Complications
Some studies suggest increased rates of respiratory distress in the newborn, despite gestational age and mode of delivery correction. In a rat model of cholestatic pregnancy, bile acids reduced lung surfactant by acting on macrophages to induce the action of phospholipase A2, which degrades surfactant.[64] In another rat model, bile acids were found to affect respiratory parameters by signalling via the farnesoid X receptor at the hypoglossal nerve.[109] If preterm birth is predicted, as for any other women at risk of preterm birth, administration of intramuscular corticosteroids (betamethasone/dexamethasone) is recommended, ideally within 1 week of delivery, to promote fetal lung maturity.[76][110][111] Intravenous magnesium sulfate is also recommended for neuroprotection of the baby.[110][112]
Typically occurs after 28 gestational weeks. The rate of spontaneous preterm birth increases with higher peak bile acid concentrations, with rates between 6.7% and 16.5%, despite additional high rates of iatrogenic preterm birth.[2]
The reasons for increased neonatal unit admission are likely as a consequence of prematurity (both spontaneous and iatrogenic) and respiratory distress. Although individual studies have reported higher rates of intrapartum fetal distress, mechanisms of determining this are often subjective and not comparable by meta-analysis. There was no increased rate of low Apgar score (<7 at 5 minutes) or low cord pH (umbilical arterial pH <7.0) detected overall.[2]
Compared with control pregnancies, there is an increased risk of gestational diabetes mellitus for women with ICP (pooled odds ratio 2.19, 95% CI 1.58 to 3.03).[20]
Compared with control pregnancies, there is an increased risk of pre-eclampsia for women with ICP (pooled odds ratio 2.58, 95% CI 2.37 to 2.81).[20]
Typically occurs after 35 gestational weeks. For 90% of women with ICP, bile acid concentrations will not rise above 100 micromol/L, and so the risk of stillbirth will not be increased compared with the background population.[2] However, women with bile acids ≥100 micromol/L have an approximately 10-fold risk of stillbirth. Although the risk of stillbirth for this group is higher throughout pregnancy, the risk increases markedly during the 35th gestational week.[2] Similarly, women with multiple pathologies in pregnancy (e.g., gestational diabetes mellitus and pre-eclampsia) may have higher risks of stillbirth.[103]
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