Sociodemographic and obstetric characteristics of participants

As presented in Table 1, women undergoing GA had a significantly higher mean age than those receiving CSEA (32.4 ± 4.8 vs 31.5 ± 4.1 years, p = 0.020). Pre-pregnancy BMI was also greater in the GA group (26.5 vs 23.5 kg/m2, p < 0.001), while gestational weight gain was modestly lower (12.0 ± 3.5 vs 13.3 ± 4.1 kg, p = 0.024). GA group had markedly higher parity and gravidity, with 91.8% of GA patients were multiparous compared to 78.4% in CSEA (p < 0.001), and 62.9% had been pregnant at least twice before versus 31.1% in CSEA (p < 0.001). Correspondingly, a history of multiple abortions was more common in the GA group (52.4% in GA vs 36.8% in CSEA underwent more than 2 prior abortions, p = 0.002). Significantly higher proportion of patients in the GA cohort had a history of prior CD, with two-thirds (≈66%) had one previous CD (vs 28.4% in CSEA, p < 0.001), and 13.5% had at least 2 prior CD (vs 1.3% in CSEA). They were also more likely to have undergone a previous emergency CD (11.8% vs 5.8%, p = 0.015). Consistent with this, uterine scarring was much more frequent in GA patients (61.8% vs 26.6%, p < 0.001). The placenta was often abnormally located in GA cases, with nearly half of GA patients (49.7%) had a placenta completely covering the uterine incision (cesarean scar) compared to only 4.2% in CSEA, with any placental coverage of the scar (partial or complete) in 47.6% vs 8.7% of cases (p < 0.001). Lastly, concurrent miscarriage was more often noted in the GA group (4.1% vs 0.8%, p = 0.009), whereas other comorbidities (e.g. syphilis, hepatitis, hypertension) did not differ significantly between groups.

Table 1 Sociodemographic and obstetric profile of PP complicated pregnancies undergoing GA or CSEAMaternal perioperative outcomes

The maternal perioperative outcomes of patients underwent different anesthesia methods were listed in Table 2. The GA group had more severe PP, with nearly half (47.1%) had complete PP, compared to 19.0% in the CSEA group. Conversely, marginal PP was more common with CSEA (28.7% vs 4.1%) (p < 0.001). PAS disorders were also markedly more frequent in GA group. In particular, placenta increta and percreta occurred in a combined 48.8% of GA cases, versus 15.8% in CSEA, while cases with no accreta were far fewer in GA (17.7% vs 45.0%) (p < 0.001). The placental attachment site differed as well. GA cases were much more likely to have a posteriorly attached placenta (posterior uterine wall in 47.1% of GA vs 0.5% of CSEA, whereas in CSEA the placenta was usually on the anterior uterine wall (71.1% vs 45.9% in GA) (p < 0.001). Peripartum hysterectomy was significantly more common in the GA group (p < 0.001), with 12.9% of GA patients required a hysterectomy (10% total, 2.9% subtotal) compared to virtually none in CSEA (only 1 case of cornual resection, accounting for 0.3% of). To manage anticipated hemorrhage, preoperative abdominal aortic balloon occlusion was employed in the majority of GA patients (71.2%) but in almost none of the CSEA group (0.3%, p < 0.001). An intrauterine balloon tamponade for hemorrhage control was also used slightly more often in GA (67.1% vs 56.3%, p = 0.045). Unplanned reoperations were rare but occurred only in the GA group (1.8% vs 0%, p = 0.029). Postoperative hypoproteinemia was noted in 14.1% of GA patients, significantly higher than 1.6% in CSEA (p < 0.001). There were also four cases of intraoperative bladder injury in the GA group (2.4%) versus one case (0.3%) in CSEA (p = 0.034). The duration of postoperative antibiotic therapy was longer in GA patients (mean 76.8 vs 50.4 h, p < 0.001). ICU admissions were much more frequent in the GA group, with 15.3% required ICU care postoperatively, compared to only 0.5% of the CSEA group (p < 0.001). Other complications (ileus, fever, and poor incisional wound healing) were not significantly different between groups.

Table 2 Maternal perioperative outcomes of PP complicated pregnancies undergoing GA or CSEAFetal characteristic and neonatal outcomes

We subsequently investigated the fetal characteristic and neonatal outcomes (Table 3). The mean gestational age at delivery was 35.6 ± 2.0 weeks for GA vs 36.7 ± 1.7 weeks for CSEA (p = 0.001). Consequently, preterm birth was far more common with GA (81.8% of cases) than with CSEA (46.3%, p < 0.001). There were also differences in how the pregnancies were conceived, with the vast majority of GA cases were naturally conceived (97.1% vs 87.1%), whereas CSEA cases included a higher proportion of IVF conceptions (12.9% vs 2.9% in GA, p = 0.001). Twin or multiple gestations and fetal growth restriction rates were similar between groups (no significant differences). Neonatal outcomes were notably worse in the GA group. Neonatal asphyxia was significantly more frequent in GA-delivered infants: 26.5% experienced asphyxia (mostly mild), compared to only 3.7% of neonates in the CSEA group (p < 0.001). There was a single neonatal death in the GA group (0.6%) and none in CSEA (not statistically significant). GA neonates were also smaller on average, with a lower mean birth weight (2631 ± 486 g vs 2881 ± 524 g, p < 0.001) and were shorter in length at birth (p < 0.001). There was no significant difference in congenital anomalies between the groups. Overall, the earlier gestational age and associated complications under GA translated into higher rates of preterm, low-weight babies with neonatal respiratory depression compared to the CSEA group.

