## Introduction

Against the backdrop of declining global fertility rates,¹ improving the childbirth experience holds meaningful strategic importance for enhancing fertility intentions and addressing negative population growth.with the widespread adoption of electronic fetal monitoring (EFM), clinicians’ ability to identify fetal heart rate deceleration patterns has markedly improved. Prolonged deceleration (PD) is defined as a decrease in fetal heart rate of 15 beats per minute (bpm) or more below the baseline, lasting for at least 2 minutes but less than 10 minutes; if it persists for 10 minutes or longer, it is indeed classified as a baseline change.^2-4 The primary mechanisms involve fetal myocardial hypoxia and vagal reflexes. The clinical management of PD remains contentious. some experts regard it as a sign of acute fetal distress, advocating for active intervention and expedited delivery.⁴ Conversely, others suggest that not all PD episodes require immediate cesarean section, especially when caused by reversible factors such as uterine tachysystole or maternal supine hypotension.^2,5 Moreover, increasing duration or depth of deceleration significantly raises the risk of neonatal acidosis and adverse outcomes.⁶ In the first stage of labor, there is a general clinical consensus to consider cesarean delivery when persistent decelerations indicate acute fetal hypoxia, aiming to optimize perinatal outcomes.⁷ In contrast, decision-making in the second stage is more complex, involving a choice between proceeding with an operative vaginal delivery (vacuum or forceps) or performing a full-dilatation cesarean section, each with distinct maternal and neonatal risks. The American College of Obstetricians and Gynecologists (ACOG) advises against the combined use of vacuum extractor and forceps in an operative vaginal delivery.⁸ Selecting the appropriate delivery mode is crucial for optimizing both maternal and neonatal outcomes.⁹ Despite its clinical significance, comparative evidence on the outcomes of these different approaches specifically during PD in the second stage is scarce.

This study aimed to compare the impact of vacuum extraction, forceps delivery, and cesarean section on maternal and neonatal outcomes following PD in the second stage of labor. Our goal is to provide evidence-based guidance to assist obstetric teams in making timely and rational decisions, ultimately enhancing maternal and neonatal safety.

## Materials and Methods

### Study Population and Design

This single-center retrospective observational study was conducted at Nanning Second People’s Hospital. We included singleton, vertex-presenting pregnancies at ≥34 weeks gestation who experienced PD in the second stage of labor between January 2022 and December 2024.PD was defined per standard criteria:^2-4 a fetal heart rate deceleration of ≥15 bpm below baseline, lasting ≥2 minutes but <10 minutes, occurring after full cervical dilation.### Inclusion and Exclusion Criteria

Inclusion criteria were:

(1) PD in the second stage;

(2) singleton, vertex presentation;

(3) gestational age ≥34 weeks;

(4) complete clinical data.

Exclusion criteria were categorized as:

(1) Fetal factors: non-vertex presentation, known congenital anoma

Results

comparison of Baseline characteristics

No statistically significant differences were observed among the three groups regarding maternal age, pre-pregnancy BMI, pre-delivery BMI, gestational weight gain, gravidity, or parity (all P > 0.05, Table 1).

Table 1 Comparison of General Data of the Three Groups

Comparison of Fetal monitoring Indicators and Pregnancy characteristics

Key differences were observed in parameters influencing delivery method selection and timing (Table 2). The deceleration-to-delivery interval was significantly longer in the cesarean section group compared to both the vacuum and forceps groups (P < 0.05). Conversely, the number of deceleration episodes was lower in the cesarean group than in the vacuum group (P < 0.05). Fetal station was significantly higher (less descent) in the cesarean group than in both operative vaginal delivery groups (P < 0.001). Pre-delivery hemoglobin was lower in the vacuum group than in the forceps group (P < 0.05). No significant differences were found in other fetal monitoring parameters or pregnancy complication rates.

