Neonatal complications and risk factors associated with assisted vagin*l delivery (2024)

Adverse events related to vagin*l delivery are uncommon, given that delivery is a natural process that can occur spontaneously. However, there are instances where assisted vagin*l delivery becomes necessary due to labour difficulties. Factors such as the duration of labour and its phase (latent or active) can influence delivery outcomes. Before attending to delivery, it is crucial to consider potential birth injuries, complications and relevant factors. A birth injury can be linked to an impairment in the neonate’s bodily function or structure. Such injuries often occur during labour, delivery or post-delivery, particularly in neonates needing resuscitation.

vagin*l delivery can either be spontaneous or assisted. Spontaneous vagin*l delivery occurs when a pregnant woman goes into labour without requiring drugs or techniques to induce labour and delivery¹. Assisted vagin*l delivery involves using instruments such as forceps or a vacuum to aid delivery².

Assisted vagin*l births are performed to expedite birth for the benefit of both mothers and babies but can occasionally be associated with morbidity for both parties. Indications for assisted vagin*l delivery include a prolonged second stage of labour, suspicion of fetal compromise, or the need to shorten the second stage of labour for maternal benefit³. The decision to use instruments such as forceps or vacuum extraction often hinges on their availability, the clinical circ*mstances, and the obstetrician’s preference and experience. Assisted vagin*l delivery is crucial for mothers facing challenging labour. Both forceps assistance and vacuum extraction should only be administered by obstetricians with ample experience to minimise potential complications. In the United States, 3.1% of all births in 2017 occurred via an assisted vagin*l approach⁴. Forceps-assisted births constituted 0.5% of vagin*l deliveries, while vacuum-assisted ones accounted for 2.6%. The prevalence of assisted vagin*l births varied both within and across US regions⁴, suggesting that the choice of method may depend on practitioners’ familiarity and expertise⁵. Overall, rates of assisted vagin*l births have declined both nationally and regionally in the United States⁵.

However, complications and unexpected events can still arise from vagin*l deliveries. Our study investigated complications in newborns resulting from vagin*l deliveries by reviewing the details of complications encountered at Siriraj Hospital. We also explored the risk factors related to complications.

This retrospective study was conducted within the statistical unit of the Department of Obstetrics and Gynaecology at the Faculty of Medicine Siriraj Hospital. Prior to commencing the research, we secured approval from the Ethics Committee of the Faculty of Medicine Siriraj Hospital (approval number Si 185/2022) and registered the study in the Thai Clinical Trials Registry (TCTR 20220126004).

Data regarding pregnant women who underwent caesarean sections between 2020 and 2022 were sourced from hospital records. We identified a total of 3500 cases. Neonatal injuries and complications stemming from vagin*l deliveries at Siriraj Hospital were documented.

We employed multivariable analysis to determine the factors contributing to neonatal cephalic injuries and neonatal complications. These factors were identified based on their significance in univariate analysis. For neonatal cephalic injuries, the variables considered included the type of vagin*l delivery, maternal health conditions such as hypertension (HT) and diabetes mellitus (DM), the prolongation of the second stage of labor, the surgeon who performed delivery, the time of delivery and gestational age at delivery. For neonatal complications, significant variables from univariate analysis comprised the type of vagin*l delivery, maternal health conditions (HT, DM), prolongation of the second stage of labor, the surgeon who performed delivery, gestational age at delivery, birth weight, and time of delivery.

Statistical analysis

Demographic data were compiled using descriptive statistics. Categorical data are presented as numbers and percentages, while continuous data are reported as the means ± standard deviations or medians and ranges. We employed PASW Statistics (version 18; SPSS Inc, Chicago, IL, USA) for our statistical analyses. Baseline data (qualitative parameters, maternal complications and infant complications arising from caesarean section) were compared using the chi-squared and Fisher’s exact tests. For quantitative variables, the Mann–Whitney U test was employed for univariate analysis, while multiple logistic regression was utilised for multivariate analysis.

Terminology

The following terms were used in this study⁶:

• Bruising: this occurs when capillaries rupture, allowing blood cells to seep deep beneath the skin, resulting in the characteristic ‘black and blue’ marks on the skin. Over time, as the body metabolises the substances in the blood cells, the bruise changes colour, potentially appearing purple, brown, or even green.

