This application allows estimation of risks for trisomies 21, 18 and 13 at 11-13 weeks’ gestation by a combination of maternal age, fetal nuchal translucency thickness, fetal heart rate and maternal serum free ß-hCG and PAPP-A. At a risk cut-off of 1 in 100 the detection rate is 90% for trisomy 21 and 95% for trisomies 18 and 13, at false positive rate of 4%.

It is strongly recommended that those undertaking assessment of risk receive the Fetal Medicine Foundation Certificate of competence in the 11-13 weeks scan. MoM values for PAPP-A and free ß-hCG depend on maternal characteristics but also on the equipment and reagents used at a specific laboratory; you will therefore need to obtain the MoM values from your laboratory.

This software is based on research carried out by The Fetal Medicine Foundation. Neither the FMF​ nor any other party involved in the development of this software shall be held liable for results produced using data from unconfirmed sources. Clinical risk assessment requires that the ultrasound and biochemical measurements are taken and analyzed by accredited practitioners and laboratories.

Please record the following information and then press Calculate.

Maternal characteristics


Pregnancy findings


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