It is possible to have a critical risk baby, but it is advisable to have further tests to clarify the risk.
A critical risk fetus is one that is between high risk and low risk. Down’s syndrome screening itself is only a screening method, not a diagnostic test. It is a matter of probability and does not confirm that the fetus is Down’s syndrome. If you are concerned, you can follow your doctor’s instructions for further non-invasive DNA or amniocentesis to confirm the diagnosis.
The vast majority of fetuses at “critical risk” for Down’s syndrome are normal after amniocentesis. Only a very small number of fetuses may be diagnosed with Down’s syndrome and require prompt termination of pregnancy as prescribed by the doctor.
Pregnant women with low risk of Down’s syndrome or normal amniocentesis test still need to have regular checkups and 4D ultrasound at 22 to 26 weeks. Consult your doctor for details.