Prenatal cocaine: What's known about outcomes?

Prenatal cocaine:
What's known about outcomes?

By Steven D. Blatt, MD, Victoria Meguid, MD, and Catharine C. Church, PhD

As new data correct past misconceptions and add new knowledge, it's up to pediatricians to debunk myths about "crack babies," watch for varied developmental consequences in infancy and beyond, and help parents and other caregivers maximize these children's potential.

During the past two decades, the impact of prenatal exposure to cocaine has received a great deal of media and scientific attention. As many as 15% to 20% of inner-city pregnant women use cocaine, according to some estimates, which means that most pediatricians will encounter patients and parents whose lives have been affected by this drug.¹ Precisely what prenatal cocaine exposure means for a child's fate has been a matter of considerable controversy, and some of the predictions have been dire. For a comparison of cocaine myths with what is actually known, see Table 1.

TABLE 1
Myths and facts about cocaine

Many aspects of prenatal cocaine exposure continue to need clarification by researchers. The relationships of exposure in utero, abuse and neglect after birth, and health and developmental outcomes for cocaine-exposed children are very complex. We will try to unravel some of these complexities here, by reviewing the pathophysiology of cocaine exposure, examining the research on cocaine's longer-term developmental effects, and suggesting management strategies for the newborn period and beyond.

Who uses cocaine?

Efforts to document rates of illicit drug use are hampered by study participants' lack of candor. Somewhere between 20 and 40 million Americans have used cocaine and 5 to 6 million are regular users. One million women of child-bearing age use cocaine.² Illicit drug use in a private obstetrical practice setting is similar to that found in public clinics.³

A survey done by the National Institute on Drug Abuse found that among the 4 million women who gave birth during the 1992 to 1993 study period, use of substances known to have adverse effects on the fetus was common.⁴ Some 757,000 of these women drank alcohol, 820,000 smoked cigarettes, and 221,000 thousand used illicit drugs while they were pregnant. The figure for drug use includes 119,000 who used marijuana and 45,000 who used cocaine. Illicit drug use was strongly linked to alcohol and cigarette consumption and was more prevalent in women who were not married, had less than 16 years of education, were not working, and were receiving public assistance. Rates of cocaine use were higher among African-American mothers than white mothers, but the estimated total number of white women who use drugs during pregnancy far exceeds that of African-American women and other minorities.

How cocaine affects newborns

Cocaine acts by preventing catecholamine (norepinephrine and epinephrine) reuptake at presynaptic nerve endings. The increase of catecholamine concentration at synapses stimulates the peripheral and central nervous systems.⁵ These effects increase blood pressure and cause tachycardia and vasoconstriction. During pregnancy, vasoconstriction decreases uterine and placental blood flow. Fetal hypoxemia can result, leading to focal or diffuse cerebral ischemia.⁶ Because placental blood flow is decreased, there may be a decrease in nutrients reaching the fetus, which can adversely affect fetal growth. The hypertensive effects of catecholamines can lead to intracranial hemorrhage in the fetus. Cocaine also blocks tryptophan and serotonin uptake, altering the baby's sleep-wake cycling.

Prematurity and low birth weight. In the mother, cocaine ingestion increases uterine contractility. This is the main mechanism of abruptio placentae, which often leads to the precipitant delivery of a premature infant. A recent study showed that 47% of infants known to be exposed to cocaine in utero were born at less than 37 weeks gestation.⁷ This compares with 16% of matched infants in a presumed non-cocaine­exposed group. The premature births in the cocaine-exposed group were not necessarily caused by maternal cocaine use, however. Prematurity may also result from other maternal conditions that are sometimes associated with cocaine abuse, including poor maternal nutrition, poor or no prenatal care, infectious diseases, use of other illicit drugs, physical abuse, and untreated sexually transmitted diseases including hepatitis B and C, syphilis, and infection with human immunodeficiency virus (HIV).

Fetal distress and meconium staining. Fetal distress with meconium-stained amniotic fluid prior to or during delivery is also more common in cocaine-exposed infants. Meconium in amniotic fluid may also be a direct effect of recently used cocaine on the infant bowel, causing it to constrict and empty prior to delivery.

