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briefly the high observed neonatal inten- sive care unit (NICU) admission rate, and did not compare .... 2013 Royal College of Obstetricians and Gynaecologists.
BJOG Exchange

Elective caesarean section at 38 versus 39 weeks of gestation: neonatal and maternal outcomes in a randomised controlled trial Are we trivialising neonatal intensive care unit admissions?

Sir, We have read with interest the article by Glavind et al.1 published in your last edition. The study concluded that elective caesarean section scheduled before 39 weeks of gestation carried a similar risk of neonatal intensive care unit admission, compared with those scheduled after 39 weeks of gestation. Some points, however, need to be addressed. The authors discussed only briefly the high observed neonatal intensive care unit (NICU) admission rate, and did not compare this with previously published data where NICU admission rates were 8.1, 5.9, and 4.8% at 38, 39, and 40 weeks of gestation, respectively.2 A 13.9% rate of NICU admissions and an 8.7% rate of continuous positive airway pressure (CPAP) treatment among low-risk neonates seems unacceptable. With the available evidence in favour of vaginal birth for women without a clear indication for caesarean section, and with observational data indicating higher neonatal risks for early elective delivery (before 39 weeks of gestation), including higher mortality rates, it is surprising that a randomised cotrolled trial allocating women to elective caesarean section at 38 versus 39 weeks of gestation was deemed ethically appropriate. Reasons stated by the authors include a potential selection bias in previous cohort studies, which is likely to have led to an over-representation of high-risk neonates in the early-delivery group; however, a proper statistical analysis of observational data could address this issue without conducting a study that raises ethical concerns, by exposing newborns and women to significant risks. It is already known that caesarean section at term for non-

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medical reasons affects overall maternal morbidity rates, and increases the mortality rate by three to five times, when compared with vaginal birth.3 A total of 1274 women (243 nulliparous) had caesarean sections without precise indication in the study. The authors affirmed their intention to ‘fully investigate neonatal and maternal benefits or adverse events associated with elective caesarean section timing’, which cannot be achieved without a comparison group (i.e. spontaneous labour and vaginal birth, a mode of delivery with evidence showing better neonatal and maternal outcomes). If the authors insist on merely making comparisons between different timings of caesarean section, current evidence would point towards a comparison between elective caesarean at 39 and 40 weeks of gestation. The sample size was not sufficient for most of the outcomes examined, and the authors reported that the expected difference employed to calculate the sample was abstracted from a cohort study4; however, these data were not available in the published version. Figures 2 and 3 of the original paper indicate a slightly greater number of births before 38 weeks of gestation in the group assigned to elective caesarean at 39 weeks of gestation, and it is reasonable to question if this adversely interfered with the neonatal outcomes for this group. It is also important to examine the potential impact of these conclusions on public health, particularly in settings where caesarean section rates are rising. Despite a statistically insignificant difference (2%) in the primary outcome, we could consider this magnitude as the incremental risk of elective caesarean at 38 weeks of gestation to project possible scenarios following the adoption of this practice. In Brazil, considering that 35% of caesareans performed are elective, we could estimate about 500 000 elective procedures each year. If 200 000 of these women have no clear medical indication for surgical birth, and were scheduled at 38 weeks of gestation,

we could project 4000 neonates being admitted to NICUs unnecessarily. &

References 1 Glavind J, Kindberg S, Uldbjerg N, Khalil M, Møller A, Mortensen B, et al. Elective caesarean section at 38 weeks versus 39 weeks: neonatal and maternal outcomes in a randomised controlled trial. BJOG 2013;120:1123–32. 2 Tita ATN, Landon MB, Spong CY, Lai Y, Leveno KJ, Varner MW, et al. Timing of elective repeat cesarean delivery at term and neonatal outcomes. N Eng J Med 2009;360: 111–20. €lmezoglu A, Lumbiganon P, 3 Souza J, Gu Laopaiboon M, Carroli G, Fawole B, et al. Caesarean section without medical indications is associated with an increased risk of adverse short-term maternal outcomes: the 2004– 2008 WHO Global Survey on Maternal and Perinatal Health. BMC Medicine 2010;8:71. 4 Hansen AK, Wisborg K, Uldbjerg N, Henriksen TB. Risk of respiratory morbidity in term infants delivered by elective caesarean section: cohort study. BMJ 2008;336:85–7.

MM Amorim,a,b M Nakamura-Pereira,c MLS Takemoto,d R Knobel,e L Katza,b & CB Andreuccif a

Instituto Paraibano de Pesquisa Prof. Joaquim Amorim Neto, Campina Grande, Paraıba, Brazil bInstituto de Medicina Integral Prof. Fernando Figueira, Recife, Pernambuco, Brazil cInstituto Fernandes Figueira da Fundacß~ao Oswaldo Cruz, Rio de Janeiro, Brazil dUniversidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil eUniversidade Federal de Santa Catarina, Florianopolis, Santa Catarina, Brazil fUniversidade Federal de S~ao Carlos, S~ao Carlos, S~ao Paulo, Brazil Accepted 10 August 2013. DOI: 10.1111/1471-0528.12470

Authors’ reply Sir, We thank Amorim and colleagues for their interest in our study and wish to clarify the important points raised. As written in our article, we defined admission to the neonatal ward (regardless of level of care) as a neonatal intensive care unit (NICU) admission. In addition, we included NICU admissions within 2 days of birth, and did not exclude women delivered by an

