Article

Impact of maternal substance use during pregnancy on childhood outcome

Wayne State University School of Medicine, Detroit, MI, USA. <>
Seminars in Fetal and Neonatal Medicine (Impact Factor: 3.03). 05/2007; 12(2):143-50. DOI: 10.1016/j.siny.2007.01.002
Source: PubMed
ABSTRACT
The impact of maternal substance abuse is reflected in the 2002-2003 National Survey on Drug Use and Health. Among pregnant women in the 15-44 age group, 4.3%, 18% and 9.8% used illicit drugs, tobacco and alcohol, respectively. Maternal pregnancy complications following substance use include increases in sexually transmitted disorders, placental abruption and HIV-positive status. Effects on the neonate include a decrease in growth parameters and increases in central nervous system and autonomic nervous system signs and in referrals to child protective agencies. In childhood, behavioral and cognitive effects are seen after prenatal cocaine exposure; tobacco and alcohol have separate and specific effects. The ongoing use of alcohol and tobacco by the caretaker affects childhood behavior. Therefore, efforts should be made to prevent and treat behavioral problems as well as to limit the onset of drug use by adolescent children born to women who use drugs during pregnancy.

Full-text

Available from: Charles R Bauer
Impact of maternal substance use during
pregnancy on childhood outcome
Seetha Shankaran
a,b,
*
, Barry M. Lester
c
, Abhik Das
d
, Charles R. Bauer
e
,
Henrietta S. Bada
f
, Linda Lagasse
g
, Rosemary Higgins
h
a
Wayne State University School of Medicine, Detroit, MI, USA
b
NeonatalePerinatal Medicine, Children’s Hospital of Michigan and Hutzel Women’s Hospital, Detroit, MI, USA
c
Brown Medical School, Women & Infants Hospital of Rhode Island, Providence, RI, USA
d
Research Triangle Institute, Rockville, MD, USA
e
Department of Pediatrics, University of Miami School of Medicine, Miami, FL, USA
f
University of Kentucky, Lexington, KY, USA
g
Department of Pediatrics, Brown Medical School, Providence, RI, USA
h
Center for Developmental Biology and Perinatal Medicine, NICHD, National Institute Health, Bethesda, MD, USA
KEYWORDS
Alcohol;
Child medicine;
Cocaine;
Neonatal;
Neurobehavioral
outcome;
Polydrug use;
Tobacco
Summary The impact of maternal substance abuse is reflected in the 20 02e2003 National
Survey on Drug Use and Health. Among pregnant women in the 15e44 age group, 4.3%, 18%
and 9.8% used illicit drugs, tobacco and alcohol, respectively. Maternal pregnancy complica-
tions following substance use include increases in sexually transmitted disorders, placental
abruption and HIV-positive status. Effects on the neonate include a decrease in growth param-
eters and increases in central nervous system and autonomic nervous system signs and in re-
ferr als to child protectiv e agencies. In childhood, be havioral and cog nitive effects are seen
after pren atal c ocaine exposure; tobacco and alcohol have separat e and specific effects.
The ongoing use of alcohol and tobacco by the caretaker affects child hood behavior. There-
fore, efforts should be made to prevent and t reat behavioral probl ems as well a s to limit
the onset of drug use by adolescent children born to women who use drugs during pregnancy.
ª 2007 Elsevier Ltd. All rights reserved.
Introduction
Currently, about 11% of the adult population of the United
States suffers from a substance-abuse problem during any
one year. The cost to society of this drug use is estimated at
over US$300 billion annually; this figure includes the costs of
crime, heath-related problems and reduced work produc-
tivity. The impact of maternal substance abuse is reflected in
the 2002e2003 National Survey on Drug Use and Health,
which found that, of pregnant women aged 15e44, 4.3%, 18%
and 9.8% used illicit drugs, tobacco and alcohol, respec-
tively. In 2002, the approximate numbers of births compli-
cated by maternal use of drugs were 172,934 for illicit drugs,
* Corresponding author. Children’s Hospital of Michigan, Division
Neonatology, 3901 Beaubien, Detroit, MI 48201, USA. Tel.: þ1 313
745 1436; fax: þ1 313 745 5867.
E-mail address: sshankar@med.wayne.edu (S. Shankaran).
1744-165X/$ - see front matter ª 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.siny.2007.01.002
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/siny
Seminars in Fetal & Neonatal Medicine (2007) 12 , 143e150
Page 1
723,911 for tobacco and 394,129 for alcohol.
1
Thus, from the
public health perspective, the impact of substance use
during pregnancy in the United States extends far beyond
the health of the mother and affects a large number of the
unborn population.
In the 1980s, the ‘war on drugs’ associated with the
crack-cocaine epidemic focused national attention on to
the relationship between drug use and social and economic
problems in society. Early reports on the effects of prenatal
cocaine exposure created a public frenzy and prompted the
myth about ‘unfit to parent’ women and their damaged
‘crack babies’. This in turn had an impact on legal and
policy decisions made by individual US States and affected
women who use illegal drugs during pregnancy. However,
studies performed since the 1980s have failed to support
significant associations between prenatal cocaine exposure
and the increased prevalence of serious newborn congen-
ital malformations and medical complications at birth.
The focus of this paper is the impact of substance use on
maternal, neonatal and preschool child outcome. Data
from recent cohort studies, and from studies using state-
of-the-art methods of documenting substance use, will be
examined.
