Ultrasound Found Rim of Fluid Around Head


Dear Ms Ultrasound,
At the 12-week ultrasound, the tech / midwife found swelling around the head, like a outer rim of fluid around the head. She said vaguely this is usually sign of chromosomal problems, but we must wait 2 weeks more for doctors and an amniocentesis. What exactly could be wrong? Can this be something that just looks strange now?

Thanks for any help!


Hello Nancy,
When a woman has an ultrasound where there is an unusual finding, my first question is who has done the exam. If it is not a licensed sonographer, then an appointment should be scheduled to have an exam done by a specialist.

At 12 weeks, seeing a thin rim of fluid around the head could be anything from NORMAL to a genetic problem. In our facility we do amniocentesis around 16 weeks. In a situation such as yours, once a problem has been identified on an ultrasound, the mother is scheduled to see the perinatalogist and the genetic counselor. Together they look at the mother and the father's family histories, do an in depth ultrasound (Level II) and an amniocentesis.

I would like you to know that it is not unusual for mistakes to be made in a first trimester ultrasound. As the fetus develops there can be fluid collections that are perfectly normal, yet just caught at a moment that makes the person doing the exam think its abnormal.

Unfortunately you are in that awkward waiting period that can last an eternity for a mom to be. Hang in there and know that most often these kinds of things turn out to be cause for unnecessary worry, and the scan is normal.

-- Jane, RDMS

Jane Foley

Jane Foley has worked as a Sonographer (Ultrasound Technologist) since 1979. Jane has lived and worked in many parts of the world including Saudi Arabia. She is a Registered Diagnostic Medical Sonographer or RDMS. She pulls a wealth of information from her experience in the field of Radiology and her interactions with such a broad cross-section of cultures she has visited. She now makes her home on the island of Maui with her English husband, Michael.