Objective
The purpose of this investigation was to examine the economic impact of performing elective repeat cesarean during 37 or 38 weeks of gestation relative to the American College of Obstetricians and Gynecologists recommendation of a 39-week delivery.
Study Design
Decision analysis modeling was used to estimate economic outcomes for a hypothetical cohort of neonates using data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network study of “Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes.” Costs and charges were estimated using the Florida Healthcare Cost and Utilization Project.
Results
A total of 82,541 deliveries occurring between 37-39 completed weeks of gestation were analyzed for the incidence of adverse outcomes and their hospital costs and charges. The model demonstrated increased costs through increasing adverse outcomes among elective repeat cesarean deliveries performed <39 weeks of gestation.
Conclusion
Our findings suggest that there are benefits to waiting until 39 weeks of gestation to perform an elective repeat cesarean delivery.
The number of births by cesarean section was 31.8% of all births in the United States as reported in 2007. This represents the 11th consecutive year of increase in the cesarean birth rate. It has been well characterized that infants who are delivered at <39 weeks of gestation have increased rates of adverse outcomes that primarily result from respiratory complications and the need for prolonged hospitalization. As the cesarean delivery rate has increased by >50% from 1996 through 2006, there has been growing concern over the impact of elective repeat cesarean delivery on neonatal health. This is especially concerning given the known increase in adverse outcomes for infants who undergo elective repeat cesarean delivery in the absence of labor <39 weeks of gestation. However, the practice of elective repeat cesarean delivery <39 weeks of gestation remains common. This was recently noted in an investigation of a cohort of patients who underwent repeat cesarean delivery within the 19 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network (NICHD-MFMU). In this investigation that examined elective repeat cesarean delivery from 1999 through 2002 in these centers, 35.8% of these elective repeat cesarean deliveries were performed <39 weeks of completed gestation. Thus, the practice of elective repeat cesarean delivery remains common despite the American College of Obstetricians and Gynecologists (ACOG) recommendation to await 39 weeks of completed gestational age prior to elective repeat cesarean delivery. The purpose of this investigation was to utilize the rates of adverse outcome characterized in the NICHD-MFMU study of elective cesarean delivery at term to characterize the cost benefits of delay of elective repeat cesarean delivery to 39 weeks of completed gestational age in a hypothetical cohort of neonates using a decision tree analysis.
Materials and Methods
The Institutional Review Board at the Medical University of South Carolina approved this cost benefit economic investigation. This study utilized cost benefit modeling to integrate outcomes data with cost information by different gestational ages at time of elective repeat cesarean delivery. The goal of using this approach is to estimate the difference in cost expected in a population of neonates undergoing an elective repeat cesarean delivery at 37, 38, or 39 completed weeks of gestational age. In this investigation, the costs of care for infants delivered at either 37 or 38 weeks of completed gestational age would be compared to those encountered at the ACOG-recommended 39 completed weeks of gestational age. Adverse outcomes considered in this decision economic analysis included respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), admission to the neonatal intensive care unit (NICU), neonatal sepsis, neonatal hypoglycemia, requirement for ventilation, and hospital stay of ≥5 days. Proportions for each adverse outcome were derived from the prior patient cohort of elective cesarean delivery and are provided in Table 1 . The incidence of these same outcomes was determined from the Florida 2007 discharge data from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID). As each of these outcomes are not independent (ie, a single live birth can experience multiple adverse outcomes simultaneously), the cost benefit analysis was undertaken with the consideration of each adverse outcome independently. Data used in this investigation consisted of: (1) the incidence of adverse outcomes as reported in the NICHD-MFMU investigation of “Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes”; and (2) neonatal discharge costs and data as derived from the 2007 discharge data from the HCUP SID for Florida, which was developed by the Agency for Healthcare Research and Quality. The Florida HCUP SID data comprise approximately 90% of inpatient discharge abstracts that include both clinical and nonclinical data from 269 of 294 (91.5%) hospitals across Florida. Costs were assessed from this database as the mean cost for health care of an infant in the hospitalization following delivery. The cost of a delivery that involved an adverse outcome of interest was assessed through the use of the International Classification of Diseases, Clinical Modification (ICD-9) coding in a pregnancy that was delivered by repeat cesarean delivery between 37-39 weeks of completed gestational age (259-279 days from last menstrual period). As the HCUP records primary and secondary diagnosis at discharge, the ICD-9 code of interest had to be listed in either of these fields for the neonatal record to be included in the calculation of mean cost for the specific adverse outcome. Actual charges were used to estimate costs using a birth-specific set of cost-to-charge ratios developed from a proprietary data set for Florida that contained both cost and charges for each admission (personal communication with Dr Kit N. Simpson, January 31, 2010). The effects of early delivery on charges were also reported because charges are a good estimator of differences in the medical care resources used for treating specific competing hospital conditions. Costs were adjusted for inflation to 2009 US dollars according to the 2007-2009 Hospital-Related Services Consumer Price Index. The adverse outcomes that were analyzed in this manner included RDS (ICD-9 code 769.0), TTN (ICD-9 code 770.6), neonatal hypoglycemia (ICD-9 code 775.6), and confirmed neonatal sepsis (ICD-9 code 771.81). The required admission to the NICU following birth was recorded in this database as was the need for early ventilator management (within 24 hours of delivery) allowing ascertainment of these complications. Births that were complicated by fetal anomalies or stillbirth were excluded from these costing data. In this manner, infant costs at discharge were obtained for infants discharged with these outcomes within the same gestational age strata (37-39 weeks of gestational age) as were used in the NICHD-MFMU investigation of “Timing of Elective Repeat Cesarean Delivery at Term and Neonatal Outcomes” where adverse event incidence was derived. This allowed a representative (mean) cost to be assigned to each neonate discharged from the hospital with or without an adverse outcome following repeat cesarean delivery. In this investigation, costs and outcomes were calculated using a hypothetical cohort of 100 neonates delivered at each gestational age. Using a decision tree methodology, the total cost of care for each 100-neonate hypothetical cohort was calculated based upon the sum total cost of the anticipated incidence of the adverse event multiplied by 100 and then multiplied by the mean cost for that adverse outcome with the remainder of the neonates without the adverse event present multiplied by 1 (the incidence of the adverse event rate) multiplied by the discharge mean cost for uncomplicated neonatal care. The decision analysis model utilized in this investigation was constructed in software (Excel 2007, Microsoft, Seattle, WA) and is shown in the Figure .
