Costs of Newborn Care in California: A Population-Based Study

Abstract

OBJECTIVE.

We sought to describe the current costs of newborn care by using population-based data, which includes linked vital statistics and hospital records for both mothers and infants. These data allow costs to be reported by episode of care (birth), instead of by hospitalization.

METHODS.

Data for this study were obtained from the linked 2000 California birth cohort data. These data (n = 518 704), provided by the California Office of Statewide Health Planning and Development (OSHPD), contain infant vital statistics data (birth and death certificate data) linked to infant and maternal hospital discharge summaries. In addition to the infant and maternal hospital discharge summaries associated with delivery, these data include discharge summaries for all infant hospital-to-hospital transfers and maternal prenatal hospitalizations. The linkage algorithm that is used by OSHPD in creating the linked cohort data file is highly accurate. More than 99% of the maternal and infant discharge abstracts were linked successfully with the birth certificates. These data were also linked successfully with the infant discharge abstracts from the receiving hospital for 99% of the infants who were transferred to another hospital. The hospital discharge records were the source of the hospital charges and length-of-stay information summarized in this study. Hospital costs were estimated by adjusting charges by hospital-specific ratios of costs to charges obtained from the OSHPD Hospital Financial Reporting data. Costs, lengths of stay, and mortality were summarized by birth weight groups, gestational age, cost categories, and types of admissions.

RESULTS.

Low birth weight (LBW) and very low birth weight (VLBW) infants had significantly longer hospital stays and accounted for a significantly higher proportion of total hospital costs. The average hospital stay for LBW infants ranged from 6.2 to 68.1 days, whereas the average hospital stay for infants who weighed >2500 g at birth was 2.3 days. Overall, VLBW infants accounted for 0.9% of cases but 35.7% of costs, whereas LBW infants accounted for 5.9% of cases but 56.6% of total hospital costs. Although total maternal and infant costs were similar (~$1.6 billion), the distribution of maternal costs was much less skewed. For infants, 5% of infants accounted for 76% of total infant hospital costs. Conversely, the most expensive 3% of deliveries accounted for only 17% of total maternal costs.

CONCLUSIONS.

The very smallest infants make up a hugely disproportionate share of costs; more than half of all neonatal costs are incurred by LBW or premature infants. Maternal costs are similar in magnitude to newborn costs, but they are much less skewed than for infants. Preventing premature deliveries could yield very large cost savings, in addition to saving lives.

MEDICAL AND TECHNOLOGIC advances in the care of infants with low birth weight (LBW; <2500 g) and very low birth weight (VLBW; <1500 g) have resulted in substantial increases in survival rates¹ but the NICUs and technologies that are required to achieve these improved survival rates have produced extraordinary medical costs.^2,3 Previous research has shown that the costs associated with premature births that result in LBW infants are extremely difficult to quantify.⁴ Although there is a small but growing literature on the economic costs associated with LBW infants, little research has quantified the maternal costs connected to pregnancy complications and hospitalizations that result in these high-risk births.⁵

Because of the relative frequency of delivery and birth, compared with other hospital discharges, they make up a very large share of all hospital discharges; in California in 2000, delivery/birth-related hospitalizations accounted for 32% of all hospital discharges. The renewed growth of health care costs in recent years⁶ and the growing reports of the adverse effects of employer health insurance costs on industrial competitiveness and labor markets^7,8 are causing increased focus on the costs of health care. Because of their sheer volume, it is almost certain that birth-related hospitalizations will be the focus of cost containment efforts. To provide information for these and other policy decisions, this article describes the current costs of newborn care by using population-based linked data for both mothers and infants and quantifies maternal hospital expenditures associated with delivery. It highlights the costs for the delivery of LBW infants and presents the maternal costs that result from prenatal and delivery hospitalizations.

METHODS

After approval of this study by the Stanford University Institutional Review Board and the California Department of Health and Human Services Committee for the Protection of Human Subjects, linked data were obtained for the 2000 California birth cohort. These data link the California Office of Statewide Health Planning and Development (OSHPD) infant and maternal hospital discharge summaries to the infant vital statistics data (birth and death certificate data). Infant hospital discharge summaries included the delivery hospital discharge summary and those of any subsequent interhospital transfers. Maternal discharge summaries included prenatal hospitalizations and the delivery hospitalization.

