What is FBS?

This involves taking a sample of the baby`s blood. In the blood are cells that can be grown on culture media and then analysed.

How is it performed?

Under ultrasound guidance a fine needle is passed through the abdominal wall and into the umbilical cord, usually near its insertion into the placenta.

How long does the result take?

The result of the baby's chromosomal makeup is available after 2 days. A number of other tests can be performed, such as checking the baby's haemoglobin or blood group. Often these results are available within a few hours.

Is there a risk to my pregnancy?

Yes. The procedure related to the risk of miscarriage or fetal death is around 3%. As this risk is higher than for an amniocentesis or CVS, it is only performed when this is the only way to get the result or the risk is high enough to justify it.