Understanding an Inconclusive Ultrasound

by Teresa J. Mitchell

getting an ultrasound scanWorry. Fear. Anxiety. You might experience these emotions if your early ultrasound came back as "inconclusive." The phrase "inconclusive" means the ultrasound couldn't date the pregnancy and/or determine if your baby is growing and developing. If you're in this situation we hope this article will encourage you and help you understand an "inconclusive" ultrasound.

Most medical caregivers prefer to wait until after the eight-week mark before scheduling an ultrasound. Why? It eliminates unnecessary stress. There might be a situation where an early scan might be necessary.

"When I had my first ultrasound at 5weeks, 5days, there was only a sac. I was worried. Then at 7weeks 5days, there it was! Embryos grow very fast." ~katibug, Pregnancy.org member

Why Would an Ultrasound be Inconclusive?

Inaccurate dating: Your midwife or doctor use your last menstrual period to date your pregnancy. Because women's cycles vary -- some women ovulate much later in their menstrual cycle -- your baby could be younger than predicted.

The type of ultrasound: A vaginal ultrasound allows much better resolution. The technician gets a closer and more accurate look at your tiny babe. The technician will keep you completely covered and ask you to insert the probe or transducer into your vagina, making a sometime awkward moment, more comfortable. If your doctor performed an abdominal ultrasound, the baby might be developing normally but the equipment wasn't able to confirm.

The technician: For most reliable results, an early ultrasound should be performed by an experienced, certified ultrasound technician.

Older equipment: Registered Diagnostic Medical Sonographer and Pregnancy.org Expert, Jane Foley says, "The most common reason a heart beat could not be found on an early ultrasound is the equipment used." She goes on to explain, "The ultrasound equipment found in many doctor's offices is lower quality and might not have the capability to image certain body types. The ultrasound machines used in a dedicated ultrasound department are usually of better quality."

"My vaginal scan at a family practitioner's old machine showed my pregnancy was not viable. My information was transferred to an OB/GYN. He ordered a higher level scan at the hospital that showed the baby -- now a growing child -- was just fine." ~faith, Pregnancy.org member

Ultrasound Heartbeat Timeline

Our "Ask the Ultrasound Expert," Jane Foley explains that:

  • At just over five weeks we're now able to see the first flickering of the heart beating. If your pregnancy is dated in the fifth week, you might get to see a heartbeat. If you don't, doesn't it mean something wrong? No. Even if the baby's growing and developing just fine, you might not see a heartbeat yet.
  • At about six weeks into pregnancy (four weeks from conception), you should be able to see your baby's heartbeat on ultrasound. If you can't, try not to worry. You could have conceived later in your cycle and baby bean's heart isn't scheduled to start thumping.
  • At seven weeks you'll definitely see and hear a strong heart beat and maybe even a little movement from the fetus. Again, if your cycles are irregular or longer than normal, your pregnancy might not actually be at seven weeks.
  • Early heart rate: The typical heart rate at 6½ to 7 weeks is 90-110 beats per minute. As your pregnancy progresses, your baby's average heartbeat increases to 120 and 160 beats per minute.

Any time a first, early ultrasound shows a less mature fetus or no heartbeat than expected, a second ultrasound is scheduled after 7 to 14 days. This waiting period gives the baby time to grow enough that your technician can easily see the changes. That first ultrasound gives you a baseline. The follow-up ultrasound will tell the story. Usually on this second scan, a fetal pole with a heartbeat will be obvious if the pregnancy is progressing normally.

While You Wait

Jane Foley's advice to women in this situation is to try and remove yourself from the medical side of it all. Relax, connect with the life created inside you until it is time to have your next ultrasound.

Have you had an inconclusive ultrasound? Share your story in the comments!

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