Appendix D: Glossary of terms

Abortion

Expulsion from the uterus of an embryo or foetus before it is viable (capable of surviving independently). It may be either spontaneous (occuring from natural causes) or induced (see ‘Termination of Pregnancy’).

Advisory Committee on Assisted Reproductive Technology (ACART)

The advisory committee established under New Zealand’s Human Assisted Reproductive Technology Act 2004.

Amniocentesis

A medical procedure used in prenatal diagnosis of genetic risk factors. A small amount of amniotic fluid (which contains foetal cells) is extracted from the amnion or amniotic sac surrounding a developing foetus, and the foetal DNA is examined for genetic abnormalities.

Carrier testing

Carrier testing is used to identify people who carry one copy of a gene that, when present in two copies, causes a genetic disorder. This type of testing is offered to individuals who have a family history of a genetic disorder, and to people in ethnic groups with an established risk of specific genetic conditions. If both parents are tested, the test can provide information about a couple’s risk of having a child with that genetic condition.

Chorionic villus sampling

A prenatal diagnostic test in which a small sample of the placenta is removed for genetic testing of the foetus.

Chromosomes

Nucleic acid protein structures contained in the nucleus of the cell.

Cystic fibrosis

A hereditary disease in which mucus is abnormally sticky, leading to obstruction of passageways in the lungs and in those associated with the gut. It causes progressive disability and early death.

Duchenne’s muscular dystrophy

An inherited disorder characterised by rapidly progressive muscle weakness of the legs and pelvis, later affecting the whole body. It appears in early childhood and survival is rare beyond the late 20s.

Ethics Committee on Assisted Reproductive Technology (ECART)

The Ethics Committee established under New Zealand’s Human Assisted Reproductive Technology Act 2004.

Embryo

Includes a zygote and a cell or group of cells that has the capacity to develop into an individual, but does not include stem cells derived from an embryo.

Established procedure

Procedures that are not prohibited under the Human Assisted Reproductive Technology Act 2004 and do not require Ethics Committee approval.

Fertilisation

The process (over 22–24 hours) whereby the male and female gametes unite to form a single cell, called a zygote.

Foetus

The early human form, from week eight until the birth of a child.

Gene

A section of the DNA molecule that contains a distinct package of genetic material and is located in a specific site on a chromosome.

Haemophilia

An inherited disorder of blood coagulation in which there is a permanent tendency to bleed (spontaneously or from injury) because an essential clotting factor is either partly or completely missing. The commonest form is sex linked as the gene is carried on the X chromosome.

Human Assisted Reproductive Technology (HART) Act 2004

An Act to secure the benefits of, and regulate, assisted reproductive technology and human reproductive research.

Huntington’s disease

A genetic disease that causes cell death in localised areas of the brain, resulting in abnormal body movements, dementia and death. Its onset is usually in the third or fourth decade.

Implantation

The embedding of the early embryo in the lining of the uterus.

Informed consent

A person’s voluntary agreement, based on adequate knowledge and understanding of relevant information, to participate in research or to undergo a diagnostic, therapeutic or preventive procedure.

In vitro

In relation to an embryo, a foetus, gamete or cell, this means an embryo, foetus, gamete or cell that is outside a living organism.

In vitro fertilisation (IVF)

The uniting of egg and sperm in vitro (in the laboratory).

Late onset condition

A condition developing after childhood.

NGO

Non-government organisation.

Nuchal Translucency (NT) Screening Test

The NT test uses ultrasound to measure the clear (translucent) space in the tissue at the back of a developing baby’s neck. In some developmental abnormalities, there may be an accumulation of fluid in this space. Babies with abnormalities tend to accumulate more fluid at the back of their neck during the first trimester, causing this clear space to be larger than average. For diagnostic purposes, the NT scan should be done when the woman is between 11 and 14 weeks pregnant.

Penetrance

The extent to which a genetically determined condition produces its specific effect in an individual carrier. 

Preimplantation

The state of an embryo before it adheres to the lining inside the uterus. In most successful human pregnancies, the preimplantation state lasts for 8 to 10 days.

Preimplantation genetic diagnosis (PGD)

The genetic testing of an embryo before it is implanted into the uterus. Either the polar body of the egg or a cell from the four- to eight-cell embryo may be extracted for biopsy.

Prenatal diagnosis

A medical test intended to detect a disorder in the foetus during pregnancy; diagnostic techniques include amniocentesis, ultrasound and chorionic villus sampling.

Termination of pregnancy

A medically directed miscarriage before independent viability, using pharmacological or surgical means.

Ultrasound

A procedure that uses high-frequency sound waves to scan a woman’s abdomen and pelvic cavity, creating a picture (sonogram) of the baby and placenta. Although the terms ultrasound and sonogram are technically different, they are used interchangeably and refer to the same examination.

Uterus

The womb; the female reproductive organ in which a fertilised egg implants and a foetus develops.