Comparison of intraoperative hemodynamic changes and recovery outcomes between non-menopausal and postmenopausal women undergoing total abdominal hysterectomy under general anesthesia.

This study included 48 women undergoing total abdominal hysterectomy (TAH) at Kamali Hospital. Of these, 23 patients (47.9%) were postmenopausal, and 25 (52.1%) were non-menopausal. The mean age of the study population was 53.85 ± 8.74 years, and the mean body mass index (BMI) was 29.55 ± 3.87 kg/m². None of the participants had a history of smoking, alcohol consumption, or illicit drug use. Normality was assessed using the Shapiro–Wilk test. Age and baseline body temperature were normally distributed and were compared between groups using the independent-samples t-test. In contrast, BMI, baseline heart rate, SPO₂, MAP, duration of surgery, and recovery time were not normally distributed and were analyzed using the Mann–Whitney U test. Categorical variables were compared using Fisher’s exact test. Baseline comparisons demonstrated statistically significant differences in age, BMI, baseline MAP, and preoperative body temperature between the two groups. As expected, postmenopausal women were significantly older than non-menopausal women (61.17 ± 5.65 vs. 47.12 ± 4.68 years, p  < 0.001) and had higher BMI, baseline MAP, and preoperative body temperature compared with non-menopausal women (BMI: p  < 0.001; MAP: p  = 0.014; temperature: p  = 0.023). No statistically significant differences were observed between the groups in baseline heart rate, SPO₂, duration of surgery, or recovery time. The baseline characteristics of the study population are summarized in Table  1 . Table 1 Baseline characteristics of study participants Variable Total ( n  = 48) Non-menopausal ( n  = 25) Postmenopausal ( n  = 23) P value Age (years)* < 0.001  Mean ± SD 53.85 ± 8.74 47.12 ± 4.68 61.17 ± 5.65  (Min–Max) 39.00–71.00 39.00–55.00 51.00–71.00 BMI (kg/m²) † < 0.001  Median [IQR] 30.30 [6.73] 28.90 [6.80] 30.90 [2.80]  (Min–Max) 21.70–35.20 21.70–35.20 23.30–34.20 Alcohol consumption 0 0 0 - smoking 0 0 0 - Drug abuse 0 0 0 - Surgery time (min) † 100.0 [30.0] 100.0 [25.0] 100.0 [30.0] 0.489 Recovery time (min) † 30.0 [15.0] 45.0 [15.0] 30 [17.5] 0.069 Baseline MAP (mmHg) † 100.0 [16.07] 95.0 [19.6] 103.7 [14.0] 0.014 Baseline SPO 2 (%) † 95.0 [5.0] 94.0 [6.0] 96.0 [4.0] 0.528 Baseline HR (bpm) † 76.5 [27.0] 80.0 [29.0] 65.0 [30.0] 0.074 Baseline body temperature (°C) * 36.6 ± 0.48 36.56 ± 0.22 36.76 ± 0.36 0.023 BMI body mass index, MAP mean arterial pressure, SPO ₂ peripheral oxygen saturation, HR heart rate, SD standard deviation, bpm beats per minute, IQR interquartile range * Normally distributed continuous variables are presented as mean ± standard deviation (SD) and were compared using the independent-samples t-test † Non-normally distributed continuous variables are presented as median [interquartile range (IQR)] and were compared using the Mann–Whitney U test Categorical variables were compared using Fisher’s exact test Baseline characteristics of study participants BMI body mass index, MAP mean arterial pressure, SPO ₂ peripheral oxygen saturation, HR heart rate, SD standard deviation, bpm beats per minute, IQR interquartile range * Normally distributed continuous variables are presented as mean ± standard deviation (SD) and were compared using the independent-samples t-test † Non-normally distributed continuous variables are presented as median [interquartile range (IQR)] and were compared using the Mann–Whitney U test Categorical variables were compared using Fisher’s exact test Overall postoperative outcomes showed the occurrence of at least one episode of each complication during the observation period. Shivering was significantly more frequent in the non-menopausal group than in the postmenopausal group (76% vs. 13%, P  < 0.001). In contrast, blood pressure variability was significantly more common in the postmenopausal group (65.2% vs. 60%, P  = 0.002). No significant between-group differences were observed for postoperative nausea and vomiting, heart rate changes, level of consciousness, pain, agitation, or oxygen desaturation (all P  > 0.05). The overall incidence of perioperative complications is presented in Table  2 . Table 2 Comparison of overall perioperative adverse events and recovery outcomes between postmenopausal and non-menopausal women Complication Non-menopausal n (%) Postmenopausal n (%) p -value (Fisher) Effect size (φ) PONV 9 (36%) 9 (39.1%) 1.00 0.032 HR change 14 (56%) 15 (65.2%) 0.566 0.094 Pain 15 (60%) 16 (69.6%) 0.556 0.100 Shivering 19 (76%) 3 (13%) < 0.001 * 0.631 Agitation 16 (60%) 18 (78.3%) 0.221 0.197 SPO₂ <92% 11 (44%) 15 (65.2%) 0.161 0.213 BP variability 15 (60%) 15 (65.2%) 0.002 * 0.542 LOC decrease 21 (84%) 23 (100%) 0.111 0.289 P values were calculated using Fisher’s exact test. Effect sizes for categorical variables were estimated using Phi coefficient (φ) * A two-sided p-value < 0.05 was considered