| NICHD-MFMU data wk of gestation, % a | Florida HCUP SID data, % | |||
|---|---|---|---|---|
| Outcome | 37 wk of completed gestation (6.3%) | 38 wk of completed gestation (29.5%) | 39 wk of completed gestation (49.1%) | 37-39 wk of completed gestation |
| Respiratory distress syndrome, % | 3.7 | 1.9 | 0.9 | 2.47 |
| Transient tachypnea of newborn, % | 4.8 | 3.9 | 2.7 | 4.75 |
| Admission to NICU, % | 12.8 | 8.1 | 5.9 | NR |
| Newborn sepsis (proved cases), % | 0.4 | 0.1 | 0.1 | 0.00 |
| Treated hypoglycemia, % | 2.4 | 0.9 | 0.7 | 1.97 |
| Ventilation required in first 24 h, % | 1.9 | 0.9 | 0.4 | 0.19 |
| Hospital stay ≥5 d, % | 9.1 | 5.7 | 3.6 | 4.37 |
a Elective repeat cesarean deliveries occurring in NICHD-MFMU investigation.
Results
A total of 82,541 repeat cesarean deliveries occurred between 37-39 completed weeks of gestation in the 2007 Florida HCUP SID. Of these deliveries, there was a 0.26% incidence (n = 214) of neonatal death. Costs and charges accrued at repeat cesarean delivery were obtained in US dollars based on the 2007 Florida HCUP SID and are reported as the mean costs and charges of neonatal discharge billing with either no adverse outcome (uncomplicated delivery) or with an adverse outcome affecting neonatal care in Table 2 . Each of the adverse events examined in this investigation resulted in at least a 5-fold increase in neonatal discharge costs, as evidenced by neonates affected by TTN, when compared to a normal outcome after repeat cesarean delivery as experienced in the window of 37-39 completed weeks of gestational age. Costs at discharge were noted to rise as much as 152-fold over an uncomplicated neonate delivered by repeat cesarean delivery in the case of confirmed neonatal sepsis. These costs were used with the observed rates of adverse neonatal outcome reported in the NICHD-MFMU study of timing of elective cesarean delivery in the decision tree model to estimate the cost of delivery of 100 hypothetical neonates at each of 37, 38, and 39 weeks of completed gestational age. In each of these cohorts, the contribution of each neonatal adverse event was found to be in excess of the cost of management of an uncomplicated neonatal delivery. It was noted that the excess costs of delivery at 37 or 38 weeks of completed gestation compared to 39 weeks of gestation were greater when repeat cesarean delivery occurred at 37 weeks rather than 38 weeks ( Table 3 ). Both of these cohorts (37 and 38 weeks) had greater costs associated with elective cesarean delivery than those encountered at 39 weeks of completed gestational age. Thus, this model is a dominant model where costs were always greater with delivery at earlier gestation than 39 completed weeks of gestation. The cost savings associated with a delay of elective repeat cesarean delivery from 37 weeks or 38 weeks to 39 weeks of gestation are reported in Table 4 for each 100-infant hypothetical cohort. It is noted that there is a cost savings for delaying delivery by either 2 weeks (37-39 weeks) or by 1 week (38-39 weeks). The costs were noted to decline the most when NICU admission or RDS was avoided through delay of elective cesarean delivery by either 1 or 2 weeks. However, there were also savings encountered with delay of elective repeat cesarean delivery in avoiding TTN, proved newborn sepsis, and hypoglycemia that required treatment. Thus, with any of the adverse events analyzed, there was cost savings with each incremental week of delay of elective cesarean delivery from 37-39 completed weeks of gestational age.
