A

Abandoned Cycle: an IVF cycle which is terminated after drug administration but before egg collection.

Adoption: a legal process where an individual or couple become the legal guardians/parents of a child who is not biologically their own.

Agglutination: a clumping of sperm.

Amenorrhoea: the complete absence of a menstrual bleed (no periods).

Amniocentesis: a test carried out on the foetus aged 14-18 weeks. A needle is inserted under ultrasound guidance and amniotic fluid along with foetal cells are removed from the amniotic sac to look for genetic diseases such as Down's Syndrome.

Amnion: the inner membrane of the sac in which the embryo and foetus develops.

Amniotic Fluid: the fluid surrounding the foetus, inside the amniotic sac.

Anovulation or Anovulatory Cycle: when a woman has a menstrual cycle but fails to shed an egg. Ovulation fails to occur.

Anti-sperm Antibody Test: a test to determine whether antibodies to sperm are present. If present, these may prevent sperm from traveling through the cervix.

Artificial Insemination: the method whereby sperm are collected and processed and then deposited inside the female reproductive tract. This can be in the vagina, at the cervix, inside the uterus or fallopian tubes. Fertilisation then takes place naturally.

Assisted Hatching: a method which weakens or breaches the outer layer (zona pellucida) of the fertilised egg before implantation.

Assisted Reproduction Technology (ART): a general term to encompass various assisted conception techniques such as IVF, GIFT, ZIFT and ICSI.

Autosomal Dominant: these are genetic (inherited) diseases which require only 1 of the 2 genes (in a pair of similar genes) to be faulty for the disease to develop, e.g. Huntington's Chorea. See "Gene".

Autosomal Recessive: these are genetic (inherited) diseases which require both genes (in a pair of similar genes) to be faulty for the disease to develop, e.g. Tay-Sachs Disease. See "Gene".

Azoospermia: the complete absence of all sperm in the male ejaculate (semen).
B

Basal Body Temperature (BBT): a temperature reading taken daily to chart and predict ovulation.

Blastocyst: a 5-6 day old embryo.

Blastomere: a cell taken (by biopsy) from a blastocyst for analysis.
C

Carrier: a person can be a genetic carrier or have the "trait" for a disease without actually developing the disease. This occurs in autosomal recessive disease where only one faulty gene is present. As these conditions require both genes to be faulty for disease to develop, the person cannot develop the condition him/herself but can transfer the faulty gene in 50% of cases to his/her offspring.

Cell: a basic unit of all living things. Humans are made of trillions of cells which serve specific functions.

Cervical Mucus: a substance produced by the cervix. Its appearance, consistency and function changes depending on the stages of the menstrual cycle.

Cervix: the entrance to the uterus at the top of the vagina.

Chlamydia: a sexually transmitted infection which may or may not cause symptoms. Left undetected, it can be a cause of infertility as it damages vital areas such as fallopian tubes.

Chorion: the outer placental membrane.

Chorion Villus Sampling (CVS): a test involving the removal of chorionic villi from the placenta for genetic testing. This occurs at 8-12 weeks gestation.

Chromosome: long, thin structures of DNA (genetic material) found inside the nucleus of cells. These contain genes which serve specific functions inside cells. Humans have 46 chromosomes composed of 23 pairs.

Cleavage: cell division of a zygote to form a blastocyst.

Clomid: see Clomiphene.

Clomiphene: a fertility drug used to stimulate the production of egg follicles in the ovaries.

Congenital malformations: any developmental defects or abnormalities in a new born baby resulting from any cause such as an inherited (genetic) disorder or environmental causes such as uterine infections.

Corpus Luteum: this is a small yellow body within the ovary and is the remnant of an egg sac which has shed its egg at ovulation. The corpus luteum secretes progesterone in order to maintain the lining of the womb and pregnancy. But if no pregnancy occurs the corpus luteum breaks down and progesterone levels rapidly decline causing shedding of the womb lining.

Cryopreservation: the freezing and storage of sperm, eggs or embryos at very low temperatures in liquid nitrogen.

Cysts: abnormal swellings found in many organs. Although mainly benign, some cysts can become malignant. Cysts can when very large, cause disruption in the functioning of the organ in which it is found e.g. ovarian cysts.
D

Deoxyribonucleic Acid (DNA): this very long molecule which forms the structure of a double helix carries the genetic code for all living organisms and is the main constituent of chromosomes.

