Maternal and neonatal outcomes following emergency cesarean section or operative vaginal delivery for fetal distress in the second stage of labor

Abstract

Background

Operative vaginal delivery and emergency cesarean section are critical interventions used in the second stage of labor when fetal distress threatens maternal or neonatal well-being. Prompt recognition of fetal compromise and timely decision-making are essential to ensure safe delivery outcomes while minimizing complications for both mother and baby. The aim of this study is to compare maternal and neonatal outcomes between operative vaginal delivery and emergency cesarean section in cases of fetal distress occurring during the second stage of labor.

Methods

This is a retrospective cohort study involving pregnant women conducted at a tertiary care center between 2012 and 2024. A total of 397 pregnant women diagnosed with fetal distress in the second stage of labor were included. The operative vaginal delivery group comprised 302 patients, while the emergency cesarean delivery group included 95 patients who underwent emergency cesarean delivery for fetal distress. Maternal and neonatal outcomes were compared. Neonatal outcomes constituted the primary endpoints of the study.

Results

Analysis of neonatal outcomes demonstrated that the operative vaginal delivery group had significantly lower median Apgar scores at both 1 min (6; range 0–8) and 5 min (8; range 4–10). Furthermore, this group exhibited higher incidences of neonatal intensive care unit admission (n = 96, 30.7%), respiratory distress (n = 25, 8.2%), requirement for phototherapy (n = 28, 9.2%), meconium aspiration syndrome (n = 51, 16.9%), cephalohematoma (n = 21, 6.73%), and caput succedaneum (n = 99, 33%). Additionally, one neonate had facial paralysis; six had brachial plexus injuries; three had clavicular fractures; three had periorbital hematomas; three had intracranial hemorrhage; and one had pneumothorax. There was no significant difference between the groups in the incidence of intracranial hemorrhage or hypoxic-ischemic encephalopathy. Bladder injury and surgical site infection were significantly more common in the emergency cesarean delivery group, whereas vaginal lacerations were more frequent in the operative vaginal delivery group.

Conclusion

Operative vaginal delivery is significantly associated with adverse neonatal outcomes compared with emergency cesarean delivery. However, maternal complications were more common following emergency cesarean section.

Background

Operative vaginal delivery (OVD), encompassing both forceps-assisted and vacuum-assisted methods, is an important obstetric intervention when complications arise during the second stage of labor. This procedure is performed to facilitate delivery, prevent emergency cesarean sections, and reduce associated morbidities when labor is arrested, maternal health requires shortening the duration of labor, or fetal distress is detected. According to 2017 data, 3.1% of all births in the United States involved assisted vaginal delivery, with vacuum-assisted deliveries accounting for the majority (2.6%) and forceps-assisted deliveries representing a smaller proportion (0.5%). These statistics underscore the continuing relevance of OVD techniques in modern obstetric practice and emphasize their role in ensuring safe and effective birth outcomes when spontaneous vaginal delivery is not possible or advisable [1, 2].

Cesarean delivery is one of the most common surgical procedures performed worldwide [3]. Over the past decade, the prevalence of cesarean delivery has increased significantly across both developed and developing nations [4, 5]. In the United States, the cesarean section rate, which was 5.5% in the 1970s, increased to 32.3% in 2023 [6, 7]. Cesarean deliveries performed during the second stage of labor constitute a significant proportion of primary cesarean procedures in the United States, accounting for approximately 23% of these cases [8]. Primary cesarean deliveries represent nearly half of all cesarean sections and are the leading cause of subsequent cesarean deliveries [9, 10]. However, in many clinical situations, such as failure to progress during the second stage of labor or a compromised fetal condition, timely OVD may prevent the need for emergency cesarean section (ECS) [11]. OVD may be indicated in several scenarios, including maternal fatigue or ineffective pushing, maternal cardiac conditions requiring avoidance of Valsalva maneuvers, prolonged second stage of labor, or suspected acute fetal compromise [12]. While cesarean delivery remains an option in these settings, the appropriate use of OVD techniques can reduce the rate of primary cesarean deliveries and their associated short-and long-term complications. OVD is performed only when a high probability of success is anticipated, as the risk of birth trauma increases after unsuccessful attempts [13–15]. The decision to proceed with an intervention involves continuous reassessment based on the success of each step in the procedure. Clinicians cannot be certain of a successful outcome, as preprocedural risk factors do not reliably predict procedural success or failure [16, 17]. OVD, also referred to as assisted vaginal delivery, involves extraction of the fetus using forceps, vacuum, or another instrument, with or without concurrent maternal effort. The second stage of labor, typically lasting approximately two hours, begins with complete cervical dilatation (10 cm) and ends with the birth of the fetus [18].