statistically significant Comparison of overall perioperative adverse events and recovery outcomes between postmenopausal and non-menopausal women P values were calculated using Fisher’s exact test. Effect sizes for categorical variables were estimated using Phi coefficient (φ) * A two-sided p-value < 0.05 was considered statistically significant The mean intraoperative MAP was significantly higher in the menopausal group than in the non-menopausal group (105.91 ± 11.87 vs. 94.60 ± 11.27 mmHg, respectively; independent-samples t-test, t(46) = 3.385, P  = 0.001), with a mean difference of 11.31 mmHg (95% CI: 4.59–18.04). In contrast, the mean intraoperative heart rate differed significantly between the two groups, with the non-menopausal group demonstrating significantly higher values than the menopausal group (mean rank: 32.76 vs. 15.52, respectively; Mann–Whitney U = 81.0, Z = − 4.262, P  < 0.001). Intraoperative SPO₂ did not differ significantly between menopausal and non-menopausal patients (Mann–Whitney U = 252.5, Z = − 0.733, P  = 0.464). The mean intraoperative body temperature was comparable between the two groups, with no significant difference observed between menopausal and non-menopausal women (36.61 ± 0.27 °C vs. 36.57 ± 0.26 °C, respectively; independent-samples t-test, t (46) = 0.533, P  = 0.597). Table  3 summarizes the hemodynamic changes observed during the first 60 min after surgery in the PACU. No significant between-group differences were found in MAP changes at any time point. However, HR changes were significantly greater in the non-menopausal group at 30 and 45 min ( P  = 0.011 and P  = 0.042, respectively). Body temperature remained consistently higher in postmenopausal women throughout the PACU stay. At 15 min after surgery (T1), postmenopausal women had significantly higher temperatures than non-menopausal women (37.05 ± 0.36 °C vs. 36.28 ± 0.30 °C; t (46) = 8.179, P  < 0.001), with a mean difference of 0.78 °C (95% CI: 0.59–0.97). This difference persisted at 30 min (T2) (37.07 ± 0.31 °C vs. 36.65 ± 0.22 °C; t (43) = 5.255, P  < 0.001) and 45 min (T3) (37.11 ± 0.29 °C vs. 36.80 ± 0.22 °C; t (26) = 3.206, P  = 0.004). At 60 min (T4), postmenopausal women continued to have higher temperatures (37.55 ± 0.07 °C vs. 36.60 ± 0.20 °C; t (3) = 6.183, P  = 0.009); however, this result should be interpreted with caution because only five patients remained in the PACU at this time point (postmenopausal: n  = 2; non-menopausal: n  = 3). Furthermore, as shown in Table  4 , postoperative shivering was significantly more frequent in the non-menopausal group during the first 30 min. In contrast, no significant between-group differences were observed for SPO₂, level of consciousness, pain, postoperative nausea and vomiting, or agitation. Table 3 Comparison of postoperative hemodynamic changes between postmenopausal and non-menopausal women at different PACU time points Variable Category 15 min Post ( n  = 23) 15 min non ( n  = 25) P -value 30 min post ( n  = 23) 30 min non ( n  = 22) P -value 45 min post ( n  = 16) 45 min non ( n  = 12) P -value 60 min post ( n  = 2) 60 min non ( n  = 3) P -value MAP changes (%) > 50% 1 (4.3) 1 (4.0) 0.765 2 (8.7) 1 (4.5) 1.000 3 (18.8) 0 (0.0) 0.216 1 (33.3) 0 (0.0) 1.000 20–49% 6 (26.1) 9 (36.0) 1 (4.3) 1 (4.5) 6 (37.5) 7 (58.3) 1 (33.3) 2 (66.7)  50% 0 (0.0) 2 (8.0) 0.765 0 (0.0) 4 (18.2) 0.011 0 (0.0) 1 (8.33) 0.042 0 (0.0) 0 (0.0) 1.000 20–49% 10 (43.5) 11 (44.0) 14 (60.9) 16 (72.7) 8 (50.0) 10 (83.3) 1 (50.0) 2 (66.7)  92% Without oxygen 9 (39.13) 0 0.348 13 (56.5) 17 (77.2) 0.184 13 (81.2) 3 (25.0) 1.000 1 (50.0) 2 (66.6) 1.000 > 90% With oxygen 12 (52.1) 12 (48.0) 7 (30.4) 5 (22.7) 3 (18.7) 9 (75.0) 1 (50.0) 1 (33.3) < 90% With oxygen 2 (8.6) 13 (52.0) 3 (13.0) 0 0 0 0 0 Data are presented as n (%). P-values were calculated using Fisher’s exact test MAP, mean arterial pressure; HR, heart rate; min, minutes The number of available observations varied across time points because of missing measurements. At 60 min, only five observations were available (postmenopausal: n  = 2; non-menopausal: n  = 3); therefore, results should be interpreted cautiously Comparison of postoperative hemodynamic changes between postmenopausal and non-menopausal women at different PACU time points SPO2 Changes (%) > 92% Without oxygen 9 (39.13) 13 (56.5) 17 (77.2) 13 (81.2) 3 (25.0) 1 (50.0) 2 (66.6) > 90% With oxygen 12 (52.1) 12 (48.0) 7 (30.4) 5 (22.7) 3 (18.7) 9 (75.0) 1 (50.0) 1 (33.3) < 90% With oxygen 2 (8.6) 13 (52.0) 3 (13.0) Data are presented as n (%). P-values were calculated using Fisher’s exact test MAP, mean arterial pressure; HR, heart rate; min, minutes The number of available observations varied across time points because of missing measurements. At 60 min, only five observations were available (postmenopausal: n  = 2; non-menopausal: n  = 3); therefore, results should be interpreted cautiously Table 4 Comparison of postoperative recovery outcomes between postmenopausal