Maternal serum-alpha-fetoprotein (MSAFP)

The AFP test

Blood can be drawn for this test at the same time as other prenatal tests. Your GP or midwife will talk with you about the reasons for this test, and the procedure that will be suggested should there be abnormal findings, and seek your consent prior to testing.

A woman has the right to refuse this test if she chooses. If the test reveals abnormal values, a follow-up with an ultrasound and amniocentesis may be recommended for a more definitive diagnosis.

Women who have opted for amniocentesis do not need the MSAFP because the AFP test is included in amniocentesis screening.

The results

Normal levels and accuracy of the test are dependent on factors such as maternal age, race, weight and gestational age. A complete medical history must accompany the sample to allow accurate interpretation of the results by the specialist who will look at the results.

The information supplied will include such details as date of last menstrual period, estimated date of delivery, date of ultrasound, if the mother is an insulin-dependent diabetic, and if there is a family history of Down's syndrome, chromosomal abnormalities or neural tube defects.

MSAFP blood levels fall in three ranges: low, normal or elevated. An elevated MSAFP level (2 1/2 times above normal) is associated with open neural tube defects (like spina bifida) and central nervous system defects (anencephaly).

Elevated levels are also associated with twins and an open anterior abdominal wall defect of the foetus (where the front wall of the abdomen has not closed properly during development). Elevated levels may also play a role in late-pregnancy complications such as premature delivery, intrauterine growth retardation (not growing properly within the womb) and haemorrhage.

Abnormally low MSAFP levels are associated with Down's syndrome and other chromosomal abnormalities. However, a high or low result does not necessarily mean that the baby has any of those abnormalities.

Frustrating, isn't it? This, of course, is important to remember. Any actions that may be suggested, as a result of abnormal findings, will only be carried out when the patient herself has given permission.

Usually, a second opinion will always be added as a matter of course, if findings suggest a drastic action.