Table 2 Comparison of Fetal Monitoring Indicators and Pregnancy Conditions

Neonatal Outcomes

Most importantly, no statistically significant differences were observed among the three groups for any neonatal outcome measure, including birth weight, gestational age, umbilical artery pH <7.20,lactate levels,rates of neonatal asphyxia,or NICU admission (all P > 0.05, Table 3).

Table 3 comparison of neonatal Outcomes

Maternal Outcomes

Cesarean section was associated with significantly increased maternal morbidity across multiple domains (Table 4). The cesarean group had a longer postpartum hospital stay, higher hospitalization costs, longer durations of antibiotic use and urinary catheterization, and greater estimated blood loss compared to both operative vaginal delivery groups (all P < 0.0

### Analysis of Delivery Methods and Neonatal Outcomes in Second-Stage Labor with Prolonged Deceleration

Prolonged deceleration (PD) during the second stage of labor presents a significant obstetric challenge, demanding rapid assessment and intervention to mitigate fetal risk. This study compared delivery characteristics and neonatal outcomes across three groups – cesarean section, vacuum extraction, and forceps – in cases of second-stage PD.

The analysis revealed a longer interval from deceleration to delivery in the cesarean group, attributable to the time required for operating room transfer, anesthesia, and preoperative preparation.interruptions in fetal monitoring during these processes likely contributed to fewer recorded deceleration episodes in this group, highlighting the need for efficient multidisciplinary collaboration and standardized protocols to minimize fetal hypoxia. Fetal station proved a key determinant in delivery mode selection, with the cesarean section group exhibiting a significantly higher fetal station (less descent) compared to operative vaginal delivery groups (P<0.05), consistent with established clinical practice favoring vaginal delivery when the fetal station is ≤ +2. Therefore, rapid assessment of fetal station alongside fetal descent, maternal condition, labor progress, and operator experience is crucial for selecting the safest delivery method. A lower pre-delivery hemoglobin level was observed in the vacuum extraction group compared to the forceps and cesarean groups (P<0.05).However, given the retrospective design and unequal group sizes (vacuum extraction, n=62; forceps, n=30; cesarean, n=22), this finding may be subject to confounding factors and warrants further investigation in larger, prospective studies to determine its influence on delivery method choice and maternal/neonatal outcomes. The pathophysiology of PD involves fetal myocardial hypoxia and the vagal reflex, potentially leading to anaerobic metabolism, increased lactate production, and subsequent neurotoxicity.Prompt correction of hypoxia is vital to prevent neonatal acidosis, NICU admission, birth asphyxia, and, in severe cases, multi-organ dysfunction or perinatal death. Notably, this study found no statistically significant differences among the three groups in birth weight, gestational age, preterm birth rate, amniotic fluid characteristics, umbilical artery pH, incidence of acidosis (pH<7.20), lactate levels, rates of birth asphyxia, or NICU admissions (all P > 0.05). This suggests that timely recognition of PD and subsequent expedited intervention – regardless of the final delivery route – is the most critical factor in preserving neonatal well-being. The comparable neonatal results across the three delivery## Limitations

This study has several limitations inherent to its retrospective design. The potential for selection bias and unmeasured confounding must be acknowledged, notably regarding operator experience and preference, which significantly influenced the choice of delivery method but could not be analyzed.The small sample size, especially in the forceps and cesarean groups, limits the statistical power and generalizability of our findings. Future prospective studies are needed to validate these results.

## Conclusion

during prolonged deceleration in the second stage of labor, the choice of delivery method presents a trade-off between maternal morbidity and procedural expediency. Our findings support a management strategy centered on rapid assessment: prioritizing operative vaginal delivery when fetal station is low and operator expertise is sufficient, and opting for cesarean section when conditions are unfavorable for vaginal birth. The consistent neonatal outcomes across all modes of delivery should reassure clinicians that, within this framework, the primary focus can be on selecting the safest and most efficient route to achieve delivery for the individual mother-baby dyad.