• Petechiae: this involves bleeding under the skin, characterised by marks resembling a rash of small dots. Petechiae occurs when tiny blood vessels break open, causing blood to leak into the skin and giving it the appearance of a rash.

• Caput succedaneum: this refers to scalp swelling that occurs during labour and is usually evident shortly after delivery. It is commonly associated with prolonged pressure on the fetal head during delivery or a prolonged second stage of labour.

• Cephalohaematoma: this condition involves a subperiosteal collection of blood that occurs due to the rupture of vessels beneath the periosteum, typically over the parietal or occipital bone. It presents as swelling that does not cross suture lines.

• Subgaleal haematoma: this refers to the accumulation of blood in the loose areolar tissue between the periosteum of the skull and the aponeurosis.

Ethics approval and consent to participate

Prior to the commencement of this study, the requisite ethical clearance was procured from the Siriraj Ethics Committee of the Faculty of Medicine, Siriraj Hospital (Si 185/2022). Additionally, this research was registered with the Thai Clinical Trials Registry (20220126004). This study was a retrospective chart review andinformed consent was not required.

We retrieved data for 3500 neonates born through vagin*l deliveries. For assisted vagin*l deliveries, vacuum assistance was associated with significant increases in neonatal jaundice (63/221 [29.86%], P < 0.001), caput succedaneum (87/221 [41.23%], P < 0.001), cephalohaematoma (35/221 [16.59%], P < 0.001) and subgaleal haematoma (11/221 [8.06%], P < 0.001; Table 1).

The most common neonatal complications observed were neonatal jaundice (507/3500, 14.5%), caput succedaneum (291/3500, 8.3%) and transient tachypnea of the newborn (153/3500, 4.4%; Table 2).

When comparing complications between primigravida and multiparity, it was found that neonatal jaundice (16.9%/12.3%, P < 0.001), mild birth asphyxia (5.17%/3.70%, P = 0.034), caput succedaneum (12.75%/4.3%, P < 0.001), cephalohaematoma (2.89%/1.69%, P = 0.017), subgaleal haematoma (1.14%/0.27%, P = 0.002) and total neonatal complications (43.42%/34.08%, P < 0.001) were higher in the primigravida group (Table 3).

Among mothers with gestational diabetes mellitus, those with class A2 (GDMA2) had a higher incidence of mild birth asphyxia (3/21 [14.29%], P = 0.028), cephalohaematoma (3/21 [14.29%], P = 0.028), scalp laceration (2/21 [(9.52%], P = 0.007) and total neonatal complications (13/21 [61.9%], P < 0.01; Table 4).

In mothers with hypertension, those with mild to severe pre-eclampsia showed elevated rates of hypoglycaemia (2/16 [12.50%], P = 0.002), transient tachypnoea (3/16 [18.75%], respiratory distress syndrome (1/16 [6.25%], P = 0.002) and hypocalcaemia (1/16 [6.25%], P < 0.001). However, the total number of neonatal complications was not significantly different (Table 4).

Neonates born preterm had significantly more complications than those born at term. The complications were a need for ventilator support (5.77%/0.44%, P < 0.001), neonatal jaundice (38.46%/13.75%, P < 0.001), hypoglycaemia (7.69%/1.27%, P < 0.001), sepsis (2.88%/0.68%, P = 0.040), respiratory distress syndrome (2.88%/0.32%, P = 0.007), hypocalcaemia (1.92%/0.12%, P = 0.012), and skin abrasion (7.69%/1.65%, P < 0.001). The total complication rates were 59.62% for neonates born preterm and 37.87% for those born at term (P < 0.001; Table 5).

Neonates born to mothers with a prolonged second stage of labour had significantly higher rates of complications (P < 0.001). The complications were neonatal jaundice (26.73%), mild birth asphyxia (13.86%), caput succedaneum (38.61%), cephalohaematoma (17.82%), scalp laceration (5.94%) and subgaleal haematoma (9.9%; Table 6).

Similarly, neonates with fetal distress (145/3500 cases) exhibited significant increases in neonatal jaundice (30.34%), mild birth asphyxia (20.0%), caput succedaneum (45.52%), cephalohaematoma, (14.48%), subgaleal haematoma (7.59%), with P < 0.001 (Table 6).

