(A813) Dynamic Modulation of Semicircular Canal Function During Late Pregnancy and Postpartum Recovery: A Longitudinal Study

Introduction: While pregnancy induces significant physiological changes, its specific impact on vestibular function across different semicircular canals remains under-explored. This study explores the modulation of vestibulo-ocular reflex (VOR) gains in the semicircular canals during late pregnancy and the postpartum period.

Methods: Three pregnant patients (age range: 20-34 years-old) underwent VOR gain assessments of the lateral, anterior, and posterior semicircular canals using video head impulse test (vHIT). Measurements were conducted during late pregnancy (>35 weeks) and the postpartum period, which was further divided into early (first 3 weeks) and late phases (1-3 months post-partum).

Results: During pregnancy the lateral canal VOR gains showed a consistent increase, peaking 1.2-1.8 above baseline by late gestation. In the early post-partum phase the lateral canal VOR gains (1.0 -1.15) declined significantly (p>0.05) from peak pregnancy levels but remained slightly above baseline. In the late postpartum phase, the lateral canal VOR gains continued to decrease and normalized to baseline levels by three months post-partum. Anterior and posterior canal gains remained stable throughout all the different stages.

Conclusions: Lateral semicircular canal function exhibits dynamic modulation during late pregnancy, peaking near term, and progressively settles in the post-partum period. In contrast, anterior and posterior canal functions remain unaffected, suggesting a canal-specific response to the physiological demands of pregnancy and post-partum recovery. Further studies with a larger sample size need to be conducted to validate these findings.