Fetal distress, as assessed during a nonstress test, is characterized by the absence of baseline fetal heart rate variability in conjunction with one or more of the following features: bradycardia, recurrent late decelerations, recurrent variable decelerations, or a sinusoidal pattern. This condition is classified as abnormal, as empirical evidence has demonstrated a significant association between the presence of category III fetal heart rate patterns and an increased risk of fetal hypoxic acidemia [19].

Previous studies have compared OVD and ECS in the second stage of labor [13, 15]. However, in cases where fetal distress develops during the second stage, evidence directly comparing maternal and neonatal outcomes of OVD and ECS remains limited. Most available studies have small sample sizes or methodological limitations [20]. Therefore, this study aimed to compare maternal and neonatal outcomes of these two approaches in second-stage fetal distress cases at or below + 2 station. In such cases, rapid and informed decision-making is essential in modern obstetric practice. This study seeks to provide clinicians with more robust evidence to guide management.

Methods

This was a retrospective cohort study including pregnant women who underwent either OVD or ECS due to a diagnosis of fetal distress during the second stage of labor. The study was approved by the Institutional Review Board (IRB) / Ethics Committee of Zeynep Kamil Women and Children’s Diseases Training and Research Hospital (Istanbul, Turkey) (Approval No. 89/2025) and written informed consent authorizing the use of anonymized clinical data for research purposes was obtained from all participants. The study was conducted in accordance with the principles of the Declaration of Helsinki and carried out at a tertiary referral hospital between May 2012 and May 2024.

Participants were categorized into two groups: those who underwent OVD and those who underwent ECS, both performed due to fetal distress in the second stage of labor. Fetal distress or the potential for fetal distress was defined according to the National Institute of Child Health and Human Development (NICHD) criteria. Category II tracings were defined as those that did not meet the criteria for Category I or III and included features such as minimal or marked variability, absence of accelerations after stimulation, or recurrent variable or late decelerations with moderate baseline variability. Category III tracings were characterized by absent baseline variability with recurrent late decelerations, recurrent variable decelerations, bradycardia, or a sinusoidal fetal heart rate pattern [21]. Only patients presenting with Category III tracings were classified as experiencing fetal distress and were subsequently included in the final analysis.

The OVD group included patients who underwent OVD, while the ECS group consisted of patients who underwent ECS for fetal distress. Exclusion criteria included preterm delivery, congenital anomalies, multiple pregnancies, cesarean section following failed OVD, more than one OVD attempt, and incomplete or inconsistent medical records.

Data collection

Data were obtained retrospectively from the hospital’s obstetric records. Patient files meeting the inclusion criteria were reviewed individually. Maternal demographic and clinical data were extracted, including age, body mass index (BMI), hypertension (HT), smoking status, parity, gestational age, gestational diabetes mellitus (GDM), obstetric history, mode of labor initiation (spontaneous or induced), admission diagnosis, mode of delivery, and fetal ultrasound findings. Neonatal outcomes and complications were also recorded.

The primary outcome measures were neonatal death, umbilical cord blood pH, 5-minute Apgar score, admission to the neonatal intensive care unit (NICU), and the occurrence of hypoxic-ischemic encephalopathy (HIE), which was determined according to the criteria described by Sarnat et al. [22]. The secondary outcome measures included maternal and neonatal complications.

