Comparative study on the outcome of obstetric cholestasis.

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 > or =6 micromol/L, N=151) and idiopathic pruritus of pregnancy (TBA <6 micromol/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 micromol/L, 21.2% had a TBA >40 micromol/L, and the remaining 30.5% had a TBA between 6 and 10.9 micromol/L. Of the OC group with preterm delivery, all had a raised TBA >11 micromol/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 micromol/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.