Acute maternal and neonatal effects
The risk of congenital malformations following fetal cocaine
exposure was evaluated in a prospective study of 154
prenatally identified cocaine users and 154 controls matched
for race, parenting and location of care.
2
It was noted that
the infants who were exposed to cocaine in utero hada higher
rate of premature birth, lower birth weights and smaller birth
length and head circumference; however, no difference in
the type or number of congenital abnormalities was noted
between the cocaine-exposed and non-exposed infants.
The effects of cocaine exposure on neonatal cranial
sonographic findings were evaluated in a prospective study
(of 241 term infants) in which the level of exposure to cocaine
was documented by meconium assay of metabolites.
3
After
controlling for infant sex, gestational age and birth weight,
and for maternal parity, ethnicity and drug use, the cranial
sonographic findings in infants who received light cocaine
exposure were similar to those seen in infants who were
unexposed to cocaine. However, heavily cocaine-exposed
infants had a higher risk of subependymal hemorrhage,
with an adjusted odds ratio (OR) of 3.89 and 95% confidence
interval (95% CI) of 1.45e10.35.
The impact of prenatal exposure to substance use on
height, weight and head circumference at birth has been
examined while controlling for multiple substance use and
prenatal care. A study by Richardson et al.
4
compared
women who received no prenatal care (n Z 98) with
women who had received prenatal care (n Z 295) through-
out pregnancy. The women who had not received prenatal
care were interviewed at delivery. At the time of birth, it
was noted that, in both groups, cocaine use in early preg-
nancy resulted in reduced gestational age, birth weight
and head circumference after controlling for multiple cova-
riates of cocaine use.
The impact of substance (polydrug) use was evaluated
by Eyler et al.,
5
who matched 154 cocaine users with 154
non-users for race, parity, socioeconomic status and loca-
tion of prenatal care. Substance use during pregnancy
was evaluated by maternal history and a urine drug screen.
It was noted that the amount of substance use during tri-
mesters 2 and 3 impacted on the infant’s growth measure-
ments at birth. There was a negative relationship between
cocaine use in trimester 3 and birth length and head cir-
cumference; this effect remained after adjusting for the
effects of marijuana, tobacco and alcohol.
5
Radioimmunoassay of cocaine metabolites in maternal
hair during the third trimester provides a more sensitive
assessment of substance use during pregnancy than in-
terview and urine assay. In a study of 240 infants, 136 of
whom were not exposed to cocaine, 52 had low exposure
and 52 had high exposure to cocaine.
6
It was noted that,
after adjusting for the effects of infant birth weight, ges-
tational age and sex, and for maternal height, weight-gain
during pregnancy and other drug use, newborns with
high exposure have a head circumference that is dispro-
portionately smaller than birth weight, resulting in
‘head-wasting’.
The largest study evaluating the impact of substance use
on pregnancy outcomedthe Maternal Lifestyle Study
(MLS)dwas developed in the early 1990s by the National
Institutes of Child Health and Human Development (NICHD)
NICU Neonatal Research Network with additional support
from National Institute on Drug Abuse (NIDA). Against the
backdrop of debate and controversy about the effects of
prenatal cocaine exposure on child outcome, the MLS
recognized that cocaine use by pregnant women is a marker
variable for two critical factors thatdin addition to pre-
natal cocaine exposuredcan affect child outcome: the use
of drugs other than cocaine and an inadequate caregiving
environment.
7,8
The MLS was designed to address these and
many other methodological issues in the field, including
sample size, methods of drug detection, prematurity, other
confounding variables (such as medical factors, interven-
tions and protective services) and neurodevelopmental
assessments that are sensitive to putative drug effects.
The study is ongoing and is being conducted in four sites:
the University of Miami, the University of Tennessee at
Memphis, Wayne State University and Brown University.
Of 19,000 mothers screened between 1993 and 1995,
approximately 11,800 agreed to participate. Drug exposure
is determined by self-report and meconium toxicology with
confirmatory analysis. The study is currently divided into
four phases. The acute Phase I period extends through to
hospital discharge. Phase II is a longitudinal follow-up of
a subsample of 1388 exposed and comparison children
between 1 month and 3 years of age. Phase III extends the
follow-up to school performance at 7 years of age. Phase
IV is evaluation from age 8 years to age 11.
In total, 8527 newborn meconium analyses were per-
formed and a history of substance use by the mother taken.
The prevalence of cocaine and opiate exposure was 10.7%.
The confirmation of positive cocaine screens by Gas
Chromatography Mass Spectrometry (GCMS) was 75.5%. It
should be noted that in 38% of cases in which the meconium
analysis was positive for cocaine/an opiate, the mother
denied use. There was 66% agreement between positive
meconium results and positive maternal report. Only 2% of
the women used cocaine alone without any other drug.
144 S. Shankaran et al.
Page 2
Polydrug use was very common and it was noted that
women were 49 times more likely to use another drug if
cocaine was used.
9
The impact of both drug exposure during pregnancy and
of short-term maternal outcomes was evaluated in the same
study (MLS). A total of 19,079 mothere infant dyads were
screened; 11,811 women agreed to participate.
