What Does No Fetal Heartbeat on Early Ultrasound Mean?

It could be a miscarriage or if could simply be too early to tell.

Pregnancy Ultrasound
Getty Images/Tim Hale

Seeing the baby's heartbeat on an early pregnancy ultrasound is one of the surest indicators that a pregnancy is proceeding as it should—in general, the risk of miscarriage is much lower once the pregnancy has reached this point.

But what does it mean if you go in for an ultrasound, and there is no fetal heartbeat? Does this indicate  a miscarriage?

Should I Worry If No Fetal Heartbeat Is Detected on Ultrasound?

If you are not yet six or seven weeks pregnant, it is normal to not see a heartbeat on an ultrasound.

Using a transvaginal ultrasound, the developing baby's heartbeat should be clearly visible by the time a woman is seven weeks pregnant.

Abdominal ultrasound is considerably less sensitive, so it can take longer for the heartbeat to become visible.

This being said, if you are only four or five weeks pregnant, you should not worry about not seeing a heartbeat on the ultrasound—it is simply too early.

If you are past seven weeks pregnant, seeing no heartbeat may be a sign of miscarriage—but this is not a hard and fast rule. In early pregnancy, being off by a few days with your estimated last menstrual period, or having an irregular ovulation pattern can make a difference in whether or not you see a heartbeat on an early ultrasound. For example, if you did not ovulate exactly two weeks after your menstrual period started, there is a chance you are not really "seven weeks pregnant" in gestational age, even if it has been seven weeks since your last menstrual period.

In this situation, unless your physician has other evidence to make a firm diagnosis, you will probably be asked to wait a week and come in for another ultrasound.

Still, sometimes a lack of a fetal heartbeat does indicate a definite miscarriage. These situations would include:

  • Having previously seen the heartbeat but finding no heartbeat on a subsequent ultrasound
  • Seeing no heartbeat and having falling hCG levels
  • Having a follow-up ultrasound after a week and detecting no change (still no heartbeat)

Having ultrasound measurements that indicate a heartbeat should definitely be present are also signs of a miscarriage. These ultrasound measurements include:

  • Crown-rump length of 7 mm or greater and no heartbeat
  • No embryo with a heartbeat 2 weeks or more after an ultrasound scan that showed a gestational sac without a yolk sac
  • No embryo with a heartbeat 11 days or more after an ultrasound that showed a gestational sac with a yolk sac

When You Are Told You Miscarried

If your physician is recommending treatment for a miscarriage after one ultrasound and you are not 100 percent sure that treatment is the right choice, you should discuss the matter with your physician and possibly ask for a follow-up ultrasound.

You need to feel at peace with your decision one way or the other, and you do not want to be second guessing your choices years from now.

Alternatively, you can always get a second opinion from another OB-GYN.

Please remember that there's nothing wrong with getting the advice of another physician if you are in doubt.

A Word from Verywell

Having to wait for word on whether you're miscarrying is understandably difficult and may be one of the hardest weeks of your life—but it is definitely better to be absolutely sure before getting a diagnosis.

Sources:

American College of Obstetrics and Gynecology. (May 2015). Practice Bulletin: Early Pregnancy Loss.

American Pregnancy Association. (August 2015). Concerns Regarding Early Fetal Development

Doubilet PM et al. Diagnostic criteria for nonviable pregnancy early in the first trimester.  N Engl J Med. 2013 Oct 10;369(15):1443-51.

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