Will It Be Obviously Twins?

Jane Foley's picture


Dear Ms Ultrasound,
I had an u/s today at just over 5 weeks. The nurse called the doctor in to look at the screen because there were two gestational sacs. They said that I need to return in two weeks for another u/s because they could not determine much at this point or whether both sacs will continue to term.One sac was smaller than the other -- about half the size and flatter in appearance. The doctor said that the larger sac measured to be 5 weeks. Can you shed any light on this finding? What are the statistics regarding having two gestational sacs? How common is it? When I go back in 2 weeks will it be obvious if I am having twins?



Hi Elisa,
You had an ultrasound too early to make any kind of diagnosis. 2 sacs are not uncommon to see on an early ultrasound. Since we have had the technology to appreciate early pregnancies, we discovered that twins happen much more than anyone really knew.

What than happens is, upon a second look, many times one of the gestational sacs has not grown. This is not to say this is the case with you. Just a bit of information on this subject matter of early twin detection.

I cannot really comment any more than to say that you must wait a couple of weeks and have a second ultrasound to learn anything about your pregnancy. You will know for sure at the next ultrasound if you have 2 fetal poles (babies) and 2 heartbeats. If you have 2 heartbeats things will be looking good for twins.

-- Jane, RDMS