Chances of Miscarrying After Seeing the Fetal Heartbeat on an Ultrasound

One common concern among hopeful parents, especially early in pregnancy, is the risk of miscarriage. If you're newly pregnant and trying to make sense of the myriad of statistics around miscarriage, you're not alone.

Research suggests that your odds of having a miscarriage are lower after a fetal heartbeat has been detected by ultrasound. This is especially true if you're not experiencing vaginal bleeding and you're without other risk factors (such as being older, smoking, drinking, or having an infection).

Learn more about the common risk factors for first and second trimester miscarriages. We also explain how your chances decrease once the heartbeat is seen.

How Many Pregnancies End in Miscarriage?

Research suggests that between 10% and 20% of medically confirmed pregnancies will end in miscarriage, and 80% of these will occur during the first trimester. But many people experience pregnancy loss without realizing it, as some miscarriages occur before a positive pregnancy test result.

Many factors influence your personal risk of pregnancy loss, including your age, body weight, certain medical conditions, and history of prior miscarriages. Overall, the farther along the pregnancy is, the greater the chances of carrying the baby to term. With each passing week, the risk of miscarriage is less and less.

Odds of Miscarriage After Heartbeat

Confirmation of a fetal heartbeat means that the baby has passed the initial stages of development wherein the majority of first trimester miscarriages occur. According to one study, here's the overall risk of miscarriage in asymptomatic pregnant people after detecting a heartbeat:

• Risk after 6 weeks: 9.4%
• Risk after 7 weeks: 4.2%
• Risk after 8 weeks: 1.5%
• Risk after 9 weeks: 0.5%

An older study found a 3.2% miscarriage rate after 8 weeks (it didn't differentiate between people with and without miscarriage symptoms).

It's natural to feel anxious about the health of your developing baby. But if their heartbeat has been detected by ultrasound, that's a positive sign that everything is progressing well. Research shows the risk of miscarriage is reduced once the baby's heartbeat is seen.

First Trimester Miscarriage After Heartbeat

Physicians generally agree that the risk of miscarriage decreases once an ultrasound can detect a heartbeat, which happens around six weeks of gestation. The exact amount the risk decreases, however, varies.

For example, those with vaginal bleeding have a heightened miscarriage risk even after a heartbeat is detected, especially if the bleeding is heavy.

Other factors that increase your chances of miscarriage include:

• Age over 35 years
• Certain medical conditions
• Problems with the uterus or cervix
• Previous history of miscarriages
• Excess weight
• Alcohol, smoking, or drugs

Second Trimester Miscarriage After Seeing a Heartbeat

Having an incompetent cervix is a common cause of second trimester pregnancy loss. Also called "cervical insufficiency," this is a condition in which the cervix weakens and dilates too early, leading to miscarriage or (depending on the length of gestation) pre-term delivery.

If a pregnant person has a history of incompetent cervix, seeing a heartbeat doesn’t reduce the risk of this particular cause of miscarriage, and early prenatal care is essential.

Other risk factors for second trimester miscarriage include:

• Fetal abnormalities
• Problems with the placenta
• Uterine problems
• Certain maternal health conditions, especially if uncontrolled or untreated (diabetes, kidney disease, severe high blood pressure, lupus, thyroid issues, etc.)
• Certain infections
• Certain medications
• Abdominal trauma