INTRODUCTION

The utilization of health care resources by women and their newborn infants following cocaine use during pregnancy could be increased for the following reasons: (a) reduction in length of gestation and/or birth weight,^1,2,3,4 (b) the increased incidence of other perinatal effects ⁵ and (c) increased length of hospitalization because of the social aspects of maternal cocaine use with infants remaining in the hospital for social evaluation, foster care placement or adoption, rather than medical needs.^6,7,8

We have recently demonstrated in a multisite study evaluating outcome following in utero cocaine and opiate exposure that abnormal anatomical outcomes (congenital abnormalities) were less prevalent than previously reported. Transient symptoms of the autonomic and central nervous system were more significant in the cocaine-exposed cohort.⁹

Studies evaluating health-care costs following substance use in pregnancy have categorized exposure by maternal history and analysis of urine for illicit drugs.^1,2,3,4,5 Analysis of meconium for metabolites of illicit drugs is now recognized as an improved method of detection as compared to urine sampling.¹⁰

Our hypothesis was that utilization of health-care resources by women who have used cocaine during pregnancy and their infants would be higher than those maternal–infant dyads that were not exposed to cocaine during pregnancy. Our objective was to examine health-care resource utilization after categorizing exposure by maternal history of cocaine use or presence of metabolites of cocaine in infant's meconium.

METHODS

This present analysis was conducted as part of the primary study evaluating the impact of maternal substance use during pregnancy on infant outcome¹¹ in four centers of the National Institute of Child Health and Human Development Neonatal Research Network. The 4 centers were Brown University, Providence, University of Miami, University of Tennessee, Memphis and Wayne State University, Detroit. The study was approved by the institutional review board of each center, and enrollment of women into the study was conducted between May 1993 and May 1995. A Certificate of Confidentiality from the National Institute on Drug Abuse exempted reporting to the state child protective services by the research staff.

Screening criteria for study entry were as follows: for 1500 g birth weight, all infants were screened for study entry; for >1500 g birth weight, the recruitment hours were limited to weekdays. Exclusion criteria were: outborn birth, infant who was unlikely to survive, maternal age <18 years, multiple gestation or maternal psychosis. Eligible women were approached in hospital after delivery of the infant and consent obtained for study participation. A detailed interview of the pregnancy and delivery course was obtained by trained and certified interviewers. The infants had a physical and Ballard examination (for assessment of gestational age) by a trained research nurse masked to exposure status. Meconium was collected on all study infants and sent to a central laboratory for analysis of metabolites of illicit drugs by EMIT screening followed by GCMS analysis of all positive samples.¹² The results of meconium testing were not available to the clinical staff providing care to the infants. Maternal and infant charts were abstracted by the research nurse prior to discharge from the hospital. There were site-to-site differences in reporting of illicit drug use; Florida and Rhode Island had a policy of mandatory reporting to the state child protective services. This policy was followed by the clinical staff.

Maternal data recorded by interview and chart abstraction included prenatal care (defined as at least one prenatal visit other than the visit resulting in delivery of the infant), hospitalizations other than the hospitalization resulting in delivery of the infant (for preterm labor, chronic or infectious illness, surgery, injury/accident, violence or detoxification), and medications during pregnancy (anticonvulsants, tocolytics, antibiotics, analgesics, sedatives, antihypertensives and corticosteroids), medications during the hospitalization for delivery (demerol, morphine, dilaudid, codeine, hydrocodone) and mode of delivery.

Infant data recorded by chart abstraction included nursery course, whether in the neonatal intensive care unit (NICU), progressive or intermediate care nursery, or nursery for medically stable infants. Neonatal therapies including delivery room interventions and type of nutrition and medications administered during the hospital course were noted. Neonatal procedures, including ventilatory support, arterial and venous line insertions, surgical procedures and laboratory investigations were documented. There was site-to-site and within-site variability in screening procedures used for cardiac, renal and cranial lesions; this was based on individual neonatologist preference. Data collected at discharge included home apnea monitor and oxygen therapy. Social services interventions, including referrals for child protective services (CPS), and health insurance status were noted. Data were entered into a local database using a distributed data entry system. Data were transmitted on a weekly basis and quality control maintained by editing at entry and after transmission to the data center.