Table 3 Fetal characteristics and neonatal outcomes of PP complicated pregnancies undergoing GA or CSEAAnesthesia related characteristics

Then we analyzed the anesthesia related characteristics of both groups (Table 4). Operative times and blood loss were substantially greater in the GA group. The duration of anesthesia was prolonged under GA, averaging 100.5 ± 5.5 min vs 69.2 ± 2.4 min for CSEA cases (p < 0.001). Similarly, surgery lasted significantly longer with GA (78.6 ± 4.6 vs 49.4 ± 1.0 min, p < 0.001). There was also higher intraoperative blood loss, with an estimated mean hemorrhage volume of 1132 ± 77 mL in GA group, about 60% more than in the CSEA group (708 ± 17 mL, p < 0.001). In line with larger fluid shifts, urine output during surgery was also higher under GA (270 ± 279 vs 135 ± 87 mL, p < 0.001). Their hemodynamic management also differed, with vasopressor support was needed more often with CSEA (to counter spinal-induced hypotension), reflected by a significantly higher use of other vasoactive agents in the CSEA group (28.2%) compared to GA (14.1%, p < 0.001).

Table 4 Anesthesia related characteristics of PP complicated pregnancies undergoing GA or CSEA

Although preoperative hemoglobin was only slightly lower in the GA group (112.8 ± 12.4 vs 115.9 ± 12.7 g/L, p = 0.008), the drop in hemoglobin post-surgery was more pronounced. By the third postoperative day, mean hemoglobin in GA patients was 96.3 g/L, significantly below the CSEA mean of 100.9 g/L (p = 0.002). On average they received nearly one unit of packed red blood cells per patient (0.95 units), versus virtually no transfusion in the CSEA group (0.13 units, p < 0.001). Plasma transfusion was likewise higher under GA (about 90 mL vs 8 mL in CSEA, p < 0.001), and cell-salvaged autologous blood use was also greater under GA (88 mL vs 16 mL, p < 0.001).

Correlation analysis of sociodemographic and perioperative features with estimated intraoperative blood loss stratified by anesthesia methods

Table 5 presents a stratified multivariate logistic regression analysis examining the associations between sociodemographic and perioperative variables and estimated peripartum blood loss among patients underwent CSEA or GA. The model included maternal age, gestational age at delivery, mode of conception (natural vs. IVF), number of previous CDs, number of abortions, hepatitis B status, history of recurrent miscarriage, placenta covering the uterine incision, PAS, type of PP, use of preoperative abdominal aortic balloon occlusion, and surgical duration. Among patients who underwent CSEA, factors significantly associated with increased blood loss included placenta covering the uterine incision (adjusted HR = 58.49, p = 0.017), type of PAS (adjusted HR = 29.02, p = 0.036), type of PP (adjusted HR = 34.72, p = 0.048), and surgical duration (adjusted HR = 9.35, p < 0.001). Conversely, preoperative aortic balloon occlusion was associated with reduced blood loss (adjusted HR = –115.08, p = 0.009). Among GA patients, significant predictors of increased blood loss included placenta covering the uterine incision (adjusted HR = 71.88, p = 0.015), type of PAS (adjusted HR = 103.01, p = 0.042), type of PP (adjusted HR = 106.16, p = 0.046), and surgical duration (adjusted HR = 13.83, p < 0.001); while the application of aortic balloon occlusion is a protective factor for intrapartum blood loss within GA group(adjusted HR = –300.01, p = 0.015).

Table 5 Multivariate Logistic Regression Analysis on the Associations Between Sociodemographic and Perioperative Factors and Estimated Peripartum Blood Loss Stratified by Anesthesia Type (CSEA vs GA)Correlation analysis of sociodemographic and perioperative features with neonatal asphyxia

Correlation analysis of sociodemographic and perioperative features with neonatal asphyxia was conducted using multivariate logistic regression analysis (Table 6). Several factors were found significantly correlated with the severity of neonatal asphyxia. Gestational age at delivery was a significant predictor, earlier delivery was associated with higher odds of asphyxia (p = 0.040). PAS emerged as a strong risk factor for neonatal asphyxia. Even after adjustment, placenta accreta was associated with increased odds and severity of neonatal asphyxia (p = 0.024), and the risk became progressively higher with placenta increta (p = 0.011) and percreta (p = 0.003). The mode of anesthesia also showed an independent association with neonatal outcomes, with CD under GA carried higher odds of neonatal asphyxia compared to those under CSEA (p = 0.002). Maternal demographic factors (age, conception method) were not significantly correlated with neonatal asphyxia risk.

Table 6 Multivariate logistic regression analysis of sociodemographic, perioperative features and neonatal asphyxia