and non-menopausal women at different PACU time points Outcome 15 min P 30 min P 45 min P 60 min P Temperature < 0.001 < 0.001 0.004 0.009 SPO₂ 0.348 0.137 0.137 1.000 Shivering < 0.001 0.035 NA* NA* LOC 0.844 0.445 0.645 1.000 Pain 0.733 0.189 0.639 1.000 PONV 1.000 1.000 NA* NA* Agitation 0.222 0.373 0.252 1.000 SPO ₂ peripheral oxygen saturation, LOC level of consciousness, PONV postoperative nausea and vomiting, min minutes, NA * Not Applicable P-values were calculated using Fisher’s exact test for categorical outcomes and independent-samples t-test for normally distributed temperature measurements NA * indicates that statistical testing was not performed because no variability was observed in the outcome at that time point Comparison of postoperative recovery outcomes between postmenopausal and non-menopausal women at different PACU time points SPO ₂ peripheral oxygen saturation, LOC level of consciousness, PONV postoperative nausea and vomiting, min minutes, NA * Not Applicable P-values were calculated using Fisher’s exact test for categorical outcomes and independent-samples t-test for normally distributed temperature measurements NA * indicates that statistical testing was not performed because no variability was observed in the outcome at that time point Repeated-measures ANOVA revealed that the pattern of perioperative changes differed among the evaluated physiological variables. No significant main effect of time was observed for HR or MAP; however, a significant time × menopausal status interaction was detected for HR, indicating different temporal trends between postmenopausal and non-menopausal women. For MAP, neither the main effect of time nor the interaction effect was statistically significant. For SPO₂, a significant change over time and a significant interaction with menopausal status were observed, suggesting different oxygen saturation patterns between the two groups during the perioperative period. Body temperature also showed significant changes over time, with a significant time × menopausal status interaction, indicating distinct temperature trajectories between postmenopausal and non-menopausal women. Detailed results of the repeated-measures ANOVA are presented in Table  5 , and Fig.  1 illustrates the time-dependent changes in the assessed variables between the two groups. Detailed results of the repeated-measures ANOVA are presented in Table  5 , and the temporal trends of these variables in postmenopausal and non-menopausal women are illustrated in Fig.  1 . Table 5 Results of repeated-measures ANOVA assessing changes in physiological parameters over time and the interaction with menopausal status Outcome Correction Time F (df1, df2) P η² p Time × Menopause F (df1, df2) P η² p HR Greenhouse–Geisser 2.748 (2.413,103.744) 0.058 0.060 6.706 (2.413,103.744) 0.001 0.135 MAP Greenhouse–Geisser 1.497 (2.128,91.493) 0.229 0.034 1.719 (2.128,91.493) 0.183 0.038 SPO₂ Sphericity Assumed 35.841 (3,129) < 0.001 0.455 2.772 (3,129) 0.044 0.061 Temperature Sphericity Assumed 6.658 (4,104) < 0.001 0.204 8.771 (4,104) < 0.001 0.252 HR heart rate, MAP mean arterial pressure, SPO ₂ peripheral oxygen saturation, ANOVA analysis of variance, df degrees of freedom, F F-statistic, P p-value, η ² p partial eta squared Mauchly’s test was used to assess the assumption of sphericity. Greenhouse–Geisser correction was applied when the sphericity assumption was violated; otherwise, sphericity-assumed results are reported. Effect sizes are presented as partial eta squared (η²p) Results of repeated-measures ANOVA assessing changes in physiological parameters over time and the interaction with menopausal status HR heart rate, MAP mean arterial pressure, SPO ₂ peripheral oxygen saturation, ANOVA analysis of variance, df degrees of freedom, F F-statistic, P p-value, η ² p partial eta squared Mauchly’s test was used to assess the assumption of sphericity. Greenhouse–Geisser correction was applied when the sphericity assumption was violated; otherwise, sphericity-assumed results are reported. Effect sizes are presented as partial eta squared (η²p) Fig. 1 Changes in mean arterial pressure, heart rate, oxygen saturation, and body temperature over time in menopausal and non-menopausal women during the preoperative, intraoperative, and postoperative recovery periods. The number of patients decreased over time because participants were discharged from the PACU once discharge criteria were met, resulting in fewer observations at later postoperative time points Changes in mean arterial pressure, heart rate, oxygen saturation, and body temperature over time in menopausal and non-menopausal women during the preoperative, intraoperative, and postoperative recovery periods. The number of patients decreased over time because participants were discharged from the PACU once discharge criteria were met, resulting in fewer observations at later postoperative time points Because significant baseline differences were observed between the