The mother–infant dyads were grouped by birth weight 1500 g and >1500 g to assess impact of low birth weight on resource utilization. Within each birth-weight category exposure status was defined as exposed (EXP) if the mother gave history of cocaine use during the pregnancy or if the infant's meconium screened positive and was confirmed positive for cocaine metabolites by GCMS assay. Mother–infant dyads were categorized as nonexposed (non-EXP) if the mother indicated that she did not use cocaine during pregnancy and cocaine metabolites were not detected in the meconium analysis. Alcohol, nicotine and marijuana exposure occurred in both the EXP and non-EXP groups since polydrug use is common along with cocaine use.^13,14 The medical and support staff caring for mothers and infants were unaware of the exposure status as defined by this study.

Statistical methods

Health-care resources utilized were compared between EXP and non-EXP dyads within the two birth-weight strata using t-tests for continuous variables and ² analysis for dichotomous variables. Odds ratios (OR) and 99% confidence intervals (99% CI) were calculated for each of the items of resource utilization; 99% was used because multiple comparisons were made between groups. The statistical software (Statistical Analysis System, SAS Institute, Cary, NC) package was used for all data management and analysis.¹⁵

All results were adjusted by multivariate logistic regression analysis with adjustment for the covariates of clinical site, maternal race, infant gender and maternal education. Maternal education level (<12 years of education, 12 years, and >12 years) was used as a marker of socioeconomic status.

RESULTS

During the 2-year enrollment period, 8627 women consented to participate in the primary study evaluating the impact of maternal substance use during pregnancy on infant outcome.¹¹ Of these 8627 mother–infant dyads, 7442 were categorized as not exposed to cocaine (non-EXP). In all, 1072 dyads were exposed to cocaine, 100 were exposed to opiate only and 13 had opiate with inconclusive results for cocaine in the meconium analysis. Exposure rate was 17% in Detroit, 12% in Memphis, 7% in Miami and 5% in Providence. The 8514 maternal–infants dyads (7442 comparison and 1072 cocaine EXP) are subjects of this study with 490 in the 1500 g strata and 8024 in the >1500 g weight strata. The gestational age was 282 (meanSD) weeks in both EXP and non-EXP infants in the 1500 g strata and 372 (EXP) and 382 (non-EXP) in the >1500 g strata.

Maternal Health-Care Resource Utilization, 1500 g Group

In the 1500 g strata, significantly fewer women exposed to cocaine received prenatal care as compared to nonEXP women (Table 1). Among the women who received prenatal care, the average number of prenatal care visits was 5.6 in the EXP group and 7.7 in the non-EXP group (p<0.05). There was a trend toward less frequent hospitalizations during pregnancy of EXP women as compared to non-EXP women (OR 0.48(0.21-1.09)). Fewer women in the EXP group (79%) had medications administered during pregnancy, as compared to the non-EXP group (94%). Medication use during delivery and mode of delivery was similar in the two groups.

Table 1 - Maternal: Health-care Resource Utilization.

Full table

Among women receiving medications during pregnancy, fewer EXP women received steroids as compared to non-EXP women (Table 2).

Table 2 - Reasons for Hospitalizations (a) and Maternal Medical Use (b) During Pregnancy.

Full table

Maternal Resource Utilization, >1500 g Group

In the >1500 g birth-weight strata, fewer women exposed to cocaine (78%) received prenatal care as compared to non-EXP women (97%, Table 1). The average number of prenatal visits was 8.4 in the EXP group and 11.5 in the non-EXP group. There was no difference in the frequency of women hospitalized during pregnancy between EXP and non-EXP groups. Fewer women in the EXP group (68%) had medications during pregnancy as compared to non-EXP group (83%). There was no difference between groups when evaluating mode of delivery.

Among hospitalized women, fewer women in the EXP group (29%) were hospitalized for preterm labor as compared to non-EXP group (44%), while more women in the EXP group were hospitalized for violence and detoxification (6 and 13% vs 0.4 and 0.4%, respectively, Table 2). When the type of medications was analyzed among women who received them, more women in the EXP group (51%) received antibiotics as compared to women in the non-EXP group (40%, Table 2). Fewer women in the EXP group (60%) received anesthetics during delivery than non-EXP women (72%).

