Bleeding when you are pregnant
Bleeding during pregnancy is relatively common. However, bleeding from the vagina at any time in pregnancy can be a dangerous sign, and you should always contact your midwife or GP immediately if it happens to you. Bleeding is not often caused by something serious, but it's very important to make sure and find out the cause straight away.
In early pregnancy you might get some light bleeding, called 'spotting'. This is when the developing embryo plants itself in the wall of your womb. This often happens around the time that your first period after conception would have been due.
Causes of bleeding
During the first 12 weeks of pregnancy, vaginal bleeding can be a sign of miscarriage or ectopic pregnancy. However, many women who bleed at this stage of pregnancy go on to have normal and successful pregnancies.
If a pregnancy ends before the 24th week of pregnancy, it's called a miscarriage. Miscarriages are quite common in the first three months of pregnancy and around one in five confirmed pregnancies ends this way. Many early miscarriages (before 14 weeks) happen because there is something wrong with the baby. There can be other causes of miscarriage, such as hormone or blood clotting problems.
Most miscarriages occur during the first 12 weeks (three months) of pregnancy and, sadly, most cannot be prevented. Find out more about symptoms of miscarriage.
Ectopic pregnancies are less common than miscarriages. Bleeding may be a sign of ectopic pregnancy, when a fertilised egg implants outside the womb, for example in the fallopian tube. The fertilised egg can't develop properly outside the womb and your health may be at serious risk if the pregnancy continues. The egg has to be removed – this can be through an operation or with medicines. Find out more about symptoms of ectopic pregnancy.
In the later stages of pregnancy, vaginal bleeding can have many different causes. Some of the most common are:
Changes in the cervix
The cells on the cervix often change in pregnancy and make it more likely to bleed, particularly after sex. These cell changes are harmless, and are called cervical ectropion. Vaginal infections can also cause a small amount of vaginal bleeding.
The most common sort of bleeding in late pregnancy is the small amount of blood mixed with mucus that is known as a 'show'. This occurs when the plug of mucus that has been in the cervix during pregnancy comes away. This is a sign that the cervix is changing and becoming ready for labour to start. It may happen a few days before contractions start or during labour itself. Find out about signs of labour and what happens.
This is a serious condition in which the placenta starts to come away from the womb wall. Placental abruption usually causes stomach pain, and this may occur even if there is no bleeding. Placental abruption is a serious probem and may necessitate delivery of your baby.
Low-lying placenta (or placenta praevia) is when the placenta is attached in the lower part of the womb, near to or covering the cervix. The position of your placenta is recorded at your anomaly scan, when it's not uncommon to have a low-lying placenta.
However, in most cases the placenta 'moves' upwards away from the cervix as pregnancy progresses. If the placenta remains low in the womb, there is a higher chance that you could bleed during your pregnancy or at the time of the birth. This bleeding can be very heavy and put you and your baby at risk. You may be advised to come into hospital so that you can be given emergency treatment very quickly if you do bleed. Sometimes, an internal (vaginal) scan is needed to find out how close the placenta is to the cervix. This is completely safe.
If the placenta is near the cervix or covering it, the baby cannot get past it to be born vaginally, and a caesarean will be recommended.
The Royal College of Obstetricians and Gynaecologists (RCOG) has more information on placenta praevia.
Vasa praevia is a rare condition. It occurs when the baby's blood vessels run through the membranes covering the cervix. Normally the blood vessels would be protected within the umbilical cord and the placenta. When your waters break (the membranes rupture), these vessels may be torn and this can cause vaginal bleeding. The baby can lose a life-threatening amount of blood.
It is very difficult to diagnose vasa praevia, but it may occasionally be identified before birth by an ultrasound scan. Vasa praevia should be suspected if there is bleeding and the baby's heart rate changes suddenly after the rupture of the membranes.
Finding out the cause of bleeding
To work out what is causing bleeding, you may need to have a vaginal or pelvic examination, an ultrasound scan or blood tests to check your hormone levels. Your doctor will also ask you about other symptoms, such as cramp, pain and dizziness. Sometimes the cause of bleeding cannot be found.
If your symptoms are not severe and your baby is not due for a while, you will be monitored and, in some cases, kept in hospital for observation. How long you need to stay in hospital depends on the cause of the bleeding and how many weeks pregnant you are. Being in hospital enables staff to keep an eye on you and your baby so that they can act quickly if there are any further problems.
Find out about common health problems in pregnancy.