Large Yolk Sac, Low Heart Rate?

Jane Foley's picture


Dear Ms. Ultrasound,
I had my first ultrasound yesterday (Jan 7) and I just came from the doctor's office. My last period was Nov 10, which would make me LMP 8w2d, but I know I ovulated late (Nov 28) because I was artificially inseminated on Nov 28/29.

The ultrasound showed my yolk sac was 6mm, which is apparently larger than the normal range by 0.2mm and the heart rate was 109bpm which is just a little low of the normal heart rate. She said these numbers wouldn't matter if I was over 8 weeks, but the ultrasound dated me at just over 6weeks?

The doctor made everything sound very dire. How worried should I be? I'm really trying not to panic, especially since she said there is absolutely nothing I can do about either problem...but it's still so scary. Is this pregnancy in jeopardy?



Anytime a mild increase in size is seen on an early ob ultrasound, whether it is the yolk sac, the fetal pole or the gestational sac, a repeat ultrasound is in order.

The first 2 months of pregnancy, in combination with ultrasound, can result in very precarious results. The results of an ultrasound can mean that you are not as far along as you thought. It can mean that there is a problem with the pregnancy. There is a list of possibilities.

In so many cases the early ob ultrasound cannot accurately assess a pregnancy without a follow up in at least a week and preferably ten days. This time period allows for the pregnancy to grow to a size that can be appreciated on an ultrasound and growth can be measured.

With regards,
-- Jane RDMS