Volume 88, Issue 3 p. 359-361
Free Access

Cesarean section is associated with more frequent pneumothorax and respiratory problems in the neonate

TORKIL BENTERUD

Corresponding Author

TORKIL BENTERUD

Neonatal Intensive Care Unit, Department of Paediatrics, Ullevål University Hospital, NO-0407, Oslo, Norway

: Torkil Benterud, Department of Paediatrics, Ullevål University Hospital, NO 0407, Oslo, Norway. E-mail: [email protected]Search for more papers by this author
LEIV SANDVIK

LEIV SANDVIK

Department of Statistics, Ullevål University Hospital, NO-0407, Oslo, Norway

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ROLF LINDEMANN

ROLF LINDEMANN

Neonatal Intensive Care Unit, Department of Paediatrics, Ullevål University Hospital, NO-0407, Oslo, Norway

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First published: 31 December 2010
Citations: 26

Abstract

We have investigated whether the incidence of neonatal pneumothorax (NP), use of mechanical ventilation (MV) or Continuous Positive Airways Pressure (CPAP) is increased in neonates delivered at term and preterm by cesarean section (CS). All deliveries at Ullevål University Hospital, Oslo, during the period 2001–2005 (n = 29,358) were included, among whom 5,957 were delivered by CS (20.3%). Data were collected on mode of delivery, elective or emergency CS, gestational age, maternal age, gender and parity. Among the 26,664 neonates born at term (≥37th gestational week), 4,546 were delivered by CS (17.0%), of whom 0.5% by elective and 0.6% by emergency CS with NP. The incidence of diagnosed NP was significantly higher after CS than after vaginal delivery (0.6% vs. 0.10%, p<0.001). In addition, the need for MV was significantly increased (0.41% vs. 0.19%; p = 0.01) but use of CPAP was not (0.28%vs. 0.15%; p = 0.08). Among 2,694 neonates born preterm (<37th gestational week), 1,266 were delivered by CS (47.0%). The incidence of diagnosed NP was 2.05% when delivered by CS but only 0.63% when delivered vaginally (p<0.01). Among the preterm infants delivered by CS, 17.7% needed CPAP compared to 6.9% when delivered vaginally (p<0.001) and MV was required for 8.1 and 3.7% (p<0.001), respectively. Among neonates delivered at term or moderately preterm (30–36 weeks) by CS the incidence of NP and other respiratory problems was significantly increased.

Introduction

A number of studies have shown an increased incidence of respiratory insufficiency among children delivered by cesarean section (CS) (1–6). In a recent Italian study, pneumothorax occurred in 0.45% after vaginal delivery and 5.4% after CS (7). However, only a few of the previous studies have distinguished between elective and emergency CS (2), (4–7) and only a few were population based (4–7).

The primary objective of the present study was to investigate, in a large population-based retrospective study, whether the incidence of neonatal pneumothorax (NP), use of mechanical ventilation (MV) and/or Continuous Positive Airways Pressure (CPAP) was increased in neonates delivered by CS. The relation was investigated separately for preterm and term neonates. A secondary objective was to assess whether these endpoints differed between elective and emergency CS.

Material and methods

Information on all neonates born at Ullevål University Hospital in Oslo was collected from January 1st 2001 through December 31, 2005. Information on delivery mode, parity, gender and gestational age (in general estimated by early ultrasound) were obtained from the Norwegian Birth Register. According to the neonatal journals, the patients were divided into three groups gestational age; term neonates (≥37 weeks), moderately preterm infants (30–36 weeks) and very preterm infants (≤29 weeks). This was done since respiratory problems are markedly more common among preterm infants, and especially among the extremely preterm infants.

The study was approved by the Ullevål University Hospital Ethical Committee.

For comparing the incidence in two groups a chi-squared test was used, with a 5% significance level. Logistic regression analysis was used to adjust for confounders. The statistical analysis was performed using SPSS version 16.0.

Results

Of the 29,629 births, 5,957 were delivered by CS (20.3%). Gestational age was not documented in 271 deliveries, thus 29,358 births, of which 48.6% were girls, were eligible for the study. There was no association between age of the mother and preterm delivery, nor between previous term and preterm delivery.

