Evaluation of the vestibular system with video head impulse test in pregnant women with hyperemesis gravidarum.

Aim: We aimed to evaluate the semicircular canal functions of the vestibular system in pregnant women with hyperemesis gravidarum.

Methods: This is a prospective case-control study. Among pregnant women in their first trimester (<14. gestational weeks) who presented to our outpatient clinic, 36 patients diagnosed with hyperemesis gravidarum defined as persistent nausea and vomiting requiring intravenous hydration or loss of at least 5% of prepregnancy weight and 34 healthy pregnant without nausea and vomiting were included. Otorhinolaryngologic examination and video head impulse test (vHIT) was performed to all patients. Vestibular-ocular reflex (VOR) gain and gain asymmetry were assessed between groups.

Results: The VOR gains in each semicircular canal did not differ between hyperemesis and control groups. Using a VOR gain cut-off value of 0.8, the groups were compared in terms of the frequency of low values. In the hyperemesis group, abnormally low gain values of left anterior canal were more frequently observed than in the control group (32 [88.9%], 22 [64.7%], respectively, P = 0.01). In left anterior-right posterior (LARP) plane VOR gain asymmetry was higher in hyperemesis group (13.5 [1.0-71.0], 6.0 [0.0-35.0], P = 0.001). No significant gain asymmetry was detected between the groups in the other planes.

Conclusion: Semicircular canal functions were not abnormal globally in women with hyperemesis gravidarum. However, higher LARP plane asymmetry and low LA gain in women with hyperemesis suggests need for further research to clarify functional role of vestibular system on hyperemesis gravidarum.