Main findings
In this multicenter retrospective cohort of 1,523 cesarean deliveries under general anesthesia, prolonged anesthesia ID time was identified as an independent predictor of neonatal resuscitation. Additional risk factors included gestational hypertension, gestational diabetes mellitus, previous cesarean delivery, antenatal dexamethasone exposure, non-cephalic presentation, lower gestational age, higher ASA physical status, and certain anesthetic regimens. A steady, dose–response relationship was observed between ID time and resuscitation probability, indicating that even minor prolongations in delivery may compromise neonatal adaptation. These findings emphasize the importance of minimizing the anesthesia-to-delivery interval to reduce neonatal respiratory depression during cesarean delivery under GA. Optimization of anesthetic technique and intraoperative coordination may mitigate fetal exposure to anesthetic agents, thereby improving perinatal outcomes in high-risk obstetric populations.
For patients with contraindications to regional anesthesia, GA remains an important alternative for cesarean delivery [11]. In such cases, the primary concern is the potential depressive effects of anesthetic agents on the neonate [12]. During GA, neonatal compromise is largely attributable to the transplacental passage of anesthetic drugs and uteroplacental hypoperfusion secondary to maternal hypotension, both of which can result in respiratory depression and hypotonia [13–15]. In our study, prolonged ID time during GA was independently associated with an increased likelihood of neonatal resuscitation, confirming the adverse impact of extended fetal exposure to anesthetics on neonatal adaptation after birth. The restricted cubic spline analysis further demonstrated a continuous, nonlinear rise in the probability of resuscitation with increasing ID time, suggesting a dose–response relationship. These findings align with previous reports that longer ID times heighten neonatal exposure to anesthetic agents, leading to respiratory depression, hypoxia, and acidosis [16–18]. For example, Swanson et al. showed that extended ID time during cesarean section under GA independently increased adverse perinatal outcomes, primarily through lower Apgar scores and a higher incidence of respiratory support needs [16]. Collectively, this evidence underscores the importance of expediting delivery following anesthesia induction to reduce neonatal respiratory compromise, even in the context of modern anesthetic and neonatal care.
Several clinical and procedural factors have been reported to influence the prolongation of anesthesia ID time during cesarean delivery under general anesthesia. Maternal obesity is a well-recognized contributor, as increased BMI can complicate airway management, slow anesthetic induction, and make surgical exposure more challenging due to excessive adipose tissue and reduced operative visibility [19–21]. Previous cesarean delivery is another important factor, as postoperative adhesions and altered pelvic anatomy can hinder surgical access and delay uterine incision [22,23]. Similarly, technical challenges observed in our study, arising from complex obstetric conditions such as placenta previa or accreta, may also contribute to prolongation of the ID interval.
The choice of anesthetic regimen plays a critical role in neonatal outcomes during cesarean delivery under general anesthesia. Etomidate has long been used as an induction agent in obstetric anesthesia because of its rapid onset and minimal cardiovascular depression, providing hemodynamic stability during induction and facilitating timely tracheal intubation, particularly in patients with compromised circulatory function [24–26]. These pharmacologic properties make etomidate-based regimens suitable for emergency cesarean deliveries or for parturients with limited cardiopulmonary reserve. In contrast, combinations involving propofol and sevoflurane have been associated with a higher incidence of neonatal respiratory depression and maternal hypotension, likely due to their greater depressive effects on the cardiovascular and respiratory systems [27,28]. The use of remifentanil, a short-acting opioid with rapid metabolism and minimal accumulation, has been shown to reduce maternal catecholamine response while limiting neonatal exposure because of its low placental transfer and rapid neonatal clearance [29]. Consequently, the propofol + remifentanil regimen may provide a more favorable balance between adequate maternal anesthesia and minimized fetal drug exposure compared with volatile anesthetic techniques. Overall, these findings suggest that anesthetic selection significantly influences the neonatal condition at birth. Regimens that ensure stable maternal hemodynamics and minimize drug accumulation in the fetus, such as etomidate- or remifentanil-based approaches, may help mitigate the risk of neonatal respiratory depression and reduce the need for resuscitation. However, individualized selection of agents remains essential, considering maternal comorbidities, surgical urgency, and institutional experience.
Our study also identified several non-anesthetic predictors of neonatal resuscitation, reflecting the multifactorial nature of perinatal compromise. Preterm delivery (< 34 weeks and 34–37 weeks) markedly increased the need for resuscitation, consistent with the vulnerability of premature infants to respiratory failure due to immature pulmonary and neurological function [30]. Gestational hypertension and diabetes were also associated with higher neonatal risk, possibly through impaired placental perfusion and altered fetal oxygenation. Furthermore, higher ASA physical status (III/IV) independently predicted resuscitation, aligning with prior evidence that compromised maternal health status contributes to decreased uteroplacental reserve and fetal hypoxia during operative delivery [31].
The strengths of this study include its multicenter design, large sample size (n = 1,523), and comprehensive assessment of both maternal and perinatal factors. The use of logistic regression and restricted cubic spline analysis provided a detailed understanding of the relationship between continuous ID time and neonatal outcomes. The inclusion of multiple tertiary hospitals in China enhances the external validity and applicability of our findings. However, several limitations must be considered. As a retrospective study, potential selection bias and unmeasured confounders cannot be completely excluded. Institutional differences in anesthesia protocols, surgical urgency, and obstetric practices may have influenced ID time and outcomes, despite standardized perioperative monitoring. Future prospective and comparative studies are warranted to further clarify the causal role of ID time and anesthesia modality on neonatal outcomes and to establish optimal intraoperative management strategies.