Infant Health-care Resource Utilization, 1500 g Group

Neonatal therapies, procedures and hospital course are noted in Table 3. The frequency of delivery room resuscitation was similar between groups. There was no difference in the percent of EXP infants who were admitted to the NICU or the intermediate care newborn nursery as compared to non-EXP infants. However, a higher percent of infants in the EXP group had length of stay prolonged for social reasons as compared to non-EXP infants. The majority of infants (in both EXP and non-EXP groups) received a neonatal therapy or procedure. Few women initiated breast-milk feedings in both groups. When therapies and procedures were analyzed among infants who received them, there was no significant difference in the frequency of use of therapies or procedures between EXP and non-EXP infants (Table 4).

Table 3 - Infant: Health-care Resource Utilization.

Full table

Table 4 - Health-care Resource Utilization: Infant Therapies and Procedures.

Full table

The length of stay in the nursery for social reasons after medical stability was reached among 17 EXP babies was longer (mean of 4.8 days) compared to the one infant in the non-EXP group (3.0 days). The survival rate, length of hospital stay and days in oxygen were similar between EXP and non-EXP infants in the 1500 g category (Table 5). At hospital discharge, there was no significant difference in the number of infants who were discharged on home oxygen therapy or apnea monitors between EXP and non-EXP infants. More infants in the EXP group were referred to CPS and there was a trend for more infants in EXP group to have Medicaid coverage as compared to the non-EXP group.

Table 5 - Health-care Resource Utilization: Infant Discharge Status.

Full table

Infant Health-care Resource Utilization, >1500 g Group

More infants in the EXP group required NICU, intermediate care, or nursery care for social reasons as compared to the non-EXP group (Table 3). More infants in the EXP group received neonatal therapies and procedures as compared to the non-EXP group. Use of intravenous fluid therapy and formula feeds (rather than breast-milk feeds) was also higher among EXP group than non-EXP group infants.

When use of neonatal therapies was evaluated among infants who received them, surfactant, respiratory stimulants and diuretic use was similar between groups while antibiotics, sedatives and antiseizure therapy was used more frequently among EXP infants (Table 4). When procedures were evaluated among infants who received them, more infants in the EXP group were investigated for suspected sepsis. Cranial and abdominal sonograms were performed more frequently among infants in the EXP group as compared to the non-EXP group at all four sites.

The length of hospital stay was longer among EXP infants, while the survival rate was similar between EXP and non-EXP infants in the >1500 g stratification (Table 5). There was a trend for the mean length of stay in the infants with social needs who were medically stable among the 183 EXP babies to be longer (7.1 days) as compared to the 38 non-EXP babies (5.4 days). At hospital discharge, there was no difference in the percent of infants who were discharged on home oxygen therapy or apnea monitors between EXP and non-EXP groups. More infants in the EXP group were referred to CPS and had Medicaid coverage than infants in the non-EXP group.

DISCUSSION

We have prospectively evaluated health-care resource utilization following cocaine exposure during pregnancy in a large cohort of mother–infant dyads (n=8514). In all, 6% of mother–infant dyads evaluated had an infant birth weight 1500 g. Thus, we had an opportunity to assess health-care resource utilization following both term and preterm delivery. Cocaine exposure was diagnosed by GCMS detection of metabolites in meconium as well as maternal history. Meconium analysis reflects use by the mother during pregnancy; detection of metabolites in urine demonstrates only recent use.

Information regarding health-care resource utilization by women exposed to illicit drugs during pregnancy is scarce. The most consistent finding reported is that women who use illicit drugs during pregnancy utilize prenatal care services less frequently than women who do not use illicit drugs.^6,16 We confirmed this finding in the present study where fewer women exposed to cocaine (in both 1500 and >1500 g birth-weight strata) received prenatal care as compared to non-EXP women. We also found that when prenatal care services were utilized, the mean number of visits was fewer in the EXP women as compared to non-EXP across both birth-weight stratifications.