Growth retardation and other abnormalities. Intrauterine growth retardation (IUGR), which may result from cocaine exposure itself or from poor prenatal care, is also more common in infants exposed to cocaine. Unlike IUGR due to malnutrition, which does not affect brain growth, IUGR from cocaine exposure is symmetric, with birth weight, birth length, and head circumference all affected. Microcephaly may occur, as cocaine has many of its direct effects on the forming brain.⁸ In one study, not replicated elsewhere, 40% of cocaine-exposed newborns had abnormal cranial ultrasounds, a rate similar to that of infants with hypoxic-ischemic injury.⁹ Although there is no consistent dysmorphologic picture like the one present in fetal alcohol syndrome, teratogenic changes have been documented. Optic nerve abnormalities, retinal dysgenesis and colobomata, and genitourinary tract anomalies, while rare, have a higher incidence in infants born to cocaine-using mothers than in other infants.¹⁰

Newborn behavior. Many of the effects of intrauterine exposure to cocaine occur in the central nervous system. Although most cocaine-exposed infants do well, some display symptoms in the newborn period that mimic sepsis: lethargy, hypotonia, and decreased responsiveness to external stimuli. Suck may be poor, and infants may have to be awakened for feedings. These findings relate to changes in serotonin levels. After the first few weeks of life, the infant may experience tremor, increased muscle tone, and brisk startle reflexes in all four limbs. The intensity of these findings increases until about 9 months and then decreases gradually, ceasing by 1 to 2 years of age. The infant may also be hyperirritable from the first few weeks of life until 2 to 3 months of age. An intense sucking reflex may develop as the infant gets older, so that an underweight newborn may grow into a well-nourished or even overweight child. Using a pacifier between feedings can prevent excessive weight gain.

The risk for SIDS. The rate for sudden infant death syndrome is 8.5/1,000 live births in cocaine-exposed infants, twice as high as the 4.5/1,000 rate for infants who have no history of exposure.¹¹ Mothers can reduce that risk by the same measures recommended for all newborns: putting the baby to sleep on his or her back on a firm surface and refraining from cigarette smoking.

Conditions associated with prenatal exposure to cocaine are listed in Table 2.

TABLE 2
Conditions associated with cocaine use

What about development?

Many parents and pediatricians have erroneous notions about the developmental impact of prenatal cocaine exposure. According to the popular press, these babies had sustained severe neurologic damage that was bound to lead to behavior problems and significant learning difficulties during the school years. Although experience has not supported this negative picture, the image has perpetuated itself. Parents, guardians, teachers, and other adults in the child's world may label developmentally normal behavior as problematic simply because of the negative expectations they hold.¹² By providing accurate information about cocaine exposure, pediatricians can counter these self-fulfilling prophesies and exert a positive influence in the child's relationships.

The body of research on the impact of prenatal exposure on development continues to grow, but much remains controversial and contradictory. The variability in results is due in part to difficult research challenges. Researchers must try to separate the effects of cocaine from those of other drugs the mother may use during pregnancy. They have to account for differential effects that depend on the amounts of cocaine and the timing of the exposure. Further, cocaine must be separated from factors often associated with cocaine use that also have deleterious effects on development, such as lead poisoning, iron deficiency, poor parenting skills, substandard prenatal care, prematurity, and a non-nurturing, non-supportive home environment. Finally, many of the early studies suffered from small sample sizes or used developmental instruments that were not sensitive enough to detect subtle developmental effects.

Neurobehavioral effects. Several large prospective studies have shown very few significant differences in neurobehavior at birth between infants exposed to cocaine and matched controls.^13,14 Some studies have shown differences in alert responsiveness, state regulation, and orientation while others have demonstrated differences in irritability, high-pitched cry, tremor, and feeding.^15­18 When these differences occur, they seem to be related to the amounts of cocaine used during pregnancy. The greater the amount, the more likely there will be neurobehavioral effects. Fortunately, many of the neurobehavioral symptoms present in infancy diminish over time and disappear completely by 3 to 4 months of age.

Behavior problems. A small but growing body of evidence indicates that infants with extended and intensive prenatal exposure have more problem behaviors such as attention deficit hyperactivity disorder during early childhood than children who are not exposed.^19,20 Young children whose mothers used cocaine briefly and early in pregnancy do not have behavior problems, whereas problem behavior has been associated with sustained cocaine use through the end of pregnancy.

Cognitive effects. Studies on the impact of cocaine on cognition to date have had highly variable and contradictory outcomes. Several studies have found no effect on cognitive functioning in infants heavily exposed to cocaine while others show a decrease in standard IQ scores.^21,22 There is much less information available for the effects of cocaine on cognitive abilities of older children. Test scores for receptive language, visual motor integration, and verbal reasoning in 4- to 6-year-old children exposed to cocaine before birth are significantly lower than scores in control groups.^23,24

A meta-analysis of 101 studies on prenatal cocaine exposure found a difference of 3.26 IQ points between cocaine-exposed and control groups.²⁵ While this difference may not seem very large, a shift downward of 3.26 IQ points results in a 1.6-fold increase in the number of children with IQs below 70. Since special education and early intervention services are provided for children who score more than two standard deviations from the mean (IQ less than 70), the social costs these children represent may be considerable.

