Itching could also be a result of skin conditions that develop in - and are specific to pregnancy. In this latter category, there is almost always a rash. It is discussed in more detail below.

Experts acknowledge that there are many cases of generalized itching in pregnancy which do not fit in any of these categories and whose causes therefore remain unknown.

What are the liver conditions causing itching?
There are several liver conditions that cause symptoms of generalized itching, be it in pregnancy or a non-pregnant state. A doctor has to be on the lookout for and always try to exclude the pregnancy-specific cholestasis. It is generally called "obstetric cholestasis". In the USA, it is also called "pruritus gravidarum".

Its importance lies in the fact that, if unrecognised, it could lead to loss of the baby through stillbirth. It also makes the woman prone to premature labour. Some specific blood tests are required to establish the diagnosis, after which close monitoring of the disease and well-being of both the mother and the baby has to be maintained.

If seen to be progressive, delivery may have to be brought forward. Typically, apart from itching, the mother remains well. Obstetric cholestasis clears up soon after delivery.

How common is obstetric cholestasis?
Uncommon. The estimated incidence in the UK is five to seven in every 1000 pregnant women. Severity varies widely. It is relatively more common among Swedes and some native American tribes.  In Chile for instance, one in every 40 pregnancies is affected and for women of some native tribes, the incidence is double that. This  means there is almost certainly some genetic susceptibility.

How is Obstetric cholestasis diagnosed?
The condition is suspected from the symptoms. This will prompt blood tests based mainly on liver function. Some liver enzymes (transaminases) and specifically bile salts tend to be raised in this condition. The levels will be monitored approximately every week to monitor the progression of the condition.

Are those enzymes always raised in this condition?
No, and that can make the management and decision making rather tricky. However, if the symptoms are typical and other itchy skin conditions have been conclusively excluded, it will be treated as obstetric cholestasis and managed accordingly.

Are there any risks associated with this condition?
Obstetric cholestasis is known to be associated with an increase in the risk of stillbirth the timing of which is very hard to predict. Up to 2% of affected pregnancies will end in stillbirth.

There is also an increase in premature delivery which could be spontaneous or through induction of labour or emergency caesarean section when there is significant concern about fetal wellbeing. Up to 60% of affected women will deliver prematurely.

Can the condition be treated?
Strictly speaking, no.
Emmolients such as calamine lotion, E45®, Diprobase® etc. are offered to try to relieve symptoms. Effectiveness is modest at best.
Ursodeoxycholic acid (UDCA) has been suggested as a possible treatment for relieving symptoms and possibly protecting the baby. The evidence to its effectiveness in this regard remains weak. Brand names of UDCA include Destolit®, Urdox®, Ursogal® etc.