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Titre du document / Document title

Cesarean section on request at 39 weeks : Impact on shoulder dystocia, fetal trauma, neonatal encephalopathy, and intrauterine fetal demise

Auteur(s) / Author(s)

HANKINS Gary D. V. ; CLARK Shannon M. ; MUNN Mary B. ;

Résumé / Abstract

PURPOSE The purpose of this analysis was to determine the impact on specific forms of neonatal morbidity and mortality by allowing women to opt for delivery by elective cesarean section at 39 weeks of gestation (EGA). According to the National Vital Statistics Reports, over 70% of deliveries in the U.S. annually are at gestational ages ≥39 weeks EGA. Estimating that over 4 million deliveries occur annually in the United States, this would yield approximately 3 million pregnancies wherein the woman may exercise her choice for either primary or repeat cesarean section at 39 weeks EGA or at the point when labor is established. METHODS A search was conducted using Ovid Medline spanning the past 10 years using the following key words: fetal trauma, shoulder dystocia, brachial plexus palsy, neonatal skull fracture, obstetrical trauma, traumatic delivery, intrauterine fetal demise, stillbirth, fetal demise, and neonatal encephalopathy. Using this search technique, over 2100 articles were identified. The abstracts were reviewed and pertinent articles were chosen for further consideration. The identified articles and their applicable references were obtained for inclusion in this review. Preference was given to publications on or after the year 2000 with the exception of classical or sentinel articles, which were included without regard to year of publication. RESULTS Four major categories of neonatal morbidity and mortality are discussed: Shoulder dystocia: Accepting that we do not have a successful method for the prediction or prevention of shoulder dystocia, the question becomes, "What is the chance that a baby will sustain a permanent brachial plexus injury at delivery?" Additionally, is there a significant protective effect of cesarean section in reducing the risk of such injury? Currently, the occurrence rate of brachial plexus palsy at the time of vaginal delivery ranges from 0.047% to 0.6% and for cesarean section from 0.0042% to 0.095%. Using a composite estimate of the risk of 0.15% for vaginal deliveries and applying it to the 3 million deliveries ≥39 weeks EGA, approximately 4500 cases of brachial plexus palsy would occur. If only 15% of these injuries were permanent, 675 permanent brachial plexus palsies would occur annually. If the risk of permanent injury is 1 in 10,000 as reported by Chauhan, 300 permanent brachial plexus palsies would occur annually in the United States. The range then for permanent brachial plexus injury that could be avoided with cesarean section on request would appear to vary between 1 in 5000 and 1 in 10,000 vaginal births. Fetal trauma: The incidence of significant birth trauma varies from 0.2 to 1 to 2 per 1000 births. The use of sequential instruments, for example, vacuum followed by forceps or vice versa, is specifically associated with an unacceptably high injury rate. Intrapartum-related neonatal deaths of vertex singleton fetuses with birthweights >2500 g from traumatic cranial or cervical spine injury secondary to vacuum- or forceps-assisted vaginal delivery are still occurring. Overall, the frequency of significant fetal injury is significantly greater with vaginal delivery, especially operative vaginal delivery, than with cesarean section for the nonlaboring woman at 39 weeks EGA or near term when early labor has been established. Neonatal encephalopathy: The prevalence of moderate to severe neonatal encephalopathy is 3.8/1000 term live births with a neonatal fatality rate of 9.1%. In 4% to 10% of cases, the etiology appears to be pure intrapartum hypoxia. Intrapartum hypoxia superimposed on antepartum risk factors may account for up to 25% of the moderate to severe encephalopathies, according to one cohort. A paradox in the data thus far is that infants born to nonlaboring women delivered by cesarean section had an 83% reduction in the occurrence of moderate or severe encephalopathy.

Revue / Journal Title

Seminars in perinatology    ISSN  0146-0005   CODEN SEMPDU 

Source / Source

2006, vol. 30, no5, pp. 276-287 [12 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Elsevier, New York, NY, ETATS-UNIS  (1977) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 17785, 35400015877369.0090

Nº notice refdoc (ud4) : 18208466



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