A total of 26,664 neonates (90.9%) were born ≥ the 37th gestational week, 2,306 (7.9%) were born between the 30th and 36th gestational week and 388 (1.3%) were preterm ≤29 weeks gestational age (Table I). As expected, the incidence of vaginal delivery was significantly lower among the preterm than among the term babies (53.0% vs. 82.4%), while the incidence of emergency CS was highest among the preterm babies with the lowest gestational age (31.7%).

Table I. Prevalence of neonatal pneumothorax (NP) in relation to gestational age and mode of delivery.
Gestational age
23–29 weeks 30–36 weeks 37–42 weeks
Number of births 388 2.306 26.664
Vaginal delivery (n) 224 1.242 22.118
 No. with NP (%) 4 (1.8%) 5 (0.4%) 22 (0.1%)
Cesarean section (n) 164 1,064 4.546
 No. with NP (%) 4 (2.4%) 22 (2.1%) 34 (0.6%)
p-value* 0.73 <0.001 <0.001
Elective CS (n)** 41 492 2.115
 No. with NP (%) 1 (2.4%) 14 (2.8%) 10 (0.5%)
Emergency CS (n)** 123 572 2.431
 No. with NP (%) 3(2.4) 8 (1.4%) 14 (0.6%)
  • *Comparing vaginal and CS delivery (emergency and elective).
  • **No significant differences in NP between elective and emergency CS in the three groups.

In neonates born at term, the incidence of pneumothorax was significantly higher when delivered by CS compared to vaginal delivery (0.55% vs. 0.10%; p<0.001). Corresponding results for neonates born preterm (n = 2,694) was 2.05% vs. 0.63% (p<0.01). At term, the need for CPAP was not increased when delivery was by CS compared to vaginally (0.28% vs. 0.15%; n.s.). Corresponding results for those born preterm were 17.7% vs. 6.9% (p<0.001). Between emergency and elective CS the difference in the need of CPAP was not significant, neither in the preterm nor the term group.

Of all the neonates delivered vaginally 0.4% needed MV. Corresponding results for those delivered by elective/emergency CS were 1.7 and 2.4%, respectively. Among the term neonates, the need for MV was significantly increased after CS compared to vaginal delivery (0.41% vs. 0.19%; p = 0.01). In addition to the need for MV, the use of CPAP was not (0.28% vs. 0.15%; p = 0.08). However, among the preterm infants delivered by CS, 17.7% needed CPAP compared to 6.9% when delivered vaginally (p<0.001) and MV was required for 8.1 and 3.7% (p<0.001), respectively.

The risk of pneumothorax was higher for boys than girls (0.35% vs. 0.19%; p<0.01). This difference remained significant after adjusting for gestational age. The use of CPAP and MV, as well as the incidence of pneumothorax, did not differ significantly between elective and emergency deliveries, irrespective of gestational age. However, all differences related to mode of delivery remained significant when adjusted for gender, mothers’ age and parity.

Discussion

Although NP is still a problem, we assume that the incidence is markedly lower than three decades ago (7–9). During the last 30 years, there have been no large studies confirming this assumption, because it would not have been ethical to x-ray a whole population of children for this purpose. Pneumothorax is, however, a relatively frequent complication in the newborn infant that may lead to morbidity and longer hospital stay. This reduction is due to the introduction of antenatal steroids (10), (11) and the introduction of surfactant replacement therapy (12), (13). However, we assume that some cases are not diagnosed because many of the children have minimal symptoms and therefore a chest-x-ray is not indicated.

Our study demonstrates a strong association between modes of delivery and the incidence of pneumothorax, need for CPAP and MV. These findings indicate that being delivered vaginally might have a positive influence on the pulmonary system in neonates. This association was particularly strong among preterm neonates (Table I). Previous studies have shown an association between CS and respiratory problems, supporting our findings (see Results). Pneumothorax was significantly more frequent after CS than after vaginal delivery. After an elective CS the baby is not stressed and often has ‘wet lungs’ followed by forced respiration that may lead to pneumothorax. CS also increases the need for MV compared to vaginal delivery. Among neonates delivered by CS at term or moderately preterm (30–36 weeks), the incidence of NP and respiratory problems was significantly increased. Such iatrogenic problems must be avoided by delaying delivery and giving antenatal steroid therapy where appropriate and possible.

Acknowledgement

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.