Statistics

The Statistical Package Programme for Social Sciences (SPSS; SPSS Inc., Chicago, IL) version 16.0 was used for statistical analysis. Descriptive data are expressed as mean ± SD or number of cases and percentages in parentheses. The distribution of variables was assessed using the Kolmogorov-Smirnov test. The independent samples t-test, ANOVA test and chi square test were used to compare variables. All p values were two-tailed, and statistical significance was set at p < 0.05.

Results

A total of 91,997 births, including 47,807 vaginal and 44,170 cesarean deliveries, were reviewed from the hospital database during the study period. The number of OVD was 874, corresponding to an incidence of 0.95% (874/91,997). Among these 874 patients, 218 were excluded due to insufficient or inconsistent medical records. Of the remaining 656 cases in which OVD was attempted, 14 underwent ECS following failed OVD. The OVD failure rate (14/656) was 2%, and these 14 cases were excluded from the analysis.

Among the remaining 642 cases, 330 had OVD indications due to prolonged second stage of labor or maternal benefit; these cases were also excluded. The remaining 312 cases had OVD indications for fetal distress. Of these, 85 were delivered using Simpson forceps, 120 with a soft cup vacuum (Kiwi Omni Cup), 97 with a metal cup vacuum, and 10 with more than one interventional delivery method (e.g. soft cup vacuum + forceps, soft cup vacuum + metal cup vacuum, metal cup vacuum + forceps). The rate of patients who required more than one OVD method (10/656) was 1.5%, and these cases were also excluded. The final OVD group thus comprised 302 patients.

During the same period, there were 164 ECS performed in the second stage of labor. Sixty-nine patients who underwent surgery due to obstructed labor, eclampsia, asynclitism, placental abruption, HELLP syndrome, or uterine rupture were excluded. The remaining 95 patients who underwent ECS due to fetal distress constituted the ECS group (Fig. 1).

Fig. 1.

Flow chart of study population

In total, 397 patients were evaluated in this study: 302 (76%) in the OVD group and 95 (24%) in the ECS group.

There were no significant differences between the groups in terms of mean gestational age, parity, smoking status, GDM, HT, or rates of labor augmentation. However, the mean age and BMI were significantly lower in the OVD group. Descriptive statistics of the cases are presented in Table 1.

Table 1.

General and clinical characteristics of the patients

	Emergency cesarean section (n = 95)	Operative vaginal delivery (n = 302)	p
Age, year	28.79 ± 6.25(16–44)	26.83 ± 6.12(15–53)	0.07
BMI, kg/m2	30.25 ± 4.25(21–44)	27.49 ± 7.05(19–45)	0.001
Weight, kg	77.39 ± 12.63(54–136)	74.15 ± 13.25(50–135)	0.04
Height, cm	159.91 ± 5.83(149–175)	161.11 ± 6.13(146–179)	0.10
Parity, median (range)	0(0–7)	0(0–5)	0.08
Smoking, n(%)	4 (4.2)	13(4.3)	0.594
Gestational diabtes mellitus, n(%)	11(11.5)	25(8.2)	0.303
Hypertension, n(%)	5(5.3)	12(4)	0.561
Gestational age, day	279.31 ± 9.95(238–300)	276.83 ± 10.77(224–301)	0.052
Postterm pregnancy, n(%)	22(23.1)	49(16.2)	0.122
Spontaneous labor n(%)	42(44.2)	123(40.7)	0.407
Labor augmentation, n(%)	73(76.8)	245(81.1)	0.777

No statistically significant differences were observed between the two groups regarding the mean neonatal weight and biparietal diameter (BPD) measurements. The incidences of oligohydramnios, polyhydramnios, and fetal growth restriction (FGR) were similar between the groups. However, the incidence of premature rupture of membranes (PROM) was significantly higher in the OVD group (Table 2).

Table 2.

