Relationship Between Serum Estrogen Concentration and Propofol Injection Pain: A Prospective and Observational Study

This prospective observational study aims to evaluate the association between serum estrogen levels and the incidence and severity of propofol injection pain (PIP) in adult female patients undergoing general anesthesia. Although propofol is a widely used intravenous anesthetic, it frequently causes pain upon injection. Estrogen is believed to play a role in modulating pain perception and inflammatory responses, yet the effects of elevated estrogen levels on PIP are not well understood.

The study will be conducted at a single tertiary hospital and will include 90 ASA I-II female patients aged 18-45 years. One group will consist of IVF patients with elevated serum estradiol levels due to controlled ovarian stimulation. The control group will include patients with normal estradiol levels scheduled for elective procedures under general anesthesia. Preoperative serum estradiol levels will be recorded, and injection pain will be evaluated using a validated four-point behavioral pain scale based on vocal response, facial expression, limb movement, and tearfulness.

Anesthesia induction will follow standard clinical practice without additional interventions. Pain data will be collected through routine clinical observation. The results may offer new insights into hormonal modulation of acute nociceptive responses and help improve patient experiences during anesthesia.