I am 31 years old and 20 weeks pregnant. At my 19 week ultrasound they discovered a Cystic Hygroma. I was sent for a level II and it was measured at about half an inch. Everything else looked and measured normal. A fetal echocardiogram showed no heart defects. I had an amnio and the Fish test was normal, though I'm still waiting for full report. What is the likelihood of the CH getting larger and causing hydrops? What is the likelihood it will resolve on its own? Is Noonan's Syndrome still a major concern with a good level II ultrasound and fetal echo?
The biggest worry over cystic hygroma is it's relationship to genetic disorders, like Turner's Syndrome. Noonan's Syndrome, Turner-like without the genetic genotype, is associated with the same Turner worries, including cardiac problems. The normal cardiac echo is a good sign. If the amnio comes back normal, that will stack the deck your way. It's important to know if the hygroma, a lymphatic anatomy growth, is on the back of the neck or the front. The front ones have a better prognosis and can even spontaneously resolve, but if still present at birth, could prove an airway problem. It sounds like your doctor's on top of this, and so far all of your studies have been reassuring. Hopefully, the amnio will be fine, too.