10
Of these,
3184 were excluded (because of inadequate meconium
samples, etc.) 1185 were cocaine exposed and 7442 were
not exposed to cocaine. Cocaine exposure was found to be
higher in AfricaneAmerican women, in those who had a his-
tory of polydrug use and in those who were older than the
non-cocaine-exposed women. Cocaine-exposed women had
significantly fewer prenatal care visits than non-cocaine-
exposed women. Exposed women had a significantly higher
risk of medical complications, including syphilis (OR 6.7;
99% CI 4.8e9.6), gonorrhea (OR 1.9; 99% CI 1.3e3.0) and hep-
atitis (OR 4.8; 99% CI 2.6e8.9). They also had a higher inci-
dence of psychiatric, nervous and emotional disorders (OR
4.0; 99% CI 2.2e7.4) and of abruptio placenta (OR 2.3; 99%
CI 1.4e3.9). Among those women who were tested for HIV
(28% of the cohort), the risk (OR) was 8.2 (99% CI 14.3e
15.4). The frequency of hospitalizations, fetal distress and
cesarean section did not differ between the two groups.
The impact of substance exposure during pregnancy on
neonatal outcome was evaluated in the MLS, which
compared 717 cocaine-exposed infants with 7448 non-
cocaine-exposed infants.
11
It was noted that infants in the
cocaine-exposed group were 1 week younger in gestational
age, weighed 322 g less, were 1.7 cm shorter and were
1.0 cm smaller in head circumference than the non-
cocaine-exposed group. The cocaine-exposed infants also
had a higher frequency of central nervous system (CNS)
symptoms (adjusted OR 1.7; 99% CI 1.2e2.2), autonomic ner-
vous system (ANS) symptoms (OR 1.5; 99% CI 1.0e2.1) and
neonatal infections (OR 3.1; 99% CI 1.8e5.4). The frequency
of child protective service referrals was higher in the cocaine
group (OR 48.9; 99% CI 28.8e83.0) and less breast feeding
was also noted in this group (OR 0.3; 99% CI 0.1e 0.4) than
in the non-cocaine-exposed group. No differences were
detected in organ systems by ultrasound examinations.
In a subsequent publication evaluating central and
autonomic system (CNS/ANS) signs within the same study
sample, Bada et al. reported that the prevalence of CNS/
ANS signs was low in the infants exposed to cocaine only and
highest in the infants exposed to opiate and cocaine.
12
After
controlling for confounders, cocaine exposure was associ-
ated with an increased risk of manifesting a constellation
of CNS/ANS outcomes (OR 1.7; 95% CI 1.2e2.2) independent
of opiate effect (OR 2.8; 95% CI 2.1e3.7). Opiate plus co-
caine had additive effects (OR 4.8; 95% CI 2.9e7.9). Smoking
also increased the risk for the constellation of CNS/ANS signs
(OR 1.3; 95% CI 1.04e1.55 and OR 1.4; 95% CI 1.2e2.6, re-
spectively, for use of less than half a pack a day and half
a pack a day or more).
Neonatal size at birth and subsequent growth
Percentile estimates for birth weight, length and head
circumference in MLS have revealed that growth deceler-
ation in cocaine-exposed infants is evident after 32 weeks
gestation.
13
After controlling for confounders, at 40 weeks
gestation, cocaine exposure was estimated to be associated
with decreases of 151 g in birth weight, 0.71 cm in length
and 0.43 cm in head circumference. Smoking has a negative
impact on all growth measurements, with some indication
of a doseeeffect relationship. Heavy alcohol use was asso-
ciated with decreases in weight and length only. Opiates
had a significant effect only on birth weight.
When the impact of patterns of drug use during pregnancy
(consistently high, moderate, low, increasing or decreasing
use across all trimesters) in full-term gestations was exam-
ined on infant growth parameters in infants born to mothers
with multiple drug use, birth weight, birth length and head
circumference were noted to be significantly greater in
infants born to women who used no drugs than in those born
to women with any history of cocaine, opiate, alcohol,
tobacco or marijuana use during pregnancy.
14
Growth
parameters are also greater in infants born to cocaine
non-users than to cocaine users. When adjustment was made
for confounders, birth weight was significantly affected by
cocaine (deficit Z 250 g), even with a consistently low pat-
tern of use during the pregnancy. Birth weight was also af-
fected by tobacco (deficit Z 232 g with a consistently high
pattern of use, 173 g with a consistently moderate pattern
of use, 153 g with a decreasing pattern of use and 103 g
with a consistently low pattern of use). Head circumference
was affected by cocaine (deficit Z 0.98 cm with a consis-
tently moderate pattern of use) and by tobacco (defi-
cit Z 0.72 cm with a consistently high pattern of use and
0.89 cm with a consistently moderate pattern of use). Birth
length was affected by tobacco use only (deficit Z 0.82 cm
with a consistently high pattern of use and 0.98 cm with de-
creasing use). When the factors that would increase the like-
lihood of low birth weight, preterm birth and intrauterine
growth restriction (IUGR) were evaluated, prenatal cocaine
exposure increased the likelihood of low birth weight (OR
3.59), prematurity (OR 1.25) and IUGR (OR 2.24) after
adjusting for covariates.
15
Tobaccodbut not marijuanad
significantly influenced these outcomes. Alcohol had an
effect on low birth weight and IUGR. Etiologic fractions esti-
mated as the percentage of populationeattributable risk
(PAR%) attributable to tobacco for low birth weight, prema-
turity and IUGR were 5.57, 3.66 and 13.7%, respectively.
