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Study breakdown

Cannabinoid Hyperemesis Syndrome Caused Severe Vomiting Mistaken for Morning Sickness

Case ReportPreliminary evidence
The takeaway

Two pregnant women had repeated hospitalizations for severe vomiting that was ultimately traced to cannabinoid hyperemesis syndrome, with symptoms resolving after cannabis cessation.

OB-GYN providers, emergency physicians, pregnant cannabis users

What the researchers found

Two cases of CHS in pregnancy were described. Case 1: a woman with vomiting episodes at weeks 5, 14, and 30 of gestation; the link to hot bathing for relief led to CHS diagnosis. Symptoms resolved with cannabis cessation; healthy baby born at 38+5 weeks. Case 2: vomiting at weeks 16 and 18; 14+ year cannabis use history disclosed after hot bathing pattern identified. Symptoms resolved with cessation; baby born at 37 weeks with low birth weight (2180g) requiring 5 days in NICU. No relapse at 5 months postpartum with sustained cessation.

Why it matters

CHS in pregnancy is likely underdiagnosed because severe nausea and vomiting are expected symptoms of pregnancy. When anti-emetic treatments fail, the hot bathing clue should prompt inquiry about cannabis use. Misdiagnosis leads to repeated hospitalizations and delays appropriate management.

The numbers in context

Only 11 prior CHS-in-pregnancy cases reported in literature; Case 1: symptoms at weeks 5, 14, 30, resolved with cessation, healthy delivery at 38+5 weeks; Case 2: 14+ years cannabis use, low birth weight baby (2180g), 5 days NICU

How the study worked

Case series of two pregnant women diagnosed with cannabinoid hyperemesis syndrome, with clinical workup, treatment course, and outcomes documented through delivery and postpartum follow-up.

What this study cannot tell us

Case series of only two patients. Cannot establish prevalence. Case 2 had confounding factors (14+ years of heavy cannabis use, low birth weight may have multiple causes). No standardized CHS diagnostic criteria applied.

How to read the evidence

Preliminary: case series of two patients, contributing to a very small literature on this topic.

When this study was published

2025 publication

The bigger picture

As cannabis use during pregnancy increases (6-10% by recent estimates), CHS cases in pregnancy will likely rise. The condition is easily missed when clinicians attribute all vomiting to typical pregnancy-related nausea.

Questions still open

  • How many cases of pregnancy hyperemesis are actually undiagnosed CHS?
  • Should routine prenatal intake include specific CHS screening questions?

Read the original research

Cannabinoid hyperemesis syndrome in pregnancy: a case series and review.

Obstetric medicine, 18(4), 264-271

Citation

Hanley, Sarah; Imcha, Mendinaro; Mohamad, Mas Mahady. (2025). Cannabinoid hyperemesis syndrome in pregnancy: a case series and review.. Obstetric medicine, 18(4), 264-271. https://doi.org/10.1177/1753495X241307415

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