Objective. To test the hypothesis that near-term infants have more medical problems after birth than full-term infants and that hospital stays might be prolonged and costs increased.
Methods. Electronic medical record database sorting was conducted of 7474 neonatal records and subset analyses of near-term (n = 120) and full-term (n = 125) neonatal records. Cost information was accessed. Length of hospital stay, Apgar scores, clinical diagnoses (temperature instability, jaundice, hypoglycemia, suspicion of sepsis, apnea and bradycardia, respiratory distress), treatment with an intravenous infusion, delay in discharge to home, and hospital costs were assessed.
Results. Data from 90 near-term and 95 full-term infants were analyzed. Median length of stay was similar for near-term and full-term infants, but wide variations in hospital stay were documented for near-term infants after both vaginal and cesarean deliveries. Near-term and full-term infants had comparable 1- and 5-minute Apgar scores. Nearly all clinical outcomes analyzed differed significantly between near-term and full-term neonates: temperature instability, hypoglycemia, respiratory distress, and jaundice. Near-term infants were evaluated for possible sepsis more frequently than full-term infants (36.7% vs 12.6%; odds ratio: 3.97) and more often received intravenous infusions. Cost analysis revealed a relative increase in total costs for near-term infants of 2.93 (mean) and 1.39 (median), resulting in a cost difference of $2630 (mean) and $429 (median) per near-term infant.
Conclusions. Near-term infants had significantly more medical problems and increased hospital costs compared with contemporaneous full-term infants. Near-term infants may represent an unrecognized at-risk neonatal population.
Newborn infants are defined as premature when birth takes place before 37 weeks of gestation (259 days from the first day of the mother's last menstrual period).1,2 Premature birth is known to place infants at increased risk for morbidity and death compared with infants who are born at term. A subgroup of more mature premature infants, so-called “near term” infants of 35 to 36 6/7 weeks' gestation, has recently become a focus of increased interest.3–5 In obstetric and pediatric practice, near-term infants are often considered functionally full term, and management decisions are made accordingly. However, this practice pattern is largely not data driven, and clinical experience indicates that this practice may not always be appropriate. We hypothesized that despite relatively large size and apparent functional maturity, near-term infants are at increased risk for neonatal medical problems compared with full-term infants and that clinical assessment and treatment might prolong hospitalization and increase cost.
Newborn infants who were born between October 1997 and October 2000 (inclusive) were identified using the obstetric electronic medical record database of the Massachusetts General Hospital, a tertiary teaching hospital with 3200 births per year. This secure database contains pertinent information on all mothers and neonates delivered at the Massachusetts General Hospital. Using the medical record number and gestational age of each neonate based on best obstetric estimate, we sorted through 7474 records (593 records of infants of 35–36 6/7 weeks' and 6881 records of infants 37–40 weeks' gestation) and randomly selected 120 near-term (35–36 6/7 weeks' gestation) and 125 full-term (37–40 weeks' gestation) records. To achieve 80% power for a 2-tailed α of .05 with an estimated clinical diagnosis rate of 50% and 30% in near-term and term infant groups, respectively, it was calculated that analysis of 90 near-term and 95 full-term neonatal records were needed.
Exclusion criteria were 1) incomplete medical record, 2) major congenital anomaly, 3) multiple gestation above twins, and 4) maternal substance abuse. This investigation was approved by our institutional review board.
Chart review was performed on each of the randomly selected medical records, and data were entered into a Microsoft Access 97 relational database. Statistical methods incorporated dichotomous variables comparing near-term and full-term infants using Fisher exact test. For significant associations, the maximum likelihood estimate of the conditional odds ratio (OR) and 95% confidence interval (CI) are reported. For nondichotomous categorical variables (eg, management of possible sepsis), Fisher exact test for an R × C table is used. For ordinal variables (eg, length of stay, Apgar scores), the Wilcoxon rank sum test was used for comparison of medians. The R statistical package (version 1.5.0) was used for statistical computations.6
Cost and charge information was obtained through the Eclipsys Sunrise Decision Support Manager (previously Transition Systems, Inc). Patient unit numbers were used to identify patient admissions in the system. When multiple admissions existed for the same patient, admit dates were evaluated to distinguish the newborn admission from subsequent admissions, which were excluded. Reports were then generated to capture each patient's direct costs and actual total cost (including overhead), which were then summarized and analyzed by gestational age categories. All information obtained from the Eclipsys SDSM system reflected hospital-based activity only. The physician component of expense was not included.
