History and exam

Key diagnostic factors

common

pruritus

Itch in the absence of another cause in pregnancy is suggestive of ICP, but can occur in uncomplicated pregnancies.

excoriations without rash

Absence of papules, urticaria, pustules, ulcers, or plaques, along with the presence of excoriations.

Other diagnostic factors

uncommon

mild jaundice

Only a few will have developed noticeable jaundice; women may report dark urine, pale stools, and yellowing of conjunctivae.

Risk factors

strong

family history of ICP

Genetic predisposition seems to have a role in ICP in many patients. Liver dysfunction in pregnancy was common in first-degree relatives of Finnish women with ICP (odds ratio 4.8 to 9.2).[31]

previous history of ICP

The recurrence risk of ICP is around 70% in subsequent pregnancies.[21][25] This is unsurprising given the association with genetic variations. There is no evidence to establish whether severity differs in subsequent pregnancies.

history of hepatitis C infection

A meta-analysis of three studies demonstrated an odds ratio of 20.40 (95% CI 9.39 to 44.33) for women with hepatitis C to develop ICP.[74]

cholelithiasis

Women with ICP have relatively high rates of gallstones, or biliary sludge, on ultrasound scan.[17] Although gallstones do not cause the disease themselves, the genes in which there is genetic variation in ICP are also associated with increased risk of gallstones.[48]

weak

chronic hepatitis B infection

Chronic hepatitis B infection (serum hepatitis B surface antigen [HBsAg] positive) is associated with an increased risk of ICP (adjusted odds ratio 3.83, 95% CI 3.14 to 4.68), with higher risk for those also with hepatitis B e antigen (HBeAg).[75]

multifetal pregnancy

Women with multifetal pregnancy have higher rates of ICP. A Chinese study reported the rate of ICP in twin pregnancies to be 6.7%, compared with 1.3% in singleton pregnancies.[50]

assisted reproduction

Women who have conceived with assisted reproduction have higher rates of ICP than those with spontaneous conception; in a Chinese study, conception by assisted reproduction was associated with an odds ratio of 2.79 (95% CI 2.15 to 3.64) for the development of ICP.[51] This increase is seen for both single and multifetal pregnancies.

ethnicity

The incidence of ICP shows geographic variation, which might reflect differences in susceptibility according to ethnicity or environmental factors. See Epidemiology.

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