With additional drug exposure, including cocaine, the esti-
mated PAR% increased to 7.20% (low birth weight), 5.68%
(prematurity), and 17.9% (IUGR).
The effects of cocaine exposure during pregnancy and
IUGR status at birth on longitudinal growth until 6 years of
age have been evaluated.
16
At birth, cocaine-exposed in-
fants weighed 150 g less than non-cocaine-exposed infants;
however, between 1 and 6 years there were no significant
differences in weight between cocaine-exposed and non-
exposed children. For height, exposed children were
0.85 cm shorter than non-exposed infants at birth and
were still shorter than the non-exposed children at 1e2 years
of age; this difference was no longer apparent after age 3.
Head circumference was 0.5 cm less in the cocaine-exposed
infants at birth and was still smaller at 1 year of age;
subsequently, the difference disappeared.
At birth, term IUGR infants weighed 0.5 kg less than the
non-IUGR infants; this difference had increased to 2.1 kg
difference by 6 years of age. At birth, children who were
Impact of maternal substance use 145
Page 3
small for gestational age were 1.0 cm shorter and continued
to be significantly impaired in height throughout childhood,
compared with non-IUGR children. At 6 years, the average
height of the IUGR children was 1.8 cm less than the non-
IUGR children. The head circumference of IUGR children
was on average 0.85 cm less than the non-IUGR children
and IUGR children continue to have a smaller head circum-
ference, with a difference of 0.9 cm at 6 years of age.
There was an interaction between cocaine exposure and
IUGR status on weight at 6 years of age. The negative effect
of cocaine exposure was significant in the non-IUGR chil-
dren but not in the IUGR children. The negative effect of
IUGR status at birth on weight at 6 years was greater in
the non-cocaine-exposed than in the cocaine-exposed co-
hort. The negative effect of cocaine exposure on height
was significant only in the non-IUGR children at 6 years.
The negative effect of IUGR status on height was larger in
the non-cocaine-exposed children than in the cocaine-
exposed children. Thus, the effect of IUGR status at birth
has a greater impact on growth in childhood than cocaine
exposure status.
The association between prenatal cocaine exposure and
elevated blood pressure in early childhood is unclear, with
two studies producing differing results.
17,18
Nineteen per-
cent of the MLS cohort of 891 full-term children followed
for 6 years had hypertension.
19
Of the 144 children with
IUGR, 25% had hypertension, as compared with the children
without growth restriction. Twenty percent of cocaine-
exposed children had hypertension, compared with 16% of
non-exposed children (P Z 0.2). IUGR status at birth was
significantly associated with hypertension when multivari-
able regression analysis was performed to adjust for site,
maternal race, education and tobacco, marijuana, alcohol
and cocaine use during pregnancy and the child’s current
body mass index.
Utilization of healthcare resources following
substance use during pregnancy
Data on utilization of healthcare resources by substance-
abusing women are limited. Maternal hospital costs are
higher among illicit drug users and neonatal hospital costs
have been found to be higher due to increased length of
stay.
20
In a study that matched cocaine-exposed with non-
cocaine exposed infants, those exposed to cocaine were
noted to have an increased length of hospital stay, more
investigations for sepsis, more admissions to the NICU and
more social and family problems delaying discharge.
21
The
MLS is the largest study to evaluate the utilization of health-
care resources by mothers and infants following cocaine use
during pregnancy. The use of medical and social services
resources by 8514 mothereinfant dyads was examined;
1072 of the mothers had used cocaine and 7442 had not.
22
Fewer cocaine-exposed women received prenatal care or
used medication during pregnancy. Length of hospital stay
for social reasons and referrals to child protective services
were increased for the infants in the cocaine-exposed group.
Length of stay in the neonatal intensive care unit was
increased in cocaine-exposed infants weighing >1500 g, as
was the need for therapies, procedures, formula feeds and
intravenous fluids. The investigators noted that cocaine ex-
posure had no deleterious or protective effects on medical
resource needs of infants weighing <1500 g, or their
mothers. The investigators suggest that the use of healthcare
resources for surveillance and monitoring of >1500-g
cocaine-exposed infants in the absence of an increase in
congenital anomalies should be discouraged.
Neurobehavior in children prenatally
exposed to illicit drugs
No major neurological deficits in motor development have
been found after intrauterine exposure to cocaine. When
motor skills were assessed in the same infantsdusing the
NICU Network Neurobehavioral Scale (NNNS) at 1 month,
the posture and fine motor assessment of infants (PFMAI)
at 4 months, the Bayley Scale of Infant Development at
12 months and the Peabody Developmental Motor Scales
at 18 monthsdit was noted that infants with exposure to
cocaine showed lower motor skills at their initial status at
1 month; however, they displayed significant increases
over time.
23
Both higher and lower levels of tobacco use re-
lated to poor motor performance. Compared with no use,
heavy cocaine use related to poorer motor performance
but there were no effects of level of cocaine use on change
in motor skills.
There is now a move away from evaluating major neuro-
logical deficits towards the evaluation of neurologic ‘soft’
signs. These signs are becoming more clinically relevant
because of their association with cognitive deficits and
because of the increased prevalence of attention deficit
hyperactive disorder and behavior problems. Neurologic soft
signs are defined as deviations in motor, sensory and in-
tegrative functions that do not signify localized brain
dysfunction, examples are: cranial nerve abnormalities,
lateralized dysfunction and the presence of pathologic re-
flexes. Neurologic soft signs (non-focal signs with no localized
findings) cover ten areas: speech, balance, coordination,
double simultaneous stimulation (extinction), gait, sequen-
tial fingerethumb opposition, muscle tone, graphesthesia,
astereognosis, and choreiform signs.
24
After scoring for each
of these areas, the total score has been shown to exhibit
acceptable internal consistency, as well as inter-rater and
testeretest reliability.
25
Soft signs exhibit marked stability
over a 1-year period in 6e9-year-old children. The symptoms
of both internalizing and externalizing disorders correlate
with poor performance on the soft sign examination.
26
In 1999, Breslau et al. found that soft signs increased the
risk of a subnormal intelligence quotient (IQ) and of learning
disorders in children with a normal IQ.
27
Soft signs were
associated with excess internalizing problems in low birth-
weight (LBW) and normal birth-weight (NBW) children, and
with attention and externalizing problems in LBW children
at 6 years of age. Hence, soft signs are a marker of a high
risk of cognitive and psychiatric problems. In the MLS evalu-
ation of 943 children, 416 of whom were exposed to cocaine
and 527 of whom were in the comparison group, more than
two soft neurological signs were seen among 23.5% children,
with comparable rates between children born to cocaine
users and those in the comparison group.
28
When the effect
of birth weight was examined, a greater percentage of
146 S. Shankaran et al.
Page 4
children with soft signs were noted to have a birth weight
<1500 g. Of these children (n Z 110), more than two soft
signs were seen in 53% of cocaine-exposed and 27% of non-
cocaine-exposed children (OR 3.0; 95% CI 1.4e6.7), in 71%
of high-alcohol-exposed and 28% no or low-alcohol-exposed
children (OR 6.4; 2.5e16.6) and in 67% of children exposed
to alcohol binging and 36% who were not exposed to binging
(OR 3.6; 1.0e12.8). The effect of cocaine use and alcohol
use on soft neurological signs persisted after controlling
for other substance use, birth weight, site, infant sex
and race.
Current research suggests that although there are effects
of cocaine on child development, these effects are in-
consistent and subtle and need to be understood in the
context of polydrug use and the caregiving environment. At
1 month of age, the NICU Network Neurobehavioral Scale
demonstrated that cocaine exposure was related to lower
arousal, poorer quality of movement and self-regulation,
higher excitability, more hypertonia and more non-optimal
reflexes, with most effects maintained after adjustment
for covariates. This was also noted in the MLS study, in 658
exposed and 730 comparison infants matched for race, sex
and gestational age.
29
Some of the effects were associated
with heavy cocaine exposure but effects were also found for
opiates, alcohol, marijuana and birth weight. Acoustic cry
characteristics that reflect reactivity, respiratory and neu-
ral control of the cry sound were also compromised by pre-
natal drug exposure, including cocaine, opiates, alcohol and
marijuana; they were also affected by birth weight. Fewer
cry effects remained after adjustment for covariates.
Prenatal cocaine and/or opiate exposure also affects
neural transmission when examined on auditory brain re-
sponse at 1 month of age.
30
The MLS found that heavy pre-
natal cocaine exposure led to an increase in the IeIII, IeV
and IIIeV interpeak latencies and to a shorter latency to
peak I. Infants with prenatal opiate exposure showed a lon-
ger latency to peak V and a longer IIIeV interpeak latency.
The MLS measured the direct effects of prenatal cocaine
exposure and prenatal opiate exposure on infant mental
motor and behavioral outcomes. Outcomes were evaluated
longitudinally between 1 and 3 years of age.
31
The infants
were evaluated at 1, 2 and 3 years of age by the Bayley
Scales of Infant Development, which were administered to
1227 infants who had been exposed to cocaine (n Z 474),
opiates (n Z 50), cocaine plus opiates (n Z 48) and neither
substance (n Z 655). Overall, mental developmental index
points were 1.6 below in the cocaine-exposed infants
compared with infants who were not exposed to cocaine.
Opiate-exposed infants scored 3.8 psychomotor develop-
mental index points below infants who were not exposed
to opiates. Neither the cocaine nor the opiate effect re-
mained significant after controlling for covariates. Neither
the cocaine nor opiate exposure was associated with the
Bayley behavioral record score during the examination.
Low birth weight and indices of non-optimal caregiving
were associated with lower Mental Developmental Index
(MDI), Psychomotor Developmental Index (PDI) and behav-
ioral record scores among all groups of infants.
The MLS has also carried out the largest study to date
evaluating the effect of prenatal cocaine exposure on
childhood behavior problems. A total of 1056 children was
followed using the childhood behavior checklist at ages 3, 5
and 7.
32
Longitudinal, hierarchical, linear models were used
to determine the effects of prenatal cocaine exposure on
behavior-problem trajectories while controlling for other
prenatal exposures and for time-varying covariates (includ-
ing ongoing caretaker level of use of legal and illegal
substances, demographic factors, family violence and
caretaker psychological distress). After controlling for
confounders (including other drug use), the internalizing,
externalizing and total behavior-problem scores were
higher for high prenatal cocaine exposure than for some
or no cocaine use during pregnancy. Significant effects per-
sisted to age 7 years. Additional factors (including other
drug use) also had significant effects on childhood behavior
problems. Prenatal tobacco and alcohol exposure were sig-
nificantly associated with total behavior-problem trajecto-
ries until the age of 7, with a significant doseeresponse
relationship, i.e. higher behavior-problem scores were as-
sociated with a greater average number of cigarettes/day
and a greater average volume of alcohol/day. Moreover, on-
going tobacco and alcohol exposure significantly affected
externalizing and total behavior problems. Caretaker re-
port of physical or sexual abuse and caretaker depression
were significantly associated with all behavior problems.
