Wednesday, November 14, 2007

Outcomes of Cesarean Delivery Vary Based on Breech or Cephalic Presentatation

Outcomes of Cesarean Delivery Vary Based on Breech or Cephalic Presentations
News Author: Laurie Barclay, MDCME Author: Désirée Lie , MD , MSEd

November 7, 2007 — Cesarean delivery independently reduces overall risk in breech presentations and the risk for intrapartum fetal death in cephalic presentations but increases the risk for severe maternal and neonatal morbidity and mortality in cephalic presentations, according to the results of a multicenter, prospective cohort study reported in the October 30 Online First issue of the BMJ.

"Profound changes have occurred during the past three decades regarding the mode of delivery and perinatal outcomes, including recent efforts to reduce high rates of caesarean delivery while at the same time attempting to incorporate women's obstetric preferences," write José Villar and colleagues from the World Health Organization (WHO) 2005 Global Survey on Maternal and Perinatal Health Research Group. "The increase in rates of caesarean delivery at an institutional level is not associated with any clear overall benefit for the baby or mother but is linked with increased morbidity for both. There is therefore an urgent need to provide women and care providers with information on the potential individual risk and benefits associated with caesarean delivery."

Within the 2005 WHO global survey on maternal and perinatal health, the investigators conducted a prospective cohort study to determine the risks and benefits associated with cesarean vs vaginal delivery. In 24 areas of 8 randomly selected Latin American countries, 123 of 410 health facilities were randomly selected; of these, 120 participated and provided data.
During the 3-month study period, 106,546 deliveries were reported, and data were available for 97,095 (91%) deliveries. The primary endpoints were maternal, fetal, and neonatal morbidity and mortality associated with intrapartum or elective cesarean delivery, after adjustment for clinical, demographic, pregnancy, and institutional characteristics.

Compared with women undergoing vaginal delivery, women undergoing cesarean delivery had an increased risk for severe maternal morbidity. Odds ratio (OR) was 2.0 (95% confidence interval [CI], 1.6 - 2.5) for intrapartum cesarean and 2.3 (95% CI, 1.7 - 3.1) for elective cesarean. After either type of cesarean delivery, the risk for antibiotic treatment was 5 times that associated with vaginal deliveries.

After adjustment for possible confounding variables and gestational age, there was a trend towards a reduced OR for fetal death with elective cesarean delivery with cephalic presentation of 0.7 (95% CI, 0.4 - 1.0). With breech presentation, cesarean delivery was associated with a large protective effect for fetal death.

Independent of possible confounding variables and gestational age, intrapartum and elective cesarean when there was cephalic presentation increased the risk for a stay of 7 or more days in the neonatal intensive care unit (NICU) of 2.1 (95% CI, 1.8 - 2.6) and 1.9 (95% CI, 1.6 - 2.3), respectively) , as well as the risk for neonatal mortality up to hospital discharge of 1.7 (95% CI, 1.3 - 2.2) and 1.9 (95% CI, 1.5 - 2.6), respectively. This risk remained higher even when all cesarean deliveries for fetal distress were excluded, but increased risk was not seen with breech presentation.

For babies delivered by elective cesarean delivery, lack of labor was a risk factor for a stay of 7 or more days in NICU and for neonatal mortality up to hospital discharge, although rupturing of membranes may be protective.

"Caesarean delivery independently reduces overall risk in breech presentations and risk of intrapartum fetal death in cephalic presentations but increases the risk of severe maternal and neonatal morbidity and mortality in cephalic presentations," the study authors write. "Women undergoing caesarean deliveries, either intrapartum or elective, independent of demographic and clinical characteristics or experience of pregnancy had double the risk for severe maternal morbidity and mortality (including death, hysterectomy, blood transfusion, and admission to intensive care) and up to five times the risk of a postpartum infection compared with women undergoing vaginal delivery."

Limitations of the study include difficulties in working with a large number of health institutions, staff, medical protocols, and records formats; limited standardization of diagnoses and indications for cesarean delivery, which could have produced some misclassification between elective and intrapartum cesarean; limited relevance to institutions with lower rates of cesarean deliveries or to other regions of the world; consideration of maternal morbidity and mortality only up to the time of women's hospital discharge; and possible unmeasured confounding variables.

"Any net benefit from the liberal use of caesarean delivery on maternal and neonatal outcomes, at the institutional or individual level, remains to be demonstrated, with the exception of fewer severe vaginal complications after delivery and better fetal outcomes among breech presentations," the study authors conclude.

The United Nations Development Programme/United Nations Population Fund/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, WHO, and the US Agency for International Development funded this study. The study authors have disclosed no relevant financial relationships.

In an accompanying editorial, Allison Shorten, RN, PhD, from the University of Wollongong in Australia , notes that more accurate risk estimates are needed to support informed choices regarding childbirth.

"Cohort studies may provide more accurate estimates of risk factors for mode of birth when the complex relations between process factors such as induction of labour, epidural pain relief, type of practitioner, and funding arrangements are modelled as endogenous rather than exogenous variables in the analysis," Dr. Shorten concludes. "Future work should help to establish a consistent set of probabilities for the range of outcomes according to these factors, to support practitioners who guide and inform individual women's birth decisions. Exploring models of pregnancy and childbirth care that provide the best birth outcomes as well as supporting birth environments and practices that complement rather than counteract the normal physiology of childbirth is imperative."

No comments: