Epidural analgesia for pain relief in labor may not be suitable for all patients, and intravenous patient controlled analgesia (IV PCA) with opioids offers the best alternative. The purpose of this study is to assess the effectiveness of two methods remifentanil administration in the form of either an infusion or PCA demand bolus (intravenous injection of a single dose over a short period of time). Currently, our hospital gives remifentanil by demand bolus, however it may be equally effective, with less side effects, to give the drug as an infusion.