1) Birth weight: the neonatal weight in grams obtained within 1 hour of birth. 2) Gestational age: the number of weeks of gestation achieved at the time of birth for a given neonate based on best obstetric estimate as calculated from early fetal ultrasound examination on or before 18 weeks of gestation obtained in >90% of patients (M.F. Greene, personal communication) assumed to be accurate to ±8%.7 3) Length of stay: the birth date subtracted from the discharge date. Hospital protocol dictates discharge by 11 am. When birth occurs after 8 pm, an extra calendar day of hospital stay is allowed beyond 2 days after a vaginal delivery and 4 days after a cesarean delivery.
1) Respiratory distress: documentation in the infant's record of sustained respiratory distress >2 hours after birth, defined as grunting, flaring, tachypnea, retractions, and/or supplemental oxygen requirement. 2) Temperature instability: infant rectal temperature measured <97.5°F documented in the medical record and requiring intervention beyond immediate wrapping or dressing (ie, placement in a prewarmed isolette or on a radiant warmer). 3) Apgar scores: 1- and 5-minute Apgar scores documented in the medical record. 4) Hypoglycemia: laboratory documentation of a neonatal blood sugar concentration <40 mg/dL. 5) Management using intravenous infusion: intravenous fluid infusion treatment for a medical condition such as hypoglycemia, respiratory distress, very poor feeding, or clinical evidence of sepsis, documented in the infant's record. 6) Clinical jaundice: documentation of clinically apparent jaundice in the infant, with or without laboratory measurement of serum bilirubin concentration. 7) Sepsis evaluation: neonatal laboratory data obtained in the setting of suspicion of early-onset sepsis, with or without associated antibiotic treatment. Pediatricians used 1 of 3 clinical approaches: a) blood culture and complete blood count with differential count, b) option “a” plus antibiotic treatment for 48 hours, c) option “a” plus antibiotic therapy for at least 7 days. Study neonates were managed using Centers for Disease Control and Prevention neonatal sepsis recommendations in place during the study period.8 8) Apnea, bradycardia: documentation of a clinically significant apnea or bradycardic episode (apneic episode >15 seconds, nonsleeping heart rate <80 bpm) on a record entry specific for cardiorespiratory events. 9) Discharge delay: infant hospital stay prolonged because of a specific clinical problem (eg, poor feeding ability, pneumonia and associated antibiotic treatment, jaundice) beyond the standard hospital stay expected on the basis of mode of delivery. Specifically, a hospital stay beyond 48 hours after a vaginal delivery and beyond 96 hours after a cesarean delivery were defined as prolonged.
1) Total costs: the sum total of direct and indirect operating costs assigned to a department or patient within the Eclipsys SDSM system on the basis of utilization of products (charges) for hospital care of the patient. 2) Direct costs: operating costs identified with providing services directly to a patient. These costs are identifiable with a specific cost center, objective, service, or product. All cost information obtained through the Eclipsys SDSM system reflects hospital-based activity only and does not account for physician activity and expense associated with delivery of patient care.
Unit costs are developed in SDSM by allocating hospital general ledger operating expenses using a relative value unit method. Direct cost, defined as hospital operating expenses generated by patient care activities, are allocated to specific product codes (charge codes) within a department on the basis of the “relative value or intensity” of a particular product or service versus another. Indirect costs, defined as hospital operating expenses not directly generated by patient care activities, are also allocated to direct departments using standard step-down allocation methods and then further to products (charge codes) within each direct department, on the basis of the ratio of each product's direct cost to total department direct cost.
The sum of direct and indirect unit costs for a product determines its total unit cost. Unit costs are linked to patients through utilization of products (charge codes). The quantity and mix of products used by a patient determine the amount of direct and indirect cost that is allocated to each individual patient in the system.
Ninety near-term and 95 full-term infants of the 120 near-term and 125 full-term infant records selected for enrollment met inclusion criteria and avoided exclusion criteria for data collection and analysis. All medical records selected for enrollment were available to review. Medical records of 29 full-term infants and 19 near-term infants were incomplete and excluded from analysis.
