Specialist laboratories in the UK and USA are now able to test blood samples at 14 weeks to detect the liklihood of CdLS. This must be requested in advance, The CdLS Foundation has details of laboratories which offer this free service to medical professionals.
If a liklihood of CdLS is detected then a detailed ultrasound test is recommended. Detailed ultrasound scanning can detect heart defects and missing arms. In most hospitals, however, this quality of scanning can only be offered to mothers with special needs. Affected pregnancies are usually missed because there was no reason to suspect a problem. After a couple have had an affected child they should be offered detailed scanning which will be reassuring and show normal growth in the womb of the next baby.