When to seek help

Many women experience some blood loss while pregnant and although there is no bleeding that should be called normal, there are different causes, with the more serious causes being much less common. It is important that if you are worried by the amount of blood lost, or experience any bleeding in the later part of pregnancy (the third trimester), you get checked out straight away.

Bleeding in pregnancy — at any time

Bleeding can come from the cervix or vagina at any time during pregnancy, and can be caused by normal hormonal changes (an “ectropion” on the cervix), or from polyps or infection. This is commonly the type of bleeding brought on by sex. You are likely to be offered examination and testing to determine whether any of these are the cause of your bleeding. Often these causes will have no implications for pregnancy, although some infections can affect the pregnancy too. In some very rare cases, bleeding in pregnancy can be attributable to a cancer, but if this a concern, your doctor will tell you clearly and organise further tests.

Bleeding in Early Pregnancy (less than 14 weeks)

1 in 5 women experience bleeding in pregnancy during the first trimester, and though it may not always indicate a problem it should always be investigated. Your local Early Pregnancy Unit will be able to advise you as to how soon this should happen. Although bleeding is always concerning in pregnancy, if you have had a scan and it has detected your baby’s heartbeat, you will most likely have an ongoing pregnancy. Heavy bleeding that also causes pain or occurs later in the first trimester is more of a concern than light, early bleeding.

Here we discuss some potential causes:

Threatened miscarriage

Any bleeding during this time is medically referred to as a “threatened miscarriage”, but many pregnancies are healthy despite this worrying event, especially if a fetal heart beat can be detected. Unfortunately, there is no medical treatment that can prevent miscarriage, and so providing you do not have other worrying symptoms, a scan is usually arranged within a few days. It may be necessary to repeat this scan 10-14 days later to see how the pregnancy is progressing.

Implantation bleeding

Some women experience spotting right at the beginning of pregnancy (10-14 days after fertilisation). This is thought to be due to the embryo attaching itself to the side of the womb and is sometimes called an “implantation bleed”, although it is not medically well understood. This event is usually painless and, because it happens so early, Early Pregnancy Units may not need to arrange a scan, as the health of the pregnancy cannot be accurately assessed until around 6-7 weeks.

Molar pregnancy

Sometimes, early pregnancy bleeding indicates a molar pregnancy — a rare type of pregnancy in which the baby is never formed but some abnormal pregnancy tissue grows instead. In these cases, your pregnancy hormone level may be very high. A doctor will always discuss this diagnosis with you, because it requires a surgical procedure and follow-up tests.

Ectopic pregnancy

Bleeding can also indicate an ectopic pregnancy. This is where the pregnancy sac grows outside the womb, usually in one of the fallopian tubes. This needs to be investigated and may need treatment as it can be dangerous. If you experience pain as well as bleeding, have a tender belly or feel faint or breathless, you should arrange to be seen immediately, or go to A&E. As well as a scan, you may require blood tests 48 hours apart to further investigate a possible ectopic pregnancy.

Subchorionic haematomas

Areas of bleeding around the pregnancy sac are sometimes seen on early scans; these are called “extrachorionic haemorrhage/haematomas”. They are usually small and are absorbed by your body, although they sometimes cause brownish vaginal bleeding or discharge. In most cases they don’t impact the pregnancy and follow-up isn’t needed, although if they are very big they can unfortunately lead to miscarriage. The nurse or doctor will be able to give you more information if this is seen on your scan.

Bleeding later in pregnancy — before 20 weeks

Few women experience bleeding between 14 and 20 weeks, but the investigations that accompany such bleeding are largely the same as those offered in the first trimester. Unfortunately, babies at this stage are still unable to survive outside the womb, and if the bleeding indicates a miscarriage there are few medical treatments that can help.

If you have no pain and light bleeding, this may suggest your cervix is opening too early even though you are not in labour. This is medically referred to as “cervical insufficiency” (previously “cervical incompetence”) and in some cases, it is possible to perform an emergency procedure called “cerclage” to keep the cervix closed and hold the pregnancy in. However, for this to be offered, the cervix can only be a little dilated (open), and there needs to be no heavy bleeding, no sign of infection and no pain or contractions.

Heavier bleeding with pain can mean the placenta is separating from the womb; sadly, this is likely to lead to a miscarriage, which will be seen on a scan. As this occurs at a later stage of pregnancy, there may be heavy bleeding, and you should be cared for in a private area of the maternity hospital in case you need urgent medical attention.

Bleeding later in pregnancy — after 20 weeks

A pregnancy bleed after 20-24 weeks is referred to as an “antepartum haemorrhage” (APH). Around half of the time a cause is not found, and is often put down to a small amount of placental separation around the edge (a “marginal bleed”). Any APH of fresh blood usually warrants an overnight stay in hospital for observation.

Placental abruption

The placenta can separate suddenly (called a “placental abruption”). This is an emergency as it is dangerous for you and your baby. You may need an emergency caesarean, even if it means that your baby will be very premature.

Placenta Praevia

Around 1 in 5 cases are due to placenta praevia. This is where the placenta is growing too close to the cervix on the inside of the womb. It may be identified at your anomaly scan. Although no treatment is possible and you may continue to bleed intermittently and need frequent hospital stays, the placenta often moves away by the end of pregnancy, allowing for a vaginal delivery. If it doesn’t, a doctor will explain the need for a caesarean. As with a marginal bleed, as long as you are not losing too much blood and your baby remains well, close observation in hospital may be all that is needed.

Vasa praevia

A rarer complication is vasa praevia. This is where the blood is coming from the baby’s blood vessels in the placenta. Babies have very small volumes of blood to start with, and so what looks like a small bleed can still be very dangerous; this is why even small bleeds later in pregnancy need to be assessed straight away.

A “show”

When you are near the end of your pregnancy, it is normal to lose some mucus, and this can have some blood mixed in with it. This mucus is inside the cervix to keep infection out, and comes out as your body prepares for labour (although it cannot be reliably used to predict when your baby is coming). This is nothing to worry about, but if the blood loss is heavier than you would expect or it is fresh red blood rather than mucus, you should contact your Maternity Assessment Centre.

Main points

• Just like any other bleeding, if you are worried by the amount of blood you have lost you should attend A&E or call 999, especially if you are continuing to bleed.
• Although bleeding in early pregnancy can indicate a miscarriage, your pregnancy may also be fine. If you feel well, you do not necessarily need immediate assessment; an early pregnancy scan within a few days is usually offered.
• If you feel faint, short of breath or have shoulder or abdominal pain in early pregnancy, you should call the Early Pregnancy Unit or attend A&E.
• All vaginal bleeding in the third trimester should be assessed at a Maternity Assessment Centre straight away.