Dizygotic: dizygotic twins are formed from two separate eggs which are fertilised separately by two sperm. The twins are therefore non-identical.

Donor: this is a person who gives their sperm, eggs or embryos for the purpose of assisted conception to another couple or for research. For further details regarding donors, please read the page entitled "Using Donor Sperm, Eggs and Embryos".

Donor Insemination (DI): this is the process by which donated sperm is used in artificial insemination.
E

Ectopic Pregnancy: a pregnancy outside the uterus, most commonly in the fallopian tubes. This is a non-viable pregnancy and must be removed.

Egg: an oocyte, ovum or female gamete. This is the female reproductive cell.

Ejaculate: the fluid release by a man on ejaculation, usually at sexual climax.

Ejaculation: the process of release of semen by a man. This usually occurs at sexual climax.

Embryo: a fertilised egg that eventually develops into a foetus.

Embryo Biopsy: this is the removal of cells from the embryo in the laboratory before transfer into the womb. It is used for analysis of various conditions.

Embryo Freezing: spare embryos can be cryopreserved (frozen in liquid nitrogen) for future use or for research.

Embryo Transfer: after fertilisation of the egg(s), embryos are formed and if all is well, they are replaced back into the female recipient either into the fallopian tubes or uterus.

Endometriosis: a female condition where endometrial cells (cells lining the inside of the womb) are found outside the womb. This causes pain, bleeding and can reduce fertility due to tissue damage. For further details, please read the page entitled "Causes of Infertility".

Endometrium: specialised cells which form the womb lining. These cells develop with the menstrual period and are shed as menstrual blood if no pregnancy occurs. If pregnancy does occur, these cells maintain and support the embryo.

Epididymis: a very long coiled tube attached to each testicle. Immature sperm called spermatids slowly mature inside the tube. These mature sperm are stored inside the epididymis until ejaculation.
F

Fallopian Tubes: a tube down which eggs are transported from each ovary to the uterus. Eggs are usually fertilised inside a fallopian tube in natural conception.

Fertilisation: the process whereby a single sperm and an egg fuse together to form an embryo (a fertilised egg) which can then develop into a baby. This occurs naturally in the fallopian tube (in vivo) but can occur with assisted conception techniques in a glass dish in the laboratory (in vitro).

Fibroid: a mass or ball of fibrous muscle tissue growing in the muscular wall of the uterus. Several fibroids of various sizes can be present. They can disrupt the normal menstrual cycle causing pain and reduce fertility.

Flow Cytometry (Sperm Sorting): a method of sperm selection on the basis of sex. X and Y chromosome sperm cells are separated by colour by staining them with different coloured fluorescent dyes. This should be used for gender selection on medical grounds only.

Foetus: an embryo having developed for 8 weeks is then called a foetus until birth.

Follicle: an egg sac or cavity in the ovary where an egg develops.

Follicle Stimulating Hormone (FSH): a hormone secreted by the pituitary gland which stimulates the production of follicles (egg sacs) inside the ovary. This happens naturally in the menstrual cycle. However, FSH can also be artificially given to women undergoing assisted conception to stimulate the ovaries to produce eggs.

Fostering: a process where an individual or couple look after and care for a child short term until the child can be relocated to a more long term care environment such as an adoptive family.
G

Gamete: a cell of reproduction. A male gamete is the sperm and a female gamete is the egg or ovum. One each of the male and female gamete is needed for fertilisation to occur.

Gamete Intra-Fallopian Transfer (GIFT): an assisted conception technique where collected eggs and sperm are mixed together and placed inside a fallopian tube for fertilisation to occur in vivo (naturally inside the female).

Gene: this is a single unit of genetic information and made from DNA. Thousands of genes are found in a single chromosome. As chromosomes are found in pairs, 2 copies of each gene are present in each cell. In "dominant" genetic disorders (autosomal dominant diseases), only one of the two genes needs to be defective to produce the disease e.g. Huntington's Chorea. In "recessive" genetic disorders (autosomal recessive diseases), both genes in the pair need to be defective to produce the disease e.g. Sickle Cell Disease. In recessive conditions, if only one faulty gene is present, the person is said to be a "carrier" or have the "trait" but does not develop the disease.

Genetic: or inherited, this is the transferring of information from parent to progeny (offspring). This is done by the passing of chromosomes through the gamete. See also “Gene”.

