hearts are present
Natural cycle fertility treatment synchronised with a woman’s natural ovulation, which requires fewer fertility drugs
Neonatal death the death of a baby within 27 complete days of delivery
Oocyte another name for an egg
Ovarian Hyperstimulation Syndrome (OHSS) a rare but serious consequence of over-response to the drugs used to stimulate the ovaries
Ovarian cysts each month a small perfectly normal cyst, or sac, starts to grow in one ovary and will contain the egg. It continues to grow for the first 2 weeks of the period and when it is about 2cm, bursts and releases the egg. This sac /follicle makes the hormone oestrogen. The follicle becomes more solid in the second half of the period and is then called a corpus luteum, which makes the hormones oestrogen and progesterone. If the corpus luteum does not go away it may become an abnormal cyst which should be checked by a GP to ensure it will not reduce a woman’s fertility
Ovarian reserve the ability of the woman to recruit a good number of ovarian follicles in response to the stimulating drugs used in fertility treatment
Ovary one of a pair of female reproductive organs which produce eggs and hormones
Ovulation the release of an egg from the ovary into the Fallopian tube
PCOS polycystic ovarian syndrome: a condition where many small cysts form on the ovary causing an hormonal imbalance which may lead to the need for fertility treatment to conceive
Percutaneous Epididymal Sperm Aspiration (PESA) retrieving sperm directly from the coiled tubing outside the testicles that store sperm (epididymis) using a very fine needle
Perinatal death The death of a baby either in the uterus after 24 weeks pregnancy (stillbirth) or within 28 days after the birth
Pregnancy scan the first scan, usually about, two weeks after a positive pregnancy test to confirm a clinical pregnancy
Routine infection screening blood tests to check for transmissible diseases  HIV, Hepatitis B and Hepatitis C
Recurrent miscarriage numerous pregnancy losses before 12 weeks gestation
Semen the fluid which contains the sperm
SFA a semen analysis appointment when a semen sample is analysed by the laboratory
Short protocol a form of fertility treatment that does not involve a down regulation phase
Slow-freeze method a method of freezing eggs where eggs go through a series of solutions to remove and replace their water content with a cryoprotectant to help preserve the delicate cell structures and avoid crystallisation during the freezing and thawing processes, then loaded into glass straws and stored in liquid nitrogen (see also ‘vitrification’)
Sperm the male gamete; the cell which carries the male genes
Stimulation drugs Drugs used to stimulate a woman’s ovaries to produce more eggs than usual in a monthly cycle; also known as superovulatory drugs
Superovulation/stimulation the stimulation of a woman’s ovaries with drugs to produce more eggs than usual in a monthly cycle
Surrogacy a method of reproduction where a woman agrees to become pregnant and deliver a child fro another woman
Testicular Sperm Aspiration (TESA) retrieving sperm directly from the testis with a very fine needle
Testosterone the principal male sex hormone which is present in both men and women.  On average, an adult human male produces about forty to sixty times more testosterone than an adult  female
Testis testicle or male gonad
Tubal patency test a test that involves injecting a solution through the fallopian tubes to check for any anomalies or blockages
Ultrasound investigation using sound waves to make a picture of the uterus and ovaries appear on a monitor screen. Ultrasound is used to monitor egg development, in egg collection and for embryo transfer
Uterus/uterine the womb; the main female sex organ where an embryo implants and grows into a baby
Vas deferens a pair of tubes which connect the epididymis to the urethra and transport sperm during ejaculation and which are absent in men with cystic fibrosis
Vasectomy/vasectomy reversal the male sterilisation procedure where the vas deferens are cut and tied / the surgical procedure to re-join the vas deferens
Vitrification a flash-freezing process for preserving eggs and embryos with cryopreservation
X-Linked Disorders disorders due to a mutation on the X chromosome. X-linked disorders usually only affect males, but the disorders can be transmitted through healthy female carriers
Zona pellucida the transparent membrane or ‘shell’ surrounding the egg