At what point can an anencephaly be diagnosed?
An experienced specialist using a high-resolution ultrasound scan can detect an anencephaly as early as the 10th week. In less-than-ideal circumstances, however, an anencephaly cannot be picked up or ruled out by an ultrasound scan until the 16th week of the pregnancy. AFP levels can be measured via a maternal serum screening test (blood test). If levels are high, there is a risk that the child may be suffering from an NTD. Further tests must then be carried out (ultrasound scan or amniocentesis) to determine whether there really is a problem. Screening must take place between the 15th and the 20th week, the best time being the 16th week.
