Noonan syndrome

The asymptomatic population is not screened for Noonan syndrome (NS). However, If there is clinical evidence of NS in the fetus, or a first-degree relative has NS, obstetric ultrasound is indicated at 12 to 14 weeks' and at 20 weeks' gestation, and again in the third trimester.[42]van der Burgt I. Noonan syndrome. Orphanet J Rare Dis. 2007 Jan 14;2:4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1781428 http://www.ncbi.nlm.nih.gov/pubmed/17222357?tool=bestpractice.com Features suggestive of NS include polyhydramnios, cystic hygroma, increased nuchal translucency, pleural or pericardial effusion, ascites, and/or fetal hydrops.