In New Zealand, women can access pre‐natal (before birth) screening and diagnostic tests for a number of conditions including aneuploidies such as Down Syndrome. Screening is not the same as diagnosis.
A screening test indicates the level of risk that is present for a condition such as Down Syndrome. A positive result from screening suggests that there is an increased chance of a particular condition being present and a negative result means there is a decreased risk. People with positive screening results may decide to take the next step of pre‐natal diagnostic testing which will tell them whether the condition is present or not in the fetus. Pre‐natal screening is not compulsory for anyone. Women who do choose to undergo pre‐natal screening are supported throughout the process as shown in Box 1.
Women may decide to participate in pre‐natal screening for a number of reasons including:
- Wanting to know as much as possible about the pregnancy
- Wanting to know whether or not the fetus is affected by a condition that is common in the whanau/family
- Wanting the option of termination of an affected pregnancy
- Wanting to know if the pregnancy is affected by a condition so that she and her partner can prepare in advance for a baby with an abnormality
Some people prefer not to participate in screening programmes. There is a small risk of miscarriage associated with some screening procedures. A false-positive or high-risk result for an otherwise normal, healthy fetus may cause expectant parents to experience considerable stress and anxiety during pregnancy.
Conditions that can be tested for in New Zealand by pre‐natal testing include:
- Aneuploidy syndromes (Down [Trisomy 21], Edwards [Trisomy 18] and Patau [Trisomy 18])
- Aneuploidy syndromes affecting the sex chromosomes (Turner [XO], Klinefelter [XXY] and Jacob [XYY])
- Physical abnormalities including neural tube defects (spina bifida), cardiac, renal and digestive abnormalities