two groups, particularly in age, BMI, baseline MAP, and body temperature, additional analysis of covariance (ANCOVA) was performed to assess whether the associations between menopausal status and postoperative physiological outcomes remained after adjustment for these potential confounders. Age was included as a covariate in all models because it differed significantly between groups and may influence perioperative physiological responses. For MAP, the models were adjusted for age, BMI, baseline MAP, and baseline body temperature. For heart rate, the models were adjusted for age, BMI, baseline heart rate, and baseline body temperature. Body temperature analyses were adjusted for age, BMI, and baseline body temperature, whereas SPO₂ analyses were adjusted for age, BMI, and baseline SPO₂. After adjustment, menopausal status remained significantly associated with MAP at 15 and 30 min after PACU admission, heart rate at 15 and 30 min, and body temperature at 15 and 30 min. However, no significant association was observed between menopausal status and postoperative oxygen saturation after adjustment (Table  6 ). Table 6 Adjusted ANCOVA analyses assessing the association between menopausal status and postoperative physiological outcomes after controlling for baseline covariates Outcome Adjusted effect of menopausal status (F) P value Partial η² MAP (15 min PACU) 5.244 0.027 0.111 MAP (30 min PACU) 5.971 0.019 0.133 Heart rate (15 min PACU) 12.614 0.001 0.231 Heart rate (30 min PACU) 20.463 < 0.001 0.344 SPO₂ (15 min PACU) 0.112 0.740 0.003 SPO₂ (30 min PACU) 0.500 0.484 0.012 Body temperature (15 min PACU) 19.559 < 0.001 0.313 Body temperature (30 min PACU) 6.501 0.015 0.140 ANCOVA analysis of covariance, MAP mean arterial pressure, PACU post-anesthesia care unit, SPO ₂ peripheral oxygen saturation ANCOVA models were adjusted for age, BMI, and the baseline value of the corresponding outcome variable. F statistics and p-values represent the adjusted effect of menopausal status. Effect sizes are presented as partial eta squared (η²p) Adjusted ANCOVA analyses assessing the association between menopausal status and postoperative physiological outcomes after controlling for baseline covariates ANCOVA analysis of covariance, MAP mean arterial pressure, PACU post-anesthesia care unit, SPO ₂ peripheral oxygen saturation ANCOVA models were adjusted for age, BMI, and the baseline value of the corresponding outcome variable. F statistics and p-values represent the adjusted effect of menopausal status. Effect sizes are presented as partial eta squared (η²p)

This study was designed as a prospective comparative observational study to evaluate intraoperative hemodynamic changes and postoperative anesthesia-related outcomes in non-menopausal and postmenopausal women undergoing elective abdominal hysterectomy under standardized general anesthesia. The study was conducted and reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. The study was conducted at Kamali Hospital, Alborz, Iran and was conducted in accordance with the ethical principles of the Declaration of Helsinki. Ethical approval was obtained from the institutional review board of Alborz University of Medical Sciences (IR.ABZUMS.REC.1404.009). Written informed consent was obtained from all participants before enrollment. Confidentiality and anonymization of data were strictly maintained throughout the study. A total of 48 patients scheduled to undergo elective hysterectomy between December 2025 and March 2026 were enrolled in the study. Because of the limited number of eligible patients during the study period, no formal sample size calculation was performed. All consecutive eligible patients who met the inclusion criteria were enrolled, resulting in a final sample of 48 participants. Of the enrolled patients, 23 were postmenopausal, and 25 were non-menopausal. To minimize assessment bias, participants were assigned anonymous study codes before data collection. The investigator responsible for recording intraoperative hemodynamic variables and postoperative recovery outcomes was blinded to the participants’ menopausal status throughout the study. Participants were classified into menopausal and non-menopausal groups only after completion of data collection during the statistical analysis. Inclusion criteria included ASA physical status I and absence of significant systemic diseases, including hypertension, diabetes mellitus, asthma, or thyroid disorders. Menopausal status was determined based on preoperative clinical history; women were classified as postmenopausal if they had experienced spontaneous amenorrhea for ≥ 12 consecutive months before surgery. Patients were excluded if they required blood transfusion or vasoactive support, had anticipated or actual difficult intubation, surgical duration exceeded 2 h, recovery time exceeded 60 min, intraoperative instability necessitated deviation from the standardized anesthetic protocol, or had surgical menopause. Patients