At my 20 week us i was told my baby has a choroid plexus cyst and a small fetal stomach. odds of trisomy 18? f/u is in 4 weeks for routine us.

Blood test: The risk of trisomy 18 is assessed by doing blood genetic testing. A triple, quad or penta screen or alternatively fetal dna sequencing. If the blood test is normal then the presence of a unilateral choroid plexus cyst does not increase the risk of t18. If t18 is abnormal then a unilateral choroid plexus cyst can be supportive evidence.