Muscle tone and reflexes. Changes in tone (both hypertonia and hypotonia) and in reflexes have been noted in infants exposed to cocaine. These early changes appear to be transient and resolve by 1 to 2 years of age.¹⁸ Whether they translate into motor deficits in older children is not known.

Recent evidence suggests that young children who were exposed to cocaine prenatally do not perform as well on the Bayley Scales of Infant Development Psychomotor Index as children who were not exposed. By 2 years of age, children exposed to cocaine performed less well than unexposed children in fine motor development, hand use, and eye-hand coordination.²⁶ A lag in motor development beyond the neonatal period is a serious concern, since it can affect a child's ability to learn to write and lead to continuing academic difficulties. As in other areas of development, however, a causal relationship between lagging motor skills and cocaine exposure has not been established. A variety of social, cultural, and environmental factors may work together to create developmental difficulties. Whatever the etiology, the pediatrician's task is to monitor development and make timely referrals to early intervention agencies as appropriate.

Although many of the effects of cocaine may disappear over time, caring for infants affected by cocaine exposure can be challenging. These babies may have low thresholds for stimulation. They cry more frequently and are more difficult to soothe. Relationships between mothers and such "difficult" infants are often disturbed. Studies have shown that mothers of exposed infants spend more time than other mothers disengaged from their newborns and are less sensitive to their infants' cues.²⁷ Children who have been placed in out-of-home care may have a particularly difficult time because they must adjust to the different rhythms of different caretakers. The pediatrician and nursing staff can teach caregivers a variety of techniques for soothing hyperirritable infants, such as tight swaddling and vertical holding and rocking. Techniques like these can improve the infant-caregiver relationship and thus have a positive impact on development. Suggestions for caregivers are contained in the guide below.

Protecting the child

Pediatricians evaluate an infant's family structure and support system as part of routine health supervision. Paying attention to what may be red flags for parental drug use should be part of that process. Such signs include poor prenatal care, repeated failure to keep medical appointments, and a poor record of caring for other children in the family. A history of drug or alcohol use, family violence, incarceration, or involvement with child protective services should heighten concern.

The most widely available method for documenting maternal drug use is maternal or neonatal urine testing. Tests of newborn hair or meconium are also reliable, but they are not as widely available. The newborn's urine will remain positive for cocaine for five to seven days after exposure. Meconium or infant hair will be positive for cocaine used from the sixteenth week of pregnancy onward and can give more quantitative data.²⁸

As health-care providers, pediatricians, nurse practitioners, and nurses are mandated to report maternal cocaine use to child protective services. Each jurisdiction handles child abuse and neglect reports differently. Typically, a social services protective worker contacts the health-care provider and the mother. However, because the unborn child is not legally a person, courts cannot hold that a child has been abused or neglected before being born. An infant can be taken from the mother at birth only if there is supporting evidence that neglect has occurred in the past with other children or that it is likely to occur with the newborn. If the social service investigation finds such evidence, the case is termed "founded" and will continue through the legal process. If no abuse or neglect is found, the case is "unfounded" and is no longer pursued.

Even when prenatal cocaine use is at issue, the social services agency must evaluate the parents' competence to care for the child. Sometimes the agency decides that—with additional services and supervision—the parents can provide proper care, and the child is sent home. If the evaluation determines that the parents are not competent, the baby may be placed in foster care or with a relative or friend.

Although children in foster care confront many hurdles, they are removed from a neglectful and often toxic environment.²⁹ At the very least, the child is no longer living with a drug-abusing parent. The same cannot be said of kinship care, however. Some families are wonderful in caring for their young, drug-exposed relatives; others are no more nurturing or successful than the biologic parents. Kinship care comes with minimal oversight from social services, and it is not uncommon for the drug-abusing mother, against court orders, to re-establish custody while the child is in the care of relatives.

