Association of adverse perinatal outcomes of intrahepatic cholestasis of pregnancy with biochemical markers: results of aggregate and individual patient data meta-analyses

Background Intrahepatic cholestasis of pregnancy is associated with adverse perinatal outcomes, but the association with the concentration of specific biochemical markers is unclear. We aimed to quantify the adverse perinatal effects of intrahepatic cholestasis of pregnancy in women with increased serum bile acid concentrations and determine whether elevated bile acid concentrations were associated with the risk of stillbirth and preterm birth. Methods We did a systematic review by searching PubMed, Web of Science, and Embase databases for studies published from database inception to June 1, 2018, reporting perinatal outcomes for women with intrahepatic cholestasis of pregnancy when serum bile acid concentrations were available. Inclusion criteria were studies defining intrahepatic cholestasis of pregnancy based upon pruritus and elevated serum bile acid concentrations, with or without raised liver aminotransferase concentrations. Eligible studies were case-control, cohort, and population-based studies, and randomised controlled trials, with at least 30 participants, and that reported bile acid concentrations and perinatal outcomes. Studies at potential higher risk of reporter bias were excluded, including case reports, studies not comprising cohorts, or successive cases seen in a unit; we also excluded studies with high risk of bias from groups selected (eg, a subgroup of babies with poor outcomes were explicitly excluded), conference abstracts, and Letters to the Editor without clear peer review. We also included unpublished data from two UK hospitals. We did a random effects meta-analysis to determine risk of adverse perinatal outcomes. Aggregate data for maternal and perinatal outcomes were extracted from case-control studies, and individual patient data (IPD) were requested from study authors for all types of study (as no control group was required for the IPD analysis) to assess associations between biochemical markers and adverse outcomes using logistic and stepwise logistic regression. This study is registered with PROSPERO, number CRD42017069134. Findings We assessed 109 full-text articles, of which 23 studies were eligible for the aggregate data meta-analysis (5557 intrahepatic cholestasis of pregnancy cases and 165 136 controls), and 27 provided IPD (5269 intrahepatic cholestasis of pregnancy cases). Stillbirth occurred in 45 (0·91%) of 4936 intrahepatic cholestasis of pregnancy cases and 519 (0·32%) of 163 947 control pregnancies (odds ratio [OR] 1·46 [95% CI 0·73–2·89]; I2=59·8%). In singleton pregnancies, stillbirth was associated with maximum total bile acid concentration (area under the receiver operating characteristic curve [ROC AUC]) 0·83 [95% CI 0·74–0·92]), but not alanine aminotransferase (ROC AUC 0·46 [0·35–0·57]). For singleton pregnancies, the prevalence of stillbirth was three (0·13%; 95% CI 0·02–0·38) of 2310 intrahepatic cholestasis of pregnancy cases in women with serum total bile acids of less than 40 μmol/L versus four (0·28%; 0·08–0·72) of 1412 cases with total bile acids of 40–99 μmol/L (hazard ratio [HR] 2·35 [95% CI 0·52–10·50]; p=0·26), and versus 18 (3·44%; 2·05–5·37) of 524 cases for bile acids of 100 μmol/L or more (HR 30·50 [8·83–105·30]; p<0·0001). Interpretation The risk of stillbirth is increased in women with intrahepatic cholestasis of pregnancy and singleton pregnancies when serum bile acids concentrations are of 100 μmol/L or more. Because most women with intrahepatic cholestasis of pregnancy have bile acids below this concentration, they can probably be reassured that the risk of stillbirth is similar to that of pregnant women in the general population, provided repeat bile acid testing is done until delivery. Funding Tommy's, ICP Support, UK National Institute of Health Research, Wellcome Trust, and Genesis Research Trust

A multi-centre, open label, randomised, parallel-group, superiority Trial to compare the efficacy of URsodeoxycholic acid with RIFampicin in the management of women with severe early onset Intrahepatic Cholestasis of pregnancy : the TURRIFIC randomised trial

