Prenatal cannabis and nicotine use linked to adverse pregnancy outcomes

The risks of maternal and neonatal morbidity, as well as infant and neonatal death, are increased by co-occurring maternal cannabis and nicotine use during pregnancy, according to a recent study in JAMA Network Open.¹

Takeaways

Combining cannabis and nicotine during pregnancy elevates the risks of adverse outcomes for both mothers and babies, including preterm delivery, hypertensive disease, and severe maternal morbidity.
Mothers who use both cannabis and nicotine during pregnancy have a significantly higher infant death rate compared to controls, underscoring the seriousness of combined substance exposure.
Neonates exposed to both substances are at an elevated risk of adverse health outcomes, such as NICU admission, respiratory distress syndrome, and hypoglycemia, highlighting the importance of addressing prenatal substance use.
There are demographic differences among substance users, with combined users more likely to be White and have public or no insurance, suggesting potential socioeconomic and cultural factors at play.
The study underscores the necessity for additional research to fully understand the short- and long-term impacts of prenatal cannabis and nicotine exposure on maternal and neonatal health outcomes.

In the United States, prenatal cannabis rates have reached up to 30% among younger, urban populations. Since Δ9-tetrahydrocannabinol can cross the placenta, concerns have arisen about associated adverse pregnancy outcomes.

Pregnant women are at increased vulnerability for cannabis use, with 23% of pregnant or postpartum women who used cannabis reporting daily exposure.² Additionally, 66% of pregnant or postpartum cannabis users had cannabis use disorder.

Notably, prenatal cannabis use has increased over time, with tobacco and nicotine product use co-occurring among half of patients who use cannabis during pregnancy.¹ However, data about outcomes following combined prenatal use of cannabis and nicotine during pregnancy is lacking.

To determine outcomes following combined prenatal exposure to cannabis and nicotine, investigators conducted a retrospective, population-based cohort study. Vital statistics were obtained from the California Department of Public Health and discharge data from Health Care Access and Information.

Participants included pregnant individuals with a singleton pregnancy at 23 to 42 weeks’ gestation. Individuals with multiple births, gestational age under 23 or over 42 weeks, and self-reporting more than 1 race were excluded.

Cannabis and nicotine product use were the primary exposures of the analysis, reported using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM codes. Cohorts included control, cannabis use, nicotine use, and combined cannabis and nicotine use.

Additional maternal characteristics obtained included maternal age, race and ethnicity, parity, insurance, educational attainment, and prepregnancy body mass index. Comborbidities included alcohol-related use disorder, mental health disorders, chronic hypertension, and preexisting diabetes.

ICD-9-CM and ICD-10-CM codes were used to determine adverse outcomes. These included hypertensive disease, preterm and very preterm delivery, severe maternal morbidity (SMM), infant death, neonatal death, postneonatal death, neonatal intensive care unit (NICU) admission, hypoglycemia, small for gestational age, respiratory distress syndrome, and bronchopulmonary dysplasia.

There were 3,129,259 pregnant individuals included in the final analysis, 52.9% of whom were Hispanic, 28.5% White, 13.1% Asian or Pacific Islander, 5.2% Black, and 0.3% Alaska Native. Cannabis use was reported in 0.7% of participants, nicotine in 1.8% and combined cannabis and nicotine in 0.3%.

Patients using cannabis and nicotine were more often White, had public or no insurance, and had under 5 prenatal visits during their pregnancy. Hypertensive disease was reported in 12.3%, 9.6%, 11.2%, and 7.6% of cannabis-users, nicotine-users, users of both, and controls, respectively.

Preterm delivery rates were also increased among cannabis-users, nicotine-users, and users of both vs controls, with adjusted risk ratios (ARRs) of 1.47, 1.48, and 1.83, respectively. Similar patterns were reported for very preterm delivery. For SMM, the ARRs were 1.33, 1.42, and 1.46, respectively.

Combined cannabis and nicotine users had an infant death rate of 1.2%, which was 4 times higher than the death rate of 0.3% among controls. In comparison, a rate of 0.7% was reported for users of either cannabis or nicotine products.

For neonatal death, rates among users of both, either, and controls were 0.6%, 0.3%, and 0.2%, respectively. Similar results were reported for postneonatal death. When evaluating NICU admission risk vs controls, the ARRs were 1.78 for combined users, 1.56 for nicotine users, and 1.33 for cannabis users.

The ARR for small for gestational age among combined users vs controls was 1.94, indicating a nearly 2-fold increased risk. Rates for combined users, cannabis users, and nicotine users were 18%, 14.3%, and 13.7%, respectively. Similar patterns were reported for respiratory distress syndrome, hypoglycemia, and bronchopulmonary dysplasia.

These results indicated increased rates of adverse maternal and neonatal outcomes from combined cannabis and nicotine exposure during pregnancy.Investigators recommended further studies to characterize the impact of prenatal cannabis and nicotine exposure on short- and long-term outcomes.