Median lengths of hospital stay for near-term and full-term infants were comparable; however, wide variations in hospital stay were documented for near-term infants after both vaginal (P = .03, Wilcoxon rank sum) and cesarean (P = .003, Wilcoxon rank sum) deliveries (Table 1, Fig 1). The mean birth weight (±standard deviation) of near-term and full-term infants was 2638 ± 436.6 g and 3294 ± 497.2 g, respectively. Median Apgar scores at 1 and 5 minutes were 8 and 9, respectively, for both near-term and full-term infants; Apgar scores were also concordant between quartiles (Table 2). No study patient had an Apgar score at 5 minutes assigned <3.
Nearly all analyzed clinical outcomes differed between near-term and full-term neonates (Fig 2). Near-term newborns were more likely than full-term newborns to exhibit temperature instability (10% vs 0%; OR: infinite; P = .0012, Fisher exact test [FE]) or hypoglycemia (15.6% vs 5.3%; OR: 3.30; 95% CI: 1.1–12.2; P = .028, FE). Near-term infants received intravenous infusions more often (26.7% vs 5.3%; OR: 6.48; 95% CI: 2.27–22.91; P = .0007, FE). The near-term infants had respiratory distress much more often than the term newborns (28.9% vs 4.2%; OR: 9.14; 95% CI: 2.9–37.8; P < .00001, FE) and were clinically jaundiced more often (54.4% vs 37.9%; OR: 1.95; 95% CI: 1.04–3.67; P = .027, FE). Apnea and bradycardia were seen infrequently and only in the near-term group; this difference was insignificant (4.4% vs 0%; P = .054, FE).
Near-term infants were much more likely than full-term infants to have a clinical problem resulting in the assignment of 1 or more diagnoses (77.8% vs 45.3%; OR: 4.20; 95% CI: 2.14–8.49; P < .0001, FE). Near-term infants were twice as likely to have several clinical problems resulting in the assignment of 2 or more diagnoses (50% vs 21.1%; OR: 3.72; 95% CI: 1.88–7.55; P < .0001, FE). Additional analysis showed that 18 of the 95 near-term infants had 6 or more diagnoses compared with 0 of 90 term infants.
Near-term infants underwent sepsis evaluations more frequently than full-term infants (36.7% vs 12.6%; OR: 3.97; 95% CI: 1.82–9.21; P = .00015, FE). For those who underwent sepsis evaluations, we compared clinical assessment and treatment approaches (Table 3). Although more near-term infants received 7-day antibiotic courses, differences in clinical management of possible sepsis did not reach statistical significance.
Near-term infants with diagnoses of clinically apparent jaundice or poor feeding were more likely to have a delay in discharge beyond 48 hours of hospitalization after vaginal delivery and beyond 96 hours after cesarean delivery (Table 4). Fifty near-term infants compared with 7 term infants had a delayed discharge home. Seventy-six percent of near-term infants with poor feeding experienced a delay in discharge to home, whereas 28.6% of term infants with poor feeding had delayed discharge (95% CI: 0.94–93.4; OR: 7.3; P = .029, FE).
Total and direct costs were calculated and analyzed for each study patient. Cost analyses revealed that the relative increase in total costs for near-term compared with term infants was 2.93 (mean) and 1.39 (median), resulting in a cost increase of $2630 (mean) and $429 (median; P = .0004, Wilcoxon rank sum test). The relative increase in direct costs for near-term infants was 2.89 (mean) and 1.32 (median), resulting in a cost difference of $1596 (mean) and $221 (median) per patient (P = .0003, Wilcoxon rank sum test).
Important differences in clinical outcomes became apparent when the hospital courses of near-term infants were compared with those of full-term infants. Despite appropriate size and favorable Apgar scores, near-term infants had significantly more documented medical problems when compared with contemporaneous full-term neonates. This resulted in increased health care costs in the group born near to term. Near-term newborns, in this retrospective analysis, were observed to exhibit certain clinical problems associated with prematurity. In clinical nursery settings, we have the experience that near-term infants “masquerade” as term infants on the basis of their relatively large size and mature, chubby appearance. Although progressive developmental immaturity is expected with very low birth weight and extremely low birth weight infants, this may not be the clinical expectation for near-term infants, despite the recognized direct relationship between gestational age and maturation.
