Increasing cesarean delivery rates, due in part to changing maternal characteristics and obstetric practice patterns1 and to increasing interest in cesarean delivery without labor by patient request in the absence of medical or obstetric indications,2–5 have led to numerous studies evaluating maternal and fetal mortality and morbidity associated with cesarean delivery. Data from our center suggest that maternal morbidity is increased when cesarean delivery is performed in labor compared with cesarean delivery without labor6 and that these differences may be compounded with cesarean delivery at full dilatation.7 The long-term impact of cesarean delivery on future reproductive health, relative to assisted and spontaneous vaginal delivery, is also gaining increasing attention with implications for abnormalities in placentation,8,9 adverse perinatal outcomes,10–12 and complications of pelvic floor function.13–15
Not surprisingly, the increased morbidities seen with cesarean delivery in labor are reflected in increased health care costs associated with cesarean delivery in labor compared with other methods of delivery.16 The impact of initial method of delivery on subsequent reproductive health care costs is unknown. We performed a population cohort study using data from a large provincial perinatal database to examine the cumulative costs associated with initial and subsequent deliveries in a low-risk obstetric population.
MATERIALS AND METHODS
We conducted a population-based, cohort analysis using data from the Nova Scotia Atlee Perinatal Database for initial deliveries occurring from 1985 to 2002 (18 years) at the IWK Health Centre. The Nova Scotia Atlee Perinatal Database is a provincial, population-based, clinically oriented computerized database, which codes information on demographic variables, procedures, maternal and newborn diagnoses, and morbidity and mortality for every birth of 500 grams or more occurring in Nova Scotia hospitals and of Nova Scotia residents. Nova Scotia has a homogeneous, predominantly white population of approximately 1,000,000,17 with approximately 10,000 live births in Nova Scotia each year.18
Data for this study were collected data on variables that included type of labor (spontaneous or induced), maternal length of stay in the labor and delivery unit, epidural use, method of delivery, and maternal and neonatal length of stay postpartum. Comprehensive details on the cost analysis for the initial delivery are reported elsewhere.16 In-house consultant physicians provide obstetric and obstetric anesthesia care at the Women’s Hospital, IWK Health Centre, a tertiary level, “stand-alone” maternity facility. Women in active labor receive continuous one-to-one nursing care. Uncomplicated postpartum hospital discharge policy includes a 48-hour stay for spontaneous and assisted vaginal deliveries and a 72-hour stay for cesarean deliveries. A structured follow-up visit by nurses competent in postpartum care, organized by the provincial health department, is available for all local patients discharged from hospital postpartum.
Inclusion and exclusion criteria were used to define the low-risk population at first delivery. For the initial delivery, pregnancies were included if there was a live singleton at term (37–42 weeks) born to a nulliparous woman, and were excluded if there was a major fetal anomaly, if there was nonvertex presentation with spontaneous or induced labor, or if there was preexisting maternal disease (such as hypertension, diabetes, or renal or cardiac disease), small for gestational age (less than the 10th percentile birth weight for gestational age), pregnancy complications (such as hypertension or diabetes), or premature rupture of membranes. Maternal and infant summary characteristics included maternal age, smoking status, maternal weight at delivery, gestational age at delivery, and birth weight. Ethical approval for this database study was obtained from the Reproductive Care Program of Nova Scotia and the Research Ethics Board at the IWK Health Centre.
In addition to the costs that were estimated for the initial delivery (including physician and nursing costs, duration of stay in the labor and delivery, postpartum and neonatal intensive care units, induction of labor agents, and consumables),16 costs for each subsequent delivery recorded in the database were estimated. In Nova Scotia, the physician fee for obstetric services is the same for all methods of delivery and attending physician (family physician or specialist), and estimated physician costs in this study included the base fee with premium additions for deliveries occurring at night or on weekends or holidays. At the IWK, the surgical assistant is an obstetric resident, and midwives do not practice obstetric care. The physician fee for anesthesiology services incorporated epidural placement and maintenance during labor and delivery and in the operating room and included the base fee with premium additions. Hours in the labor and delivery unit were calculated from time and date of admission to the unit to time and date of delivery, which are recorded in the database. Women in early labor or with prolonged latent phase are not routinely admitted to the labor and delivery unit, but instead are managed either as outpatients or as inpatients on the antepartum or self-care units, depending on maternal and fetal status and geographical considerations. Costs estimated for induction of labor included number of doses of cervical ripening agents, but not the cost of oxytocin ($0.44 per 10 unit/mL ampule). In our center, women undergoing cervical ripening do not require admission to labor and delivery, and the cost of the medication required for medical induction, augmentation, and active management of the third stage was approximated by the continuous nursing care costs and hours in the labor and delivery unit. Consumable costs included costs of vaginal and cesarean delivery packs (such as drapes, gowns, instruments, catheters, needles, syringes, and sponges). Hours in hospital postpartum were calculated from time and date of admission to the unit to time and date of discharge, which are recorded in the database. The costs of maternal postpartum and neonatal length of stay were felt to account for short-term morbidity. Costs for antepartum hospital admissions in subsequent deliveries, and costs for peripartum hysterectomies, peripartum dilatation and curettages, and peripartum tubal ligations were also included in this longitudinal study, since they may represent increased maternal morbidity and/or length of hospital stay.