receiving any form of hormone therapy, including menopausal hormone therapy, were also excluded to minimize potential confounding effects of exogenous hormones on physiological and thermoregulatory responses. To minimize inter-individual variability, all patients received an identical standardized anesthetic protocol. Anesthesia induction was performed using fentanyl (3 µg/kg), midazolam (0.01 mg/kg), propofol (1.5 mg/kg), and atracurium (0.6 mg/kg), followed by endotracheal intubation under standardized conditions using a Macintosh laryngoscope (blade size 4). Anesthesia was maintained with 1% isoflurane and intermittent atracurium administration (0.2 mg/kg every 30 min as required). Intraoperative fluid management was conducted according to the standard anesthesia fluid replacement formula, including maintenance requirements, preoperative fasting deficit, and ongoing surgical losses. Patients received approximately 2.5–3.0 L of warmed Ringer’s solution during surgery. Allowable blood loss (ABL) was calculated based on an assumed hemoglobin concentration of 10 g/dL, and patients requiring intraoperative blood transfusion due to blood loss exceeding the calculated ABL were excluded. Intraoperative analgesia was standardized with a total morphine dose of 0.1 mg/kg, and neuromuscular blockade was reversed using neostigmine (0.04 mg/kg) combined with atropine (0.02 mg/kg). Perioperative temperature management was standardized for all patients. The operating room temperature was maintained at 23 °C and the PACU temperature at 25 °C. Warming blankets were applied as part of routine thermal management. Body temperature was measured non-invasively using a forehead (temporal) thermometer at baseline and at predefined postoperative time points. All procedures were performed by the same surgeon and managed by the same anesthesiologist to further reduce operator- and anesthesia-related confounding factors between study groups. Level of consciousness was assessed using a three-point scale adapted from the Aldrete recovery score, where 2 indicated alert and oriented status, 1 indicated response to verbal stimulation, and 0 indicated no response. Mean arterial pressure (MAP) and heart rate were recorded both as continuous numerical values and as categorical scores in the recovery unit every 15 min. For categorical assessment of circulatory recovery, blood pressure changes from baseline were evaluated according to the circulation component of the modified Aldrete scoring system. A score of 2 was assigned when the change in blood pressure from baseline was < 20%, a score of 1 for changes of 20–49%, and a score of 0 for changes ≥ 50%. Oxygen saturation (SPO₂) was evaluated both as a continuous variable and according to modified Aldrete-based criteria, where SPO₂ ≥92% on room air was assigned a score of 2, SPO₂ ≥90% with supplemental oxygen was assigned a score of 1, and SPO₂ <90% was assigned a score of 0. Body temperature was recorded as a continuous numeric variable. A standardized case report form (CRF) was used solely for prospective recording of study variables, including demographic characteristics, preoperative and intraoperative hemodynamic parameters, and postoperative recovery outcomes. The form served as a data recording tool and did not constitute a newly developed measurement instrument. Intraoperative hemodynamic variables, including blood pressure, heart rate, Body temperature, and SPO₂, were recorded as continuous values at 5-minute intervals throughout surgery, and baseline preoperative values were also documented for comparison. Postoperative outcomes in the recovery unit, including shivering, pain, agitation, nausea, and vomiting, were recorded and coded as binary variables (yes/no). Two analytical approaches were used for data analysis. In the first approach, the overall incidence of postoperative complications and intraoperative hemodynamic changes was assessed. Patients who experienced at least one episode of blood pressure changes, heart rate variations, or nausea and vomiting both intraoperatively and in the recovery were categorized as 1, while those without any occurrence were assigned a score of 2. In the second approach, continuous physiological variables, including preoperative body temperature, mean intraoperative body temperature, postoperative body temperature measured at 15-minute intervals in the PACU, mean arterial pressure, heart rate, and oxygen saturation, were analyzed to evaluate temporal changes and differences between the menopausal and non-menopausal groups. Pain, shivering, and agitation were recorded at each 15-minute assessment and classified as present or absent (coded as 1 and 2, respectively), allowing comparison of their frequency over time between the two groups. To address potential confounding due to baseline differences between groups, additional analysis of covariance (ANCOVA) was performed. For postoperative MAP, the analyses were adjusted for age, BMI, baseline MAP, and