Mediation analysis revealed that the child’s living situation
was a significant mediator for the relationship between pre-
natal cocaine exposure and behavior outcomes.
In another analysis of behavior problems, structural
equation modeling was used to describe developmental
pathways from birth to predict Child Behavior Check List
(CBLL) scores at age 7.
33
Prenatal drug exposure was related
to poor neurobehavioral scores at 1 month. The children
who showed poor neurobehavioral scores had a more diffi-
cult temperament at 4 months. Children with difficult tem-
perament had behavior problems on the CBCL at age 3 and
also at age 7. This model was able to explain 52% of the var-
iance in 7-year CBCL scores (all paths P < 0.05). The study of
developmental pathways might be particularly useful for
identifying ‘touch-points’ for intervention.
When evaluated up to 36 months in MLS, the attachment
status in children exposed prenatally to cocaine and other
substances showed that those children exposed to cocaine
and opiates were more likely to be insecurely attached.
The type of insecurity was more likely to be ambivalent
than avoidant.
34
Continued postnatal alcohol use was asso-
ciated with higher rates of insecurity and disorganization at
18dbut not 36dmonths of age. Stability of attachment
across the 18-month period was barely above chance ex-
pectation. Attachment status at 18 months was associated
with child temperament and caregiver child interaction;
at 36 months attachment was associated with child temper-
ament, child behavioral problems and the caregiver’s par-
enting and self-esteem.
In a longitudinal analysis of the trajectory of mental
development at ages 1, 2, 3, 4.5 and 7 years, the MLS
looked at 1270 subjects. After adjustment for covariates,
the effects of cocaine on IQ were 1.45 points up to age 3;
this increased to 4.4 points between 4.5 and 7 years of
age (P Z 0.003).
35
In addition, cocaine-exposed children
were more likely (OR Z 1.56; P Z 0.03) to be referred for
special education services in school than unexposed chil-
dren. It was estimated that the additional cost to society
for this cocaine effect alone is US$25,248,384 per year.
Impact of maternal substance use 147
Page 5
The fact that cocaine effects increased as children grew
older could reflect latent effects of the drug, which affect
later-emerging prefrontal cortical areas of the brain.
Opiates
In comparison with cocaine, marijuana, alcohol and to-
bacco abuse, opiate addiction during pregnancy is rare.
1
However, the introduction into the drug market of a smoke-
able form of cheap heroin that is more potent than crack
cocaine has led to a recent resurgence in use. The effects
of acute withdrawal to opiates by the fetus are well demon-
strated in the newborn infant. Physiological and neurobe-
havioral signs and symptoms are frequent and well
described by ‘the opiate abstinence syndrome’.
36e38
Heroin
and methadone are the most common opiates abused but
many new synthetic narcotics are becoming available to
the substance-abusing population.
Infants who acutely withdraw from narcotics exhibit
signs of dysregulation, such as sweating, hyperirritability,
posturing, hypertonity, jitteriness, exaggerated startle re-
sponse, tachycardia anddoccasionallydseizures. These
infants often have extended stays in hospital due to poor
feeding, slow weight gain, electrolyte disturbances, diarr-
hea and dehydration. Reports to child protective services
often result in the infants being removed from parental
care and placed in foster or adoptive care. No obvious
teratogenic impact has been consistently demonstrated in
infants of mothers who abused opiates during their preg-
nancy.
36e38
Long-term outcome studies are rare and, as in
most follow-up reports on substance-exposed infants, out-
come is confounded by multiple medical and psychosocial
factors that make the identification of a single drug effect
difficult. Effects such as low birth weight, prematurity,
growth retardation and perinatal depression have all been
reported in opiate-exposed newborns. However, low socio-
economic status, multiple drug use, lack of adequate and
early prenatal care and sexually transmitted diseases con-
found the potential opiate effects. Studies on the long-
term outcome of opiate exposure are relatively uncommon.
The MLS, which identified and enrolled over 11,000
pregnant women at delivery, identified drug exposure as
the confirmed use of cocaine and/or opiates during preg-
nancy. Of the 8600 with documented exposuredeither by
admission of use or by meconium analysis confirming drug
metabolitesdapproximately 100 were identified as isolated
users of opiates, with an equal number having used both
cocaine and opiates. This very large, prospective, multisite
study confirmed the findings of previous reports.
11
No clear
teratogenic effects were demonstrated in any opiate-
exposed infant. Transient, but dramatic, neurobehavioral
signs were present in the first week of life, primarily rela-
ted to the ANS and including increased irritability, jitteri-
ness, sweating, hiccupping, sneezing, poor suck and
exaggerated irritability. These infants required longer hos-
pital stays due to their withdrawal symptomatology, which
often required sedation medication, and also because of
sociolegal involvement in determining their placement.
The MLS has followed the majority of these exposed
infants and compared them with a matched control group
of non-drug-exposed infants. At 3 years of age, although
opiate-exposed infants (n Z 50) had lower psychomotor
developmental scores than those who were not exposed
to either cocaine or opiates (n Z 655), the effect was
no longer significant after controlling for covariates.