Genome: the whole set of genes in all the chromosomes which defines an individual's physical appearance and characteristics.

Genotype: the genetic constitution of an individual.

Gestation/Gestational Age: this is the age of the pregnancy. It starts at conception and ends at delivery of the baby. In humans, gestation normally lasts around 40 weeks.

Gonadotrophin Releasing Hormone (GnRH): a hormone produced by the hypothalamus which stimulates the pituitary gland to produce follicle stimulating hormone (FSH) and luteinising hormone (LH).

Gonadotrophins (Agonists and Antagonists): synthetically produced hormones which act like GnRH and are used as fertility drugs.

Gradient Sperm Sorting: a method of sorting sperm on the basis of sex into X containing and Y containing sperms for gender selection. This should only be used for medical purposes.
H

Human Chorionic Gonadotrophin (HCG): a hormone secreted by the chorionic villi of the placenta. Its presence in urine or blood signifies pregnancy. This is how most pregnancy testing kits work.

Human Fertilisation and Embryology Authority (HFEA): the regulatory body in the UK responsible for all aspects of fertility treatment, licensing of clinics and ethical issues involved in embryology.

Hypothalamus: an area of the brain, located deep within the brain ultimately responsible for the control of all reproductive hormones and therefore reproductive activity. It releases Gonadotrophin Releasing Hormone (GnRH).

Hysterectomy: the surgical removal of the uterus (womb) for any reason. This can be done through the abdomen or vagina.

Hysterosalpingogram (HSG): a specialised X-ray where dye is injected into the fallopian tubes. The dye can be seen on X-ray showing the fallopian tubes and uterus. Defects, obstructions and other abnormalities can then be seen.

Hysteroscopy: this is a method to visualise the inside of the womb. A thin telescope like camera and light is inserted through the vagina and cervix into the uterus. Biopsies of the endometrium can be taken and minor procedures such as removal of small masses such as polyps can be done.
I

Implantation: this is when an embryo embeds itself into the lining of the womb (endometrium). This is the start of pregnancy. This occurs naturally after fertilisation. In IVF, embryos are transferred from the laboratory into the uterus for implantation to occur.

Impotence: the inability of a man to have successful penetration for sexual intercourse. Commonly, this is caused by a failure in erection.

Infertility: defined as the failure to conceive (get pregnant) after 1 year of trying.

Insemination: the artificial placing of sperm into the female reproductive tract.

Intra-Cytoplasmic Sperm Injection (ICSI): an assisted conception technique similar to IVF but where fertilisation occurs when a single sperm cell is injected into an egg.

Intra-Uterine Insemination (IUI): this is the commonest method of artificial insemination. Sperm is placed after washing directly into the uterus.

In vitro: a procedure or process performed outside the body (artificially in a laboratory).

In Vitro Fertilisation (IVF): the commonest assisted conception technique where collected eggs and sperm are mixed together and allowed to fertilise on their own in the laboratory. Fertilised eggs are then transferred into the womb.

In Vitro Maturation (IVM): this is a very new form of assisted conception where eggs are harvested from the ovaries at a much earlier stage compared with standard IVF. The eggs are therefore immature. Fewer drugs or no drugs may be needed in IVM. This form of assisted conception is available in only very few clinics at present.

In vivo: a procedure or process performed inside the body and therefore more naturally.
J
K

Karyotype: the appearance of chromosomes as viewed through a microscope to determine their number, shape and size.
L

Last Menstrual Period (LMP): this is the date on which the last menstrual bleeding began, i.e. the date on which the last menstrual cycle began. It is used to date gestational age until an ultrasound scan is done.

Laparoscopy: this is mainly a diagnostic procedure where the abdominal and pelvic organs can be viewed by inserting a laparoscope (a thin telescope like camera) through an incision in the abdomen. However, certain operations can also be carried out by inserting other instruments through other incisions at the same time.

Live Birth Rate: the number of live births achieved from every 100 treatment cycles started. This can be one of several measures for gauging the success rate of assisted conception clinics.

Luteinising Hormone (LH): a hormone produced by the pituitary gland when triggered by the release of gonadotrophin releasing hormone (GnRH). LH is responsible for ovulation.

Luteal Phase: this is the 2nd half of the menstrual cycle after ovulation has occurred.
M

Maternal Death Rate: this is defined as the death of a woman while pregnant or within 42 days of delivery (or termination of pregnancy) and is expressed per 100,000 total births.

