Umbilical Cord Concerns in Late Pregnancy: What to Look For

Question
I am 36 weeks pregnant.  I wrote to you about the "bubble" looking thing on my ultrasound.  The tech told me it was the baby blowing bubbles, which as you said, is impossible.  I videotaped the session and when I go back and look at it, I am concerned.  It looks like a little donut or bubble (more like a donut).  I'm starting to think it is the umbilical cord and that there may be a knot in the cord.  What would a knot in the cord look like?  If there is a knot, how dangerous is it and what should I look out for?  Thanks for your time!

Answer
One cannot see a knot in the umbilical cord  on a sonogram. On a sonogram, the cord looks like a series of short lines, one on top each other. There may, indeed, be something coming out of the baby's mouth, but, since there is no air in the baby's lungs while it is in the uterus, it really can't be a "bubble". Why don't you show the sonogram pictures to your obstetrician or the radiatiologist and ask exactly what it is. The technician is not always the best person to ask. As long as the baby's heartbeat is fine and you have good pockets of amniotic fluid (AFI) and the estimated fetal weight is good, you have nothing to worry about. As far as what is at the baby's mouth, you may have to wait until delivery to know exactly what it is.