The linkage algorithm that is used by OSHPD in creating the linked cohort data file is highly accurate.⁹ More than 99% of the maternal and infant discharge abstracts were linked successfully with the infant birth certificates (n = 518 704). These data were also linked successfully to the infant’s discharge abstract from the receiving hospital for 99% of the infants who were transferred to another hospital. The hospital discharge records were the source of the hospital charges and length of stay (LOS) information summarized in this study.

In addition to the information gained from linking hospitalizations, the data linkage provide complementary data. The hospital discharge abstracts are the source of information on hospital charges, LOS, and International Classification of Diseases, Ninth Revision diagnosis codes. Reabstracting studies have found that all of these data elements are coded reliably in the OSHPD discharge data.¹⁰ Using the birth certificate allows the very accurate data on birth weight, and the linkage to the death certificate yields accurate information on survival. The birth certificate is also the source of information on gestational age. Although the quality of the gestational-age data from the birth certificate is not as high as the birth weight data, birth weight can be used as a gross check on the reported gestational age. We used the criteria of Kotelchuck¹¹ to screen out implausible gestational-age values.

Computation of LOS and Hospital Costs

LOS

The total LOS (total inpatient hospital days) was computed for both mothers and infants by summing the hospital days associated with all relevant hospitalizations. For mothers, this included any prenatal hospitalizations and the delivery hospitalization. For infants, total LOS was computed as the total number of hospital days until first discharge to home or death. This total incorporated any interhospital transfers that may have occurred.

In some instances, LOS information was missing from the hospital discharge summary. Cases that did not include complete hospital stay information were excluded from the analyses of hospital stays. For mothers, a total of 515 372 delivery hospitalizations (of 518 704 total linked births) with complete LOS information were identified. A total of 3332 deliveries had missing maternal LOS information. The remaining difference between maternal delivery hospitalizations and total births was attributable to multiple births. For infants, a total of 518 697 births (of 518 704 total linked births) with complete LOS information were identified.

Hospital Costs

Most hospital charges represent a significant markup over actual costs, and these markups vary greatly across hospitals.¹² To provide a more accurate view of the actual costs, we multiplied the charges for each hospital stay by a hospital-specific cost-to-charge ratio derived from annual hospital financial data compiled by OSHPD.¹³ Ideally, this adjustment of charges to estimated costs would be done using department-specific cost-to-charge ratios as this yields more accurate estimates of costs.¹² Unfortunately, the OSHPD discharge data report only total hospital charges, not department-specific charges. Once charges were converted to costs, costs were adjusted by the consumer price index to reflect December 2003 levels.¹⁴

Two sets of cost variables were computed for both mothers and infants who were included in this study. These included total adjusted hospital costs and cost per inpatient hospital day. For mothers, total adjusted hospital costs were computed as the sum of adjusted inpatient hospital costs for all prenatal hospitalizations and the delivery hospitalization. For infants, total adjusted hospital costs were computed as the sum of adjusted inpatient hospital costs for the delivery hospitalization and any subsequent hospitalizations (transfers) before the infant was discharged from the hospital for the first time or before death if the infant died before being discharged.

In some instances, total adjusted costs could not be computed accurately because of missing data. Some hospitals (particularly Kaiser hospitals) do not regularly report hospital charges in the OSHPD discharge summaries. For this reason, these cases and cases involving multiple hospitalizations (eg, maternal prenatal hospitalizations, interhospital transfers) that did not include complete hospital charge data for each relevant hospitalization were excluded from our analyses. For maternal and infant cost analyses, a total of 437 514 deliveries (of 518 704 total linked births) were identified as having complete cost data. Once total adjusted costs were computed for mothers and infants, costs per hospital day were computed by dividing total adjusted costs by total LOS.

Cost Outliers

Through an examination of the distributions of maternal and infant adjusted costs, several cases with outlying/ improbable adjusted cost-per-day values were identified and excluded from our analyses. We excluded any case (infant or maternal) with an adjusted cost per day in excess of $10 000 (2498 mothers and 2530 infants). We also excluded maternal cases for which adjusted cost per day was less than $300 (1070 cases) and infant cases (survivors) with an adjusted cost per day of less than $100 (2975 cases). Surviving infants with a birth weight <1500 g were excluded when adjusted costs per day were less than $400 (94 cases). Surviving infants with birth weights between 1500 and 1999 g were excluded when adjusted costs per day were less than $250 (183 cases). Infants who died and had a total hospital stay that exceeded 1 day were excluded when adjusted costs per day were less than $400 (68 cases).

