This prospective observational cohort study aims to evaluate the association between menstrual phase (determined by postoperative serum progesterone levels), intraoperative anesthetic consumption, and the incidence and severity of postoperative nausea and vomiting (PONV) in female patients undergoing cholecystectomy. Intraoperative anesthetic requirements will be recorded, and postoperative nausea and vomiting will be assessed using standardized scoring systems.

Hormonal fluctuations during the menstrual cycle may influence anesthetic requirements and susceptibility to postoperative nausea and vomiting (PONV). However, the relationship between menstrual phase and intraoperative anesthetic consumption remains unclear.

This prospective observational cohort study will include female patients undergoing elective cholecystectomy under general anesthesia. No intervention will be applied beyond standard clinical practice. Intraoperative anesthetic drug consumption will be recorded quantitatively. Postoperative nausea and vomiting will be evaluated during the early postoperative period using validated assessment tools.

Inclusion Criteria:

• Female patients aged 18 to 65 years
• American Society of Anesthesiologists (ASA) physical status I-II-III
• Scheduled for elective laparoscopic cholecystectomy under general anesthesia
• Willing and able to provide written informed consent

Exclusion Criteria:

• Age outside the specified range (younger than 18 or older than 65 years)
• Male patients
• American Society of Anesthesiologists (ASA) physical status ≥ IV
• Severe systemic comorbidities (e.g., significant cardiovascular, hepatic, renal, or pulmonary disease)
• Conversion from laparoscopic to open cholecystectomy
• History of alcohol, drug, or substance abuse
• Visual or hearing impairment interfering with study assessments
• Current hormone replacement therapy
• Use of oral contraceptives
• Preoperative nausea or vomiting
• History of severe postoperative nausea and vomiting
• Neurological or psychiatric disorders affecting assessment reliability
• Hemodynamic instability during surgery
• Postoperative admission to intensive care unit
• Acute cholecystitis at the time of surgery
• Refusal to participate or inability to provide informed consent

This study includes biologically female patients, as the research objective involves evaluation of menstrual cycle phases and menopausal status based on hormonal measurements.1

The study population consists of female patients aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I-II-III who are scheduled for elective laparoscopic cholecystectomy under general anesthesia. Participants will be classified according to hormonal status (follicular phase, luteal phase, or postmenopausal) based on postoperative serum progesterone levels. All patients will receive standard perioperative care, and no experimental intervention will be applied.

De-identified individual participant data will be available upon reasonable request to the corresponding investigator, following publication of the study results, and subject to institutional and ethical approval.

Beginning 6 months after publication and available for up to 3 years.

Data will be shared electronically after approval of a formal data request and signing of a data use agreement.