BackgroundSevere early onset (less than 34weeks gestation) intrahepatic cholestasis of pregnancy (ICP) affects 0.1% of pregnant women in Australia and is associated with a 3-fold increased risk of stillbirth, fetal hypoxia and compromise, spontaneous preterm birth, as well as increased frequencies of pre-eclampsia and gestational diabetes. ICP is often familial and overlaps with other cholestatic disorders.Treatment options for ICP are not well established, although there are limited data to support the use of ursodeoxycholic acid (UDCA) to relieve pruritus, the main symptom. Rifampicin, a widely used antibiotic including in pregnant women, is effective in reducing pruritus in non-pregnancy cholestasis and has been used as a supplement to UDCA in severe ICP. Many women with ICP are electively delivered preterm, although there are no randomised data to support this approach.MethodsWe have initiated an international multicentre randomised clinical trial to compare the clinical efficacy of rifampicin tablets (300mg bd) with that of UDCA tablets (up to 2000mg daily) in reducing pruritus in women with ICP, using visual pruritus scores as a measuring tool.DiscussionOur study will be the first to examine the outcomes of treatment specifically in the severe early onset form of ICP, comparing "standard" UDCA therapy with rifampicin, and so be able to provide for the first-time high-quality evidence for use of rifampicin in severe ICP. It will also allow an assessment of feasibility of a future trial to test whether elective early delivery in severe ICP is beneficial.Trial identifiersAustralian New Zealand Clinical Trials Registration Number (ANZCTR): 12618000332224p (29/08/2018). HREC No: HREC/18/WCHN/36.EudraCT number: 2018-004011-44.IRAS: 272398.NHMRC registration: APP1152418 and APP117853.Peer reviewe

A multi-centre, open label, randomised, parallel-group, superiority Trial to compare the efficacy of URsodeoxycholic acid with RIFampicin in the management of women with severe early onset Intrahepatic Cholestasis of pregnancy: the TURRIFIC randomised trial

BackgroundSevere early onset (less than 34weeks gestation) intrahepatic cholestasis of pregnancy (ICP) affects 0.1% of pregnant women in Australia and is associated with a 3-fold increased risk of stillbirth, fetal hypoxia and compromise, spontaneous preterm birth, as well as increased frequencies of pre-eclampsia and gestational diabetes. ICP is often familial and overlaps with other cholestatic disorders.Treatment options for ICP are not well established, although there are limited data to support the use of ursodeoxycholic acid (UDCA) to relieve pruritus, the main symptom. Rifampicin, a widely used antibiotic including in pregnant women, is effective in reducing pruritus in non-pregnancy cholestasis and has been used as a supplement to UDCA in severe ICP. Many women with ICP are electively delivered preterm, although there are no randomised data to support this approach.MethodsWe have initiated an international multicentre randomised clinical trial to compare the clinical efficacy of rifampicin tablets (300mg bd) with that of UDCA tablets (up to 2000mg daily) in reducing pruritus in women with ICP, using visual pruritus scores as a measuring tool.DiscussionOur study will be the first to examine the outcomes of treatment specifically in the severe early onset form of ICP, comparing "standard" UDCA therapy with rifampicin, and so be able to provide for the first-time high-quality evidence for use of rifampicin in severe ICP. It will also allow an assessment of feasibility of a future trial to test whether elective early delivery in severe ICP is beneficial.Trial identifiersAustralian New Zealand Clinical Trials Registration Number (ANZCTR): 12618000332224p (29/08/2018). HREC No: HREC/18/WCHN/36.EudraCT number: 2018-004011-44.IRAS: 272398.NHMRC registration: APP1152418 and APP117853

Bile acid reference intervals for evidence-based practice

In this edition, Huri et al. (BJOG 2022) have added to the growing literature defining pregnancy-specific reference ranges for total serum bile acid (TSBA) concentrations.Reference intervals in clinical pathology are typically calculated using an ‘indirect resource’, such as stored laboratory samples. Results are partitioned into biologically relevant groups (typically age and sex), outliers are excluded to remove anomalous results due to disease, and the central 95% of the population is calculated for each group. Two large studies, that of Huri et al. and our own (Mitchell et al. BJOG 2021;128:1635–44), have recently calculated reference intervals for non-fasting TSBA concentrations in the third trimester of pregnancy, finding strikingly similar results for the upper limit (20.2 and 18.3 μmol/l, respectively). Both studies excluded samples with cholestatic pathology before analysis, treating the cohorts as a ‘direct resource’ and obviating exclusion of outliers.However, the results demonstrate outliers within each dataset. In the study by Huri et al. this may have been the result of the selected participants having other gestational diseases (for example, gestational diabetes) and originating from samples taken during hospital admission; the reason for women being inpatients may have influenced serum bile acid concentrations and therefore confounded the findings. To assess the impact of excluding outliers, we used the block D/R (Zellner et al. arXiv preprint; 1907.09637.) procedure to identify outliers in our dataset (from outpatient samples routinely taken and limited to uncomplicated pregnancies), and reanalysis revealed a slight reduction in the upper limit of the reference interval and narrowing of the confidence interval (Table 1)