Miscarriage rates by week vary between people. However, the chance of experiencing a miscarriage or a pregnancy loss drops as the pregnancy progresses.

The risk figures for pregnancy loss are just averages, so each person’s chance may be higher or lower depending on a range of factors.

A pregnancy loss can occur before a person even knows that they are pregnant. After an ultrasound detects a healthy heartbeat, the chance of pregnancy loss is significantly lower. If a person knows about the pregnancy, the chance of loss is about 10–15%.

A pregnancy loss is the loss of a fetus that occurs before 20 weeks of gestation. A stillbirth is a pregnancy loss that happens any time after 20 weeks.

In this article, learn more about average miscarriage rates by week. This article also covers signs of pregnancy loss.

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Most pregnancy losses are due to factors that the person cannot control. Early in pregnancy, genetic issues are a major cause of miscarriage.

Around 80% of pregnancy losses occur during the first trimester, between 0 and 13 weeks.

Although the loss is often devastating, these genetic issues mean the baby could not have survived outside the womb. Even if a person has this type of pregnancy loss, they can generally go on to have a healthy pregnancy in the future.

Fetuses are most vulnerable early in development, so other factors — such as exposure to alcohol — can have the most damaging effects at this time. This is why most miscarriages occur early in pregnancy.

As the fetus gets stronger, it may be less vulnerable to harm. Also, people may change any potentially damaging lifestyle habits they have once they know that they are pregnant.

A general estimate of miscarriage risk by week is as follows.

Weeks 3–4

Implantation usually occurs around 3 weeks after a person’s last period and about a week after ovulation. By week 4, they may be able to get a positive result on a home pregnancy test.

As many as 50–75% of pregnancies end before getting a positive result on a pregnancy test. Most people will never know that they were pregnant, though some may suspect that they were because of pregnancy loss symptoms.

Week 5

The rate of miscarriage at this point varies significantly. One 2013 study found that the overall chance of losing a pregnancy after week 5 is 21.3%.

Weeks 6–7

The same study suggested that after week 6, the rate of loss drops to 5%. In most cases, it is possible to detect a heartbeat on an ultrasound around week 6.

Weeks 8–13

In the second half of the first trimester, the rate of miscarriage seems to be 2–4%.

Weeks 14–20

Between weeks 14 and 20, the chance of experiencing a miscarriage is less than 1%.

By week 20, a pregnancy loss is known as a stillbirth, and this may cause a person to go into labor.

Stillbirth is relatively rare and is getting rarer because very young babies may be able to survive outside the womb thanks to modern technology.

According to a research group based in the United Kingdom, there is a minimal chance that a baby born at 22 weeks will survive. That chance increases each week.

Will I experience a pregnancy loss?

A 2012 study looked at the overall chance of pregnancy loss during the first and second trimesters and found it to be between 11–22% in weeks 5 through 20. Other research puts the percentage at around 10–15%.

These statistics suggest that the chance of pregnancy varies from person to person depending on a variety of factors, including their age and overall health.

Age is a major risk factor for pregnancy loss. This is because egg quality tends to decline over time.

The average chance of miscarriage by the age of the pregnant person is as follows:

  • Under 35 years old: There is a 15% chance of pregnancy loss.
  • Between 35 and 45 years old: There is a 20–35% chance of pregnancy loss.
  • Over 45 years old: There is a roughly 50% chance of pregnancy loss.

It is essential to note that these are average figures and do not take any other factors into account.

The effects of lifestyle issues, such as smoking or having a sedentary lifestyle, can also accumulate with age. This may worsen underlying health issues and further increase the chance of pregnancy loss.

All that said, some people have healthy pregnancies in their 40s, and a few do so in their 50s.

Most people who experience a pregnancy loss go on to have healthy pregnancies in the future. Having a single miscarriage does not mean that a person will have difficulty getting or staying pregnant in the future.

In fact, one 2016 study found that people are more likely to get pregnant again immediately after experiencing a pregnancy loss.

Some people ask for genetic testing following one or more pregnancy losses. Genetic testing may help a doctor understand the cause of pregnancy loss.

Some risk factors for pregnancy loss include:

  • being older
  • smoking
  • using certain drugs, especially stimulant drugs such as cocaine or high amounts of caffeine
  • having an uncontrolled chronic condition, such as diabetes or high blood pressure
  • having a hormonal disorder that makes it difficult for the body to produce hormones to sustain the pregnancy

Most of the time, the earliest sign of a miscarriage is bleeding. However, not all bleeding is due to a pregnancy loss.

Some people experience spotting during pregnancy. Bleeding is more likely to indicate a miscarriage when it is heavy, gets heavier with time, or occurs with intense cramps.

A miscarriage can also happen without bleeding.

Some other symptoms of a pregnancy loss include:

  • a sudden reduction in pregnancy symptoms, though symptoms can decrease even without a miscarriage due to fluctuating hormones
  • a decrease in the fetus’s movements in the second trimester
  • intense cramps
  • passing blood clots

A person should speak with a doctor about any bleeding they experience during pregnancy. If the bleeding is heavy or painful, it is best to go to the emergency room.

Some other symptoms to monitor for include:

  • cramps
  • a reduction in pregnancy symptoms
  • not feeling the fetus move after regularly experiencing movement

Most pregnancies end with a healthy birth, even if the person has a previous history of or risk factors for a miscarriage.

There is no right or wrong way to react to a pregnancy loss. The experience can be emotional or spur doubts about future pregnancies. Conversely, some people are surprised that they do not have a strong reaction to a pregnancy loss.

A pregnancy loss is not anyone’s fault. Most people can have a healthy pregnancy following a miscarriage.

Receiving quality medical care, having support from one’s friends and family, and taking time to heal can help people manage the process.