Medical Glossary

A condition in which tissue similar to the uterine lining (endometrium) grows into the muscular wall of the uterus. It can cause painful, heavy periods and is assessed with ultrasound or MRI.

The absence of menstrual periods, either never starting or stopping for at least three months in someone who had regular cycles. Pregnancy, hormonal disorders, large weight changes and ovarian problems are common causes.

A hormone produced by small follicles in the ovaries that gives an indication of ovarian reserve. It can be measured on any day of the cycle and does not on its own predict the chance of pregnancy.

A procedure in which a small sample of the amniotic fluid around the baby is taken with a fine needle under ultrasound guidance. It is usually done after week 16 for chromosome and genetic testing and carries a small risk of miscarriage.

Having too many or too few chromosomes in a cell; Down syndrome (trisomy 21) is one example. In embryos, aneuploidy is a major cause of early pregnancy loss and becomes more common with maternal age.

The number of small follicles (2-10 mm) seen in the ovaries on a transvaginal ultrasound early in the cycle. Together with AMH, it is used to assess ovarian reserve and the likely response to treatment.

A rearrangement in which parts of two chromosomes have swapped places without any genetic material being lost. Carriers are usually healthy but may have recurrent pregnancy loss or embryos with an unbalanced chromosome set.

The hormone produced by placental tissue in pregnancy; measuring it in blood confirms pregnancy at an early stage. In early pregnancy, repeat measurements two days apart can give information about progress.

The stage an embryo reaches about 5-6 days after fertilisation, when an inner cell mass and an outer cell layer have formed. In IVF, transfer or freezing may be planned at this stage.

A protein marker measured in blood. It is used in monitoring ovarian cancer, but it can also rise in benign conditions such as endometriosis, fibroids, menstruation and pregnancy, so it is not diagnostic on its own.

Delivery of the baby through an incision in the abdomen and the uterus. It is performed as a planned or emergency procedure when medically needed, and recovery is usually longer than after vaginal birth.

A genetic test that checks whether a person without symptoms carries a gene for certain inherited conditions that could be passed on to a child. It is considered before pregnancy, especially for related partners or couples with a family history of genetic disease.

A test in which a small sample of placental tissue is taken at weeks 11-14 of pregnancy to examine the baby's chromosomes and genes. It gives results earlier than amniocentesis and carries a small risk of miscarriage.

A detailed examination of the cervix with a special magnifying instrument. It is done when a smear or HPV test is abnormal, and a biopsy can be taken during the same visit if needed.

A screening test at weeks 11-14 of pregnancy that combines two hormone measurements in the mother's blood with the nuchal translucency scan. The result is a risk estimate for chromosomal differences, not a diagnosis.

An ultrasound, usually between weeks 18 and 23 of pregnancy, that systematically examines the baby's organs and growth, the placenta and the amniotic fluid. It can detect some structural differences but cannot identify every condition.

Lower abdominal and back pain during or just before menstruation. It can occur without an identifiable cause or be linked to conditions such as endometriosis, adenomyosis or fibroids.

A pregnancy that implants outside the uterine cavity, most often in a fallopian tube. It may cause pelvic pain and vaginal bleeding; beta-hCG and ultrasound are assessed together for early diagnosis, and it may need urgent medical care.

The IVF step in which eggs are collected from mature follicles with a fine needle under transvaginal ultrasound guidance. It is usually done under sedation and is short.

Freezing and storing mature eggs, obtained after ovarian stimulation, using vitrification. It may be considered for medical reasons or by women who wish to preserve fertility for later.

Storing embryos that are not transferred during IVF in liquid nitrogen after ultra-rapid freezing (vitrification). Frozen embryos can be thawed and transferred in a later cycle.

The step in IVF in which an embryo that has developed in the laboratory is placed in the uterus with a thin catheter. It is usually guided by ultrasound and takes only a few minutes.

A small, usually benign growth arising from the lining of the uterus. It can cause bleeding between periods or difficulty conceiving and can be removed by hysteroscopy.

A condition in which tissue similar to the uterine lining is found outside the uterus, for example on the ovaries or the lining of the pelvis. It can be associated with painful periods, pelvic pain and difficulty conceiving.

The inner lining of the uterus, which thickens and sheds during the menstrual cycle under the influence of hormones. As the place where an embryo implants, its thickness and appearance are monitored by ultrasound during IVF.

A common, benign growth that develops from the muscle of the uterus. Most cause no symptoms; depending on their size and position they can cause heavy periods, pressure or difficulty conceiving.

A hormone released by the pituitary gland that stimulates the growth of follicles in the ovaries. It is usually measured on day 2-3 of the cycle; high levels may suggest reduced ovarian reserve.

The length of a pregnancy expressed in weeks and days from the first day of the last menstrual period. If that date is unknown or cycles are irregular, it is set from measurements on a first-trimester ultrasound.

High blood sugar that is first recognised during pregnancy. It is usually screened for with a glucose tolerance test at weeks 24-28 and managed with dietary changes, monitoring and, if needed, medication.

A pregnancy with a higher chance of complications for the mother or baby that needs closer monitoring. Older maternal age, chronic illness, multiple pregnancy and previous pregnancy problems are among the main reasons.

A very common group of viruses transmitted through sexual contact. Most infections clear on their own; persistent infection with some high-risk types can lead to cell changes in the cervix.