Menarche: this is the time when the menstrual cycle begins in girls undergoing puberty. It therefore heralds the start of a woman's reproductive stage of life.

Menopause: this is the ending of a woman's reproductive stage of life as the ovary is no longer able to shed eggs. The menstrual cycle cannot be sustained and the balance of various hormones changes in the circulation.

Menstrual Cycle: the natural hormonal fluctuations that occur in women each month (approximately) from menarche to menopause. This enables women to ovulate and fall pregnant. The cycle begins with a menstrual bleed (a period) and ends the day before the next menstrual bleed.

Menstrual Period: this is the monthly bleed women experience at the start of a new menstrual cycle. It is caused by the expulsion of endometrial cells, tissue and blood from the uterus when there is no pregnancy to sustain the womb lining.

Microsurgical Epididymal Sperm Aspiration (MESA): this is a technique whereby relatively mature sperm are extracted from the epididymis using a small needle.

Monozygotic: this is when identical twins are formed by the splitting of a single fertilised egg into 2 zygotes.

Morphology: the size and shape of sperm.

Motility: the movement of sperm cells.

Multiple Birth: when a multiple pregnancy results in the birth of 2 or more babies. This event is far more likely with certain assisted conception techniques than in nature.

Multiple Birth Rate: the percentage of all births where more than 1 baby is born.

Multiple Pregnancy: a pregnancy in which more than one foetus is present in the womb.
N

Neonatal Death: the death of a baby between it's birth and 28 days after birth.

Neonate: a baby from birth to 28 days old.

Nucleus: the part of a cell which contains genetic material. This is made from DNA.
O

Obstetrics: this is the specialty of medicine involved with the care of pregnant women and their unborn child.

Oestrogen or Oestradiol: this is the female sex hormone and is produced by the ovary. Its levels fluctuate with the stages of the menstrual cycle.

Oligozoospermia: this term denotes a low sperm count and is defined as having less than 20 million sperm cells per millilitre of semen. It is severe if there are less than 5 million sperm per millilitre. Successful fertilisation of an egg then becomes less likely.

Oocyte: an egg, ovum or female gamete.

Ovarian Hyperstimulation Syndrome (OHSS): a serious complication of giving fertility drugs to artificially stimulate the ovary to produce eggs. For further details, please read the page entitled "Drugs Used In Infertility Treatment".

Ovary: this is the main female reproductive organ and stores the supply of eggs. Egg stimulation, maturation and release processes are controlled by hormones. The ovary also produces hormones such as oestrogen and progesterone.

Ovulation: this is when a mature egg is released from a follicle or egg sac in the ovary. It can occur at any time in the menstrual cycle but tends to happen approximately 14 days before the start of the next menstrual bleed.

Ovum: an egg, oocyte or female gamete.
P

Partial Zona Dissection (PZD): this process is used with IVF and involves making a small hole in the egg's outer coating with a glass needle. This assists the sperm to reach the outer membrane of the egg.

Pelvic Inflammatory Disease (PID): this condition can be caused by several infections of the pelvic organs, usually sexually transmitted and causes pain and reduced fertility from scarring. PID can affect the uterus, fallopian tubes or ovaries.

Penis: part of the external genitalia of men, this organ is used for copulation and urination. It is normally flaccid but becomes erect on sexual arousal in preparation for intercourse.

Percutaneous Epididymal Sperm Aspiration (PESA): this is a technique used to extract sperm from either the epididymal region of the testes or the epididymis itself. A fine needle is inserted and the sperm removed by suction.

Perinatal Mortality Rate: this is the total of foetal deaths (stillbirths) added to neonatal deaths within the first 7 days from birth.

Peritoneal Cavity: the cavity of the abdomen and pelvis where the fallopian tubes and uterus are found.

Phenotype: the way an individual or a group looks, i.e. their observable features. This is a result of the interaction between their genotype and their environment.

Pituitary Gland: the organ located at the base of the brain. It secretes FSH and LH through the menstrual cycle. These hormones trigger stimulation of follicles in the ovary and control ovulation.

Placenta: an organ which develops inside the womb along with the fetus. It is attached to the womb and is the connection or interface between mother and fetus. Nutrients and oxygen from the mothers blood are passed through the placenta and into the fetus while waste products and carbon dioxide are passed the other way from fetus to mother. A pregnancy cannot continue without a properly functioning placenta.

