Objective-The vestibular system is a major pathway to nausea and vomiting, and the vestibuloocular reflex (VOR) is a central component; its function can be studied using the vestibular autorotation test (VAT). We hypothesize that women with hyperemesis gravidarum (HG) may have VOR abnormalities.Study Design-Women with HG were compared to women without HG using the VAT. Horizontal and vertical VOR gains and phases were evaluated at three frequency ranges: low (2.0-3.5 Hz), medium (>3.5 -5.0 Hz), and high (>5.0 -6.0 Hz) during pregnancy and postpartum.Results-Twenty women with HG and 48 unaffected women were evaluated in early pregnancy. Women with HG had higher horizontal gains at all three frequency ranges. Horizontal phase differences were also observed at medium frequencies. No VAT differences were noted postpartum.Conclusions-Women experiencing HG had a higher mean VOR horizontal gain and lower horizontal phase when compared to unaffected women.