Obstetric cholestasis

What is obstetric cholestasis?

'Obstetric' means the area of medicine that is about pregnant women. 'Cholestasis' means there is a slowing down of the flow of bile down the bile ducts in the liver. This slowing of the flow of bile leads to a build-up of bile and some then leaks out into the bloodstream - in particular, the bile salts. Once in the bloodstream they can make your skin very itchy. It is also sometimes called intrahepatic cholestasis of pregnancy (ICP) and this name is being used more often.

What causes obstetric cholestasis?

Obstetric cholestasis is a problem that can occur with the way the liver works during pregnancy. To understand what obstetric cholestasis is, you first need to understand a little bit about how the liver works normally.

The liver is in your tummy (abdomen), on the upper right-hand side. The liver has many jobs. These include:

• Storing fuel for the body.

• Helping to process fats and proteins from digested food.

• Making proteins that are needed for blood to clot properly.

• Processing some medicines which you may take.

• Helping to remove toxins from the body.

Liver function

Pancreas - bile drainage

The liver also makes bile. Bile helps to break down (digest) fats in the gut. Bile is a greenish-yellow fluid which contains bile acids, bile pigments and waste products such as bilirubin. Liver cells pass bile into bile ducts inside the liver. The bile flows down these ducts into larger and larger ducts, eventually leading to the common bile duct. The gallbladder is like a cul-de-sac reservoir of bile which comes off the common bile duct. After you eat, the gallbladder squeezes bile back into the common bile duct and down into the upper part of the gut (duodenum).

Exactly why obstetric cholestasis happens is not clear. Hormonal and genetic factors may be responsible:

• Hormonal factors. Pregnancy causes an increase in oestrogen and progesterone hormones. These can affect the liver in a way which slows down the bile as it passes out along the tiny bile ducts. Some pregnant women may be more sensitive to these hormonal effects.

• Genetic factors. Obstetric cholestasis seems to run in some families (although it may skip some generations). One theory is that women who develop obstetric cholestasis may have inherited a very slight problem with the way bile is made and passes down the bile ducts. This doesn't matter when they aren't pregnant but the high level of hormones made during pregnancy may tip the balance to really slow down the flow of bile.

There may be other environmental factors which play a part. However, whatever the underlying cause, it is pregnancy that triggers the problem. Within a week or so after giving birth the itch stops and there is no long-term problem with the liver.

What are the symptoms of obstetric cholestasis?

The most common symptom is a really bad itch. You don't get a skin rash but you may get marks on your skin from where you have scratched. The itch can be all over, although it is often particularly bad on your hands and feet. It is often worst at night. Usually itch is the only symptom. The itch tends to get worse until you have your baby. The itch can become so severe that it starts to affect your sleep, your concentration and your mood. It can be really distressing.

Typically, symptoms start after 24 weeks of your pregnancy, when the hormone levels are at their highest. Sometimes it can develop earlier in pregnancy.

Note: mild itching from time to time is normal in pregnancy. However, if you develop a constant itch that gets worse, tell your doctor or midwife. A blood test can confirm if you have obstetric cholestasis.

Other less common symptoms include:

• Tiredness.

• Going off your food and feeling sick.

• Mild jaundice: you may go yellow and your urine may get very dark in colour and your stools go pale. This is uncommon and due to an increased level of bilirubin (part of bile) leaking from the bile ducts into the bloodstream. See the separate leaflet called Jaundice for more details.

A rash is not a symptom of cholestatic jaundice. If you develop a rash you should seek medical advice.

Who gets obstetric cholestasis?

Obstetric cholestasis is a rare condition that only affects you if you are pregnant. In the UK fewer than 1 in 100 pregnant women will develop obstetric cholestasis.

It is more common if you are from certain ethnic groups, such as South Asians and Araucanian Indians. If you are of South Asian origin, it affects about 1 in 67 pregnancies. In certain parts of the world, especially in Chile and Bolivia, up to 1 in 20 or more pregnant women develop this condition. It is also more common if you are carrying twins, triplets, or more babies.

Mothers, daughters and sisters of women who have had obstetric cholestasis have a higher than average risk of also being affected when pregnant. If you have obstetric cholestasis in one pregnancy, you have a high chance that it will happen again in future pregnancies.

What are the risks with obstetric cholestasis?

Many women with obstetric cholestasis feel very anxious about the risks of the condition to their baby. However, the vast majority of women with obstetric cholestasis have a normal healthy baby. If there is a risk, it is small; however, the concerns are as follows:

For your unborn baby

• You are more likely to give birth to your baby early (prematurely). This is usually because your obstetrician advises you that your baby should be delivered early rather than waiting for you to go into labour naturally. Obstetricians are doctors who specialise in pregnancy and childbirth. Being born too early can be risky for your baby. See the separate leaflet called Premature Labour for more details.

• Obstetric cholestasis may increase your chance of having a stillbirth. The risk of a stillbirth in a normal pregnancy is about 1 in 200. The risk if you have obstetric cholestasis may be a little more than this. The evidence is still not clear and further research is being done. The risk appears to have gone down in recent years but it isn't known if this is because of better pregnancy care or as a result of obstetricians advising women to have their labour induced at around 37-38 weeks.

• There is also an increased risk of your baby passing poo (called meconium) whilst they are in the womb. This can irritate the baby's lungs if breathed in when they are being born.

For you

There is possibly a slightly increased risk of more bleeding from the womb than is normal just after giving birth. However, again the research is not definite and there may not be any increased risk of this.

How is obstetric cholestasis diagnosed?

The diagnosis of obstetric cholestasis is suspected if, while pregnant, you develop an itch without any skin rash to explain the itch. A blood test can detect the level of bile acids and liver enzymes in the blood, which will be higher than normal. Other blood tests may be taken to measure other liver functions and to rule out other causes of liver problems such as viral hepatitis. In some cases the itch develops a week or more before the blood test becomes abnormal. Therefore, if the first blood test is normal then another may be done a week or so later if the itch continues.

Sometimes, if your doctor is worried that there might be another reason for your symptoms, you may also need to have an ultrasound scan of your liver and extra scans of your baby.

The diagnosis is confirmed if you have:

• Itch that is not due to any other known cause (such as a skin disorder).

• High levels of liver enzymes and/or bile salts in your blood that cannot be explained by any other liver disease.

Once diagnosed, you will usually need to have a blood test done every week or two until your baby is born. This is done to keep an eye on the levels of liver enzymes and/or bile salts in your blood - experts think that if there is going to be a problem, it is more likely in women with the highest levels.

Both the itch and the high levels of liver enzymes and bile salts will go away soon after your baby is born. A blood test is usually done at least 10 days after your baby is born to confirm that everything is back to normal. This sometimes helps to confirm that the diagnosis was obstetric cholestasis, if there had been any doubt. Sometimes the test is done again at around six weeks after the birth, shortly before your postnatal check, if the levels hadn't completely gone back to normal with the first test.

What is the treatment for obstetric cholestasis?

The condition is not usually serious but can be distressing. Treatment can vary across the UK. Research is currently looking at the safety of a medicine called ursodeoxycholic acid. This is used to lower the amount of bile acids in the blood. Otherwise the following may be advised by your specialist.

General measures

Some women have found that keeping cool helps to ease the itch. Tips to do this include:

• Lowering the thermostat in your house.

• Keeping your body uncovered at night.

• Taking cool showers and baths.

• Soaking your feet or hands in iced water.

These measures may give some temporary relief, particularly before going to bed when the itch may ease enough to allow you to fall asleep. A bland moisturising cream may also give some temporary relief from itch. Some women find aqueous menthol cream helps.