Summary: Caroline returns today for her second prenatal ultrasound. The first one was done at around 6 weeks and showed two gestational sacs.
Today, Caroline is 8 weeks pregnant. Her last ultrasound showed two gestational sacs, but heart motion was not yet seen. She chose this particular day for her ultrasound because her husband was able to get time off from work today to be with her.
This is what we saw: 
First, I did a general scan to look at the big picture. Right away, I saw two sacs, but something was wrong. One of the sacs was normal in size and contained a healthy-looking baby with positive fetal heart motion. The second sac was much smaller and contained what appeared to be a small yolk sac. However there was no sign of a fetal pole and there no motion of any sort detected within the sac. Just a look at the disparity between the sizes of the two gestational sacs made it clear that something was different between the two. Even Caroline and Darryl were able to tell.
Sac A, seen here on the left contained a fetus with positive fetal heart motion. Sac B, seen here on the right is much smaller and just more “shriveled” in appearance. There does look like there’s something in there, but it appears to be a yolk sac only. The actual fetal pole is too small to be seen and there is no fetal heart motion.
I then focused on visualizing sac A from a different angle. This second picture shows the same baby as the one seen on the left in the first picture. The measurement of the baby from head to butt is known as the Crown Rump Length. According to the table of average fetal sizes, it was expected to be about 16mm today and when I measured it, it was indeed 16mm. The yolk sac ( not seen in this picture) was measured to be a very small 3mm, which was good news, as we don’t like it at this early gestational age if the yolk sac is very enlarged, as that can lead to a higher risk of miscarriage or fetal abnormality.
You can visualize the very early outline of a baby as the head tilts downwards and to the left. The circular area with blackness inside is the baby’s head, with normal fluid seen inside it. You can see what look like two little angel wings. Those represent the arm buds. In this angle you can’t see the leg buds, but there are there.
So, I explained to Caroline that one baby was super healthy and looking as perfect as it could, but the other one had ceased to grow and was no longer living. When a woman becomes pregnant with twins, or triplets or more, there is always the possibility of something happening to ONE baby, but not to the others. Most of the time, this is because something is genetically not quite right with that specific one. This is a source of mixed feelings that can be very confusing. On one hand, if you told Caroline last month that she would be carrying a single healthy baby, she would have given anything for that to come true. However, it’s normal human nature that once that notion of twin babies enters your imagination, then anything less feels like a loss. Fortunately, Darryl was there to comfort her.
The next challenge is to stay positive while awaiting the next ultrasound. It is a common, rational fear after losing one baby, that the next ultrasound could reveal similar devastating news. Caroline dried her tears and she and Darryl left the office holding hands with ultrasound pictures of their baby in the other hand.
Check here for episode 13 when published.
I am curious about the gestational sac… I tested positive for pregnancy after taking one round of Clomid. The initial bHcg was 180 and then a week later was 2386. One week after that it dropped to 1540 and my doctor told me I would miscarry. She asked me to go in for another test three days later.. that number was 1582. So, it didn’t drop… they were concerned that the pregnancy was ectopic. I had another bHcg drawn (I won’t find out the results until tomorrow) and an ultrasound. I am supposed to be six weeks pregnant. The embryo was 5 weeks 3 days and the gestational sac looked only to be about 4 weeks. There is a fetal heartbeat. Does this always end in miscarriage? If it doesn’t should the pregnancy be terminated? So far, I have no cramping or other signs of impending miscarriage.
Rachel, based on the limited information, I can’t comment definitively on this. Some of the premises given to you seem inconsistent. I will say that if you truly were at 5 weeks and 3 days gestation and the ultrasound showed a sac consistent with 4 weeks, it is highly doubtful that a fetal heartbeat would be seen, especially if it is a few days (you didn’t mention how many days between the last hCG draw and the US) after an hCG of 1582. I’m hoping that this confusing picture is due to incorrect information and that your outcome turns out good.