Because we were interested in presenting cost analyses that were complete for both mothers and infants, if either the mother or infant was dropped as a cost outlier, then both mother and infant were excluded from the cost analyses. However, these possible outlying cases were included in the data with the LOS results. All data management and statistical analyses were conducted using the SAS Statistical Analysis System software.¹⁵

RESULTS

Table 1 shows length of infant hospitalization and survival by birth weight groups. Almost all (93.9%) of the infants with birth weight <500 g died. These findings are consistent with those of Lucey et al,¹⁶ who found that 83% of infants who weighed 401 to 500 g at birth did not survive. Among infants who weighed between 500 and 749 g, mortality was 44.8%, and the mortality rate decreased rapidly as birth weight increased. As shown in Table 1, infants who weighed 750 to 999 g had the highest mean LOS at 68.1 days, infants who weighed 500 to 749 g had the second highest mean LOS at 60.2 days, and infants who weighed 1000 to 1249 g were slightly lower at 52.2 days. Infants who weighed >1249 g had progressively shorter hospital stays. The mean LOS of infants in the 2 smallest birth weight groups (<500 and 500–749 g) are strongly influenced by the high mortality rates of these infants. In results not shown, the vast majority of infants in these birth weight groups who died did so in the first days of life, with most of the deaths occurring within 48 hours of delivery.

TABLE 1.

LOS and Survival According to Infant Birth Weight Category for Hospital Births in California in 2000

Birth Weight Group, g	Total No.	No. of Deaths (%)	LOS
			Mean, d	Median, d	SD, d	10th Percentile	90th Percentile
<500	555	521 (93.9)	8.9	0.0	33.2	0.0	3.0
500–749	1027	460 (44.8)	60.2	69.0	58.2	0.0	126.0
750–999	1207	173 (14.3)	68.1	71.0	42.2	3.0	107.0
1000–1249	1344	94 (7.0)	52.2	52.0	27.2	17.0	81.0
1250–1499	1713	65 (3.8)	35.6	34.0	21.3	13.0	57.0
All <1500	5846	1313 (22.5)	47.9	43.0	40.9	0.0	99.0
1500–1749	2438	78 (3.2)	25.3	23.0	18.0	9.0	42.0
1750–1999	3875	55 (1.4)	15.7	13.0	13.4	3.0	30.0
2000–2499	19 878	155 (0.8)	6.2	3.0	10.1	1.0	14.0
All <2500	32 037	1601 (5.0)	16.4	6.0	25.8	1.0	46.0
≥2500	486 660	512 (0.1)	2.3	2.0	3.3	1.0	4.0
Total	518 697	2113 (0.4)	3.1	2.0	8.0	1.0	4.0

The findings shown in Table 2 present infant hospital costs by birth weight category and show that infants who weighed 500 to 749, 750 to 999, and 1000 to 1249 g had the highest total costs and mean daily costs. It is important to note that infants who weighed 500 to 749 g had the highest mean daily costs of $3417, whereas those who weighed 750 to 999 g had the highest total costs of the LBW infants ($176 969 950), despite the low number of total cases (913 infants). In addition, although only 107 infants who were born at a weight of <500 g had complete cost information, these infants had the second highest mean daily costs of $3013. These same infants had the shortest average hospital stay (8.9 days), a result that reflects the very high early mortality rate in this birth weight category.

TABLE 2.

Infant Costs According to Birth Weight and Gestational-Age Category for Hospital Births in California in 2000

