Understanding an Enlarged Yolk Sac in Early Pregnancy: What to Expect

Question
You recently answered a question about a small yolk sac.  This question concerns an enlarged yolk sac.  My wife had an ultrasound last week at which time she was seven weeks pregnant.  The ultrasound showed a fetus with a heartbeat of 140 bps.  Then we got a call from the OB today telling us that there was an enlarged yolk sac so she wants to do another ultrasound in four weeks.  How concerned should we be that the enlarged sac will lead to a miscarriage?  Is it a risk or a likelihood?

Thanks for any info

Answer
As long as the sonogram showed a fetus with a good fetal heartbeat, the size of the yolk sac is insignificant, and will not cause a miscarriage. They merely want to confirm the growth of the pregnancy. An enlarged yolk sac is not an indication of an impending miscarriage. Don't worry.