Yolk Sac Is Not Perfectly Round


Dear Ms Ultrasound,
I had a ultrasound today and I am 6 weeks 2 days by ultrasound and 6 weeks 4 days by last period. There was a heartbeat (good news I know) but the doctor was a little concerned about the yolk sac. It was round, but she said that one side was "slightly collapsed" so that it was not a perfectly round circle. I had not heard of this as a concern before. Is it something that could be a problem or concern?

I'm having another ultrasound in a week so I know that I shouldn't worry. But it still has me wondering.

Thank you,


Hello Dawn,
I'm sorry to say I too have not heard of one side of a yolk sac less full than the other side. I have a sneaking suspicion, that when you return for your follow up ultrasound, everything will be normal. Sometimes when doing an ultrasound, we discover certain findings that aren't really bad, but just don''t seem 100% right. The findings are described, yet no real diagnosis is made. Upon the return of the patient the findings most commonly have disappeared.

I am hopeful in your case this was one of those kind of things. Let me know if on the follow up there is more information discussed with you about the yolk sac.

-- 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.