Birth Weight Group, g	Total Cases		Infant Costs
	No. of Cases	% of Cases	Infant Total Costs, $	Mean Infant Costs, $	Median Infant Costs, $	SD, $	Mean Daily Costs, $	Median Daily Costs, $
< 500	107	0.00	13 672 991	127 785	9230	237 642	3013	2713
500–749	667	0.15	147 275 047	220 802	195 093	196 627	3417	2907
750–999	913	0.21	176 969 950	193 833	165 248	150 244	2757	2380
1000–1249	1050	0.24	124 757 266	118 816	96 926	93 206	2130	1826
1250–1499	1352	0.31	94 368 155	69 799	50 524	71 721	1751	1454
All <1500	4089	0.91	557 043 409	136 230	93 481	142 040	2377	1962
1500–1749	1974	0.45	88 813 390	44 992	31 417	58 955	1570	1293
1750–1999	3117	0.71	85 857 662	27 545	17 325	41 303	1434	1191
2000–2499	16 806	3.84	151 034 948	8987	1260	32 912	844	466
All < 2500	25 986	5.91	882 749 409	33 970	7141	80 040	1211	895
>2500	411 525	94.06	677 834 203	1647	570	10 743	435	316
Gestational-age group, all births, wk
≤32	8282	1.9	553 345 754	66 813	25 454	108 308	1535	1225
33–36	34 800	8.0	246 431 174	7081	806	28 943	702	377
Other	394 432	90.2	760 971 632	1929	572	14 118	440	317
Total	437 514	100.0	1 560 748 560	3567	592	23 398	481	323

Overall, VLBW infants accounted for 0.9% of cases but 35.7% of costs, whereas LBW infants accounted for 5.9% of cases but 56.6% of total hospital costs. Conversely, the 94% of infants with a birth weight >2500 g incurred only 43.4% of the total infant costs. Like the LOS data in Table 1, the findings shown in Table 2 demonstrate a decrease in mean daily costs and mean total costs as birth weights increase.

Table 2 also presents infant costs by gestational-age category. Infants who were born at ≤32 completed weeks (8282 cases) represented only 1.9% of cases but had mean hospital costs of $66 813 and mean daily costs of $1535. Infants who were born at 33 to 36 completed weeks represented 8.0% of cases with mean hospital costs of $7081 and mean daily costs of $702. Although infants who were born at ≤32 completed weeks of gestation comprised only 1.9% of cases, their total combined costs ($553 345 754) represent more than one third (35.5%) of total infant hospital costs ($1 560 748 560).

Table 3 summarizes the distribution of total costs and number of cases by cost category for mothers and infants and provides additional information on the skewed nature of the distribution of costs. Although 76.6% of all infants born (335 269 cases) fell into the lowest cost category of $1 to $999, they accounted for only 11.1% of total costs. The cost category of $50 000 or more constituted 1.3% of all infants born (5696 cases), but these infants accounted for 54.6% of the total costs. Overall, there was a broad and distorted distribution of total costs of care for infants, with the majority of infants falling into the lowest cost categories. The few who did fall into the higher categories produced staggering total costs. For mothers, the distribution across cost categories was just as broad, although the majority of mothers were concentrated into slightly higher cost categories. There were also many fewer maternal cases in the 2 highest cost categories (more than $30 000). More than half (53.8%) of the maternal cases (235 333 mothers) were in the $1000 to $2999 cost category, and another 27.6% of cases (120 660 mothers) fell into the $3000 to $4999 cost category. In contrast to the infants, 76.6% of whom were in the very lowest cost category of $1 to $999, only 2.1% of mothers were in this low cost group. An interesting difference between mothers and infants in the distribution of costs is that ~60% of mothers make up ~60% of maternal costs, whereas ~5% of the infants generate ~75% of the costs.

TABLE 3.

Distribution of Total Costs for Infants and Mothers for Hospital Births in California in 2000

Cost Category, $	Total Costs for Infants				Total Costs for Mothers
	No. of Cases	% of Cases	Total Costs, $	% of Costs	No. of Cases	% of Cases	Total Costs, $	% of Costs
1–$999	335 269	76.6	172 896 257	11.1	8961	2.1	7 514 244	0.0
1000–2999	61 270	14.0	92 190 709	5.9	235 333	53.8	471 917 119	29.6
3000–4999	9446	2.2	36 815 008	2.4	120 660	27.6	461 127 898	28.9
5000–6999	5280	1.2	31 467 795	2.0	38 606	8.8	224 515 331	14.1
7000–9999	5446	1.2	45 807 797	2.9	19 390	4.4	158 173 038	9.9
10 000–29 999	11 813	2.7	202 778 611	13.0	13 099	3.0	192 734 686	12.1
30 000–49 999	3294	0.8	126 555 884	8.1	973	0.2	36 504 780	2.3
≥50 000	5696	1.3	852 236 499	54.6	492	0.1	40 706 640	2.6
Total	437 514	100.0	1 560 748 560	100.0	437 514	100.0	1 593 193 737	100.0