When this study was initiated, we hypothesized that women exposed to cocaine would have more hospitalizations because of anticipated perinatal effects of exposure. We found that the percent of women with at least one hospitalization was similar between EXP and non-EXP women. Among those hospitalized, fewer EXP women were admitted for preterm labor as compared to non-EXP in the >1500 group. This could be related to less likely identification and treatment of preterm labor owing to fewer prenatal care visits. Women in the EXP group were more likely to be admitted for detoxification and violence and for infectious illnesses than non-EXP women; these reasons for admission are probably associated with exposure to illicit drugs. Stichler et al.³ have reported that expenses for hospital care at the time of delivery were higher among women with a history of substance use as compared to a matched group. In our study, mode of delivery was similar between EXP and non-EXP women; we did not examine the length of stay or hospital charges for the hospitalization for delivery.

The decreased administration of steroids to women exposed to cocaine who delivered 1500 g birth-weight infants was an unexpected finding in our study. These findings may be related to lack of utilization of prenatal care services or delayed presentation of EXP women for preterm delivery. We and others have reported that cocaine- and opiate-exposed women had fewer prenatal visits than women not exposed to illicit drugs.^6,11,16 Data regarding length of labor or time to delivery among study participants were not available for analysis.

In the <1500 g birth-weight category, infant medical health-care resource needs were similar among EXP and non-EXP infants when we evaluated length of stay, neonatal therapies and procedures. We found that the impact of cocaine exposure did not add to the resource requirement beyond those of preterm birth. Calhoun and Watson¹⁷ and Joyce et al.,⁸ while evaluating costs of perinatal care following maternal cocaine exposure, have noted that differences in costs can be traced to associations between cocaine exposure and preterm birth.

In the >1500 g birth-weight stratum, EXP infants received more NICU services, therapies and procedures, and were hospitalized longer than non-EXP infants. We did not attempt to distinguish between active intensive care therapy vs only monitoring in the infants. We did find that among >1500 g infants, EXP infants received more diagnostic tests, such as echocardiograms and cranial and abdominal sonograms, than non-EXP >1500 g infants. The higher use of procedures in >1500 g infants in the EXP group could be because of closer surveillance by clinical staff. Neonatal procedures and therapies have been noted to be increased among EXP infants as compared to non-EXP infants by other investigators evaluating hospital charges following in utero cocaine exposure.^5,18,19 These investigators evaluated infants as a group without separating full term and premature infants. It should be noted that no increase in the rate of cardiac, renal or intracranial abnormalities were noted among EXP infants in the results of our primary study evaluating impact of maternal substance abuse on infant outcome.⁹ Behnke et al.,¹ evaluated the presence of congenital anomalies in prenatally cocaine-exposed children and did not identify an increased number, or consistent pattern of abnormalities. In term infants, an increase in subependymal hemorrhage has been reported among heavily cocaine-exposed infants.²⁰ This mild hemorrhage is not associated with abnormal neurodevelopmental outcome.²¹ Therefore, the practice of performing more diagnostic tests among infants born to women using cocaine should be re-evaluated.

The social service resources expended for EXP infants were greater than non-EXP infants across both birth-weight groups, reflected by more infants with social needs, increased CPS referrals and a higher rate of Medicaid coverage. These findings confirm those of Phibbs et al., who demonstrated that neonatal hospital costs until medically cleared for discharge as well as costs of infants remaining in the nursery for social needs are more for cocaine-exposed infants than unexposed infants. Referrals to foster care placement were higher among infants exposed to cocaine as compared to unexposed infants in the present study. Health-care utilization and expenditures have been shown to be increased when children are placed in foster care.^7,22

In this large multisite prospective evaluation of health-care resource utilization following cocaine exposure during pregnancy, there was no increase in health-care resource needs for <1500 g infants or their mothers other than medical needs related to prematurity. The increase in medical resources for >1500 g cocaine-exposed infants in the absence of an increase in congenital anomalies is not justified. Substance abuse contributes significantly to hospital costs, ²³ reducing surveillance monitoring for >1500 g infants can have an impact on health-care expenditures.

