Dear Ask The Doctor: My wife is 37. A vaginal ultrasound one week ago showed gestational sac and yolk sac. She believes she got pregnant about 1 week after Valentine's Day. A second vaginal ultrasound yesterday (1 week after the first) showed gestational sac and yolk sac, but no embryo. And importantly, it showed no growth in gestational sac (I'm not sure if this means absolutely no growth, or very little growth). My question is, is failure of the gestational sac to grow as expected, at this point in time, indicative that there WILL be a miscarriage? Or is it POSSIBLE that despite the lack of growth, she could have a viable pregnancy. My research indicates that blighted ova occur when the sac continues to grow, but no embryo grows. What about when the sac DOESN'T continue to grow between, say, the 4th and 5th week. In such a situation, is miscarriage CERTAIN? If she is not bleeding or infected or in pain, is there any medical downside to waiting another week or two before deciding to have a dc?
Dear Patient: I do understand your concern about a blighted ovum. However, ultrasound done early in the gestation cannot reliably diagnose a pregnancy. Transabdominal ultrasound cannot reliably diagnose pregnancies that are less than 6 weeks gestation. Transvaginal ultrasound, by contrast, can detect pregnancies earlier, at approximately 4 ½ to 5 weeks gestation. Sometimes it may take serial ultrasounds to confirm a diagnosis. You may even consult your doctor for quantitative HCG analysis. A rising level of HCG will indicate a viable pregnancy. If the next ultrasound shows nothing in the sac, it is either a blighted ovum (which means a baby did not form, only the sac) or it is a pseudo sac (fake sac). I wish you well and do hope for a positive outcome.