Perinatal complications and basic newborn findings

	Emergency cesarean section (n = 95)	Operative vaginal delivery (n = 302)	p
Premature rupture of membranes, n (%)	18(18.9)	94(31.1)	0.036
Oligohydroamnios, n (%)	7(7.3)	24(8)	1.0
Polyhidroamnios, n (%)	-	5(1.6)	0.59
Fetal growth restriction, n(%)	1(1.1)	2(0.6)	0.551
Newborn weight, gr	3441.02 ± 452.88(2125–4650)	3340.21 ± 422.57(1950–4470)	0.056
Biparietal diameter, cm	93.30 ± 3.55(82–99)	92.43 ± 3.74(80.3–102)	0.052
Newborn Gender Female	35(36.8)	112(37)	0.810
pH, Umblical vein	7.23 ± 0.14(6.48–7.38)	7.22 ± 0.12(6.60–7.5)	0.935
APGAR1	7(0–9)	6(0–8)	0.001
APGAR5	9(0–10)	8(4–10)	0.013

In the analysis of neonatal outcomes, the 1st- and 5th-minute Apgar scores were significantly lower in cases of OVD. This group also demonstrated higher incidences of neonatal intensive care unit (NICU) admission, respiratory distress, need for resuscitation, phototherapy, meconium aspiration, cephalohematoma, and caput succedaneum. Additionally, within the OVD group, there was one case of facial paralysis, six cases of brachial plexus injury, three cases of clavicular fracture, three cases of periorbital hematoma, and one case of pneumothorax. These complications were not observed in the ECS group (Table 3). There were no significant differences in the incidences of intracranial hemorrhage (ICH) or HIE between the two groups.

Table 3.

Neonatal complications of the study population

	Emergency cesarean section (n = 95)	Operative vaginal delivery (n = 302)	p
Neonatal intensive care unit admission, n(%)	17(17.8)	96(30.7)	0.013
Intracranial hemorrhage, n(%)	0	3(0.96)	1
Neonatal respiratory distress (NRS), n(%)	2(2.1)	25(8.2)	0.05
Intubation requirment, n(%)	3(3.15)	6(1.92)	0.441
Cephalohematoma, n(%)	0	21(6.73)	0.006
Facial paralysis, n(%)	0	1(0.32)	1
Brachial plexus paralysis, n(%)	0	6(2)	0.343
Caput succedaneum, n(%)	19(20)	99(33)	0.028
Periorbital hematoma, n(%)	0	3(0.96)	1
Pneumothorax, n(%)	0	1(0.32)	1
Clavicular fracture, n(%)	0	3(0.96)	1
Hypoxic ischemic encephalopathy, n(%)	7(7.36)	20(6.62)	0.814
Phototherapy, n(%)	2(2.1)	28(9.2)	0.024
Meconium stain, n(%)	1(1.1)	51(16.9)	0.001

Among the 302 patients in the OVD group, 85 underwent forceps delivery, 120 were assisted with a soft cup vacuum, and 97 were assisted with a metal cup vacuum. Analysis of these subgroups revealed that patients delivered with the metal cup vacuum had significantly lower mean cord blood pH values and 1-minute Apgar scores. However, no significant difference was observed in the 5-minute Apgar scores (Table 4).

Table 4.

Comparison of Operative Vaginal Deliveries Among Themselves in Terms of Newborn Apgar and pH

	Kiwi (n = 120)	Vacuum (n = 97)	Forceps (n = 85)	p
pH	7.22 ± 0.10(6.9–7.45)	7.20 ± 0.12(6.9–7.44)	7.28 ± 0.93(7.09–7.5)	0.003
APGAR1	7(3–8)	6(0–8)	6(3–8)	0.012
APGAR5	8(5–10)	8(4–10)	8(4–9)	0.365

When comparing maternal outcomes between the OVD and ECS groups, bladder injury and wound infection were significantly more common in cesarean section cases, whereas vaginal laceration was notably more frequent in OVD cases. Although the mean decrease in hemoglobin levels was greater in the OVD group than in the cesarean section group, this difference was not statistically significant. Nevertheless, because three patients in the OVD group required massive transfusion, the transfusion rate was significantly higher in this group (Table 5).

