A longitudinal study of 247 mothers and children found that prenatal tobacco exposure produced stronger behavioral effects in girls than boys, and discovered a bidirectional relationship where toddler behavior problems at age 2 predicted increased maternal cannabis use a year later.
Read this if you are interested in how prenatal substance exposure affects child development differently by sex, or how child behavior can influence parental substance use.
Behavior problems at age 2 predicted increased maternal cannabis use a year later
What the researchers found
Researchers followed 247 low-income mothers and their children from pregnancy through age 3, tracking prenatal substance exposure and child behavior problems.
Prenatal tobacco exposure showed stronger effects in girls: girls in the tobacco-exposed group had higher internalizing problems, anxiety/depression, and attention problems compared to other groups. The association between cigarettes per day during pregnancy and behavioral problems at age 3 was stronger for girls than boys.
A particularly striking finding was a bidirectional relationship between maternal cannabis use and child behavior. Higher maternal cannabis use during the infant-toddler period predicted higher behavior problems at age 2. But the relationship went both ways: those behavior problems at age 2 then predicted higher maternal cannabis use a year later, suggesting a feedback loop.
The joint effects of tobacco and cannabis exposure did not consistently produce worse outcomes than tobacco alone.
Why it matters
The bidirectional finding is clinically important: not only does maternal substance use affect child behavior, but difficult child behavior may drive increased maternal substance use, creating a cycle that could escalate without intervention targeting both the parent and child.
The numbers in context
247 mother-child pairs. Three groups: tobacco + cannabis (97), tobacco only (81), control (69). Assessments at each trimester and 5 postnatal timepoints through age 3. Girls showed stronger effects than boys for prenatal tobacco exposure.
How the study worked
Longitudinal cohort study of 247 mothers and children (97 prenatal tobacco + cannabis, 81 tobacco only, 69 non-exposed). Assessed during each trimester and at 2, 9, 16 months, 2 years, and 3 years. Primarily young, unmarried, low-income, minority participants.
What this study cannot tell us
Sample was primarily low-income, young, and minority, limiting generalizability. The three groups (tobacco+cannabis, tobacco only, control) could not fully separate individual substance effects. Cannabis use was self-reported. The sample size limited statistical power for detecting smaller effects and interaction terms.
How to read the evidence
This longitudinal cohort with multiple assessment points provides moderate evidence, limited by relatively small sample size and specific demographic characteristics.
When this study was published
Published in 2018. Research on prenatal substance exposure and child development continues to expand.
The bigger picture
This study is one of few to examine the bidirectional relationship between maternal substance use and child behavior over time. The finding that child behavior problems predict subsequent increases in maternal cannabis use highlights the importance of family-level interventions rather than focusing solely on maternal behavior.
Questions still open
- Does the bidirectional cycle between child behavior problems and maternal cannabis use continue beyond age 3? Would early intervention targeting difficult toddler behavior reduce subsequent maternal substance use? Are the sex-differential effects of prenatal tobacco exposure replicated in larger samples?
Common questions
Were the effects of prenatal exposure the same for boys and girls?
What was the bidirectional finding?
Read the original research
Pre- and postnatal tobacco and cannabis exposure and child behavior problems: Bidirectional associations, joint effects, and sex differences.
Drug and alcohol dependence, 185, 82-92
Citation
Eiden, Rina D; Zhao, Junru; Casey, Meghan; Shisler, Shannon; Schuetze, Pamela; Colder, Craig R. (2018). Pre- and postnatal tobacco and cannabis exposure and child behavior problems: Bidirectional associations, joint effects, and sex differences.. Drug and alcohol dependence, 185, 82-92. https://doi.org/10.1016/j.drugalcdep.2017.11.038
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