Polycystic Ovarian Syndrome (PCOS): a common condition and cause of reduced fertility. Multiple cysts develop on the ovary without ovulation occurring. This leads to various hormonal imbalances. For further details, please read the page entitled "Causes of Infertility".

Post-Coital Test: a fertility test where a sample of cervical mucus is taken soon after intercourse to check for the number and behaviour of sperm.

Pregnancy Rate: the number of pregnancies achieved from every 100 treatment cycles started. This is another measure of assisted conception clinic performance.

Pre-implantation Genetic Diagnosis (PGD): this diagnostic test involves the removal of one or two cells from the embryo for the detection of specific genetic disorders or characteristics prior to embryo transfer.

Pre-implantation Genetic Screening (PGS) or Aneuploidy Screening: this diagnostic test involves the removal of one or two cells from the embryo in order to assess the number of chromosomes. A normal set of chromosomes is called euploidy while an abnormal number is called aneuploidy.

Premature Ejaculation: occurs when men ejaculate sooner than desired or before the start of sexual intercourse so that sperm are not deposited in the vagina.

Premature Ovarian Failure: a state of abnormally early menopause when the ovaries cease to ovulate and produce hormones. This may be due to medical conditions, pelvic or abdominal surgery or be natural.

Primitive Streak: a thickening in the surface of embryos which is the first recognisable stage of embryonic development.

Progesterone: this is a hormone produced by the ovary and corpus luteum after ovulation. It triggers the development of the endometrium in preparation for implantation.

Prostate Gland: this is the most important of the male seminal glands. It secretes seminal fluid on ejaculation which forms the majority of volume of semen produced.
Q
R

Retrograde Ejaculation: this occurs when semen is forced backwards into the bladder on male climax rather than through the urethra. It occurs when there is damage to the bladder neck , e.g. after prostate surgery.

Round Spermatid Nucleus Injection (ROSNI): this is still an experimental technique where immature cells are removed from the testes. The genetic material containing nucleus of these cells is removed and injected into the egg. This form of assisted conception is not yet available to patients.
S

Selective Reduction: this is where some of the foetuses in a multiple pregnancy are deliberately destroyed in the hope of giving the remaining ones a better chance of survival. However, selective reduction is a risky procedure as the process of destroying the selected foetuses can also endanger the ones chosen to survive.

Semen Analysis: the male partner is asked to produce a semen sample which is then analysed. The test determines the number, shape, size and movement of the sperm as well as looking at other parameters. This is the main test used for assessing male infertility.

Seminiferous Tubules: these long convoluted tubes form the main structure of the testes. It is within these tubes that sperm are produced.

Sex Selection (Gender Selection): the sex of the embryo is selected depending on the presence of XX or XY chromosomes by PGD. This is useful in those with X-linked inherited diseases. Gender selection should not be used for any non-medical reason.

Sperm: the male gamete, of which many tens of millions are released in semen on ejaculation. Roughly half of all sperm carry an X chromosome and half carry the Y chromosome. This ultimately determines the sex of the embryo.

Sperm Sorting: this procedure is used for sex selection. Sperm carrying the X and Y chromosomes are separated and the appropriate sperm used to fertilise the egg depending on the sex of the embryo required.

Spermatid: an immature sperm cell.

Spermatozoon: a single sperm cell.

Stem Cells: these are undifferentiated (undefined) cells that have the potential to grow into almost any type of cell required for particular disease or injuries. The use of stem cells is still in its infancy.

Sterilisation: in the female, this is when the tubes are deliberately cut, tied or clipped so that eggs shed from the ovary and sperm traveling up from the uterus cannot meet. There is therefore no chance of fertilisation. This is used as a permanent method of contraception for women.

Stillbirth: the birth of a dead baby.

Stimulated Cycle: this is an assisted conception treatment cycle where drugs are used to artificially stimulate the ovary in a process called superovulation to produce more than the normal number of eggs. These eggs once matured are then collected and used for IVF or other procedures.

Stimulation Drugs: these fertility drugs are responsible for ovarian stimulation so that more eggs are collected than would otherwise be collected in an untreated or non-stimulated cycle.

Superovulation: see Stimulated Cycle.
T

Teratogen/Teratogenic: a substance or factor with the potential to cause congenital malformations and abnormalities of the embryo.