Table 4 presents prenatal hospital costs and total maternal hospital costs by infant birth weight category. The prenatal hospital costs are included in the total maternal costs shown in Table 4. Prenatal hospitalizations are almost 10% of the number of deliveries. As would be expected, the prenatal hospitalizations are somewhat skewed toward LBW and VLBW infants: 17.9% and 3.6% of prenatal hospitalizations, respectively. Furthermore, 26% of all VLBW deliveries had a previous prenatal hospitalization, as did 20% of all LBW deliveries, with some of these deliveries having >1 prenatal admission. Table 4 shows that the average prenatal hospital costs were highest for the LBW and VLBW groupings and substantially lower for births of 2500 g or greater. A similar trend is shown for total maternal hospital costs, with the highest average costs associated with births between 750 and 1500 g.

TABLE 4.

Prenatal Hospital Costs and Total Hospital Costs for Mothers According to Infant Birth Weight Category: Delivery Births in California in 2000

Birth Weight Group, g	No. of Deliveries (%)a	No. of Prenatal Admissions (%)b	Total Prenatal Hospital Costs			Total Maternal Hospital Costsc
			Total Costs, $	Mean Costs (SD), $	Median Costs, $	Total Cost, $	Mean Costs (SD), $	Median Costs, $
<500	107 (0.02)	47 (0.1)	245 865	8478 (13 756)	3971	1 130 119	10 562 (11 302)	7864
500–749	667 (0.15)	199 (0.5)	931 017	6085 (16 582)	2630	7 360 082	11 035 (12 703)	7378
750–999	913 (0.21)	326 (0.8)	1 177 484	4826 (6454)	2554	10 982 329	12 029 (14 163)	8240
1000–1249	1050 (0.24)	386 (1.0)	1 778 534	5988 (11 236)	2854	12 812 513	12 202 (12 891)	8169
1250–1499	1352 (0.31)	472 (1.2)	2 294 494	6829 (11 094)	3317	17 360 883	12 841 (22 003)	7521
All <1500	4089 (0.93)	1430 (3.6)	6 427 396	6069 (11 361)	2949	49 645 926	12 141 (16 656)	7907
1500–1749	1974 (0.45)	720 (1.8)	3 454 378	7122 (13 647)	3315	21 844 639	11 066 (14 839)	6527
1750–1999	3117 (0.71)	1058 (2.6)	4 728 553	6477 (9602)	3411	29 421 954	9439 (11 876)	5790
2000–2499	16 806 (3.84)	3957 (9.9)	16 082 071	5617 (9584)	3047	102 301 941	6087 (8408)	3915
All <2500	25 986 (5.94)	7165 (17.9)	30 692 396	5975 (10 423)	3097	203 214 459	7820 (11 357)	4696
≥2500	411 525 (94.06)	32 855 (82.1)	104 692 610	3934 (7980)	2179	1 389 971 148	3378 (3486)	2674
Total	437 511	40 020	135 382 006	4264 (8457)	2306	1 593 185 608	3641 (4494)	2747

^aPercentage of deliveries in each birth weight group.

^bPercentage of prenatal admissions in each birth weight group.

^cTotal maternal costs include total prenatal costs.

In viewing the maternal data more closely, Table 4 reveals that mothers who gave birth to infants who weighed <1750 g had the highest mean total costs. Table 4 also presents prenatal hospitalization data for mothers by infant birth weight category and provides a picture of the costs associated with possible pregnancy complications that lead to the delivery of LBW infants. Infants and mothers in the LBW categories had the highest mean total costs. By and large, the findings show that mean total costs decreased markedly for both mothers and infants as birth weights increased.

In addition to the high costs associated with premature delivery, the distributional data on newborn costs and LOS reported in Tables 1 and 2 show that whereas most large infants have short hospital stays and low costs, some of these infants do require extensive care. Phibbs et al¹⁷ previously reported that congenital anomalies were a major cause of high costs for larger infants. To provide some information on the costs associated with congenital anomalies, in results not shown, we used the International Classification of Diseases, Ninth Revision codes to identify the infants who had major anomalies that required neonatal treatment. Only 2.1% of infants had a major congenital anomaly, but these infants incurred 25.5% of neonatal hospital costs.