baseline body temperature. For postoperative heart rate, analyses were adjusted for age, BMI, baseline heart rate, and baseline body temperature. For postoperative body temperature, analyses were adjusted for age, BMI, and baseline body temperature, while postoperative oxygen saturation analyses were adjusted for age, BMI, and baseline oxygen saturation. Adjusted analyses were performed for postoperative time points with sufficient available observations. Data were analyzed using SPSS version 26 (IBM Corp., Armonk, NY, USA). Normality was assessed using the Kolmogorov–Smirnov test. Between-group comparisons were performed using an independent t-test or Mann–Whitney U test, as appropriate. To evaluate changes in hemodynamic variables and body temperature over time, a two-way repeated-measures ANOVA was performed with time as the within-subject factor and menopausal status as the between-subject factor. The assumption of sphericity was assessed using Mauchly’s test for all repeated measures. When the assumption of sphericity was violated, the Greenhouse–Geisser correction was applied. A p-value < 0.05 was considered statistically significant.

In this prospective observational study including 48 women undergoing total abdominal hysterectomy (23 postmenopausal and 25 non-menopausal), menopausal status was associated with distinct differences in perioperative autonomic and thermoregulatory responses. Specifically, postmenopausal women exhibited significantly higher perioperative MAP and body temperature, whereas non-menopausal women demonstrated significantly higher heart rate and a greater incidence of postoperative shivering. Repeated-measures analysis further demonstrated significant time-by-menopausal status interactions for heart rate, oxygen saturation, and body temperature. Moreover, these associations remained significant after adjustment for age, BMI, and baseline physiological variables using ANCOVA, indicating that the observed differences in MAP, heart rate, and body temperature at 15 and 30 min after PACU admission were not fully explained by baseline group differences. In contrast, routine postoperative recovery parameters remained largely comparable between the two groups. From a clinical perspective, the higher frequency of shivering and lower postoperative temperature observed in non-menopausal women may indicate greater vulnerability to perioperative thermal disturbances. These findings suggest that individualized perioperative temperature monitoring and active warming strategies may be particularly beneficial in this population. In contrast, mean arterial pressure remained higher in postmenopausal women throughout the intraoperative period. Previous studies have suggested that estrogen deficiency is associated with endothelial dysfunction, increased arterial stiffness, impaired baroreflex sensitivity, heightened sympathetic activity, and increased peripheral vascular resistance, all of which may influence vascular regulation [ 5 , 19 ]. However, because baseline mean arterial pressure was also significantly higher in the postmenopausal group, these pre-existing cardiovascular differences may have contributed to the observed intraoperative findings. Furthermore, hormonal markers such as estradiol and FSH were not measured; therefore, the proposed physiological mechanisms cannot be directly confirmed in the present study. Notably, the association between menopausal status and perioperative mean arterial pressure remained significant after adjustment for age, BMI, baseline mean arterial pressure, and baseline body temperature using ANCOVA. Accordingly, our findings suggest an independent association between menopausal status and perioperative blood pressure regulation, but they should be interpreted cautiously and should not be considered evidence of a direct causal effect of menopause or estrogen deficiency [ 20 ]. Although sex-based differences in perioperative outcomes have been reported, the literature remains heterogeneous, with some studies demonstrating higher rates of complications such as hemodynamic instability, pain, nausea, vomiting, and shivering in women compared with men, while others report no significant differences for specific endpoints [ 21 ]. Notably, hormonal status has been shown in some surgical populations to modulate postoperative nausea and vomiting, with reduced incidence observed in postmenopausal women, suggesting a potential role of estrogen in emetogenic pathway sensitivity [ 4 ]. In the present study, the absence of significant differences in pain and PONV may be explained by the relatively high and standardized surgical stimulus of TAH, combined with intraoperative morphine administration. In contrast, heart rate, body temperature, shivering, and mean arterial pressure differed between the postmenopausal and non-menopausal groups. These findings are consistent with previous studies suggesting that long-term estrogen deficiency may be associated with alterations in