Neonates born to anaemic mothers (haematocrit < 33%; 622/3500 cases) had a significant rise in neonatal jaundice (15.22%, P = 0.003; Table 7). Those with low birth weight (1500–2499g; 239/3500 cases) presented significant complications such as the need for ventilator support (3.77%), neonatal jaundice (28.45%), hypoglycaemia (7.95%), respiratory distress syndrome (1.67%) and hypocalcaemia (1.26%; Table 7).

Based on multivariate analysis, factors associated with caput succedaneum were assisted vacuum delivery (AOR 5.18, 95% CI 2.60–10.3, P < 0.001) and fetal distress (AOR 1.95, 95% CI 1.02–3.74, P < 0.044). Cephalohaematoma was linked to GDMA2 (AOR 11.3, 95% CI 2.96–43.2, P < 0.001) and assisted vacuum delivery (AOR 16.5, 95% CI 6.71–40.5, P < 0.001). Scalp laceration was correlated with GDMA2 (AOR 10.5, 95% CI 2.28–48.1, P = 0.003), assisted vacuum delivery (AOR 6.94, 95% CI 1.85–26.1, P = 0.004) and assisted forceps delivery (AOR 10.5, 95% CI 1.08–102.2, P = 0.042). Factors associated with abrasion and bruising were assisted forceps delivery (AOR 39.1, 95% CI 11.5–132.5, P < 0.001) and preterm delivery (AOR 3.49, 95% CI 1.39–8.72, P = 0.008; Table 8).

Factors connected with neonatal jaundice were deliveries after hours (4.00 PM–8.00 AM; AOR 1.32, 95% CI 1.07–1.63, P = 0.009), assisted vacuum delivery (AOR 2.22, 95% CI 1.09–4.52, P = 0.029), preterm delivery (AOR 3.08, 95% CI 1.92–4.93, P < 0.001), maternal anaemia (haematocrit < 33%; AOR 1.36, 95% CI 1.03–1.81, P = 0.033) and neonatal low birth weight (AOR 2.11, 95% CI 1.49–2.98, P < 0.001; Table 9).

Neonatal hypoglycaemia was associated with births from mothers with severe pre-eclampsia (AOR 10.1, 95% CI 1.94–52.6, P = 0.006) and neonatal low birth weight (AOR 7.52, 95% CI 3.79–14.9, P < 0.001; Table 9). Transient tachypnoea of the newborn was linked to births from mothers with severe pre-eclampsia (AOR 4.48, 95% CI 1.23–16.4, P = 0.023) and preterm delivery (AOR 2.28, 95% CI 1.02–5.07, P = 0.044; Table 9). Neonatal asphyxia was associated with births from mothers with GDMA2 (AOR 3.64, 95% CI 1.03–12.8, P = 0.044), assisted vacuum delivery (AOR 3.44, 95% CI 1.36–8.69, P = 0.009) and fetal distress (AOR 1.02, 95% CI 1.01–1.03, P = 0.013; Table 9). Neonates requiring ventilator support were linked to preterm delivery (AOR 5.07, 95% CI 1.61–16.0, P = 0.006) and neonatal low birth weight (AOR 5.79, 95% CI 2.02–16.6, P = 0.001; Table 9).

Our study revealed that the overall incidence of neonatal morbidities and complications arising from vagin*l delivery was 38.5% (1348/3500 cases). The most frequently observed complications were neonatal jaundice (14.5%, 507/3500 cases) and caput succedaneum (8.3%, 291/3500 cases).

Caput succedaneum refers to scalp oedema that emerges during labour and typically resolves within 48h post-birth. This condition commonly presents following prolonged engagement of the fetal head in the birth canal or after vacuum extraction. On the other hand, neonatal jaundice or neonatal hyperbilirubinaemia arises from elevated total serum bilirubin levels. It manifests clinically as a yellowish discolouration of the skin, sclera and mucous membranes. Notably, approximately 60% of term and 80% of preterm newborns exhibit clinical jaundice during their first week post-birth⁷. This manifestation is generally a mild, transient and self-limiting condition that resolves without any intervention and is termed ‘physiological jaundice’. Nevertheless, it is crucial to differentiate it from the more severe ‘pathological jaundice’ to ensure early intervention and prevention of significant complications.

