pruritus gravidarum (PG)

Last edited 10/2020 and last reviewed 11/2020

Pruritus gravidarum (PG) is a generalized, severe itchiness of late pregnancy where the only skin lesions are those secondary to scratching (1,2,3,4,5)

• is uncertain whether it is an extension of the physiologic changes (“pregnancy is cholestatic”) or a specific dermatosis
• sudden onset of generalized pruritus without primary skin lesions.
• occurs during late second (20%) and on the third trimester (80%) - peaks in the last month before delivery
• palms and soles are affected frequently (4)
• can start as early as the 8th week (4)
• pruritus in pregnancy is common, affecting 23% of pregnancies, of which a small proportion will have obstetric cholestasis (6)
• generalized pruritus is followed by secondary skin excoriations
• thought to be due to cholestasis induced by oestrogens
• environmental (increased incidence during winter) and nutritional (low selenium levels) factors may play a role in the pathogenesis (2)
• resolves at parturition, tends to reappear with consecutive pregnancies, and results from cholestasis in genetically predisposed women
• divided by some into those severe cases with jaundice [intrahepatic cholestasis of pregnancy (ICP)] and those with pruritus and biochemical abnormalities, such as elevated levels of serum bile acids, but without hyperbilirubinemia (PG) (1)
• disease results from disturbances of bilirubin excretion by the effects of estrogen and/or progestins

Consider if possible ICP:

• diagnosis of ICP is based on a combination of pruritus (itching), which classically affects palms and soles but may become generalised, but without a rash apart from excoriations, together with increased concentrations of serum bile acids (values usually at least 10 micromol/ L, or above the upper limit of the normal range for the local
  laboratory)
• increased concentrations of serum transaminases (e.g. alanine aminotransferase (ALT)) greater than 50 U/L are often seen
• there is now movement towards an international consensus that the diagnosis should only be made if serum bile acids are increased, irrespective of whether serum transaminases are increased, either alone or in combination (5)
• women with persistent pruritus and normal biochemistry should have LFTs repeated every 1–2 weeks (6)
• pregnancy-specific reference ranges for LFTs should be used
• postnatal resolution of pruritus and abnormal LFTs should be confirmed
• once obstetric cholestasis is diagnosed, it is reasonable to measure LFTs weekly until delivery(6)

Management:

• seek specialist advice

More detailed information about Intrahepatic cholestasis of pregnancy (ICP) is described in the linked item.

It has been stated if there is a history of obstetric cholestasis then it is better to avoid the oestrogen-containing contraceptive pill (7)

Reference:

• (1) (2009) Pruritus Gravidarum and Intrahepatic Cholestasis of Pregnancy. In: Obstetric Dermatology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-88399-9_11
• (2) Orr B, Usatine R.P. Pruritus in pregnancy. JFP 2007; 56(11)
• (3) Tunzi M, Gray G.R. Common skin conditions during pregnancy. AAFP 2007; 75(2)
• (4) Geenes V, Williamson C. Intrahepatic cholestasis of pregnancy. World J Gastroenterol. 2009;15(17):2049–2066
• (5) Walker KF et al. Pharmacological interventions for treating intrahepatic cholestasis of pregnancy. Cochrane Database of Systematic Reviews 2020, Issue 7. Art. No.: CD000493. DOI: 10.1002/14651858.CD000493.pub3
• (6) Royal College of Obstetricians and Gynaecologists (April 2011). Guideline No. 43 - Obstetric cholestasis.
• (7) RCOG. Obstetric cholestasis - patient information (Accessed 13/10/2020)