Nearly 30% of near-term infants in our study had clinical evidence of respiratory distress, and one third of those were delayed in their discharge to home because of it. Of these near-term infants with respiratory signs, 10% were treated with a 7-day course for presumptive pneumonia. There is clinical overlap among pneumonia, transient tachypnea of the newborn (TTN), and (mild) respiratory distress syndrome, making it difficult at times to distinguish the cause of neonatal respiratory symptoms. Amniotic fluid lecithin/sphingomyelin ratios typically suggest fetal lung maturity for fetuses of 35 weeks of gestation and above. Using a conservative criterion for lung maturity, ≥3% phosphatidylglycerol content, 30% to 65% of infants in the near-term gestational range would be predicted to have biochemically mature lungs.9 Although respiratory distress was noted to be a frequent problem in near-term infants, this analysis did not address cause. Lung immaturity should be one consideration in the differential diagnosis along with meconium aspiration, TTN, and pneumonia in these settings.
Temperature instability was a common clinical problem observed in the near-term infants. Given their relatively large size with average birth weights of >2.6 kg, when compared with very low birth infants and their risk for thermal instability,10 the number (10%) requiring active temperature management was interesting. Temperature instability may be a presenting sign of neonatal sepsis. Although documented sepsis was not seen more often in near-term infants, this data set is of insufficient size to exclude an increased incidence of sepsis, given that prematurity is a recognized risk factor for neonatal sepsis.11 Obtaining blood cultures followed by short-course antibiotic treatment (pending culture results) may be a reasonable management strategy in the setting of hypothermia and delivery before term (without maternal indications), especially when additional risk factors are present.
That Apgar scores measured in near-term and full-term infants were similar was not an unexpected finding. In addition to documenting physiologic responses, Apgar scores are related to maturity. However, infants of 35 to 36 6/7 weeks' gestation generally are not expected to have the lower Apgar scores measured in more premature infants.12 A component of perinatal depression in certain study infants cannot be ruled out, though, because additional information, such as umbilical cord blood gas data, is not available.
Low blood sugar was found 3 times as often in our near-term cohort. Of infants with blood glucose values <40 mg/dL, nearly two thirds in each group required treatment with intravenous dextrose, whereas the remaining were able to resolve initial hypoglycemia with early feedings. Premature infants are at risk for hypoglycemia because of low total body fuel stores, inadequate dietary intake, and a tendency to be affected by other conditions, such as cold stress or sepsis, known to contribute to hypoglycemia.13 The well-infant clinician must be alert to the potential for neonatal hypoglycemia and have an appropriately low threshold, particularly in near-term infants, for measuring blood sugar and treating as needed.
Twenty-seven percent of all near-term infants studied had a clinical condition whereby intravenous fluid was given compared with only 5% of all term infants. A variety of clinical problems, including hypoglycemia and poor feeding, precipitated this treatment, which is a relatively labor-intensive procedure in the well-infant nursery.
Jaundice is a frequent clinical issue in the newborn period with infrequent but potentially tragic complications. The 54% frequency of clinically appreciated jaundice in our near-term infants differed from that observed in the term infants (37.9%). More notable, though, was that 1 term infant had a delayed discharge as a result of assessment and treatment of jaundice compared with 8 in the near-term group. Maisels and Kring14 reported that infants who are discharged from the well-infant nursery of ≤38 weeks' gestation have an OR of >7 of being readmitted to the hospital with hyperbilirubinemia. The Pilot Kernicterus Registry, established in 1992 to collect data on term and near-term neonates who receive a diagnosis of kernicterus, identified 90 affected term and near- term infants by 2001.5 Near-term newborns are prone to developing hyperbilirubinemia and its sequelae and to require hospital readmission for treatment. Thus, careful observation and slightly longer initial hospital courses in some cases may be indicated.
