Declining global fertility rates have brought attention to the importance of enhancing the childbirth experience. With the widespread use of electronic fetal monitoring, clinicians can now better identify fetal heart rate deceleration patterns. Prolonged deceleration (PD), defined as a decrease in fetal heart rate of 15 beats per minute or more below the baseline lasting for at least 2 minutes but less than 10 minutes, is a critical indicator of fetal distress. The clinical management of PD, however, remains a controversial topic. Some experts advocate for immediate intervention and expedited delivery, while others suggest that not all PD episodes require a cesarean section, especially when caused by reversible factors. The duration and depth of deceleration significantly impact the risk of neonatal acidosis and adverse outcomes. In the first stage of labor, there is a general consensus to consider cesarean delivery for persistent decelerations indicating acute fetal hypoxia. However, decision-making in the second stage is more complex, involving a choice between operative vaginal delivery (vacuum or forceps) or a full-dilatation cesarean section, each with its own set of maternal and neonatal risks.
The American College of Obstetricians and Gynecologists (ACOG) advises against combining vacuum extractor and forceps in operative vaginal delivery. Selecting the appropriate delivery mode is crucial for optimizing maternal and neonatal outcomes. Despite its clinical significance, comparative evidence on the outcomes of these approaches during PD in the second stage is limited.
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.
The study was conducted at Nanning Second People's Hospital and included singleton pregnancies at ≥34 weeks gestation experiencing PD in the second stage between January 2022 and December 2024. PD was defined as a fetal heart rate deceleration of ≥15 bpm below baseline lasting ≥2 minutes but <10 minutes, occurring after full cervical dilation.
Inclusion criteria included PD in the second stage, singleton vertex presentation, gestational age ≥34 weeks, and complete clinical data. Exclusion criteria were categorized into fetal factors (non-vertex presentation, congenital anomalies, multiple gestation), maternal factors (significant comorbidities, pelvic deformities), and delivery outcome (spontaneous vaginal delivery after PD). After screening, 114 patients were enrolled and stratified by delivery method: vacuum extraction (n=62, KIWI system), forceps delivery (n=30, Simpson forceps), and cesarean section (n=22).
The decision to intervene and the choice of delivery method were at the discretion of the attending obstetrician, based on a comprehensive assessment. Standard intrauterine resuscitation was routinely attempted before intervention.
The study was approved by the Ethics Committee of Nanning Second People's Hospital, and given its retrospective nature and anonymized data, informed consent was waived.
Data extracted from electronic medical records included baseline characteristics (maternal age, BMI, parity, hemoglobin), fetal monitoring parameters (deceleration-to-delivery interval, number/duration/depth of decelerations), neonatal outcomes (birth weight, umbilical artery blood gas pH and lactate, NICU admission), and maternal outcomes (estimated blood loss, postpartum hospital stay, hospitalization costs, antibiotic/catheter duration, and complications).
The study found no statistically significant differences among the three groups regarding maternal age, pre-pregnancy BMI, pre-delivery BMI, gestational weight gain, gravidity, or parity. However, key differences were observed in parameters influencing delivery method selection and timing. The deceleration-to-delivery interval was significantly longer in the cesarean section group compared to the vacuum and forceps groups. The number of deceleration episodes was lower in the cesarean group than in the vacuum group. Fetal station was significantly higher (less descent) in the cesarean group than in the operative vaginal delivery groups. Pre-delivery hemoglobin was lower in the vacuum group than in the forceps group.
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.
Cesarean section was associated with significantly increased maternal morbidity across multiple domains. 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. The incidence of wound erythema was higher in the forceps group than in the cesarean group.
The results indicate a distinct trade-off between the approaches. Cesarean section was associated with a longer interval from deceleration to delivery, increased postpartum blood loss, prolonged hospitalization, and higher medical costs. Operative vaginal delivery demonstrated an advantage in shortening the duration of potential fetal compromise and offered benefits in terms of reduced maternal trauma and faster recovery. However, forceps delivery was linked to a higher incidence of perineal wound erythema.
There is no single universally optimal delivery method for managing PD in the second stage of labor. The cornerstone of clinical decision-making lies in a rapid, structured assessment. When fetal station is favorable (≥ +2) and an experienced operator is available, operative vaginal delivery should be prioritized to expedite delivery and minimize maternal morbidity. Cesarean section is reserved for high fetal stations (≤ +1) or when vaginal delivery is unsafe, understanding the greater maternal morbidity it entails. The choice between vacuum and forceps involves balancing risks, with forceps posing a higher risk of maternal perineal trauma and vacuum extraction carrying a greater risk of neonatal scalp injury.
