If a pre-conception medical checkup was not done, at the time of the first prenatal visit, the health care provider will order several or most of the routine tests described in the Pre-conception section and also talk about other tests. These additional tests will be used to further evaluate the health and future medical care needs of the mother. In addition to the tests listed in the Pre-conception section, the following tests may be ordered:

It is now possible during the early stages of pregnancy (10-13 weeks) to estimate the possibility of a mother having a Down’s-affected baby using biochemical tests, sometimes in combination with ultrasound measurements. These tests may also indicate the possibility of other chromosome disorders, such as Edward’s syndrome. This type of screening provides an opportunity to assess the possibility of these conditions being present without performing more invasive procedures such as chorionic villus sampling (see below) or amniocentesis. Only those women whose screening results indicate that they are in a higher risk group are currently counselled about having further tests.

Screening includes the measurement of blood levels of pregnancy associated plasma protein A (PAPP-A) and either free or total human chorionic gonadotrophin (hCG). In addition, an ultrasound scan, called nuchal translucency is done. This involves taking a measurement of the thickness of the skin and tissue at the back of the baby’s neck. The results from these tests will be combined and used to calculate the chance of the baby having Down’s syndrome or another chromosome abnormality.

The following test is not routinely performed but may be offered to and discussed with women who are at an increased risk of having a baby with chromosomal or genetic abnormalities.