Odds of Miscarriage After Seeing Heartbeat on Ultrasound

Fetal Heartbeat Begins at About 6 Weeks

fetal ultrasound
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Seeing the baby's heartbeat on an ultrasound is a good sign and does put a pregnancy into a lower risk category for miscarriage.

What Are the Odds of Miscarriage After Seeing a Fetal Heartbeat on an Ultrasound?]\

Physicians generally agree that the risk of miscarriage decreases once the pregnancy reaches a point that an ultrasound can detect a heartbeat. The exact amount that it decreases, however, seems to vary by group.

It's hard to say any exact numbers from the available research, but here are some statistics that certain studies have come up with.

For women with no vaginal bleeding, most estimates suggest that the odds or having a miscarriage after seeing a heartbeat are about 4%.

For women with vaginal bleeding but also a detected heartbeat on ultrasound, risk of miscarriage is about 13% according to one study.

One study found that about 17% of women with a history of recurrent miscarriages will miscarry after seeing a heartbeat on the ultrasound.

Mothers aged 35 and older also face significant miscarriage risk after ultrasound detects a heartbeat, even though the risk does drop after detecting the heartbeat. A 1996 study found that women over 36 have a 16% risk of miscarriage at this point, and women over 40 have a 20% risk.

Fetal Physiology Explained

Fetal heartbeat is an extremely important step in the development of a baby.

After all, we need our hearts to pump blood and survive.

Here are some other notable things that happen around the first trimester of gestation. Please note that this overview is by no means complete. For more information, visit the NIH.

Week 5 of Pregnancy

This week begins the embryonic period. During the embryonic period, the baby's major systems and structures start to develop.

The baby's external features also begin to develop during week 5.

Week 5 is a rapid period of growth for the baby. During week 5, the baby is most sensitive to teratogens or things that may cause birth defects, such as illicit drugs,  certain medications, and infections.

Weeks 6 and 7 of Pregnancy

During weeks 6 and 7 the baby's heart begins to grow and beat at a regular rhythm.

Here are some other things that happen during weeks 6 and 7:

  • eyes and ear buds form
  • spine begins to form
  • blood begins to circulate

Week 8 of Pregnancy

During week 8 of pregnancy, the arms start to grow longer. Additionally, the hands and feet look like paddles. Furthermore, the lungs start to form.

Week 9 of Pregnancy

During week 9, all the baby's organs have started to grow. Additionally, hair follicles begin to develop and the baby's toes develop.

Week 10 of Pregnancy

At end of the tenth week of pregnancy, the baby is no longer an embryo and is instead called a fetus. In other words, the baby has exited the embryonic stage.

During this week of pregnancy, the eyelids begin to form, the outer ears form and the intestines rotate.

Weeks 11 to 14

During these weeks, the genitals begin to form and the face is well formed.

Weeks 15 to 18

The liver and pancreas form. The skin is transparent and the baby starts making sucking motions.


Hill, L.M., D. Guzick, J. Fries, J. Hixson, "Fetal loss rate after ultrasonically documented cardiac activity between 6 and 14 weeks, menstrual age." Journal of Clinical Ultrasound May 1991. Accessed 11 Feb 2008.

Smith, K.E. and R.P. Buyalos, "The profound impact of patient age on pregnancy outcome after early detection of fetal cardiac activity." Fertility and Sterility Jan 1996. Accessed 11 Feb 2008.

Van Leeuwen, Ingeborg, D. Ware Branch, and James R. Scott, "First-Trimester Ultrasonography Findings in Women With a History of Recurrent Pregnancy Loss. American Journal of Obstetrics and Gynecology 1993. Accessed 11 Feb 2008.


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