Teratoma: a type of tumour containing many cell types and usually found in the gonads (ovary or testicle).

Teratozoospermia: this is when sperm have poor morphology (abnormal shape) which is a cause of reduced fertility.

Term: this word denotes the end of the natural development period for the foetus inside the womb (the end of gestation). Delivery of the foetus should then occur.

Testicular Sperm Aspiration (TESA): this sperm extraction procedure removes a small piece of testicular tissue with a fine needle, from which sperm are removed.

Testicular Sperm Extraction (TESE): this sperm extraction procedure removes a small piece of testicular tissue by making an incision in the scrotum and exposing the testes directly.

Testes: testicle, male gonad or reproductive organ.

Transvaginal Aspiration: this procedure removes eggs from the ovary by passing a needle through the vagina into the ovary.

Transvaginal Oocyte Recovery: this procedure removes eggs from the ovary by passing a needle through the vagina under ultrasound guidance.

Treatment Cycle: this is any menstrual cycle (natural or stimulated) used for the purpose of artificial insemination or assisted conception. In stimulated cycles it begins by giving fertility drugs to stimulate the ovaries and ends with the transfer of zygotes or embryos.

Trisomy: the nucleus of human cells contains 23 pairs of chromosomes, i.e. 2 of each kind. Trisomy is a group of chromosomal disorders where 3 of a particular type of chromosome is present. Examples include Down's Syndrome where there are 3 chromosome 21's (Trisomy 21).

Tubal Ligation: a surgical procedure to disrupt the fallopian tubes so that fertilisation cannot occur. See also "Sterilisation".
U

Ultrasound Guided Aspiration: ultrasound imaging is used to guide the path of the needle to its intended target. In the case of fertility, the needle can be guided to egg sacs on each ovary for egg collection.

Ultrasound Scan: this type of scan uses very high frequency waves from a probe to visualise internal organs and structures. Almost any organ can be seen in this way. It is safe to perform in pregnancy.

Umbilical Cord: this is the tube which connects the fetus to the placenta. Through this, the fetus receives all the nutrients and oxygen from the placenta. Waste products pass through the cord in the opposite direction.

Unstimulated Cycle: a treatment cycle for assisted conception where no fertility drugs are used, i.e. a natural cycle.

Urethra: a tube connecting the blabber with the outside. It is shorter in women and longer in men as it needs to pass through the penis.

Uterus: womb, a muscular organ where the embryo implants and develops into a foetus and from which a baby is delivered.
V

Vagina: a muscular canal in women used for copulation and into which sperm are deposited by the male. It is also the birth canal through which a baby exits the uterus.

Varicocele: a testicular varicose vein. This may cause overheating of the testes resulting in poorer quality sperm.

Vas Deferens: these are tubes which connect the epididymis to the urethra, through which sperm are forced during ejaculation.

Vasectomy: a permanent contraceptive option for men involving a small operation to cut or tie the vas deferens to stop sperm reaching the urethra and to the outside in semen. Normal semen (but without sperm) is still produced on ejaculation.

Vasectomy Reversal: some men may choose to have a vasectomy procedure reversed in order to father more children. But the success of reversal operations is 50% at best. Vasectomy should be seen as a way to permanent sterility even though reversal operations may be attempted. Various sperm extraction methods can be used in some instances.
W

Womb: see Uterus
X

X Chromosome: the female chromosome.

X-Ray: a medical imaging technique where the area of the body to be visualised is exposed to X-Ray radiation. An image is either captured on film and developed or is captured electronically by using digital imaging and stored on computer.

XX: this is the female chromosome karyotype.

XY: this is the male chromosome karyotype.
Y

Y Chromosome: the male chromosome.
Z

Zona Drilling: a hole can be produced in the gelatinous outer layer of the egg by chemicals. This enables sperm to enter to fertilise the egg more readily.

Zona Pellucida: the transparent membrane or shell surrounding the egg. This layer can be harder in eggs from older women making fertilisation by a sperm more difficult.

Zygote: the cell created after fertilisation. This is the early stages of the embryo.

Zygote Intra-Fallopian Transfer (ZIFT): this assisted conception technique involves collecting eggs and sperm using the various methods used in conventional IVF. Fertilised eggs (zygotes) are then placed into the fallopian tubes.