We found that near-term infants were evaluated for possible sepsis ∼3 times as often as full-term infants. The majority of evaluated near-term infants received antibiotic treatment. Term infants tended to have blood work drawn but were not started on antibiotics. Thirty percent of evaluated near-term infants were treated with antibiotics for 7 days, and pneumonia was the most frequent diagnosis. None of the infants who were treated with antibiotics in either group had a positive blood culture, but this data set is not large enough to draw conclusions about sepsis attack rates. This presents a dilemma for the clinician. Near-term study infants, often observed with (nonsevere) respiratory findings, had sterile cultures; mild respiratory distress syndrome and TTN were possible causes, but respiratory infection would seem less likely when short hospital stays were seldom prolonged for respiratory reasons. Clinical practice dictates that near-term infants be treated as term infants with respiratory signs; thus, clinicians may tend to manage such respiratory distress conservatively as potential bacterial pneumonia.
The near-term infants studied clearly had more clinical problems than term infants and were also likely to be delayed in discharge to home because of these problems. Feeding problems were the dominant reason for a delay in discharge. Given that immature infants are less able to achieve effective sucking and swallowing, this was not entirely unexpected. In our clinical experience, many near-term infants require repeated assistance and support before achieving consistent, nutritive breastfeeding. Supplementation with expressed breast milk or formula, at least initially, is often required.
We found that near-term infants were more likely to have at least 1 medical problem and also more likely to have 2 or more diagnoses assigned when compared with term infants. The developmentally less mature infants exhibited more variability in health status, particularly highlighted in the cluster of 18 near-term infants with 6 documented medical diagnoses.
One study limitation is our inability to define objectively breastfeeding success and to analyze adequately breastfeeding status at time of discharge. Successful breastfeeding is an important component of newborn discharge criteria. Discharge to home for near-term infants was delayed by suboptimal feeding in nearly one fourth of all near-term infant cases. Breastfeeding at discharge of mother and infant from our well-infant nurseries approaches 80% (K.S. Nash, personal communication); thus, breastfeeding status certainly plays a role in discharge timing. In clinical practice, we pay careful attention to potential failed breastfeeding, to prevent early dehydration, additional breastfeeding problems, and hospital readmission.
Length of stay was not increased for near-term infants who were born via the vaginal route or by cesarean section, despite increased variability compared with full-term infants. However, cost of hospitalization for near-term infants was significantly greater, again, with wide variation in data for near-term infants. Length of hospitalization and neonatal diagnosis related groups predict part of the cost of newborn care, and there exists a recognized inverse correlation between birth weight and hospital costs.15 This helps to explain the discrepancy between the median lengths of stay (which were similar) and the larger number of near-term infants with a delay in discharge. In a recent analysis of larger premature infants (34, 35, and 36 weeks of gestation), nursery-related costs and risk of respiratory distress significantly decreased with each week gained beyond 34 weeks.16
This study does not address whether the clinical outcomes studied have long-term implications. The next step will be follow-up of near-term newborns with particular emphasis on hospital readmission, frequency of pediatric visits, and feeding success (together with growth). Our aim in this study was to explore whether near-term infants had more clinical problems and longer hospital stays generating greater costs. Given that delivery decisions are driven by both maternal and fetal indications, in settings where near-term delivery is contemplated but nonurgent, these data detailing clinical problems encountered in near-term infants may be instructive.
This study was supported by a generous grant from the William Randolph Hearst Foundation.
Dr Alan B. Ezekowitz, Chief, Pediatric Service, MassGeneral Hospital for Children, is gratefully acknowledged for his support and guidance.
- Received April 4, 2003.
- Accepted December 22, 2003.
- Address correspondence to Marvin L. Wang, MD, Neonatology Unit, Pediatric Service, MassGeneral Hospital for Children, Founders 442, Fruit St, Boston, MA 02114. E-mail:
- ↵World Health Organization: www.who.int/reproductive-health
- ↵Barrington KJ, Finer NN. Recent advances: care of near term infants with respiratory failure. BMJ.1997;315 :1215– 1218
- ↵Catlin EA, Lee MM. Neonatal endocrinology. In: Oski's Pediatrics: Principles and Practice. 3rd ed. Baltimore, MD: Lippincott Williams & Wilkins; 1999:346
- ↵Maisels MJ, Kring E. Length of stay, jaundice, and hospital readmission. Pediatrics.1998;101 :995– 998
- Copyright © 2004 by the American Academy of Pediatrics