When caring for a child of a cocaine-using mother, do not let the placement decision of social services override your clinical instinct. There is ample evidence that even children felt by social services to be at low risk for abuse and neglect are in reality at increased risk in the household of the biologic parents. Two studies from New Haven, CT, found rates of abuse and neglect were five to six times higher in cocaine-exposed children than in non-exposed children.^2,30 In our study of 300 children in central New York, we compared 100 children born with urine screens that were positive for cocaine to a group of children with negative screens and to a third group of children who were thought to be at low risk for cocaine exposure and not tested.⁷ Children in all three groups were sent home to their biologic parents. We found that children with documented exposure were five times more likely to be reported for abuse and neglect in the next three years than those children thought not to be at risk for cocaine exposure. They were also 14 times more likely to be placed into foster care. The infants with negative urine screens were also at high risk for subsequent abuse and neglect. They were four times as likely to be reported for abuse and neglect and 15 times more likely to be placed in foster care than children thought not to be at risk.

These studies highlight the need for vigilance for children born to mothers at high risk for perinatal substance abuse. In the presence of a suspicious history, a negative toxicology result may be due to the limits of the laboratory test and should not be viewed as "proof" that drug use during pregnancy did not occur. On the contrary, the pediatrician is justified in continuing close supervision and should be ready to intervene promptly if care of the infant seems jeopardized.

A matter of judgment

During the past decade we have learned a lot about the effects of prenatal cocaine exposure on infants, and we have learned that much of what we once thought of as "the truth of cocaine" is really a myth. Pediatricians would be wise to remember that cocaine-exposed infants are often not identified unless we maintain a high index of suspicion. It may be a pediatrician's clinical judgment, and not the laboratory test, that marks these infants at high risk for future developmental and social problems. Like all infants at risk, they need vigilant and expert follow-up.

Acknowledgment: The authors thank Mahesh Netravali for his editorial assistance and critical review of the manuscript.

REFERENCES

1. Leventhal JM, Forsyth BWC, Qi K, et al: Maltreatment of children born to women who used cocaine during pregnancy: A population-based study. Pediatrics 1997;100:e7

2. Pelham T, DeJong AR: Nationwide practices for screening and reporting prenatal cocaine abuse: A survey of teaching programs. Child Abuse Neglect 1992;16:763

3. Chasnoff IJ, Landress HJ, Barrett ME: The prevalence of illicit-drug or alcohol use during pregnancy and discrepancies in mandatory reporting in Pinellas County, Florida. N Engl J Med 1990; 22:1202

4. National Institute on Drug Abuse: National Pregnancy and Health Survey: Drug Use Among Women Delivering Live Births: 1992. Catalogue #BKD192 Rockville, MD, National Institute on Drug Abuse, 1996

5. Volpe JJ: Effect of cocaine use on the fetus. New Engl J Med 1992;327: 399

6. Mirochnick M, Meyer J, Frank DA, et al: Elevated plasma norepinephrine after in utero exposure to cocaine and marijuana. Pediatrics 1997;99:555

7. Meguid V, Blatt SD, Doris J, et al: Newborn toxicology screening results as a predictor of subsequent child abuse and neglect. Presented at the Annual Meetings of the Ambulatory Pediatric Association, the American Pediatric Society, and the Society for Pediatric Research, New Orleans, LA, May 4, 1998

8. Richardson GA, Hamel SC, Goldschmidt MA, et al: Growth of infants prenatally exposed to cocaine/crack: Comparison of a prenatal care and no prenatal care sample. Pediatrics 1999;104(2);e18

9. Dixon JD, Bejar R: Echoencephalographic findings in neonates associated with maternal cocaine and methamphetamine use: Incidence and clinical correlates. J Pediatr 1989;115(5 pt 1):770-778

10. Bingol N, Fuchs M, Diaz V, et al: Teratogenicity of cocaine in humans [published erratum appears in J Pediatr 1987;110(3):350]. J Pediatr 1987;110(1):93

11. Ward SL, Bautista D, Chan L, et al: Sudden infant death syndrome in infants of substance-abusing mothers. J Pediatr 1990;117(6):816

12. Woods N, Eyler FD, Conlon M, et al: Pygmalion in the cradle: Observer bias against cocaine-exposed infants. Dev Behavior Pediatr 1998;19(4):283

13. Eyler F, Behnke M: Prenatal cocaine exposure: Consequences for child and family. J Fla Med Assoc 1995;82:603

14. Eyler F, Behnke M, Conlon M, et al: Birth outcome from a prospective, matched study of prenatal crack/cocaine use: Interactive and dose effects on neurobehavioral assessment. Pediatrics 1998;101(2):237

15. Black M, Schuler M, Nair P: Prenatal drug exposure: Neurodevelopmental outcome and parenting environment. J Pediatr Psychol 1993;18:605

16. Delaney-Black V, Covington C, Ostrea E, et al: Prenatal cocaine and neonatal outcome: Evaluation of dose response relationships. Pediatrics 1996;98:735

