Dear Ebot

4DUS does not play any role. The current point to your questions are the follows:

- first trimester screening for common trisomies based on combined test, according to Fetal Medicine Foundation guidelines, is still the gold standard of care and should be advise to all pregnant women;

- there are today 5 private Companies holding the copyright of performing fetal cell free DNA in  maternal blood (4 from USA, 1 form China);

- fetal cell-free DNA is currently deliver on a private and individual basis;

- fetal cell-free DNA MUST neither be evaluated per se nor without a pre-test genetic consultation to the couple;

- currently fetal cell-free DNA should be proposed as an implementation of the combined test;

- the seven RCT performed today, have seen a SEN of 97% and a FPR of 0.1%.

This figure was obtained partucularly with regards to Tr. 21.

The SEN for sexual chromosome do not perform well, at the moment;

There has been faulty result from some Companies (gave the result of 46,XX fetus in non-pregnant women), sometimes they do not indicate the rate of fetal fraction (minimum 7%).

I do hope these explnanations may be of valu in your clinical dily practice.

Kindest regards,

Gabriele Tonni, PhD, MD

Diploma in Fetal Medicine-FMF, London

Thank you very much Prof Gabriele. Really helpful

4d ultrasound may be helpful in understanding fetal behaviour.  You may want to check KANET test. Best regards.

we perform both. We do not terminate babies because they are different. Of course I have a bias. I do not recommend to perform free DNA (expensive) if not considering termination (from the parent's point of view). Most babies show something along pregnancy, some not.  Science "per se" is just numbers, and trrending to depersonalization. IMHO. It sounds like multilevel marketing brought to health care...