Prenatal Cannabis Use Increases Risk for Preeclampsia, Gestational Hypertension

Prenatal cannabis use is associated with adverse maternal health outcomes, including increased risks for gestational hypertension, preeclampsia, gestational weight gain, and placental abruption. These study results were published in JAMA Internal Medicine.

Although ample research has evaluated the effect of prenatal cannabis exposure on fetal health outcomes, the relationship between prenatal cannabis use and maternal health remains poorly understood due to reliance on self-reported data and confounding variables.

Therefore, researchers conducted a large retrospective cohort study using data collected between 2011 and 2019 from Kaiser Permanente Northern California members to investigate the relationship between prenatal cannabis use and health outcomes among pregnant individuals. The outcomes of interest included metabolic outcomes (ie, gestational hypertension, preeclampsia, and eclampsia), placenta outcomes (ie, placenta previa and placental abruption), and severe maternal morbidity. The researchers identified individuals with singleton pregnancies of 20 weeks or more who attended at least 1 prenatal visit, self-reported prenatal cannabis use, and had available tetrahydrocannabinol urine test results between 8 to 10 weeks of gestation. The researchers also evaluated demographics, parity, comorbidities, insurance, neighborhood deprivation, and prenatal care timing as potential covariates.

A total of 250,221 individuals (mean age [SD]=30.6 [5.4] years) comprising 316,722 pregnancies were included in the current analysis. Among them, 20,053 individuals (6.3%) tested positive for prenatal cannabis use, as 2.9% of pregnant individuals self-reported cannabis use, 5.3% tested positive through toxicology screening, and 1.8% exhibited positive results via both methods. Of those who had prenatal cannabis use, 0.6% (n=1930) reported daily use, 0.7% (n=2345) used weekly, 1.5% (n=4892) consumed it monthly or less, and 3.4% (n=10,886) had unknown usage patterns.

The researchers found that prenatal cannabis use was significantly associated with a higher risk for gestational hypertension (adjusted risk ratio [aRR], 1.17; 95%CI,

1.13-1.21), preeclampsia (aRR, 1.08; 95% CI, 1.01-1.15), and placental abruption (aRR, 1.19; 95% CI, 1.05-1.36). Prenatal cannabis use was also linked to gestational weight gain both below (aRR, 1.05; 95% CI, 1.01-1.08) and above (aRR, 1.09; 95% CI, 1.08-1.10) recommended guidelines. However, cannabis use was not significantly associated with eclampsia, placenta previa, placenta accrete, or severe maternal morbidity.

The researchers also observed a dose-response relationship between prenatal cannabis use and maternal health outcomes. For gestational hypertension, daily cannabis use presented the highest risk (aRR, 1.24; 95% CI, 1.14-1.36), followed by weekly (aRR, 1.21; 95% CI, 1.11-1.31) and monthly use (aRR, 1.03; 95% CI, 0.97-1.10). Sensitivity analyses supported these findings, indicating stronger associations with toxicology tests compared to self-reported data.

“The findings suggest a complex association between prenatal cannabis use and maternal health and highlight the need for continued research to understand the mechanisms through which prenatal cannabis use is associated with the health of pregnant individuals,” the researchers concluded.

These study findings may be limited, as the sample consistently only of insured pregnant patients in Northern California and the researchers did not evaluate factors like mode of cannabis use, timing of cannabis use, or potency of cannabis ingested.

This article originally appeared on Psychiatry Advisor