Obstetric cholestasis

What is obstetric cholestasis?

Itchy skin is common during pregnancy and usually harmless, but it may be a sign of the liver condition obstetric cholestasis (also known as intrahepatic cholestasis of pregnancy or ICP) that can occur during the second or third trimester.

There is an increased risk of premature birth and foetal distress with this condition but with good modern obstetric care, where it’s recognised early and managed promptly with early delivery, obstetric cholestasis should no longer result in an increased risk of stillbirth as used to be the case.

There is also an increased risk of haemorrhage in the first few days after the birth (called postpartum haemorrhage), so it’s important to get an itch checked.

Symptoms of obstetric cholestasis

The most noticeable symptom is itching. As many as one in five women complains of itching during pregnancy, especially in the latter stages.

In most cases, the cause isn't known, although it may be related to the effect on the liver of high levels of hormones, or stretching of the skin as the bump grows.

Traditionally, doctors have seen it as a normal part of pregnancy, which requires simple treatment - with calamine lotion, for example.

However, the specific symptoms of obstetric cholestasis include:

• itching that generally begins - or is most intense - on the arms, legs, palms of the hands and soles of the feet
• itching that's usually worse at night
• problems sleeping
• tiredness
• poor appetite
• nausea
• jaundice - yellowing of whites of eyes and skin (uncommon)

It's important to note these symptoms may be very minor or even unnoticeable.

Causes and risk factors of obstetric cholestasis

In obstetric cholestasis, blood tests show signs of liver damage and high levels of a pigment called bilirubin.

Bilirubin is made by the liver and normally passed into the bile (a yellow liquid released from the gall bladder into the digestive tract, containing waste products and chemicals called bile salts to help digestion).

Although the cause of obstetric cholestasis isn't known, both genetic and hormonal factors are thought to play a part.

One current theory is that it may occur in women who have a genetic problem that interferes with the removal of the breakdown products of the female hormones oestrogen and progesterone. Usually, this is so mild it doesn't cause problems.

But during pregnancy, oestrogen and progesterone levels soar. High levels of their breakdown products accumulate, which interfere with the secretion of bile from the liver cells.

Instead of being released into the tiny system of tubes that carry bile towards the gall bladder, bile chemicals such as bilirubin spill back into the blood and are carried around the body to the organs and tissues. This is what causes the itching.

The bile chemicals may also build up in the baby's blood stream, which puts the baby at risk.

In some cases there may also be a link with gallstones, especially if the stones are made of cholesterol.

The main risk is to the unborn child. If not managed properly, statistically in as many as 60 per cent of cases, the baby will be born prematurely, with foetal distress occurring in up to 33 per cent, and stillbirth (intrauterine death) in as many as two per cent.

For this reason, it’s now accepted policy to deliver the baby early, usually between 37-38 weeks, to avoid the highest risk period at the end of pregnancy.

Obstetric cholestasis doesn't usually cause long-term damage to the liver. However, some women find their liver is more sensitive to the normal monthly changes in the female hormones, and they may experience cyclical itching during their menstrual cycle.

This mild and temporary itching can occur just before ovulation or just before a period, stopping when the period starts.

In Europe, obstetric cholestasis occurs in about 0.1 to 1.5 per cent of pregnancies (although it's more common in twin or triplet pregnancies). In some South American countries, such as Bolivia and Chile, it's much more common, affecting as many as one in six pregnancies. Among the native Araucanian population in Chile, nearly 28 per cent of pregnancies are affected. These facts support a genetic cause.

Some doctors think the lower rates in Europe simply reflect the fact that many cases go undetected.

Reported recurrence rates in subsequent pregnancies vary from 40 to 90 per cent, but it’s accepted that there is generally a very high risk of recurrence and so women who have a history of obstetric cholestasis are monitored from early on in subsequent pregnancies.

Women who've had obstetric cholestasis shouldn't use a contraceptive pill containing oestrogen as this may trigger symptoms.

Treatment of obstetric cholestasis

A drug called ursodeoxycholic acid is used to treat obstetric cholestasis, although in most countries it isn't licensed for use in pregnancy. This treatment can reduce itchiness, improve the function of the liver and reduce the risk to the foetus. Possible side-effects include mild diarrhoea.

Women with obstetric cholestasis may be offered an induced birth or caesarean delivery after 37 weeks in an attempt to reduce the risk of complications affecting the baby and the mother.

Treatment with vitamin K may also be needed to prevent problems with bleeding that can result during delivery.