Table 5.

Maternal outcomes of the study population

	Emergency cesarean section (n = 95)	Operative vaginal delivery (n = 302)	p
Prepartum hemoglobin, g/dl	11.57 ± 1.31(8.6–14.6)	11.64 ± 1.4(7.5–14.7)	0652
Postpartum hemoglobin, g/dl	9.65 ± 1.56(6.1–13.7)	9.98 ± 1.7(5-14.4)	0.124
Prepartum hematocrit,%	35.26 ± 3.59(28.5–43.3)	35.44 ± 3.67(24.8–44.9)	0.683
Postpartum hematocrit,5	29.59 ± 4.55(20.2–41.4)	30.09 ± 4.89(15.5–42.7)	0.407
Hemoglobin difference, g/dl	1.93 ± 1.06(0-5.1)	1.67 ± 1.34(0–7)	0.356
Hematocrit difference,%	5.81 ± 3.42(0-14.7)	5.36 ± 3.98(0-20.3)	0.108
Need for Blood Transfusion, n(%)	4(4.2)	37(12.2)	0.032
Atony, n(%)	3(3)	15(4.96)	0.775
Bladder injury, n(%)	3(3)	0(0)	0.012
Cervical laceration, n(%)	3(3)	28(9.2)	0.076
Vaginal laceration, n(%)	3(3)	269(89.1)	0.000
Surgical site infection, n(%)	7	0	0.000

Discussion

Our findings demonstrate that neonatal trauma and low Apgar scores are more frequently associated with OVD, particularly with metal cup vacuum procedures, whereas maternal complications are more common following ECS. However, the rates of ICH and HIE did not differ according to the mode of delivery. These results provide important insight into the comparative outcomes of OVD and ECS in cases of fetal distress during the second stage of labor.

Cesarean section is increasingly preferred over OVD during the second stage of labor in many developing countries [23]. Failed OVD has been associated with increased maternal and neonatal morbidity, and the use of multiple operative devices has been linked to higher rates of neonatal trauma [24, 25]. For this reason, patients who experienced failed OVD or required more than one device were excluded from our study to avoid potential bias in maternal and neonatal outcome assessment. Higher maternal age and BMI have also been associated with increased risk of OVD failure [26]. In our study, the significantly higher maternal age and BMI in the ECS group may reflect maternal or physician preference.

In our cohort, there was no significant difference between the two groups in terms of neonatal ICH or HIE, which were the primary outcome measures. Contag et al. have similarly reported comparable neonatal outcomes and umbilical cord blood gas values among neonates delivered by forceps-assisted, vacuum-assisted, and second-stage cesarean delivery. Regardless of the indication for intervention, the incidence of significant fetal acidemia did not differ among delivery methods [20]. Polkowski et al. reported lower cord blood pH (< 7.20) in neonates delivered via cesarean section; however, 5-minute Apgar scores remained similar across delivery modes [27]. Similarly, Walsh et al. found no differences in peripartum neonatal mortality or neonatal encephalopathy when comparing OVD-delivered neonates with those born by second-stage cesarean Sect [28].

In this present study, in the OVD group, neonatal trauma including facial paralysis, brachial plexus injury, clavicular fracture, periorbital hematoma, ICH, and pneumothorax were observed, whereas no such injuries occurred in the ECS group. Additionally, the OVD group demonstrated higher incidences of NICU admission, respiratory distress, resuscitation, phototherapy, meconium aspiration, cephalohematoma, and caput succedaneum. Towner et al. [29] reported that subgaleal hemorrhage was strongly associated with vacuum extraction.

Muraca et al. reported findings from a study involving approximately 11,000 births. Although their analysis was limited to interventions performed at the midpelvic level likely at higher fetal stations than those observed in the present population they demonstrated significantly improved neonatal outcomes associated with OVD. In their evaluation of perinatal outcomes in deliveries complicated by fetal distress, the authors further observed that sequential midpelvic instrumental deliveries were associated with significantly higher rates of composite severe perinatal morbidity and mortality compared with cesarean delivery, findings that are consistent with those of the present study [30].