DISCUSSION

As expected, significant maternal and infant hospital costs were associated with LBW and VLBW births. Consistent with previous reports of hospital costs for preterm infants,¹² the current data show that costs increase dramatically with decreasing birth weight. Average total hospital costs for infants who weighed 2000 to 2499 g at birth were ~$12 000 compared with average hospital costs of nearly $119 000 for infants who weighed 1000 to 1249 g at birth.

Although maternal hospital costs associated with LBW infants were substantial (~$200 000 000), they were overwhelmed by the hospital costs for the infants, which approached $700 000 000 in California in 2000. Other findings that were consistent with previous research were longer hospital stays for LBW infants, with markedly longer stays for VLBW infants.

There are a variety of reasons for the very high hospital costs associated with LBW and VLBW infants as compared with infants who weighed >2500 g at birth. As previous studies have reported, a significant proportion of the infant costs result from an increasing use of advanced medical technologies and complex medical and surgical procedures. The current data support these findings, with higher costs and longer hospital stays for LBW infants and infants who are born at <32 weeks’ gestation.

Increased maternal costs associated with LBW and VLBW births result from more and longer hospital stays and an increased use of obstetric medical technologies and services aimed at preventing premature and low-weight births. These obstetric interventions may include tocolytic therapy and the use of prenatal corticosteroids.¹⁸ We have also provided a population-based description of the costs of maternal prenatal hospitalizations. In round terms, there is 1 maternal hospital admission that does not result in a delivery for every 11 deliveries, and these admissions account for 8.5% of total maternal hospital costs.

As reported by Franks et al,¹⁹ most hospitalizations for complications of pregnancy are the result of preterm labor. As the authors pointed out, a variety of maternal factors are related to the frequency, length, and costs of hospital stays associated with complications of pregnancy. According to Franks et al, black women had a much higher rate of hospitalization than white women and had longer stays on average than white women. Other sociodemographic factors that influenced the number and the length of antenatal hospitalizations included maternal age, marital status, and insurance status. It is also well documented that other maternal behavioral and social factors influence complications of pregnancy and subsequent maternal and infant hospital costs. These factors may include inadequate nutrition, smoking, alcohol consumption, or inadequate weight gain.¹⁹

Although the focus of this article is on the costs associated with premature delivery, we also note that congenital anomalies are another significant cause of neonatal costs, and most of these infants are term deliveries. We note that in a simple classification of the cases with major congenital anomalies, they represent a similar disproportionate share of neonatal hospital costs. These results are consistent with findings by Phibbs et al,¹⁷ who quantified and modeled infant hospital costs by 7 risk factor groups. Additional research is needed to describe more fully the costs of infants with major anomalies. We reiterate that premature delivery is not the only cause of high hospital costs for newborns.

The current data offer a significant advance toward quantifying maternal and infant hospital costs. Documentation of these costs has historically been very difficult because of limitations with available data. The current study is unique in its use of linked maternal and infant hospital discharge records. The use of linked data allows quantification and analysis of the relationships and costs associated with maternal hospitalizations and treatment with subsequent birth outcomes and infant hospital costs. The ability to analyze data that are collected across multiple hospitalizations for mothers and their infants yields a more accurate characterization of patients, medical treatments, costs, and outcomes.

Although the current study makes a significant contribution to the documentation of hospital costs associated with pregnancy and birth, there are several limitations to this report. First, as mentioned previously, some hospitals in California (primarily Kaiser hospitals) do not report charges in the hospital discharge abstracts. As a result, all maternal and infant hospitalizations that occur at these hospitals were excluded from cost analyses. Second, it is difficult to derive accurately hospital costs from hospital charges, because hospital charges reflect different markups for different services. The method of converting charges to costs by applying a hospital-level cost-to-charge ratio used here is limited in its accuracy but is a standard and accepted method for converting hospital charges to costs.²⁰ Although these clearly are limitations, we do not believe that these limitations have a meaningful affect on the results or conclusions. The cost results are driven by relatively small numbers of very expensive cases and large numbers of low-cost cases. Even relatively large differences in the cost estimates for individual cases will not change this dynamic, especially given that any hospital-specific corrections would affect the high-and low-cost cases equally. Given that the cases with missing cost estimates have similar distributions of LOS, it is unlikely that the cases with missing cost data have patterns of care that are dramatically different from those that remained in the sample.

Abbreviations

LBW

low birth weight

VLBW

very low birth weight

OSHPD

Office of Statewide Health Planning and Development

LOS

length of stay