Question: My wife and I have been trying for a baby for 4.5 years. She had been pregnant 3 times before (1st ectopic resulted in a lost tube, 2nd miscarriage at 19 weeks resulted in a diagnosis of a septate uterus resulting in 2 surgeries to remove the septum, 3rd miscarriage at 8 weeks - fetus was tested and was chromosomally abnormal). In January of this year we had our first IVF attempt but that failed.

On March 29th we had our 2nd IVF transfer and were ecstatic to find out that she was pregnant as of bloodwork on April 8th.
4/8 - hcg was 122
4/11 - hcg was 574
4/14 - hcg was 2580

It is important to mention that we had genetic testing on 11 day 5 frozen embryos. 5 of those embryos graded out to be genetically normal, grade A, etc. and all 5 of those are female embryos.

Both our first and second frozen embryo transfers were single embryo transfers...

Today we had our first ultrasound (estimated at close to 7 weeks pregnant with a due date of mid December 14-15). During the ultrasound we were really pleased to hear our baby's heartbeat (116) and to be told that she is measuring where she needs to be at this point of the pregnancy.

The ultrasound technician then noticed what to her, appeared to be a second, smaller gestational sac. This "sac" was smaller and she did not detect a heartbeat with that one. This second "sac" is not right next to the other one and appear to be separated.

We then met with a nurse who said that if the single embryo split, forming identical twins, that they would be next to each other (I believe sharing the same sac). She said that it appears that if it was a second sac it would be a case of fraternal twins.

Prior to leaving we then spoke with the ultrasound technician again and a lead ultrasound technician/manager. The manager said that her gut tells her it is not a second sac but couldn't say for sure. She said it could be fluid with some debris. To us though, the area in question looks like it definitely could be a smaller sac.

During this frozen cycle my wife was on Lupron to prevent ovulation. We both believe that we had intercourse a couple days before this transfer. Here are our questions:

1) Could she have ovulated despite the Lupron and have also become pregnant naturally? Would our RE have likely detected that she was ovulating or about to ovulate during an ultrasound lining check and canceled the cycle?
2) If it is possible that she ovulated despite Lupron and became pregnant naturally, is it possible that this second sac without a heartbeat is lagging a week or so behind the other one since the other one was a 5 day old blast?? When we go back in for a follow up ultrasound next week, could we see that the other one now has a heartbeat?
3) Or is it possible that the lab accidentally transferred a second embryo of ours or even someone else's?
4) Do you have any other thoughts or suggestions as to what could be going on? Does this situation increase the risks of us losing the baby with heartbeat?

We go in next week for a follow up so I'm sure we will know more then, but are looking for another perspective so we can be prepared as possible, ask whatever questions we need to, etc. Thanks!