The Meaning of No Fetal Heartbeat on an Early Ultrasound

Seeing your 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 and a fetal heartbeat has been detected.

Sadly, the reverse is also true. If you go in for an ultrasound, and there is no fetal heartbeat, there is a higher likelihood that the pregnancy will not be carried to term. Miscarriage is one explanation for no fetal heartbeat. However, your doctor might not write the pregnancy off yet. There may still be hope.

Sometimes, fetal heart beat cannot be detected, but that doesn't always mean that your baby's heart isn't beating. There are multiple other reasons why the heartbeat of a healthy fetus is not being picked up.

Learn more about why you might not hear a heartbeat at your early ultrasound, and whether or not you should be concerned.

Why Fetal Heartbeat May Not Be Detected

If your provider doesn't hear a heartbeat, they'll assess you for other possible miscarriage symptoms. If you have no other symptoms, rechecking with another ultrasound seven to 10 days is the most common recommendation.

Following are a few possible reasons for the absence of a heartbeat on ultrasound.

Type of Ultrasound

Ultrasounds during pregnancy can be done transvaginally or on your abdomen. Early in pregnancy, a standard abdominal ultrasound won't give your doctor a good view of your fetus. Instead, they will most likely do a transvaginal ultrasound, where a probe is inserted into your vagina to get better access to your uterus.

Transvaginal ultrasound is more accurate that abdominal ultrasound in detecting a fetal heartbeat.

Gestational Age

If you are less than seven weeks pregnant, it's unlikely to find a heartbeat by ultrasound. For this reason, many obstetrics offices won't see pregnant patients until they have passed this gestational age.

By seven to ten weeks, you a transvaginal ultrasound should be able to pick up a fetal heartbeat. But if you're not sure exactly when you conceived, you might not know exactly how far along you are.

Abdominal ultrasound is considerably less sensitive, so it can take longer for the heartbeat to become visible. Most people won't hear one until approximately 10 weeks along.

Accuracy of Your Dates

If you believe you are at least seven weeks along and have had a transvaginal ultrasound that did not detect a fetal heartbeat, consider whether your dates could be wrong. In early pregnancy, being off by a few days or having an irregular ovulation pattern can make a difference.

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. This is true even if it has been seven weeks since your last menstrual period.

If you are not sure when you conceived, your healthcare provide will be able to give you an accurate estimate based on your fetus's measurements at the ultrasound.

No Heartbeat on Follow-Up Ultrasound

If you don't show any other signs of miscarriage, your healthcare provider will most likely ask you to return after a week for a follow-up ultrasound. But if there still is no heartbeat, you might need to prepare yourself for a miscarriage.

Talk to your healthcare provider to see if there might still be a chance for your baby. If you have irregular periods there could be a chance that your pregnancy is not as far along as you think.

Either way, learn the signs of a miscarriage and gear yourself up emotionally. You might also want to buy pads and over the counter pain medication, and see if there's anything on your schedule that you might decide to opt out of during this time.

No Fetal Heartbeat After Seven Weeks Gestation

If you are past seven weeks pregnant, seeing no heartbeat may be a sign of miscarriage. By this point a transvaginal ultrasound should be able to reliable detect a heartbeat or lack thereof.

But there are many exceptions to the "heartbeat by seven weeks" rule. You've likely heard of people who were certain they had miscarried or were not pregnant, and then went on to have a normal pregnancy.

Since there can be exceptions and the approach you take next is extremely important, medical authorities have developed guidelines as to when you can be fairly certain you have had a miscarriage.

Lack of a Fetal Heartbeat Indicating Miscarriage

Sometimes a lack of a fetal heartbeat does indicate a definite miscarriage. If you saw a heartbeat at an earlier ultrasound but not at the next, that's a pretty clear indication that something is not right. It should be getting easier to detect, rather than more difficult.

This is also true if your ultrasound measurements indicate a heartbeat should definitely be present. These measurements give your healthcare provider a clearer idea of gestational age than the date of your last menstrual period. If you're still not getting a heartbeat after your fetus reaches a certain size, you can be fairly certain that you'll lose this pregnancy.

Falling hCG levels are another clue that miscarriage is imminent, especially if you're also not getting a heartbeat. Your provider may measure your hCG levels if you have certain risk factors, such as prior miscarriages.

You can also take pregnancy tests daily and watch for the positives to get darker each day. Just make sure you take the tests at the same time and aren't varying your fluid intake too much, and remember that only your healthcare provider can confirm your hCG levels.

Guidelines for Diagnosing a Miscarriage by Ultrasound

Organizations have adopted different criteria as to when ultrasound findings indicate a miscarriage. Research shows that a heartbeat should definitely be detected in embryos larger than 7 millimeters.

Other criteria that indicate a miscarriage include:

• Absence of an embryo with a heartbeat at least 11 days after an ultrasound of a gestational sac with a yolk sac
• Absence of an embryo with a heartbeat at least two weeks after an ultrasound of a gestational sac with no yolk sac
  
• Gestational sac larger than 8 millimeters without a yolk sac

If You're Told You Have Miscarried

The guidelines listed above can be confusing. It's important that you understand how and why your physician has diagnosed a miscarriage. Be sure to ask any questions you have so that you are confident in and comfortable with your treatment plan. Also, give yourself grace as you process and cope with this news.

If your physician recommends treatment for a miscarriage after one ultrasound (or even after two) and you are not 100% sure that treatment is the right choice, discuss the matter with your doctor and possibly ask for a follow-up ultrasound. Most of the time there is no significant risk associated with waiting a few more days, as long as there is no indication of problems such as an ectopic pregnancy.

Alternatively, you can always get a second opinion from another OB-GYN. 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 confirmation of whether you're miscarrying can be very difficult. However, it is definitely better to be absolutely sure about your diagnosis before moving forward with treatment. Ask as many questions as you need, and expect to receive clear and compassionate answers.

For medical professionals, miscarriages are daily occurrences, but for you, they are not. It is normal to grieve, whether it is the anticipatory grief that comes with wondering about the absence of a heartbeat or the grief of loss if you miscarry. People go through stages of grief after​ a miscarriage and everyone responds differently. Honor yourself and grieve in the way that is best for you.