We acknowledge that the exclusion of failed OVD and cases involving more than one delivery instrument may introduce some methodological limitations. The American College of Obstetricians and Gynecologists (ACOG) does not recommend the routine use of more than one instrumental delivery technique [12]. In our study, the occurrence of multiple instrumental delivery attempts was not within our control, given the retrospective cohort design of the study. Importantly, the use of multiple instruments may independently influence maternal and neonatal outcomes. In addition, in cases of failed OVD, it is often challenging to accurately attribute subsequent maternal and neonatal complications to either the operative vaginal attempt or the eventual cesarean delivery. Therefore, to minimize potential confounding and misclassification bias, we considered it methodologically more appropriate to exclude cases involving failed OVD and multiple instrumental attempts within the context of this retrospective cohort study.

In the present study, failed OVD occurred in 14 cases (2%) among women who underwent vacuum-assisted delivery. Of these cases, 13 patients were nulliparous, and the median gestational age was 40 weeks (range: 38–42 weeks). The mean maternal age was 26.93 ± 6.02 years. All cases of failed OVD were subsequently managed with cesarean delivery. One patient required blood transfusion due to prelabor anemia. The mean neonatal birth weight was 3205 ± 488 g, and the mean umbilical cord pH was 7.09 ± 0.1. Nine neonates required admission to the NICU. Among these, one case was diagnosed with transient tachypnea of the newborn, while five neonates experienced perinatal asphyxia. Additionally, three newborns required therapeutic hypothermia for the management of HIE. The overall failed OVD rate in this cohort was 2%. This relatively low rate, compared with the 6.3% reported by Palatnik et al., may be attributable to differences in clinical practice, including a higher proportion of low or outlet vacuum applications and/or greater persistence in attempting OVD [15].

Milsom et al. [31] investigated asphyxia at birth and its risk factors, identifying associations between asphyxia-related cardiotocography patterns, intrauterine meconium passage, OVD, breech presentation, oxytocin use, umbilical cord complications, external compression to facilitate labor, and neonatal weakness. In the study by Graham et al. [32], the incidence of cerebral palsy associated with intrapartum hypoxia-ischemia was 14.5% among term infants without congenital anomalies. However, most cases of cerebral palsy in term infants without abnormalities were not associated with hypoxia-ischemia at birth. Similarly, Muraca et al. [33] found that increased OVD rates were associated with higher rates of obstetric trauma and severe birth trauma, particularly among nulliparous women.

Bailit et al. [34] reported that OVD was associated with a lower incidence of postpartum infection but a higher incidence of severe perineal lacerations. In our study, surgical site infection and bladder injury were more common following ECS, whereas vaginal lacerations were more frequent with OVD. Although the change in mean hemoglobin levels did not differ significantly between groups, transfusion requirements were higher in the OVD group due to three cases requiring massive transfusion.

OVD has been associated with a higher incidence of postpartum hemorrhage and a greater mean decline in hemoglobin levels [30]. In our study, although one case in the OVD group required massive transfusion, no significant difference was observed between the two groups in terms of hemoglobin decline. This finding may be attributable to the higher-than-expected rates of bladder injury and hemorrhage secondary to cervical and vaginal lacerations in the cesarean section group. In our study, in the ECS group, cervical and vaginal lacerations occurred in 3 patients due to downward extension of the uterine incision during cesarean section.

This study addresses a clinically relevant scenario in which the choice between OVD and ECS presents a particular challenge in cases of fetal distress at or below + 2 station during the second stage of labor. Furthermore, by examining a wide range of neonatal and maternal outcomes, our analysis provides a comprehensive understanding of the relative risks and benefits of each intervention. The inclusion of a subgroup analysis comparing forceps, soft cup vacuum, and metal cup vacuum deliveries adds depth to our findings and offers additional information about the comparative safety of these techniques. Notably, our results provide valuable insight into obstetric practice in low- and middle-income countries, where evidence comparing OVD and ECS in the second stage of labor remains limited.