17. Napiorkowski B, Lester B, Freier M, et al: Effects of prenatal cocaine exposure on infant behavior. Pediatrics 1996;98:71

18. Tronick C, Frank DA, Calbral H, et al: Late dose-response effects of prenatal cocaine exposure on newborn neurobehavioral performance. Pediatrics 1996;98:76

19. Delaney-Black V, Covington C, Templin T, et al: Prenatal coke: What's behind the smoke? Ann NY Acad Sci 1998;846:227

20. Richardson GA, Conroy ML, Day NL: Prenatal cocaine-exposure: Effects on the development of school-age children. Neurotoxicol Teratol 1996;18:627

21. Jacobson S, Jacobson J, Sokol R, et al: New evidence for neurobehavioral effects of in utero cocaine exposure. J Pediatrics 1996;129(4):581

22. Alessandri SM, Bendersky M, Lewis M: Cognitive functioning in 8 to 18 month old drug-exposed infants. Dev Psychol 1998;34:565

23. Bender SL, Word CO, DiClemente RJ, et al: The developmental implications of prenatal and/or postnatal cocaine exposure in preschool children: A preliminary report. J Dev Behav Pediatrics 1995;16:418

24. Griffith DR, Azuma SC, Chasnoff IJ: Three-year outcome of children exposed prenatally to drugs. J Am Acad Child Adolesc Psychiatry 1994;33(1):20

25. Lester BM, LaGasse LL, Seifer R: Cocaine exposure and children: The meaning of subtle effects. Science 1998;282:633

26. Arendt R, Angelopoulos J, Salvator A, et al: Motor development of cocaine-exposed children at age two years. Pediatrics 1999;103:86

27. Gottwald SR, Thurman SK: The effects of prenatal cocaine-exposure on mother-infant interaction and infant arousal in the newborn period. Topics in Early Childhood Special Education 1994;14:217

28. Callahan CM, Grant TM, Phipps P, et al: Measurement of gestational cocaine exposure: Sensitivity of infants' hair, meconium, and urine. J Pediatrics 1992; 120:763

29. Blatt SD, Simms M: Foster care: Special children, special needs. Contemporary Pediatrics 1997;14(4):109

30. Wasserman DR, Leventhal JM: Maltreatment of children born to cocaine-dependent mothers. Am J Dis Child 1993;147:1324

DR. BLATT is Associate Professor of Pediatrics at the State University of New York Health Science Center at Syracuse and Director, ENHANCE Services for Children in Foster Care, Syracuse, NY.

DR. MEGUID is Assistant Professor of Pediatrics at SUNY, Syracuse, and Assistant Director, ENHANCE Services for Children in Foster Care.

DR. CHURCH is Associate Professor of Pediatrics and Interim Director, Division of Child Development, SUNY, Syracuse.

GUIDE FOR CAREGIVERS

Helping the baby exposed to cocaine before birth

Some infants who have been exposed to cocaine before birth have difficulty organizing the sensory information they receive. They may be overly sensitive to touch, movement, sights, or sounds. It is important to understand how your baby is affected by different experiences so that you can respond appropriately. If you see signs of distress such as crying, fussing, avoiding eye contact, or frowning during an activity, the baby is probably telling you there is too much stimulation. Try stopping the activity and allowing the baby time to recover. Fortunately, although infants exposed to cocaine may have early difficulties, most of their problems resolve over the first two years of life.

Following these suggestions should help the infant adapt:

If your baby is...

Then...

Use slightly stronger pressure when touching the child
Hold gently but firmly
Avoid bouncing and rapid patting
Swaddle the baby in a blanket
Carry the child snuggled up in a front carrier
Avoid passing the baby from person to person

Sensitive to textures

Use soft, cotton clothes
Keep skin clean and dry
Limit baths to one or two per week
Don't force the use of a pacifier
Limit contact with stuffed animals or textured toys

Keep baby's area quiet
Try not to startle baby with loud noises
Try quiet, rhythmic background music
Avoid noisy mobiles or rattles
Stay away from crowds in malls, movies, and athletic events

Use soft lighting or dim lights
Do not expose the baby to glaring lights in offices and malls
Have the baby wear a hat with a visor
Place child on the shady side of the car when traveling

Use a pacifier to help with the need to suckle often
Do not overfeed
Let older babies chew on teething rings
Anticipate difficulty when introducing new foods and go slowly
Use spoons with soft rubber coating
Limit the number of people who do the feedings

Steven Blatt,Victoria Meguid,Catharine Church. Prenatal cocaine: What's known about outcomes?.

Contemporary Pediatrics

2000;5:43.