Sydney IVF glossary

A GnRH-agonist, made by Syntex as Synarel and used as a nasal spray.

The philosophical term coined by G.E. Moore early in the twentieth century to devalue drawing ethical conclusions from empirical observation -- i.e. by moving from what is (facts that are observed) to what ought (morality). Moore felt that ethics should be intuitive, not inferred -- therefore he presumably favored deontological ethics over teleological ethics. Practical ethicists find this constraint unnaturally crippling as it prevents them making a value judgement.

The word pathologists use when there is death of part or all of a tissue or organ due to an outside factor, such as cutting off the blood supply. If apoptosis is regarded as cellular suicide, then necrosis could be called cellular murder. Important examples include aseptic necrosis of the femoral head and the loss of an ovary from untreated torsion.

If you have a negative history for a disease or symptom it means that you do not have or have not had that disease or symptom. Compare with positive history.

In medicine generally it may be best for tests to be negative (like tests for brain tumors or tests for sexually transmitted diseases such as HIV -- as for 'histories', compare negative history), but this is not always so in infertility. Infertility tests are generally better if they're positive, like the postcoital test, tests for ovulation, tests for tubal patency, and (not least) a pregnancy test.

The neural (nerve-containing tissue) part of the pituitary gland, lying towards the back … and so, in medical speak, called the posterior pituitary. Produces the hormones oxytocin (which acts on myometrium to cause contraction of the uterus) and vasopressin (which helps maintain blood pressure and conserves the body's water in the kidneys).

White blood cells or lymphocytes that form part of the 'innate' immune system capable of recognising foreign cells and dissolving them (hence their name: natural killer cells). Found normally, however, in the endometrium of the late secretory phase and in the decidua of pregnancy, where they have more friendly purposes in forming the boundary between mother and fetus. Unlike T cells and B cells, most NK cells do not have 'immunological memory', whereby previous contact with a particular antigen causes a faster, more deadly immune response second time round.

The ethical principle that comes from not doing harm.

Azoospermia caused by low sperm production rates in the testis, including maturation arrest. Can often be overcome with testicular sperm extraction (TESE) followed by in vitro fertilisation utilising intracytoplasmic sperm insertion (ICSI).

(NET) A progestogen of a type weakly related to the male hormone testosterone. Progestogens of this class are commonly found in the oral contraceptive pill. Norethisterone acetate is marketed as Primolut N and is made by Schering. Called norethindrone in the US.

Nature gives fertility a wide range, normally from about 7 to 45 percent per month for women in their early twenties, to about 3 to 25 percent per month for women in their early 30s; for women in their early 40s, it ranges from less than 1 to about 5 percent per month.

Preparation of hCG made by Ferring. Similar to Pregnyl and Profasi.

Nonsteroidal anti-inflammatory drugs, e.g. aspirin, ibuprofen (Advil, Nurofen etc), mefanamic acid (Ponstan), naproxen sodium (Aleve, Naprosyn, or in Naprogesic in combination with dextropropoxyphene), which stop the production of prostaglandins; useful for dysmenorrhea and prior to a hysterosalpingogram. Excessive use at the time of ovulation might predispose to a luteinised unruptured follicle, so NSAIDs should not be used for ovulation pain if you are trying to get pregnant.

A measurement done at transvaginal ultrasound of tissue in the neck of the fetus; if excessive, it implies a substantially increased risk that the fetus is affected by Down syndrome and Turner syndrome.

Central structure within a cell that contains the chromosomes. The non-nuclear part of the cell is called the cytoplasm -- which thus contains other cellular structures, including the mitochondria. Genetic inheritance is mostly by way of the nucleus (with a contribution from mother and father); a small part is by way of the cytoplasm (with a contribution only from the mother).