As in the previous study,16 the cumulative costs associated with delivery and postpartum stay were first calculated separately for each mother–infant pair. In this study, mother–infant costs, which also included duration of antepartum stay costs, were calculated for each subsequent delivery. Mean costs and standard deviations were then calculated for delivery classified by initial type of labor (spontaneous labor, induced labor, and no labor), as well as classified by initial method of delivery (spontaneous vaginal delivery, assisted vaginal delivery, cesarean delivery in labor, and cesarean delivery without labor). Hospital overhead charges were excluded from this analysis. Each category of cost was calculated in 2006 Canadian currency and then converted to U.S. dollars.
Continuous variables between groups were compared using Student t test. Categorical data were compared using χ2 and Fisher exact tests, where appropriate. Statistical significance was P<.05. Statistical analyses were performed using the SAS 8.0 programming package for Windows (Cary, NC) and EpiInfo (CDC, Atlanta, GA).
A total of 27,613 pregnancies satisfied inclusion and exclusion criteria for initial delivery. Fifty-four percent of women had one subsequent delivery, and 21% of those women had a second subsequent delivery. Ninety-three percent of women who had spontaneous vaginal delivery initially had a spontaneous delivery in their second delivery and 94% had delivered spontaneously in the third delivery. Seventy-three percent of women who had a cesarean delivery in labor had a repeat cesarean delivery, 34% of which were in labor. There were no maternal deaths or maternal readmissions to the tertiary, “stand-alone” maternity care facility. Readmissions to hospitals other than the birth hospital may have occurred; however, information regarding postpartum readmissions at these sites is coded separately and comprehensive information was not available for the analysis. Twelve (0.4%) required transfer for intensive care (67% of those after postpartum hemorrhage, 17% after a thromboembolic event, 17% for respiratory complications). No differences were seen in the number of women admitted to intensive care by method of initial delivery. Maternal and infant summary characteristics for this low-risk population16 are summarized in Table 1 for women undergoing induction of labor, women having spontaneous onset of labor, and women undergoing cesarean delivery without labor, and differences in maternal age, maternal weight at delivery, gestational age at delivery, and birth weight were not considered clinically significant. Comparison of perinatal characteristics demonstrated that women undergoing induction of labor were more likely to have infants requiring neonatal intensive care and more likely to have cesarean deliveries in labor. The primary indication for cesarean delivery without labor was breech presentation.
Although some of the costs that were considered in the analysis are summarized in Table 2 and elsewhere,16 Table 2 also summarizes the additional costs associated with this cumulative analysis. The number of blood transfusions in all groups was low (less than 1%) and was not considered in the assessment of costs. Table 3 summarizes selected subsequent delivery characteristics associated with initial method of delivery. Women who initially underwent cesarean delivery with or without labor had significantly fewer deliveries (a mean of one delivery) compared with women who initially had spontaneous vaginal deliveries or assisted vaginal deliveries (a mean of two deliveries, P<.05 for all comparisons). There were no differences in the mean number of months between the first and second, between the second and third, and between the third and fourth deliveries for any of the initial methods of delivery.
Table 4 shows cumulative costs estimates for women categorized by type of labor at initial delivery (spontaneous onset of labor, induction of labor or cesarean delivery without labor) and categorized by method of delivery at initial delivery (spontaneous vaginal delivery, assisted vaginal delivery, cesarean delivery in labor, and cesarean delivery without labor). With one additional delivery, the cumulative cost of having a cesarean delivery with no labor in the first delivery ($5,306) was more than the cost for either spontaneous onset of labor ($4,781) or induced labor ($4,982) in the first delivery, but these differences were not significant (P=.12 and P=.09, respectively). With two additional deliveries, the cumulative cost of having induced labor in the first delivery ($7,220) was more than the cost of spontaneous onset of labor ($6,919, P=.006) and cesarean delivery with no labor ($7,213, P=.26) in the first delivery.
When we examined the costs of different methods of delivery at initial delivery independent of labor type, the cumulative cost of spontaneous vaginal delivery was significantly lower than the cumulative cost of assisted vaginal delivery or cesarean delivery in labor for both one additional delivery and two additional deliveries (P<.05). The cost of initial spontaneous vaginal delivery was significantly lower than the cost of initial cesarean delivery without labor for one additional delivery (P<.001), but not two additional deliveries (P<.32). In a subset of women who underwent cesarean delivery without labor for all deliveries (up to three deliveries), the cumulative cost for delivery was $7,777. Cesarean delivery in labor in the first delivery was the most costly type of delivery regardless of the number of subsequent deliveries, and the differences in cost increased with increasing number of deliveries (P<.05).
