Expert: Catherine Beier MS CBE - 10/4/2009

Question
I am a couple weeks pregnant and had some light cramping, I went to the dr and they did an intravaginal ultrasound it showed twins, the Dr didnt seem to acknowledge this even after I pointed it out, he said it is common to see twins this early and I should not get my hoped up, what is that chance of me having twins if I conceived arround Sept 9 is this test accurate? Twins do run in my family and the last ultrasound I had with my first child never showed 2 sacks.

Answer
Stacy,


What the doctor was trying to say, although he didn't appear to do a good job of it, is that about 25% of all pregnancies start out as multiples, typically twins, but since only about 3% of all births are twins, it's very, very common to miscarry one of the babies early on, sometimes even before you know you are pregnant, or for one of the sacs to be empty, never having contained another baby.


So, at this stage, two sacs are present, which could develop into twins.  That doesn't mean that both sacs contain fertilized embryos; one could be a blighted ovum, where the embryo failed to form, or could just be an empty sac.  


Your overall chances of having twins runs about 3%, but can be higher if there is a family history of fraternal twins (identical twins are not inherited; they occur spontaneously).


So, while you currently appear to be having twins, this does not mean that both will continue to develop; only time will tell.  The ultrasound is very accurate at showing the two sacs, but at this early stage, it's impossible to yet see what's in them.  


I know it's difficult, but you'll just have to wait and see if both sacs develop a fetal pole and grow as expected.  But yes, at this stage, you would be considered to be carrying twins.  Your doctor was just aware that the odds are still high that one of the sacs is empty or won't develop, so in his own way, he was trying to prepare you in the event that one doesn't develop.



Best,
Catherine