31
Cog-
nitive outcomes at age 10 show little difference between
opiate-exposed and non-exposed infants.
39
However, scores
on calculation subtest evaluation lagged behind those in
non-exposed children, even when adjusted for site, sex,
race and socioeconomic status. Of interest, the opiate-
exposed infants ranked higher in resilience, an important
social skill. There were no significant differences in growth
parameters; in fact, the opiate-exposed children had
a slightly higher height and slightly greater head circumfer-
ence than non-opiate-exposed children. There were also
no differences in medical diagnoses, blood pressure, hospi-
talizations, motor development or overall health status.
Although assessments of language processing and phonolog-
ical processing at age 9 similarly showed no consistent
significant effects, there was a trend for the opiate-
exposed children to score consistentlyd but not statistically
significantlydlower than controls in all domains except
their understanding of complex sentences (paragraph com-
prehension), which was significantly lower. This finding
could have implications for future learning capacity as tasks
become more complex and difficult. This weakness might
reflect reduced short-term memory and attention skills.
In summary, there were no dramatic findings in children
in their pre-adolescent years who were exposed in utero to
opiates; no medical, teratogenic or growth differences
were seen. A non-significant trend toward lower cognitive
performance and complex learning skills might reflect the
complex interaction of exposure and psychosocial environ-
mental factors. Follow-up into high school, college and
work might better reflect potential disparities that are
not yet obvious. It is encouraging that, despite their dramatic
presentations in the immediate newborn period, these
children grow into pre-adolescence as healthy, capable chil-
dren not obviously different from their non-drug-exposed
peers.
Statistical implications
The MLS is a prospective, observational study examining
long-term effects of prenatal cocaine exposure in a pre-
dominantly minority and low-socioeconomic-status popula-
tion. Analysis and interpretation of the MLS data therefore
present several statistical challenges, some of which are
briefly outlined below.
Covariate selection
The MLS collects a vast amount of information, over time,
from multiple sources (child, parent/caregiver, medical
charts, school records, etc.). The statistical challenge is to
tease apart the independent effect of prenatal cocaine
exposure in the presence of all the other factors that need
to be accounted for. As there are usually too many variables
to adjust for in this observational cohort study (where
covariate imbalances are expected), methodologically
sound a priori covariate selection strategies
32,40
are
essential.
148 S. Shankaran et al.
Page 6
A related complexity is the issue of factors that might be
considered to be in the causal pathway from prenatal
cocaine exposure to long-term outcomes. This problem is
especially acute for ongoing changes in the home environ-
ment because of near-complete confounding between pre-
natal cocaine exposure and out-of-home placement for
children in the MLS. In recent articles,
32
the MLS investiga-
tors have used the mediation framework to account for
such factors in analyses.
Inter-related outcomes
At each assessment, the MLS collects information on several
outcomes from each child in the study. Frequently, such
outcomes are correlated and might purport to measure the
same underlying condition or construct. To boost statistical
efficiency, statistical analyses should reflect these aspects
and also allow for the outcome-specific cocaine-exposure
effects that are of interest. Individual analyses for each
outcome ignore correlations among multiple outcomes, thus
producing imprecise effect estimates. Multiple comparisons
are another problem with individual analyses, because
performing several tests on the data inflates the type I error
to unacceptable levels. Thus, MLS investigators have adop-
ted a multivariate modeling approach to analyze multiple
outcomes by borrowing from statistical methods for longitu-
dinal and repeated measures data to simultaneously model
all the outcomes assessed on an individual.
40,41
Missing data
Missing data are the challenge of longitudinal studies and
the MLS is no exception. Ordinary analyses, which simply
ignore the missing information, can give biased results.
Statistical methods for missing data (under certain assump-
tions) include imputations (where the missing data are
estimated) and analytic methods, such as maximum likeli-
hood estimation, which do not require complete outcome
data to produce valid inferences. Thus, MLS investigators
have utilized likelihood-based methods (as opposed to
generalized estimating equations) such as Hierarchical
Linear Modeling (HLM) for longitudinal analyses. However,
although this affords protection against missing outcomes,
missing covariates still pose a problem. In certain analy-
ses,
32
MLS investigators used multiple imputation, in which
a set of values drawn from the predictive distribution of the
missing values is imputed for each missing value, as imple-
mented in the sequential regression imputation method
(SRIM)
42
to impute missing values for selected covariates.
Conclusions
Maternal substance use has been demonstrated to be
related to an increase in maternal pregnancy complica-
tions, more sexually transmitted disorders and increases in
abruptio placenta and in HIV-positive status. Effects on the
infant include decreased birth weight, birth length and
head circumference; increased neonatal CNS and ANS signs
and an increase in referrals to child protective agencies.
Patterns of substance use during pregnancy impact on fetal
growth. Healthcare resource utilization is increased among
infants weighing >1500 g at birth. In childhood, behavioral
and cognitive effects are seen after prenatal cocaine ex-
posure; prenatal tobacco and alcohol have separate and
specific effects. Ongoing caretaker use of alcohol and to-
bacco affects childhood behavior. IUGR status at birth im-
pacts on the risk of hypertension in childhood. It is also
clear that substance use during pregnancy has physical
and mental health implications beyond childhood. Although
the behavioral and cognitive effects are subtle and not as
large as expected, they are likely to impact on how the ad-
olescent will function in society. Treatment for mental
health and special education needs poses a financial bur-
den, hence it is imperative that efforts are made for the
prevention and early treatment of behavioral problems of
drug use by adolescent children born to women who used
drugs during pregnancy.
