U.S. Study Confirms Link Between Hyperemesis Gravidarum, Adverse Pregnancy Outcomes

WEDNESDAY, July 8, 2026 (HealthDay News) — Hyperemesis gravidarum (HG) is associated with an increased risk for adverse pregnancy outcomes (APOs), according to a study based on U.S. data published online June 16 in the American Journal of Epidemiology.

Rebecca M. Gardner, from Stanford University in California, and colleagues examined the association between HG and APOs in a U.S. population-based cohort of 2.5 million singleton live births in California (2007 to 2011). HG was defined based on primary diagnosis codes present in prenatal hospitalization or emergency department records (53,681 cases; 2.2 percent).

The researchers found that HG was associated with higher risks for preeclampsia, gestational hypertension, preterm birth, small for gestational age, placental abruption, and anemia after adjustment for confounders (adjusted relative risks, 1.18, 1.15, 1.25, 1.19, 1.14, and 1.37, respectively). In general, risks were higher among women with first HG hospitalization in the second trimester (e.g., adjusted relative risk, 1.41 for preeclampsia); across nearly all strata examined, risks were elevated.

“We found HG was linked to higher risk for preterm birth, anemia, smaller-than-expected babies, preeclampsia, gestational hypertension, and placental abruption,” Gardner said in a statement. “Hospitalization for HG really does flag a pregnancy as being at higher risk for a range of serious complications.”

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