cardiovascular and thermoregulatory regulation; however, these mechanisms were not directly evaluated in the present study and therefore remain speculative. Postmenopausal women demonstrated higher perioperative and early postoperative body temperatures than non-menopausal women. Although previous studies have reported lower resting core body temperatures in postmenopausal women, differences in study populations and perioperative conditions, including surgical stress, general anesthesia, perioperative warming strategies, and body composition, may account for these contrasting findings [ 5 , 10 , 22 ]. Given the relatively small sample size, these observations should be interpreted with caution and require confirmation in larger, adequately powered studies. Although these physiological differences were not accompanied by clinically meaningful differences in early postoperative recovery, recognition of the observed perioperative hemodynamic and thermoregulatory patterns may help anesthesiologists anticipate potential physiological variations and optimize perioperative monitoring and supportive management. Patients undergoing total abdominal hysterectomy were selected because this procedure provides a relatively homogeneous surgical model with respect to patient characteristics, surgical technique, anesthetic management, and perioperative care. This standardization minimizes procedural variability and facilitates the evaluation of physiological differences associated with menopausal status. However, because the present study was limited to women undergoing elective total abdominal hysterectomy under standardized general anesthesia, the findings should be interpreted within this specific clinical context. Their generalizability to other surgical procedures, emergency surgeries, or different anesthetic techniques remains uncertain and warrants confirmation in larger studies involving more diverse surgical populations. The strengths of this study include its prospective design, a standardized anesthetic and analgesic protocol, a homogeneous surgical cohort undergoing the same procedure, and repeated perioperative assessments of autonomic and recovery variables, thereby reducing clinical heterogeneity and improving internal validity. Several limitations should be acknowledged. First, no formal a priori sample size calculation was performed, and the relatively small sample size ( n  = 48) may have limited statistical power and increased the risk of type II error. Therefore, this exploratory study should be considered hypothesis-generating, and non-significant findings should be interpreted cautiously. Larger studies with adequately powered sample sizes are needed to confirm these findings. Second, baseline differences in BMI, body temperature, and mean arterial pressure between the postmenopausal groups may have influenced the observed physiological differences. Although ANCOVA analyses were performed to adjust for these baseline imbalances, the possibility of residual confounding cannot be completely excluded. Third, although perioperative temperature management was standardized through maintaining operating room and PACU temperatures, administering warmed intravenous fluids, and applying warming blankets, other individual factors influencing thermoregulation could not be fully controlled. In addition, body temperature was assessed using a non-invasive forehead (temporal) measurement method rather than direct core temperature monitoring (e.g., esophageal or bladder temperature). Although this method is practical in clinical settings, it may not fully reflect core temperature changes and could have limited the precision of thermoregulatory comparisons between groups. Fourth, despite the use of standardized anesthetic and analgesic protocols, individual variability in pharmacodynamic responses could not be completely eliminated and may have influenced perioperative physiological responses. Fifth, follow-up was limited to the immediate postoperative period (60 min in the PACU), representing only the early recovery phase. Moreover, the number of available observations decreased substantially at later PACU time points, particularly at 60 min, when only a small number of patients remained available for analysis. Therefore, findings at this time point should be interpreted with caution, as the limited sample size reduces the reliability and statistical stability of the estimates. Consequently, longer-term outcomes, including postoperative complications, quality of recovery, and hospital length of stay, could not be assessed. Furthermore, the exclusion of patients with prolonged surgery, prolonged recovery, or protocol deviations may have introduced selection bias by limiting the inclusion of patients with more complex perioperative courses. Although these criteria improved protocol standardization and reduced potential confounding, they may limit the generalizability of the findings to broader surgical populations. Finally, menopausal