Pregnancy induces physiological changes. Plasma volume, cardiac output, hepatic blood flow and protein binding are changed from the first trimester of pregnancy. These physiological changes give effect to the onset and duration of neuromuscular blocking drugs.

Rocuronium is a commonly used neuromuscular blocking drug categorized as FDA category B. Rocuronium is widely used for pregnant women. Previous studies have evaluated the onset and duration of rocuronium in postpartum women. Lately, the investigators have evaluated the onset and duration of rocuronium in early second trimester pregnant women and the duration was significantly longer in early second trimester women compared to non-pregnant women.

Since there is little research on the onset and duration of rocuronium in the late second trimester pregnant women, the investigators planned the present research.