Hypothetical framework for a relationship between maternal thyroid function, nausea and vomiting of pregnancy, and congenital heart disease.

Our objective was to investigate whether a relationship exists among maternal thyroid function, nausea and vomiting of pregnancy, and congenital heart disease. A Medline search from 1966 to the present was conducted to look for reports on the existence of this relationship. The results were supplemented by abstract searches and personal communication with relevant authors. Our search found independent evidence that maternal hyperthyroidism is related to increased rates of nausea and vomiting of pregnancy, which in turn is significantly related to a decrease in the incidence of congenital heart disease. Early evidence indicates that the converse may be true: maternal hypothyroidism and thyroid replacement therapy are associated with an increase in congenital heart disease in children. The potential relationship between maternal thyroid function, nausea and vomiting of pregnancy, and thyroid replacement therapy needs further study. We propose a case-control study of children presenting for echocardiography to elicit specific information regarding the pregnancy.