A late miscarriage is one that happens after the first 12 weeks of pregnancy, but before 24 weeks. It is also sometimes called a second-trimester or mid-trimester loss. If a baby dies at or after 24 weeks of pregnancy, this is called a stillbirth. Late miscarriages are not very common and happen in 1-2% of pregnancies.
On this page, we explain some of the known reasons why late miscarriages may happen.
It can be very hard to understand why a late loss is called a miscarriage rather than a stillbirth. This is because, from a legal point of view, a baby is thought to have a good chance of surviving if they are born alive at 24 weeks.
This distinction can be upsetting for some women who have a late miscarriage because they may also give birth to their baby and, understandably, feel that it should be called a stillbirth.
Why do late miscarriages happen?
There are several things that may play a part in causing a late miscarriage. Doctors can do tests to try to find out why it happened, but they may not always find a cause. Many of the studies at the Tommy’s National Centre for Miscarriage Research look at why they happen and how to prevent them.
Your risk of miscarriage increases as you get older. Miscarriage may also be more common if the father is older. Find out more about how age affects fertility and pregnancy.
Antiphospholipid syndrome (APS)
APS is an uncommon syndrome that makes your blood more likely to clot. Find out more about antiphospholipid syndrome.
Thrombophilia is an inherited condition that means that your blood may be more likely to clot.
Genetic factors or chromosomal abnormalities
Sometimes, one partner will have an abnormality on one of their chromosomes, which are the genetic structures within our cells that contain our DNA and the features we inherit from our parents. Although this may not affect the parent, it can sometimes cause a miscarriage.
These miscarriages usually happen in early pregnancy (before 12 weeks) but sometimes the baby dies later in pregnancy. Examples are Downs Syndrome, Patau Syndrome, Edwards Syndrome and Turner Syndrome.
If a chromosome abnormality is thought to be a cause of a loss, tests can be carried out checking the baby’s chromosomes from blood, skin or the placenta.
In most cases a chromosome or genetic abnormality happens by chance, but sometimes it can be inherited from a parent. It is possible to check the parents’ chromosomes with blood tests. This might help check the risk of it happening again. If so, the parents can see a specialist to have more tests.
If your cervix (the entrance to the womb) is weak or opens (dilates) too soon, this can lead to a late miscarriage or premature birth.
A weak cervix can be difficult to diagnose when you are not pregnant. Your doctor may believe you have a weak cervix if your waters broke early in a previous pregnancy, or if the cervix opened without any pain.
Find out more about cervical weakness.
Developmental problems of the baby
This is when the baby doesn’t develop properly right from the start and cannot survive.
Any infection that makes you very unwell can cause a miscarriage. Milder infections that affect the baby can also cause a miscarriage. An infection that develops in the womb (intrauterine infection) during pregnancy can also result in miscarriage.
Shape of the womb (uterus)
It is not clear how much an abnormally shaped uterus contributes to late miscarriages.
Some health conditions can increase the risk of miscarriage if they are not treated well. These include diabetes and thyroid problems and should be well controlled before trying for a pregnancy.
Are there any other risk factors?
Most miscarriages are not caused by anything you have or have not done. However, there are factors that can increase the risk:
What happens next?
If you have a late miscarriage, you will need to go through labour to give birth to your baby. This can be a very distressing time and you may be in shock. The staff caring for you at the hospital will understand this and will explain what your options are clearly so you can make a decision about your treatment. Find out more about how late miscarriages are treated.
Your doctor will do some tests to try and find out why you had a late miscarriage. This will help them give you more information about your likelihood of having a successful pregnancy.
If they do find a cause, you may be able to have some treatment.
Sometimes doctors won’t be able to find a reason why you’ve miscarried. But most couples are likely to have a successful pregnancy in the future, particularly if test results are normal.
Your emotional health
Miscarriage can be devastating. You may be struggling with grief, anxiety and shock, but you do not need to go through this alone. There are lots of organisations that can provide more advice and support.
If you’re worried that you or your partner are struggling to cope after losing a baby, please talk to your GP. They will be able to help you get the support you need.
You can also talk to a Tommy’s midwife for free. You can call them Monday-Friday, 9am-5pm on 0800 0147 800 or you can email them at [email protected]. Our midwives are trained in bereavement support so will be able to talk to you about what you’re going through.
Find out more about support after a miscarriage.