References

1. Behnke M, Eyler FD, Garvan CW, Wobie K. The search for congenital malformations in newborns with fetal cocaine exposure. Pediatrics 2001;107:e74.
2. Forsyth BWC, Leventhal JM, Qi K, Johnson L, Schroeder D, Votto N. Health care and hospitalizations of young children born to cocaine-using women. Arch Pediatr Adolesc Med 1998;152:177–184.
3. Stichler JF, Weiss M, Wight NE. Examining the "cost" of substance abuse in pregnancy: patient outcomes and resource utilization. J Perinatol 1998;18:384–388.
4. Kliegman RM, Madura D, Kiwi R, Eisenberg I, Yamashita T. Relation of maternal cocaine use to the risks of prematurity and low birth weight. J Pediatr 1994;124:751–756.
5. Behnke M, Eyler FD, Conlon M, Casanova OQ, Woods NS. How fetal cocaine exposure increases neonatal hospital costs. Pediatrics 1997;99:204–208.
6. Phibbs CS, Bateman DA, Schwartz RM. The neonatal costs of maternal cocaine use. JAMA 1991;266:1521–1526.
7. U.S. Department of Health and Human Services Administration on Children, Youth and Families Children's Bureau. Report to the Congress. National Estimates on the Number of Boarder Babies, the Cost of their Care and Number of Abandoned Infants. U.S. Government Printing Office, 1994;1–42.
8. Joyce T, Racine AD, McCalla S, Wehbeh H. The impact of prenatal exposure to cocaine on newborn costs and length of stay. Health Serv Res 1995;30:341–358.
9. Bauer CR, Shankaran S, Bada HS, et al. Maternal lifestyle study (MLS): effects of substance exposure during pregnancy on acute infant outcomes. Pediatr Res 1996;39:257 (Abstract).
10. Ostrea EM, Brady M, Gause S, Raymundo AL, Stevens M. Drug screening of newborns by meconium analysis: a large-scale, prospective, epidemiologic study. Pediatrics 1992;89:107–113. | PubMed | ISI |
11. Bauer CR, Shankaran S, Bada HS, et al. The Maternal Lifestyle Study (MLS): drug exposure during pregnancy and acute maternal outcomes. Am J Obstet Gynecol 2002;186:487–495.
12. Lester BM, ElSohly M, Wright LL, et al. The Maternal lifestyle study (MLS): drug use by meconium toxicology and maternal self report. Pediatrics 2001;107:309–317. | Article | PubMed | ChemPort |
13. U.S. General Accounting Office (GAO). Report to the Chairman, Committee on Finance, U.S. Senate. Drug Exposed Infants. A Generation at Risk. Washington, DC: U.S. GAO; 1990.
14. U.S. Department of Health and Human Services. Drug Use among Racial/Ethnic Minorities. National Institute on Drug Abuse. Public Health Service. NIH Publication No. 95-3888. Washington, DC: U.S. Government Printing Office, 1995.
15. SAS Institute Inc. SAS language: Reference, Version 6. 1st ed. Cary, NC: SAS Institute Inc; 1990.
16. Racine A, Joyce T, Anderson R. The association between prenatal care and birth weight among women exposed to cocaine in New York City. JAMA 1993;270:1581–1586. | Article | PubMed | ChemPort |
17. Calhoun BC, Watson PT. The cost of maternal cocaine abuse: I. Perinatal cost. Obstet Gynecol 1991;78:731–734.
18. Chiu TTW, Vaughn AJ, Carzoli RP. Hospital costs for cocaine-exposed infants. J. FL Med Assoc 1990;77:897–900.
19. Eyler FD, Behnke M, Conlon M, Woods NS, Frentzen B. Prenatal cocaine use: A comparison of neonates matched on maternal risk factors. Neurotoxi Teratol 1994;16:81–87.
20. Frank DA, McCarten KM, Robson CD, et al. Level of in utero cocaine exposure and neonatal ultrasound findings. Pediatrics 1999;104:1101–1105. | Article | PubMed | ChemPort |
21. Shankaran S. Hemorrhagic lesions of the central nervous system. In: Stevenson D, Sunshine P, editors. Fetal and Neonatal Brain Injury: Mechanisms, Management, and Risks of Practice. 2nd editors., Oxford: Oxford University Press, 1997, p. 151–164.
22. Takayama JI, Bergman AB, Connell FA. Children in foster care in the state of Washington. JAMA 1994;271:1850–1855.
23. Fox K, Merrill JC, Chang H, Califano JA. Estimating the costs of substance abuse to the Medicaid hospital care program. Am J Public Health 1995;85:48–54. | PubMed | ISI | ChemPort |