Transient hyperthyroidism and hyperemesis gravidarum: clinical aspects.

OBJECTIVES

Our objectives were to describe the presentation and course of hyperemesis gravidarum with respect to thyroid function and to test the hypothesis that patients with biochemical hyperthyroidism differ in clinical presentation from euthyroid hyperemesis patients.

STUDY DESIGN

Sixty-seven patients seen at Los Angeles County Women's Hospital over a 10-month period with hyperemesis gravidarum were studied prospectively with respect to thyroid function.

RESULTS

Forty-four patients (66%) had biochemical hyperthyroidism (increased free thyroxine index [n = 39] or suppressed thyroid-stimulating hormone [n = 40]) that was self-limited, resolving by 18 weeks' gestation. Hyperthyroid patients were more likely than euthyroid patients to have abnormal electrolyte levels (23/39 [59%] vs 6/28 [21%] and increased liver enzyme levels (23/59 [59%] vs 5/28 [18%], p less than 0.01). The severity of hyperemesis was found to vary directly with the degree of hyperthyroidism.

CONCLUSIONS

Hyperthyroidism is a common, self-limited finding in hyperemesis. The cause of the hyperthyroidism may be linked to the cause of hyperemesis itself.