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  • Source
    • "). Drug or alcohol use during pregnancy can have a negative impact medically and socially on both the mother and newborn (Shankaran et al., 2007; Terplan & Wright, 2011). Integrated treatment during pregnancy as well as early intervention for the newborn can ameliorate these negative effects (Meyer et al., 2012; Niccols et al., 2012; Peadon, Rhys-Jones, Bower, & Elliott, 2009). "
    [Show abstract] [Hide abstract] ABSTRACT: Recent amendments to the Child Abuse Prevention and Treatment Act tie the receipt of federal block grants to mandatory reporting of substance-exposed newborns. To determine rates of screening, testing, and reporting of drug and alcohol use at the time of delivery, we administered a telephone survey of nursing managers and perinatal social workers at Maryland birthing hospitals. Of the 34 hospitals, 31 responded (response rate 91%). Although 97% of hospitals reported universal screening, only 6% used a validated instrument. Testing was reported by 94% with 45% reporting universal maternal testing and 7% universal newborn testing. Only 32% reported obtaining maternal consent prior to testing. There is significant heterogeneity in screening and testing for substance use in birthing hospitals. Given federal reporting mandates, state-level practices need to be standardized.
    Full-text · Article · Aug 2014 · Social Work in Health Care
  • Source
    • "Drug use by pregnant women can have transplacental effects or cause maternal ill-health or altered behavior. The manifestations may be acute -neonatal abstinence syndrome from opiate withdrawal, for example [109] – or lead to longer-term behavioral and cognitive changes [110]. Both drugs and alcohol are closely associated with mental illness in the user, which, in turn, can have detrimental effects on parenting ability and employment. "
    [Show abstract] [Hide abstract] ABSTRACT: The short- and medium-term effects of conflict on population health are reasonably well documented. Less considered are its consequences across generations and potential harms to the health of children yet to be born. Looking first at the nature and effects of exposures during conflict, and then at the potential routes through which harm may propagate within families, we consider the intergenerational effects of four features of conflict: violence, challenges to mental health, infection and malnutrition. Conflict-driven harms are transmitted through a complex permissive environment that includes biological, cultural and economic factors, and feedback loops between sources of harm and weaknesses in individual and societal resilience to them. We discuss the multiplicative effects of ongoing conflict when hostilities are prolonged. We summarize many instances in which the effects of war can propagate across generations. We hope that the evidence laid out in the article will stimulate research and - more importantly - contribute to the discussion of the costs of war; particularly in the longer-term in post-conflict situations in which interventions need to be sustained and adapted over many years.
    Full-text · Article · Apr 2014 · BMC Medicine
  • Source
    • "The epidemic of cocaine use [Elliot and Coker, 1991] has raised significant public attention to adolescents prenatally exposed to cocaine [Derauf et al., 2009; Frank et al., 2001; Lester and Padbury, 2009; Shankaran et al., 2007]. functioning, impulse control and attention, and evidence of internalizing and externalizing behavioral traits [Derauf et al., 2009; Frank et al., 2001; Lester and Padbury, 2009; Shankaran et al., 2007]. In general, PCE affected brains are characterized with widespread structural [Avants et al., 2007; Cohen et al., 1994; Dixon and Bejar, 1989; DowEdwards et al., 2006; Gieron-Korthals et al., 1994; GomezAnson et al., 1994; Heier et al., 1991; Kliegman et al.,1994; Rivkin et al., 2008; Warner et al., 2006] and functional alterations [Cortese et al., 2006; Dow-Edwards et al., 2006; Emmalee et al., 2002; Hurt et al., 2008; Li et al., 2009b; Miller-Loncar et al., 2005; Rose-Jacobs et al.., 2009; Sheinkopf et al., 2009; Volpe, 1987] , caused by decreased number of neurons [Lidow and Song, 2001a,b], cocaine's vasoconstrictive effects [Bassett and Hanson, 1998; Jensen et al., 1987; Koegler et al., 1991; Lipton et al., 2002; Volpe, 1987; Woods et al., 1987] , and/or alterations in the monoaminergic neurotransmitter systems [Levitt et al., 1997; Lidow and Song, 2001a,b; Malanga and Kosofsky, 1999; Meier et al., 1991]. "
    [Show abstract] [Hide abstract] ABSTRACT: Recent in vivo neuroimaging studies revealed that several brain networks are altered in prenatal cocaine exposure (PCE) affected adolescent brains. However, due to a lack of dense and corresponding cortical landmarks across individuals, the systematical alterations of functional connectivities in large-scale brain networks and the alteration of structural brain architecture in PCE affected brain are largely unknown. In this article, we adopted a newly developed data-driven strategy to build a large set of cortical landmarks that are consistent and corresponding across PCE adolescents and their matched controls. Based on these landmarks, we constructed large-scale functional connectomes and applied the well-established approaches of deriving genomics signatures in genome-wide gene expression studies to discover functional connectomics signatures for the characterization of PCE adolescent brains. Results derived from experimental data demonstrated that 10 structurally disrupted landmarks were identified in PCE, and more importantly, the discovered informative functional connectomics signatures among consistent landmarks distinctively differentiate PCE brains from their matched controls. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.
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