Prenatal cannabis use linked to sevenfold higher risk of fetal death in longitudinal study | Research

The takeaway

In a longitudinal study of 894 pregnant individuals, cannabis use during pregnancy was associated with a sevenfold increased risk of fetal death, even after adjusting for other risk factors.

Obstetricians, maternal-fetal medicine specialists, pregnant individuals, and public health professionals

Sevenfold increased fetal death risk (OR 7.30)

What the researchers found

Among 894 pregnant individuals followed in a longitudinal study, 13.1% used cannabis. Cannabis users had a sevenfold increased risk of fetal death (OR 7.30) that persisted after adjusting for confounders (aOR 6.31). Adjusted models also suggested increased low birth weight risk (aOR 1.67).

Why it matters

The association between prenatal cannabis use and fetal death is a serious finding that adds to growing concerns about cannabis safety during pregnancy, particularly as cannabis use among pregnant people increases.

The numbers in context

894 participants; 13.1% used cannabis; sevenfold increased fetal death risk (OR 7.30); adjusted OR 6.31; adjusted low birth weight risk aOR 1.67; cannabis users were younger on average (25.9 vs 27.9 years)

How the study worked

Secondary data analysis of the Stress in Pregnancy longitudinal study (2009-2013), using interviews and electronic medical record reviews to determine cannabis use status among 894 pregnant individuals and evaluate associations with perinatal outcomes.

What this study cannot tell us

Observational design cannot prove causation; relatively small number of fetal death events may produce unstable estimates; data from 2009-2013 may not reflect current cannabis potency or use patterns; potential unmeasured confounders

How to read the evidence

Longitudinal observational study with confounder adjustment, but relatively small event counts for rare outcomes like fetal death.

When this study was published

2024 publication analyzing data from 2009-2013

The bigger picture

As cannabis legalization expands and harm perceptions decline, data on pregnancy outcomes becomes increasingly important for informing clinical guidance and public health messaging.

Questions still open

What biological mechanisms could explain this association? Does the timing, frequency, or potency of cannabis use during pregnancy modify the risk?

Common questions

How strong was the link between prenatal cannabis use and fetal death?

Cannabis users had seven times the risk of fetal death compared to non-users (OR 7.30). After adjusting for potential confounders, the risk remained over six times higher (adjusted OR 6.31). However, as an observational study, this shows an association rather than proof of causation.

Were there other pregnancy risks associated with cannabis use?

In addition to fetal death, adjusted models suggested cannabis users had a 67% higher risk of low birth weight (adjusted OR 1.67). Cannabis-using mothers were also younger on average than non-users.

Read the original research

The longitudinal assessment of prenatal cannabis use on neonatal outcomes.

Journal of perinatology : official journal of the California Perinatal Association, 44(8), 1152-1156

View on PubMed ↗Publisher’s paper ↗

Citation

Habersham, Leah L; Hurd, Yasmin L; Nomura, Yoko. (2024). The longitudinal assessment of prenatal cannabis use on neonatal outcomes.. Journal of perinatology : official journal of the California Perinatal Association, 44(8), 1152-1156. https://doi.org/10.1038/s41372-024-02027-w