This study considered the cumulative costs of health service resources using a population-based database for initial deliveries to nulliparous women undergoing induction of labor, entering labor spontaneously and having no labor, as well as the cumulative costs for initial deliveries to nulliparous women by method of delivery, including delivery by cesarean in labor, cesarean without labor, and assisted vaginal and spontaneous vaginal delivery. When type of labor was considered, the cumulative costs of deliveries to women in the group undergoing induction of labor had the highest cost with two subsequent deliveries and were significantly more costly than women entering labor spontaneously. Cesarean delivery in labor in the initial delivery was the most costly method of delivery regardless of the number of subsequent deliveries. Nursing care in labor and delivery was a major contributor to the increase in costs associated with induction of labor and cesarean delivery in labor.
Previous work using data from this population suggests that maternal morbidity is increased after assisted vaginal delivery and cesarean delivery in labor compared with cesarean delivery without labor in the first delivery,6 and that costs associated with delivery were highest with induction of labor and cesarean delivery in labor.16 While numerous studies have addressed the issue of delivery costs when immediate morbidities were evaluated,19–22 the majority of studies assessing long-term outcomes evaluate the costs of a trial of labor after previous cesarean delivery using modeling23–27 which have demonstrated increased, decreased, and no difference in costs for trial of labor compared with elective cesarean delivery.
While data on up to six subsequent deliveries existed in the Nova Scotia Atlee Perinatal Database, the population of women available for comparison dropped by 98% (n=555) by three subsequent deliveries, and therefore only comparisons of cumulative costs with up to two subsequent deliveries were reported in this study. Statistically significant differences between types of labor and methods of delivery for initial, one, and two additional deliveries ranged from $200 to $3,000 per delivery, with a corresponding potential clinical impact on cost reimbursement systems such as universal health care in Canada or the United Kingdom or managed health care organizations in the United States. Based on the cumulative costs estimated in this study, the proportion of women undergoing cesarean delivery without labor would have to increase from 3% (in this study) to 15% in the initial delivery to be more costly than labor induction, and would have to increase from 3% (in this study) to 10% in a subsequent pregnancy (with a constant proportion of women entering labor spontaneously) to be more costly than labor induction. If the proportion of women undergoing assisted vaginal delivery continues to decline,28 the proportion of women undergoing cesarean delivery without labor would have to increase from 3% (in this study) to 20% in the initial delivery to be more costly than cesarean delivery in labor, and would have to increase from 3% (in this study) to 17% in a subsequent pregnancy (with a constant proportion of women having a spontaneous vaginal delivery) to be more costly than cesarean delivery in labor.
Calculation of costs in this study was based on an evaluation of low-risk women and the method of their first delivery. While previous work did not address costs associated with prematurity and obstetric complications in this low-risk population,16 the cumulative costs analysis accounted for duration of nursing care for antepartum admissions as a surrogate for subsequent antepartum maternal or obstetric complications. There were no differences in costs for the structured postpartum visits regardless of method of delivery, and therefore this cost again was not included in the analysis. The study was unable to account for costs associated with physician attendance in labor or changes in obstetric practice patterns that may have contributed to temporal differences in costs, such as increases in induction of labor for postterm indications or decreases in length of postpartum hospital stay. Although there are 11 hospitals that offer with obstetric care in Nova Scotia, the IWK Health Centre, which is the tertiary maternity care hospital, was chosen as the only patient data source to minimize the effects of temporal change on obstetric management. With universal access to obstetric care in Canada, and with financial compensation identical regardless of type of delivery in Nova Scotia, this study may have underestimated the costs of cesarean delivery where physicians’ fees are higher for operative delivery, and in countries without universal access to obstetric care, differential physician costs may exist and should be considered in cost analyses.
Data in the Nova Scotia Atlee Perinatal Database has been shown to be highly accurate and reliable29,30; however, the scope of the present study was determined to some extent by the range of variables maintained in the Nova Scotia Atlee Perinatal Database. The database was not able to account for subsequent deliveries occurring outside the IWK Health Centre. However, the region served by the tertiary obstetric referral center is known to have a stable population, with less than 5% population mobility in a 5-year time span, and with 93% of the population Canadian-born.31 The value of costs, such as the value of lost earnings, medical–legal costs, or costs of longer-term infant complications such as neurodevelopmental delay, as a result of different methods of delivery were unable to be incorporated into the cumulative costs calculated in this study.
In this unique longitudinal study, cesarean delivery in labor, with initial and with subsequent deliveries, was shown to be associated with increased costs compared to other methods of delivery. These increases in cost are due in part to nursing costs in labor, and optimizing identification of and timely intervention for dystocia or nonreassuring fetal status in labor may assist in equalizing resources required for different types of labor or methods of delivery. Local costs for nursing care, physician services, and obstetric intervention, and the proportions of obstetric interventions and method of delivery, will guide patient care policies that include consideration of the cumulative economic impact of a policy of cesarean delivery in the absence of medical or obstetric indications.
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