Obstetric cholestasis is a rare complication of pregnancy. A build-up of bile acids in the bloodstream causes a persistent itch in the last third of pregnancy. There may be a small increased risk of complications of pregnancy associated with this condition, but the evidence is not conclusive. The symptoms go when you have your baby. Some treatments may help to ease the itch.
Understanding the liver, bile and and bile ducts
The liver is in the upper right part of the abdomen. 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 essential for blood to clot; processing some medicines which you may take; helping to remove poisons and toxins from the body.
The liver also makes bile. This 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 duodenum (upper gut). Bile helps to digest fats.
What is obstetric cholestasis?
Obstetric cholestasis is a condition of the liver which occurs in some pregnant women. Cholestasis means there is a reduced flow of bile down the bile ducts in the liver. Some bile then leaks out into the bloodstream, in particular the bile salts. These circulate in the bloodstream and can cause symptoms. Obstetric cholestasis is also called intrahepatic cholestasis of pregnancy by some doctors.
Who gets obstetric cholestasis?
Obstetric cholestasis occurs in less than 1 in 100 pregnancies in the UK. It is more common in women carrying twins, triplets, or more. Mothers, daughters and sisters of affected women 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 occur in future pregnancies.
It is more common in certain parts of the world. For example, in some countries in South America, especially Chile and Bolivia, up to 1 in 20 or more pregnant women develop this condition.
What causes obstetric cholestasis?
The exact cause is not clear. Hormonal and genetic factors may be responsible:
- Hormonal factors. Pregnancy causes an increase in oestrogen and progestogen hormones. These can affect the liver in a way which slows down the rate of bile passing 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 inherit a slight problem with the way bile is made and passes down the bile ducts. This does not matter when not pregnant. However, the high level of hormones made during pregnancy may tip the balance to cause a much reduced flow of bile.
There may be other environmental factors which contribute. However, whatever the underlying cause, the pregnancy triggers the problem. Within a week or so after giving birth the symptoms clear and there is no long-term problem with the liver.
What are the symptoms of obstetric cholestasis?
Typically, symptoms occur after 24 weeks of pregnancy when the hormone levels are at their highest. Sometimes it develops earlier in pregnancy.
Itch is the most common symptom. The itch can be all over, but it is often worst on the hands and feet. Commonly, itch is the only symptom. It tends to get worse until you have the baby. The itch can become severe and affect sleep, concentration and mood. It can become distressing.
Note: mild itching from time to time is normal in pregnancy. However, if you develop a constant itch that gets worse, tell your doctor. A blood test can confirm if you have obstetric cholestasis.
Other less common symptoms include:
- Poor appetite and feeling sick.
- Mild jaundice. You may go yellow and have dark urine and pale stools. This is uncommon and due to an increased level of bilirubin (part of bile) leaking from the bile ducts into the bloodstream.
Is obstetric cholestasis serious?
The symptoms can be unpleasant for the mother - in particular the itch. But whether obstetric cholestasis causes an increased risk of harm to mother or baby is still being debated. If there is a risk, it is thought to be small, but the concerns are as follows.
For the unborn baby
Until recently it had been thought that obstetric cholestasis caused a small increased risk of stillbirth. The risk of stillbirth in a normal pregnancy is about 1 in 100. The risk if you have obstetric cholestasis was thought to be a little more than this. The evidence is still not clear and further research is being done.
There is an increased risk of your baby being born too early (prematurely). This is usually because your obstetrician may decide that your baby should be delivered early rather than waiting for you to go into labour naturally.
There is also an increased risk of your baby passing meconium (like poo) whilst they are in the womb. This can irritate the baby's lungs if breathed in during delivery.
More research is currently underway into the risks and effects of the condition and treatment. If you have obstetric cholestasis you should have a good discussion with your obstetrician and midwife about how big the risks are and how they can be prevented.
For the mother
There is possibly an increased risk of serious bleeding from the womb just after giving birth. However, again the studies are not conclusive and there may be no increased risk of this.
How is obstetric cholestasis diagnosed?
The diagnosis is suspected if you develop itch during pregnancy. A blood test can detect the raised level of bile acids and liver enzymes in the blood. 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.
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.
Both the itch and high level of liver enzymes and bile salts go away after the birth of the baby. A blood test done sometime after the baby is born can confirm this. This sometimes helps to confirm that the diagnosis was obstetric cholestasis, if there had been any doubt.
What is the treatment for obstetric cholestasis?
There is no cure for obstetric cholestasis. As mentioned, the condition is not usually serious but can be distressing. Symptoms go once you have the baby. The following may be advised by your specialist, which may help.
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.
This is a naturally occurring bile acid and is used as a medication. It is often taken to help relieve itch, and usually works. It also improves the liver blood tests. However, there is little evidence that it changes the outlook for the baby. Further research is needed to be sure.
Vitamin K supplements
Vitamin K is essential for the blood clotting mechanism to work. Sometimes the level is reduced in people with liver and bile problems. So, it seems sensible to make sure that you do not lack this vitamin. This is why supplements are often advised.
Regular antenatal checks
You may be advised to have antenatal checks more often than usual to monitor the progress of your baby carefully. You may have a blood test every two weeks, to check your liver.
Deciding about early delivery of the baby
Until recently it was thought that there was an increased risk of stillbirth with obstetric cholestasis. Because of this, many specialists used to induce labour so that you would give birth early - usually at 37 weeks of pregnancy. However, the concern about an increased risk of stillbirth is still not clear. So your obstetrician should discuss the pros and cons of early delivery with you. There are sometimes risks in having your baby early too. Your specialist can advise about the most up-to-date thinking and practice about this.
Further reading & references
|Original Author: Dr Tim Kenny||Current Version: Dr Hayley Willacy||Peer Reviewer: Dr Tim Kenny|
|Last Checked: 21/02/2012||Document ID: 4401 Version: 41||© EMIS|
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