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How Early Into The Pregnancy Does Vanishing Twin Syndrome Occur?
Question: vanishing twin syndrome occurs how early? i had an ultrasound last week, only showed 1. today it shows two. one heart beat, and my doc said it's still to early for the other sac. is this a vanishing twin and how far am i? they won't tell me that either.
Brief Answer:
The doctor may have missed the second twin the first time
Detailed Answer:
Hello, and I hope I can help you today.
First, I want to thank you for supplying copies of your ultrasounds. It was helpful to see them and I hope I can give you some helpful information.
First of all, you certainly do not have a "vanishing twin" because your second twin just appeared rather than having vanished! So, that diagnosis is not a consideration at this point.
As far as the dating of the pregnancy is concerned, there is no more accurate dating than with IVF. Your transfer date is the date of conception. The date of your IVF transfer nor the measurements of the size of the sacs is not written on either of those ultrasound reports so it is impossible for me to tell how far along you are.
But the important part is, at this time, you have two gestational sacs and in one there appears to be heartbeat. Because I can only see a fetal pole and no yolk sac I assume that this ultrasound was performed at give or take 5 1/2 to 6 weeks of gestation (from the first day of your last menstrual period).
What probably happened, because these ultrasounds are being performed so early, that the doctor just missed the second pregnancy on the first ultrasound.
There is a possibility that this second conception may also not be developing properly or as quickly as the first one. But there is no way to know this other than waiting and repeating the ultrasound in another week or two.
As the pregnancy progresses, if one sac gradually gets smaller and never develops a fetus, this is the definition of a vanishing twin. However, the outcome of the pregnancy of the surviving twin is not in any way affected by the vanishing twin in the first trimester.
I know it is hard to be patient, but you will just need to wait until your next ultrasound and see what the pregnancy looks like at that time.
I hope that I was able to adequately answer your question today, and that this information was reassuring.
Best wishes, and good luck with the rest of the pregnancy,
Dr. Brown
The doctor may have missed the second twin the first time
Detailed Answer:
Hello, and I hope I can help you today.
First, I want to thank you for supplying copies of your ultrasounds. It was helpful to see them and I hope I can give you some helpful information.
First of all, you certainly do not have a "vanishing twin" because your second twin just appeared rather than having vanished! So, that diagnosis is not a consideration at this point.
As far as the dating of the pregnancy is concerned, there is no more accurate dating than with IVF. Your transfer date is the date of conception. The date of your IVF transfer nor the measurements of the size of the sacs is not written on either of those ultrasound reports so it is impossible for me to tell how far along you are.
But the important part is, at this time, you have two gestational sacs and in one there appears to be heartbeat. Because I can only see a fetal pole and no yolk sac I assume that this ultrasound was performed at give or take 5 1/2 to 6 weeks of gestation (from the first day of your last menstrual period).
What probably happened, because these ultrasounds are being performed so early, that the doctor just missed the second pregnancy on the first ultrasound.
There is a possibility that this second conception may also not be developing properly or as quickly as the first one. But there is no way to know this other than waiting and repeating the ultrasound in another week or two.
As the pregnancy progresses, if one sac gradually gets smaller and never develops a fetus, this is the definition of a vanishing twin. However, the outcome of the pregnancy of the surviving twin is not in any way affected by the vanishing twin in the first trimester.
I know it is hard to be patient, but you will just need to wait until your next ultrasound and see what the pregnancy looks like at that time.
I hope that I was able to adequately answer your question today, and that this information was reassuring.
Best wishes, and good luck with the rest of the pregnancy,
Dr. Brown
Above answer was peer-reviewed by :
Dr. Raju A.T
Answered by
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