The interval from the onset of fetal heart rate deceleration to delivery was significantly longer in the cesarean section group. The number of deceleration episodes recorded was lower in this group, suggesting an earlier decision for surgical intervention. Fetal station was a key factor influencing delivery mode selection. The higher fetal station in the cesarean group aligns with clinical practice, as a fetal station of ≤ +2 is generally considered unfavorable for successful instrumental delivery.
Pre-delivery hemoglobin level was significantly lower in the vacuum extraction group, potentially indicating baseline differences in this cohort. Further investigation is warranted to understand the impact of hemoglobin levels on delivery method choice and outcomes.
The pathophysiology of PD during the second stage primarily involves fetal myocardial hypoxia and the vagal reflex. When fetal monitoring indicates potential hypoxia, a compensatory shift to anaerobic metabolism increases lactate production and accumulation, elevating the risk of cerebral cell injury. Prompt correction of hypoxia is critical to reducing the risks of neonatal acidosis, NICU admission, and birth asphyxia.
This study demonstrated no statistically significant differences among the three groups in neonatal outcomes. The comparable results likely reflect a balance of the advantages and disadvantages of each delivery modality, mitigated by prompt action. However, long-term neurodevelopmental follow-up studies are needed to rule out more subtle differences.
Instrumental vaginal delivery can enable rapid fetal expulsion, potentially reducing intrauterine hypoxia duration. Forceps-assisted delivery is effective for swift labor completion and may be associated with a lower risk of fetal scalp hematoma compared to vacuum extraction. However, its application is limited in certain fetal positions, and improper use increases the risk of maternal and neonatal trauma. Vacuum extraction is simpler to perform and generally causes less maternal soft tissue damage but carries a higher risk of neonatal scalp injuries. Overall, vaginal instrumental delivery may be associated with neonatal complications, although some long-term follow-up studies have not established a definitive link with adverse neurodevelopmental outcomes.
Emergency cesarean section avoids mechanical trauma but involves longer preoperative preparation, anesthesia administration, and surgical duration, potentially prolonging fetal hypoxia exposure. A deeply engaged fetal head poses technical challenges during second-stage cesarean sections, leading to difficulties in fetal extraction, increased intraoperative hemorrhage, and neonatal injury. Various techniques are employed to manage impacted fetal heads, but high-quality evidence supporting the superiority of any single method is lacking.
The results indicate no significant differences in short-term neonatal outcomes among the three delivery modes. This emphasizes the importance of individualized clinical decision-making. Obstetric teams should comprehensively evaluate fetal station, labor progress, fetal tolerance, maternal condition, and operator experience to select the most appropriate approach for rapid and safe delivery. The key is the accurate and timely identification of fetal heart rate abnormalities to enable swift, effective intervention, maximizing maternal and neonatal safety.
The cesarean section group experienced significantly longer postpartum hospital stays, higher hospitalization costs, prolonged durations of antibiotic administration and indwelling catheterization, and greater postpartum blood loss compared to the operative vaginal delivery groups. These findings align with existing literature, indicating that cesarean delivery during the second stage is typically associated with a longer recovery period and increased medical resource utilization.
The results demonstrate that each delivery method carries a distinct risk profile. Cesarean section is associated with higher risks of hemorrhage, longer recovery times, and increased medical costs. Operative vaginal delivery can shorten labor duration, but forceps assistance may elevate the risk of soft tissue trauma. Comprehensive preoperative assessment during urgent decision-making is crucial, including evaluation of maternal baseline status, labor progression, fetal station, and potential complications, to select the most suitable individualized delivery strategy. Seamless teamwork, accurate risk assessment, and adherence to standardized operative techniques are key to optimizing maternal outcomes and enhancing the childbirth experience.
This study has several limitations inherent to its retrospective design, including potential selection bias and unmeasured confounding, particularly regarding operator experience and preference. The small sample size, especially in the forceps and cesarean groups, limits the statistical power and generalizability of the findings. Future prospective studies are needed to validate these results.
In summary, the choice of delivery method during PD in the second stage 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.
