A Cochrane review included 21 RCTs involving 1197 women. The trials were small and heterogeneous assessing 11 different interventions resulting in 15 different comparisons Compared with placebo, ursodeoxycholic acid (UDCA) showed improvement in pruritus in 5 (228 women) out of 7 trials. There were no significant differences in instances of fetal distress in the UDCA groups compared with placebo (average risk ratio (RR) 0.67; 95% CI 0.22 to 2.02; 5 trials, n=304; random-effects analysis: T² = 0.74; I² = 48%). There were significantly fewer total preterm births with UDCA (RR 0.46; 95% CI 0.28 to 0.73; 2 trials, n=179). The difference for spontaneous preterm births was not significant (RR 0.99; 95% CI 0.41 to 2.36, 2 trials, n=109). Two trials (48 women) reported lower (better) pruritus scores for S-adenosylmethionine (SAMe) compared with placebo, while 2 other trials of 34 women reported no significant differences between groups. UDCA was more effective in improving pruritus than either SAMe (4 trials; n=133) or cholestyramine (1 trial; n=84), as was combined UDCA+SAMe when compared with placebo (one trial; n=16) and SAMe alone (2 trials; n=68). However, combined UDCA+SAMe was no more effective than UDCA alone in regard to pruritus improvement (one trial; n=53) and 2 trials (n=80) reported data were insufficient to draw any conclusions from. In one trial comparing UDCA and dexamethasone (83 women), a significant improvement with UDCA was seen only in a subgroup of women with severe obstetric cholestasis (23 women). No significant differences were seen in pruritus improvement with other interventions. Eight trials reported fetal or neonatal deaths, with two deaths reported overall (both in the placebo groups). Women receiving UDCA and cholestyramine experienced nausea, vomiting and diarrhoea. Guar gum caused mild abdominal distress, diarrhoea and flatulence during the first days of treatment. Women found charcoal suspension unpleasant to swallow. Dexamethasone caused nausea, dizziness and stomach pain in one woman. One trial (62 women) looked at the timing of delivery intervention. There were no stillbirths or neonatal deaths in 'early delivery' or the 'await spontaneous labour' group. There were no significant differences in the rates of caesarean section, meconium passage or admission to neonatal intensive care unit between the two groups.
Comment: The quality of evidence is downgraded by study quality unclear allocation concealment, blinding, selective reporting), by sparse data,.