Autonomic and Enteric Nervous System Dysfunction May Play a Role in Hyperemesis Gravidarum.

Background: Nausea and vomiting, seen in 70-85% of all pregnancies, becomes intractable in hyperemesis gravidarum (HG). We aimed to investigate the relationship between HG and autonomic nervous system functioning and gastric electrical activity.

Methods: Twenty-seven pregnant patients, 21 with HG and six normal, were studied with sympathetic adrenergic; percent vasoconstriction (%VC) and postural adjustment ratio (PAR); parasympathetic vagal cholinergic functions by R-to-R intervals (RRIs), a total autonomic score; and enteric nervous system measured by electrogastrography (EGG).

Results: Significant differences were found in parasympathetic measures (RRI for HG 29.98 ± 2.95 vs. control 40.91 ± 2.38, P < 0.05); sympathetic PAR was significantly lower in patients (PAR for HG 24.5 ± 5.0 vs. 67.6 ± 11.4 for controls, P < 0.01); mean total autonomic score was significantly lower in HG (131.75 ± 9.61 vs. 196.87 ± 12.8, P < 0.05). EGG results were borderline different (normal < 3.3, HG 3.4 vs. controls 3.0, P = 0.07).

Conclusion: Autonomic and enteric nervous system dysfunction may play a role in the pathophysiology of HG.