Comparative study on the outcome of obstetric cholestasis

Abstract

Objectives. The aim of this study was to determine the characteristics and outcomes of obstetric cholestasis (OC) and the significance of measuring total bile acid (TBA) to aid diagnosis.

Methods. This study was conducted over a 27-month period at a tertiary referral maternity hospital (>8000 deliveries annually). In the study period, 753 women presented with pruritus of no specific origin. This group was divided into OC (TBA ≥6 μmol/L, N=151) and idiopathic pruritus of pregnancy (TBA <6 μmol/L, N=602). The latter group served as controls. Data were collected retrospectively and analyzed using SPSS 11.4 for Windows (SPSS Inc., Chicago, IL, USA).

Results. Patients were matched for age, ethnicity, parity, and smoking status, sex of baby, and Apgar scores at 1 and 5 minutes. OC was noted to be higher in twin pregnancies. Twice as many mothers in the OC group were induced compared to controls. Of the OC group, 18.0% delivered preterm versus 7.7% of controls. Of the mothers with OC, 48.3% had a TBA in the range of 11–39.9 μmol/L, 21.2% had a TBA >40 μmol/L, and the remaining 30.5% had a TBA between 6 and 10.9 μmol/L. Of the OC group with preterm delivery, all had a raised TBA >11 μmol/L.

Conclusions. The presence of OC increases preterm delivery, both idiopathic and iatrogenic. Increasing induction, admission to the neonatal intensive care unit, and low birth weight were also noted. A TBA cut-off value of >11 μmol/L will more accurately aid the diagnosis of OC in the absence of raised liver function test results, reducing the over-diagnosis of this condition.

Keywords:

• Obstetric cholestasis
• idiopathic pruritus of pregnancy
• preterm labor
• fetal distress
• total bile acid
• transaminases
• liver function tests