The Food and Drug Administration is expected soon to announce safeguards for a controversial test to determine whether an unborn child is malformed.

The test, called an alpha-fetoprotein (AFP) reagent, involves taking a blood sample between the 16th and 18th week of pregnancy to measure the level of AFP, which is secreted by the fetus and shows up in the mother's blood. Repeated high levels of AFP can indicate a neural tube defect in the unborn child--a missing or incomplete cranium, which is fatal, or spina bifida, an unclosed spinal column that often results in paralysis and mental retardation.

In 1980, the FDA proposed rules to make sure the test was used properly. For example, women whose first test showed positive would have to take another test. If it also was positive, the findings would have to be double-checked with ultrasound (which gives a picture of the unborn child) or amniocentesis (in which amniotic fluid from the sac surrounding the child is withdrawn).

The FDA has received more than 600 public comments. Last week, Dr. Sidney Wolfe, head of the Ralph Nader-backed Health Research Group, said FDA "is likely to allow AFP testing without many of the restrictions set out in the 1980 proposal." The consequences, he said, would be "unjustified fear and emotional stress for parents and the aborting of healthy and wanted babies." An FDA spokesman would not comment on Wolfe's charge.