status was determined clinically based on menstrual history rather than biochemical confirmation using serum estradiol, follicle-stimulating hormone, or other reproductive hormone measurements. Although clinical criteria based on spontaneous amenorrhea are commonly used for defining menopause, the absence of hormonal assessment may have resulted in potential misclassification, particularly among women in the perimenopausal transition. Therefore, the observed differences should be interpreted as associations with clinically defined menopausal status rather than direct evidence of hormone-mediated mechanisms. Additionally, the use of a simple ordinal scale for assessing level of consciousness, rather than more sensitive neurocognitive instruments such as the MMSE or MoCA, may have reduced the ability to detect subtle cognitive changes. Future multicenter studies with larger sample sizes, biochemical confirmation of menopausal status, and longer postoperative follow-up are warranted to validate these findings and improve their generalizability. Incorporating heart rate variability, continuous temperature monitoring, and perioperative catecholamine measurements may also help clarify the autonomic mechanisms underlying the observed differences.

Total abdominal hysterectomy (TAH) remains one of the most commonly performed major gynecologic operations worldwide. It is undertaken for diverse clinical indications, ranging from benign conditions such as uterine fibroids, adenomyosis, endometriosis, and refractory abnormal uterine bleeding to gynecologic malignancies, including cancers of the endometrium, cervix, and ovary [ 1 ]. Despite advances in surgical and anesthetic techniques, it is still associated with significant physiological stress responses, particularly in terms of hemodynamic fluctuations during and immediately after general anesthesia [ 2 ]. These changes are clinically important because they may influence perioperative stability and postoperative recovery, especially in middle-aged women who represent a large proportion of surgical candidates for this procedure [ 3 ]. The perioperative period is characterized by dynamic alterations in cardiovascular and respiratory parameters, including heart rate, blood pressure, and oxygen saturation [ 4 ]. These responses are mainly driven by surgical stimulation, anesthetic agents, and individual patient characteristics. In this context, age-related physiological changes and hormonal status, particularly menopause, may play an important role in modifying hemodynamic responses [ 5 ]. Postmenopausal women often exhibit altered vascular reactivity and autonomic regulation, which may lead to different intraoperative and postoperative physiological patterns compared to non-menopausal patients [ 6 ]. Menopause is accompanied by a decline in circulating estrogen levels, which influences both autonomic cardiovascular regulation and thermoregulatory function. Estrogen promotes endothelial nitric oxide production, enhances arterial compliance, and modulates sympathetic and parasympathetic nervous system activity [ 5 ]. Consequently, estrogen deficiency has been associated with increased sympathetic tone, reduced baroreflex sensitivity, endothelial dysfunction, and greater arterial stiffness, potentially altering blood pressure and heart rate responses during anesthesia and surgical stress [ 7 , 8 ]. In addition, estrogen contributes to hypothalamic thermoregulation by maintaining the thermoneutral zone. Following menopause, narrowing of this zone increases susceptibility to thermoregulatory instability, leading to altered vasoconstrictive and vasodilatory responses and differences in perioperative temperature regulation [ 9 ]. Because general anesthesia itself impairs autonomic control and thermoregulation, these physiological changes may contribute to differences in perioperative hemodynamic responses and postoperative recovery between non-menopausal and postmenopausal women [ 10 ]. These physiological differences may also influence the occurrence of postoperative complications in the post-anesthesia care unit (PACU) [ 11 ]. Symptoms such as shivering, pain, nausea, vomiting, agitation, and transient oxygen desaturation are frequently observed after general anesthesia and may affect patient comfort, recovery time, and overall outcomes [ 12 , 13 ]. Understanding the distribution and severity of these complications across different patient groups can help anesthesiologists optimize monitoring strategies and improve individualized care [ 14 ]. Although several studies have investigated separately [ 15 – 18 ], limited evidence exists regarding the combined evaluation of these parameters in pre- and postmenopausal women undergoing total abdominal hysterectomy. Therefore, this study aimed to compare perioperative hemodynamic changes and PACU-related complications between non-menopausal and postmenopausal women undergoing total abdominal hysterectomy under general anesthesia.