Furthermore, caput succedaneum may give rise to compression-related necrotic lesions, potentially leading to long-term scarring and alopecia⁸. The ‘halo scalp ring’ is an annular alopecic circle seen in infants after enduring prolonged or challenging labour. This condition arises due to compression from the bony prominences of the maternal pelvis⁹. Instances of infected caput succedaneum are rare¹⁰.

Bruises and petechiae were the most frequently observed findings in our study. They are generally self-limiting and commonly appear on the presenting portion of the newborn’s body. A bruise is a risk factor for the development of hyperbilirubinaemia or jaundice. Hence, it is advisable to closely monitor infants with significant bruising to evaluate the potential development of jaundice¹¹.

Our research indicated that assisted deliveries using vacuum or forceps were closely linked to the occurrence of scalp lacerations. Additionally, assisted forceps delivery was notably associated with abrasions and bruises. Assisted vagin*l deliveries account for 10–15% of births in Canada¹², Australia¹³ and the United Kingdom¹⁴. When well-trained physicians conduct such operations, there is a demonstrated association with reduced risks for mothers and newborns^14,15,16. However, the shift from assisted vagin*l deliveries to caesarean deliveries has reduced opportunities for medical professionals to gain expertise in using vacuum and forceps^12,17,18. Consequently, it is unsurprising that there have been increasing reports of maternal and neonatal trauma related to assisted vagin*l deliveries. This has also intensified concerns regarding the comparative safety of using forceps versus vacuum^19,20,21.

In our study, clavicle fractures accounted for 0.7% (25/3500 cases) of the injuries. These fractures were not significantly linked to assisted vagin*l deliveries. According to extensive case series, the incidence of clavicle fractures stemming from birth trauma varies between 0.5 and 1.6%^22,23. Fractured clavicles often correlate with challenging vagin*l deliveries due to factors such as assisted delivery, shoulder dystocia, advanced maternal age, and babies large for their gestational age^22,23. When a clavicle fracture is identified, it is essential to investigate any concurrent brachial plexus injury. In our dataset, the incidence of brachial plexus injury was 0.1% (4/3500 cases), and all instances resulted from spontaneous vagin*l delivery. The only acknowledged risk factor for brachial plexus injury is shoulder dystocia, for which no validated predictive or preventative measures exist. Potential mechanisms leading to neonatal brachial plexus palsy encompass stretching/traction, compression, infiltration and oxygen deprivation²⁴. Physicians tasked with performing assisted vagin*l deliveries must be well acquainted with these mechanisms and be adequately trained to avoid causing injury.

Fetal asphyxia was significantly associated with mothers having GDMA2 in our research, corroborating the findings by Kawakita et al.²⁵. This association was more pronounced in pregestational diabetes than in gestational diabetes²⁵, although the exact cause remains elusive. The suggested mechanisms for this link are fetal hyperglycaemia and hyperinsulinemia, which might heighten neonatal respiratory morbidity, even in vagin*l deliveries.

The predominant neonatal morbidities we observed were hypoglycaemia, hypocalcaemia and hyperthermia, which were significantly related to neonatal low birth weight. These findings are consistent with a study by Chand et al.²⁶.

Our research indicated that neonatal birth injuries were significantly correlated with preterm delivery, assisted vagin*l deliveries, and babies large for their gestational age. Previous research found that the risk of birth injury was double for infants weighing between 4000 and 4499g compared to those of average birth weight. The risk was threefold for infants weighing between 4500 and 4999g and surged to 4.5 times for those weighing more than 5000g²⁷. Another study found a 7.7% incidence of fetal injury in infants weighing over 4500g²⁸. Other studies have emphasised that preterm infants are particularly prone to respiratory complications due to their premature birth, a finding consistent with our observations²⁹.

Maternal obesity, defined by a body mass index of > 40kg/m², increases the risk of birth injuries. This group of parturients often has higher rates of assisted vagin*l delivery and an elevated risk of bearing a large-for-gestational-age infant, which can further raise the likelihood of shoulder dystocia³⁰. However, our study did not observe a significant incidence of brachial plexus injury.

