Design: Randomised, double-blind, placebo-controlled, single centre
Population: 96 women having elective caesarean under epidural ropivacaine
Primary outcome: Pain score and heart rate variability across five time points
Effect: Nausea/vomiting 6.2% vs 25.0% (RR 0.25, 95% CI 0.08 to 0.83)

In a single-centre double-blind trial, 96 women having elective caesarean with epidural ropivacaine were randomised to 0.3 mg epidural hydromorphone or saline.

Nausea or vomiting occurred in 6.2% with hydromorphone and 25.0% with saline (RR 0.25, 95% CI 0.08 to 0.83). Pain scores during abdominal exploration were low in both groups, with medians of 1.65 and 1.90 out of 10, and the overall pain-over-time pattern differed between groups. No woman had respiratory depression, and neonatal outcomes were similar.

The nausea finding is clinically useful, as traction-related discomfort and vomiting are a common reason for intraoperative distress. But the pain comparison focused on a time point chosen after registration, and the heart-rate-variability outcome was not significant, so the pain result needs confirmation.

Consider a low-dose epidural opioid adjunct when traction discomfort or nausea is a recurring problem at elective caesarean
Agree any change with your obstetric anaesthesia team and local protocol before adopting it
Monitor respiratory rate and sedation after neuraxial opioids as usual
Warn women that pulling sensations at caesarean are common even with a good block

Why it matters

Intraoperative vomiting during traction is a frequent, distressing event that a small dose change may reduce.

The statistics, in plain English

An RR of 0.25 means nausea or vomiting was about a quarter as common, but with 48 women per group the interval is wide (0.08 to 0.83). The pain difference of 0.25 points on a 10-point scale is statistically significant but too small for most women to notice.