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BJOG Exchange

unscheduled caesarean section. All are factors likely to increase the number of NICU admissions registered in this trial, as compared with other studies.1,2 In our opinion, ethical consideration of the results from our trial seem to advocate against scheduling elective caesarean section 2–6 days prior to 39 weeks of gestation; however, we do agree that a comparison between elective caesarean section at 39 and 40 weeks of gestation would be interesting, as well as comparing outcomes after elective caesarean section at 39 weeks with (planned) caesarean section after the onset of labour. It was never the aim of the study to compare vaginal and caesarean birth, and all the women in the trial intended to deliver by elective caesarean section prior to being included in the trial. It is correct that the primary outcome estimates used in the sample size calculation were not presented in the article by Hansen et al.,3 but were extracted from the data set used for this study at the Perinatal Research Unit in Aarhus, Denmark. The best estimation for the impact on public health of the two interventions is captured by the confidence interval of the primary outcome. &

References 1 Tita AT, Landon MB, Spong CY, Lai Y, Leveno KJ, Varner MW, et al. Timing of elective repeat cesarean delivery at term and neonatal outcomes. N Engl J Med 2009;360:111–20. 2 Clark SL, Miller DD, Belfort MA, Dildy GA, Frye DK, Meyers JA. Neonatal and maternal outcomes associated with elective term delivery. Am J Obstet Gynecol 2009;200: 156.e1–156.e4. 3 Hansen AK, Wisborg K, Uldbjerg N, Henriksen TB. Risk of respiratory morbidity in term infants delivered by elective caesarean section: cohort study. BMJ 2008;336:85–7.

J Glavind,a N Uldbjerg,a SF Kindberga & TB Henriksenb a

Department of Obstetrics and Gynaecology, Aarhus University Hospital, Aarhus, Denmark b Department of Paediatrics, Aarhus University Hospital, Aarhus, Denmark Accepted 29 August 2013. DOI: 10.1111/1471-0528.12472

Elective caesarean section at 38 versus 39 weeks of gestation: neonatal and maternal outcomes in a randomised controlled trial

Sir, I read with interest the randomised controlled trial (RCT) of elective caesarean section at 38 versus 39 weeks of gestation in singleton pregnancies.1 The authors’ observation that the admission rate to the neonatal intensive care unit (NICU) at 38+3 weeks of gestation following elective caesarean section was similar to that at 39 weeks of gestation was based on the defined outcomes mentioned in their methodology. Although their observation, with respect to the NICU admission rate, has been reported before,2 other adverse neonatal outcomes (not included in their study outcomes, and that may not require NICU admission) have been investigated and found to be significantly reduced when elective caesarean section was performed at 39–40 weeks of gestation, compared with 38 weeks of gestation.3,4 These adverse outcomes, including an increased neonatal mortality rate and rate of hospitalisation for 5 days or longer, have implications for parents and clinicians, and can be avoided. Considering all possible neonatal adverse outcomes, the timing of elective caesarean section without medical indication at ≥39 weeks of gestation may be preferred to 38+3 weeks of gestation until proven otherwise. &

References 1 Glavind J, Kindberg SF, Uldbjerg N, Khalil M, Moller AM, Mortensen BB, et al. Elective caesarean section at 38 weeks versus 39 weeks: neonatal and maternal outcomes in a randomised controlled trial. BJOG 2013;120: 1123–32. 2 Yee W, Amin H, Wood S. Elective caesarean section, neonatal intensive care unit admission, and neonatal respiratory distress. Obstet Gynecol 2008;111:823–8. 3 Reddy UM, Ko CW, Raju TN, Willinger M. Delivery indications at late-preterm gestations and infant mortality rates in the United Sates. Pediatrics 2009;124:234–40.

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4 Tita AT, Landon MB, Spong CY, Lai Y, Leveno KJ, Varver MW, et al. Timing of electice repeat caesarean delivery at term and neonatal outcomes. N Engl J Med 2009;360:111–20.

O Sanu Department of Obstetrics and Gynaecology, West Hertfordshire Hospitals NHS Trust, Watford, UK Accepted 22 July 2013. DOI: 10.1111/1471-0528.12469

Author’s reply Sir, Thank you for this comment on our trial. We agree that elective caesarean section should continue to be scheduled at 39+ weeks of gestation until further evidence of short-term, and possibly long-term, adverse effects of scheduling the procedure at earlier gestational ages is found. Several observational studies found an increased incidence of neonatal morbidity after elective caesarean section conducted prior to 39 completed weeks of gestation.1–3 Some may argue that overall the results from our trial support postponing elective caesarean section until after 39 weeks of gestation, particularly if a Bayesian approach to analysing our data had been undertaken. Nevertheless, we present the first randomised trial in this field, and we found no neonatal or maternal statistically significant differences between scheduling elective caesarean section at 38+3 and 39+3 weeks of gestation.4 Therefore, scheduling elective caesarean section 3–5 days prior to 39 completed weeks of gestation may be an acceptable option for a subgroup of women in whom an acute caesarean section should be avoided. &

References 1 Tita AT, Landon MB, Spong CY, Lai Y, Leveno KJ, Varner MW, et al. Timing of elective repeat cesarean delivery at term and neonatal outcomes. N Engl J Med 2009;360:111–20.

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