Interestingly, our findings highlight a significant occurrence of neonatal injuries and morbidities after regular hospital (daytime) hours. US and Austrian national studies indicate that there are heightened risks for adverse maternal and neonatal outcomes during night deliveries^31,32,33. However, Yee et al. noted that academic medical centres equipped with round-the-clock specialists produced similar outcomes for pregnant women with postpartum haemorrhage, regardless of the delivery time³⁴. Continuous in-house staffing in obstetric units might, therefore, enhance night-time outcomes.

Implications for clinical practice

In our study, we observed a high incidence of neonatal morbidities and complications, underscoring the importance of healthcare practitioners prioritizing vigilant monitoring of newborns delivered vagin*lly, particularly those born through assisted methods like vacuum or forceps. Early detection and management of complications such as neonatal jaundice and caput succedaneum are crucial in preventing long-term sequelae.

The study emphasized the significance of ensuring healthcare professionals receive sufficient training and maintain expertise in conducting assisted vagin*l deliveries. Continuous education and simulation training are essential for sustaining proficiency in utilizing vacuum and forceps, thus reducing the risks of maternal and neonatal trauma linked with these procedures.

Our research highlights the crucial need for healthcare professionals to receive adequate training and experience in conducting assisted vagin*l deliveries. Continuous education and simulation training are vital in maintaining proficiency with vacuum and forceps, thus reducing the risks of maternal and neonatal trauma associated with these procedures.

The notable incidence of neonatal injuries and morbidities following regular hospital hours underscores the necessity of continuous in-house staffing in obstetric units. This staffing approach could enhance outcomes during nighttime deliveries, guaranteeing prompt access to specialized care as necessary.

Limitations of the study

Our study's reliance on retrospective data from medical records may introduce bias due to incomplete documentation or variations in reporting practices across different healthcare facilities. Additionally, the retrospective nature of the study limits our ability to establish causality between maternal and neonatal factors and the observed complications. The findings of our study may not be generalizable to populations outside of the study setting or to different healthcare systems with varying practices regarding vagin*l deliveries and neonatal care.

Gaps in existing literature and implications for future research

Future research could further explore the comparative safety and efficacy of vacuum versus forceps-assisted vagin*l deliveries, specifically focusing on neonatal outcomes and maternal morbidity. Longitudinal studies with larger sample sizes are necessary to offer more robust evidence in this domain.

Further investigation into additional maternal and neonatal factors, such as maternal obesity, maternal age, and birth order, could yield valuable insights into neonatal complicationsandrisk factors. This deeper understanding could aid in risk stratification and the development of targeted interventions to mitigate adverse outcomes.

Additional research is needed to investigate the effects of delivery timing, including daytime versus nighttime deliveries, on neonatal outcomes and maternal health. Prospective studies with standardized data collection protocols and comprehensive risk adjustment are warranted to better comprehend the factors influencing outcomes during various times of the day.

By addressing these limitations and suggesting avenues for future research, the contribution to the ongoing efforts to improve maternal and neonatal care and reduce the incidence of complications associated with vagin*l deliveries.

Authors and Affiliations

1. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand

   Saifon Chawanpaiboon&Vitaya Titapant

2. Clinical Epidemiological Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand

   Julap*rn Pooliam

Contributions

Saifon Chawanpaiboon was responsible for the research’s conception and design; data acquisition, analysis and interpretation; drafting and critically revising the manuscript; and endorsing the final version of the manuscript. Vitaya Titapant contributed to the research’s conception and design, revised the manuscript and approved the final version. Julap*rn Pooliam took part in data analysis and interpretation, critically reviewed the manuscript, and approved its final version.

Corresponding author

Correspondence to Saifon Chawanpaiboon.

Competing interests

Every author has completed the Form for Uniform Disclosure of Potential Conflicts of Interest, as provided by the International Committee of Medical Journal Editors. None of the authors have any conflicts of interest to declare. The procedures involved in this retrospective chart review adhere to the ethical standards of the institutional research committee (Si 060/2020) and align with the Declaration of Helsinki of 1964, its subsequent amendments, or other comparable ethical guidelines.

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