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 15%.
Both miscarriage and stillbirth describe pregnancy loss. However, they differ according to when the loss occurs. In the United States, a miscarriage describes 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 of pregnancy.
Most pregnancy losses are due to factors that the person cannot control. Early in pregnancy, genetic issues are a major cause of miscarriage.
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.
The American Congress of Obstetricians and Gynecologists (ACOG) define recurrent pregnancy loss as two or more miscarriages in a row. Evidence estimates that fewer than 5 in 100 people experience two miscarriages in a row.
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.
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.
Some people may experience pregnancy loss at such an early stage, they may not be aware they were pregnant, though some may suspect that they were because of pregnancy loss symptoms. Some healthcare experts may refer to this as a chemical pregnancy or biochemical pregnancy.
Some evidence suggests that the overall probability of a pregnancy ending in miscarriage at 4 weeks in the UK is 25%.
The rate of miscarriage at this point varies significantly. An older study suggests that the overall chance of losing a pregnancy after week 5 is 21.3%.
In some cases, it is possible to detect a heartbeat on an ultrasound around week 6 and many health experts may recommend the first trimester scan at around 7 weeks. If a doctor does not detect anything unusual, this likely increases the chance of a continuing pregnancy
In the second half of the first trimester, an older study suggest that the rate of miscarriage seems to be 2–4%.
Most miscarriages happen in the 13 weeks, or first trimester, of pregnancy. The second trimester is the phase between weeks 13–28 of pregnancy. A miscarriage is less likely in the second trimester. Once a pregnancy gets to about 20 weeks gestation, the chance of experiencing a miscarriage is less than 0.5%.
By week 20, a pregnancy loss is known as a stillbirth, and this may cause a person to go into labor.
Will I experience a pregnancy loss?
The review also highlights certain risk factors which can increase the risk of miscarriage. These include:
- very young or older age
- very low or very high body-mass index
- Black ethnicity
- previous miscarriages
- working night shifts
- air pollution
- exposure to pesticides
Some research highlights a higher chance of miscarriage as age increases About half of all first trimester miscarriages occur due to a chromosomal problem in the baby. The risk of chromosome problems increases with the parents age. As such, miscarriage is more likely.
The Royal College of Obstetricians and Gynaecologists note that at the age of 30, the risk of miscarriage is 1 in 5 and over the age of 40, the risk of miscarriage is 1 in 2. A 2019 study suggests that the risk of miscarriage was lowest in females aged
However, 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, a
Some people may 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:
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 contact 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:
- a reduction in pregnancy symptoms
- not feeling the fetus move after regularly experiencing movement
Some FAQs about miscarriage rates by week may include:
What week is most common for miscarriage?
It is difficult to specify a single week. However, most miscarriages occur during the first 12 weeks of pregnancy.
Is miscarriage less likely after 7 weeks?
The rate of miscarriage usually drops after detecting the heartbeat of the baby, which is often around 7–12 weeks.
When does miscarriage rate drop?
Most miscarriages occur at the start of pregnancy. Most miscarriages occur in the first 12 weeks, known as the first trimester or early pregnancy. After this point, the risk of miscarriage decreases.
What are the odds I’ll miscarry?
There are many factors that can influence the risk of miscarriage, such as age, general health, and ethnicity. Evidence suggests that miscarriages occur in roughly
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.