Obs & gynae clinic - obstetric cholestasis

The case

A 30-year-old primigravida at 34 weeks’ gestation presents complaining of itching. She describes it mainly over the soles of her feet and palms, and it commenced two weeks ago, although since then her symptoms have become more generalised. She has been using an emollient cream to try to relieve her symptoms. She is detecting normal foetal movements.

On examination her vital signs are stable, no rash is visible on her face, limbs, hands or feet except for a few excoriation marks. The uterus is relaxed and the foetus is in the cephalic presentation. On investigation, her blood results are haemoglobin 10.5g/dl, platelets 198x10⁹/l, ALT 31IU/l, alkaline phosphatase 120IU/l, gamma glutamyl transaminase 12IU/l, bilirubin 8µmol/l, bile acid 24µmol/l (normal range 1-14µmol/l).

Incidence

• Obstetric cholestasis is unique to pregnancy and often a diagnosis of exclusion.

• In England, the condition affects 0.7% of the multi-ethnic population and 1.2-1.5% of the Asian population.

• Obstetric cholestasis is diagnosed when otherwise unexplained pruritus occurs in pregnancy, abnormal LFTs or raised bile acids occur in the
pregnant woman, and both resolve after delivery.¹

Features

• Patients present with severe pruritus affecting the limbs and trunk, particularly the palms and soles of the feet. Excoriation is seen over the affected areas. No rash is visible.

• Symptoms occur mainly in the second half of pregnancy or in the third trimester.

• Pruritus in pregnancy affects 23% of the population, therefore it is necessary to rule out other conditions such as atopic eruption of pregnancy, polymorphic eruption of pregnancy and miscellaneous dermatoses.²

• The dominant symptom of pruritus may often interfere with sleep patterns.

• Other symptoms are pale stools, dark urine and jaundice.

• Associated risk factors are personal or family history of obstetric cholestasis, multiple pregnancy, hepatitis C carrier and presence of gallstones.

Diagnosis

• Unexplained rise in transaminases, gamma glutamyl or bile salts along
with typical presentation are
sufficient to substantiate the diagnosis
in practice.

• Primary bile acids may rise from 10 to 100 times normal.

• It is vital to rule out other causes by performing investigations such as liver ultrasound and viral serology and to check for liver autoantibodies.

• Some women will present with symptoms days or weeks before LFTs become abnormal. Therefore, it is essential to repeat LFTs every one to two weeks.

• In the presence of normal levels of bile salts, symptoms and abnormal LFTs should be sufficient to suspect obstetric cholestasis as a diagnosis.

Risks to mother

• Increased incidence of caesarean section because of early induction of labour.

• Increased risk of postpartum haemorrhage.

• Vitamin K deficiency due to malabsorption of fat-soluble vitamins.

Risks to foetus

Stillbirth is the major concern for those diagnosed with obstetric cholestasis. The RCOG states the current additional risk of stillbirth in obstetric cholestasis above that of the general population has not been determined but is likely to be small.¹ The risk of stillbirth increases towards term, but there is no correlation with severity of symptoms and transaminase levels.

Other risks are:

• intrapartum foetal distress (in 12-22% of cases)

• meconium-stained liquor (25-45%)

• spontaneous preterm delivery (25-45%).

Management

• The patient should be transferred to consultant-led care and delivery should take place in a hospital unit.

• Foetal surveillance should consist of cardiotocography (CTG), ultrasound scans for foetal growth, liquor volume and umbilical artery Doppler blood flow analyses.

• There is no evidence to state which of these methods are best to predict foetal compromise or improve outcomes, and as such there is still a need for further research.

• Focus should be placed on managing maternal symptoms and monitoring liver function and bile acids weekly.

• Emollient creams are safe in pregnancy and may be used for symptom relief.

• Ursodeoxycholic acid has been shown to improve pruritus and liver function levels. Dosages of 1,000-1,500mg in two to three divided doses help to improve symptoms. The woman should be made aware there is insufficient data regarding protection against stillbirth and safety to the foetus.

• The woman should be counselled regarding induction of labour after 37 weeks of gestation. She should be made aware of the possible foetal risks and the need for more stringent monitoring. She should be informed of the increased risk of both maternal and perinatal morbidity due to early intervention. The incidence of stillbirth is unpredictable if pregnancy continues.

• Postnatally, the symptoms usually subside and liver function levels along with bile acids normalise. It is advisable to recheck the level 10 days post-delivery.

Patients should be advised to avoid oestrogen-containing oral contraceptives. There is a 90% risk of recurrence in subsequent pregnancies.

Mrs Ruchira Singh is a consultant obstetrician and Dr Tina Verghese is a registrar at Birmingham Women’s Hospital.

Birmingham Women’s NHS Foundation Trust is a centre of excellence for specialist healthcare for women and their families in the West Midlands. It has approximately 1,500 staff and treats 50,000 patients a year. In 2012 it increased births to 8,000 per year. Click here for more information.

References