Lin H, et al. - Researchers determined how different phases of the menstrual cycle influence circulatory function relative to changes in body position and combined spinal-epidural anaesthesia (CSEA). Participants were 46 women who had scheduled gynaecological surgery, were classified as American Society of Anesthesiology (ASA) I-II, met the test criteria, and were grouped as follicular and corpus luteal groups. These subjects were examined for heart rate measurements as well as systolic, diastolic, and mean blood pressure measurements taken upon entering the operating room, at the beginning of the spinal-epidural anaesthesia, and 10, 20, and 30 min after anaesthesia was administered. Findings showed better ability of women in the follicular phase vs those in the luteal phase to compensate and tolerate circulatory fluctuations, however, the observed effect was slight.