A vaccine that protects against the HPV types linked to cervical cancer and genital warts. It is most effective when given before sexual activity begins; cervical screening continues after vaccination.

Surgical removal of the uterus. It may be done for reasons such as fibroids, adenomyosis, abnormal bleeding or cancer, and can be performed through an open, laparoscopic or vaginal approach.

An X-ray test in which contrast dye is introduced into the uterus to assess the uterine cavity and whether the fallopian tubes are open. It is usually done after the period ends and before ovulation.

Examination of the inside of the uterus with a thin camera passed through the vagina and cervix. It can be used both for diagnosis and to treat problems such as polyps, adhesions or a uterine septum.

An IVF technique in which a single sperm is injected directly into an egg with a fine needle. It is used particularly when sperm count or motility is low or after previous fertilisation problems.

The process by which an embryo attaches to and embeds in the uterine lining (endometrium). In a natural cycle it happens about 6-10 days after fertilisation; both embryo quality and a receptive endometrium play a role.

A treatment in which the ovaries are stimulated, eggs are collected and fertilised with sperm in the laboratory, and a resulting embryo is transferred to the uterus. Procedures take place in licensed IVF centres.

Not becoming pregnant after one year of regular unprotected intercourse, or after six months for women aged 35 or over. Assessment involves both partners.

A small contraceptive device placed inside the uterus, containing either copper or a hormone. It provides long-term protection, and fertility returns once it is removed.

A treatment in which washed and prepared sperm is placed inside the uterus with a thin catheter around the time of ovulation. It is used for some couples whose fallopian tubes are open and whose sperm parameters are suitable.

A genetic test that examines the number and structure of chromosomes in cells from a blood or tissue sample. It may be recommended to couples with recurrent pregnancy loss or some forms of infertility.

Keyhole surgery in which a camera and fine instruments are inserted through small incisions in the abdominal wall. It can be used to diagnose and treat conditions such as endometriosis, ovarian cysts, ectopic pregnancy and fibroids.

The first day of the last period before pregnancy. Gestational age and the estimated due date are calculated from this date.

A hormone released by the pituitary gland whose sudden surge triggers ovulation. Home ovulation tests detect this rise of LH in urine.

The part of the cycle from ovulation to the next period, usually lasting 12-14 days. During this phase progesterone prepares the uterine lining for a possible pregnancy.

The permanent end of menstrual periods as ovarian function stops, defined after 12 months without a period. It usually occurs between the ages of 45 and 55.

A screening test that analyses fragments of placental DNA circulating in the mother's blood. It can be done from week 10; a high-risk result should be confirmed with amniocentesis or CVS.

An ultrasound measurement of the fluid at the back of the baby's neck at weeks 11-14 of pregnancy. It is part of combined screening with blood tests and is used to estimate the chance of chromosomal differences.

An excessive response of the ovaries to IVF medication. It can cause abdominal bloating, pain and fluid build-up; individually adjusted doses and close monitoring reduce the risk.

A test in which blood sugar is measured at set intervals after drinking a measured glucose solution. In pregnancy it is usually done between weeks 24 and 28 to screen for gestational diabetes.

A sac filled with fluid or other material that forms on or in an ovary. Most are functional cysts linked to ovulation and disappear on their own; some types need monitoring or surgery.

The number of eggs remaining in the ovaries, which declines with age. It is estimated from AMH levels and the antral follicle count, and does not directly reflect egg quality.

The release of a mature egg from the ovary. In a regular 28-day cycle it usually happens around day 14, and the egg can be fertilised for roughly 12-24 hours.

A test in which cells are collected from the cervix with a small brush and examined under a microscope. It is repeated at regular intervals to detect early cell changes that could develop into cervical cancer.

A common hormonal condition defined by irregular or infrequent ovulation, signs of raised androgens (male-type hormones) and many small follicles on ultrasound. It is a frequent cause of irregular periods and difficulty conceiving.

Genetic testing of a few cells taken from an embryo before transfer in IVF. It can look at chromosome number (PGT-A), single-gene conditions (PGT-M) or structural chromosome rearrangements (PGT-SR).

The period of about six weeks after birth during which the body returns towards its pre-pregnancy state. Bleeding, breastfeeding, mood and recovery are monitored during this time.

A pregnancy condition, usually after week 20, involving high blood pressure together with protein in the urine or signs of organ involvement. Headache, visual disturbance or sudden swelling need prompt medical assessment.

Reduced or stopped ovarian function before the age of 40. It may present with irregular or absent periods, and genetic causes are investigated in some cases.

The loss of two or more pregnancies. Assessment looks at chromosomal, uterine, hormonal, clotting and immune causes; in some couples no cause is found.

The possibility that a mother with Rh-negative blood develops antibodies against an Rh-positive baby. It is monitored with blood group and antibody tests in pregnancy, and anti-D injections given at the right times help prevent sensitisation.

The basic laboratory test that assesses sperm count, motility and shape in a semen sample. It is usually done after 2-7 days of abstinence, and an abnormal result is confirmed with a repeat test.

An increased tendency of the blood to clot, which may be inherited or acquired. Because it can raise the risk of blood clots (thrombosis) in pregnancy, preventive treatment is planned in some cases.

Involuntary tightening of the muscles around the vaginal opening that makes intercourse or examination difficult or impossible. Treatment may include education, sex therapy and relaxation exercises.

Enlargement of the veins that drain the testicle. It can affect sperm production and quality; treatment is decided after assessment by a urologist.