Despite these strengths, several limitations should be acknowledged. First, this was a single-center retrospective study, which may limit the generalizability of our findings. Second, inherent selection bias may have influenced the results, as obstetricians might be more likely to choose OVD in clinically favorable cases. Third, although all procedures were performed by experienced clinicians, variations in operator skill were not analyzed and may have affected outcomes. Fourth, incomplete documentation in some cases may have influenced data accuracy. Fifth, the lack of homogeneity in group sizes may have introduced bias, potentially affecting the validity of comparisons across the study groups. Finally, long-term neurodevelopmental outcomes were not evaluated, limiting the study’s ability to provide broader prognostic conclusions.

In summary, fetal distress during the second stage of labor presents significant challenges for both the clinician and the mother. In such circumstances, the choice of intervention depends on the operator’s expertise, the available instruments, the clinical environment, and rapid cognitive decision-making. Ultimately, no delivery method can be considered entirely risk-free for the mother, infant, or practitioner in this context.

Conclusion

In conclusion, emergency cesarean section (ECS) remains an essential intervention in the management of second-stage fetal distress. However, when applied in carefully selected cases and by experienced operators, operative vaginal delivery (OVD) may represent a reasonable alternative with broadly comparable maternal and neonatal outcomes. In this study, neonatal trauma and lower Apgar scores were observed more frequently following OVD particularly with metal cup vacuum whereas maternal complications, including infection and bladder injury, appeared more common after ECS. These findings should be interpreted with caution given the retrospective design and potential selection bias. Further well-designed prospective, multicenter studies with standardized criteria and long-term neonatal follow-up are needed to better define the relative risks and benefits of these delivery strategies.

Abbreviations

OVD

Operative vaginal delivery

ECS

Emergency cesarean section

BMI

Body mass index

HT

Hypertension

GDM

Gestational diabetes mellitus

NICU

Neonatal intensive care unit

HIE

Hypoxic-ischemic encephalopathy

FGR

Fetal growth restriction

BPD

Biparietal diameter

PROM

Premature rupture of membranes

ICH

Intracranial hemorrhage

Authors’ contributions

Research ethics This study was approved by the Institutional Review Board (IRB) / Ethics Committee of Zeynep Kamil Women and Children’s Diseases Training and Research Hospital (Istanbul, Turkey) (Approval No. 89/2025). Informed consent Written informed consent was obtained from all participants. Author contributions (for double- anonymized journals: please use initials) Conceptualization ÖT, RKData curation ÖT, RKFormal analysis ÖTFunding acquisition NONEInvestigation ÖT, SSK, RGİ, BG, ZAMethodology ÖT, RKProject administration ÖT, RKResources ÖT, SSK, RGİ, BG, ZASoftware ÖT, TASupervision NONEValidation ÖT, RGİVisualization Preparation ÖT, TAWriting - original draft ÖT, RK, ATWriting - review &editing ÖT, TAThe author has accepted responsibility for the entire content of this manuscript and approved its submission.Use of Large Language Models, AI and Machine Learning Tools. None declared.Conflict of interest. The author states no conflict of interest. Research funding None declared.Data availability Data will be made available to the editors of the journal for review or query upon request.Data Sharing Statement: The data is available for sharing.If needed, data will be submitted to the journal website.Corresponding Author: Önder Tosun M.D.Address: Uskudar Opr. Dr. Burhanettin Ustunel street No:10, Istanbul – AsiaPostal code: 34668 E-mail: dr.ondertosun@gmail.com. Phone: 0216 391 06 80.

Funding

The authors received no specific funding for this study.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the Institutional Review Board (IRB) / Ethics Committee of Zeynep Kamil Women and Children’s Diseases Training and Research Hospital (Istanbul, Turkey) (Approval No. 89/2025). The study was conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent authorizing the use of anonymized clinical data for research purposes was obtained from all participants.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.