Changes in Diabetes Insipidus During Pregnancy and Lactation

A patient with diabetes insipidus repeatedly demonstrated an increase in the requirement for vasopressin during pregnancy, a decrease during lactation, and a less striking increase during the latter part of the menstrual cycle. Results of water deprivation tests on this patient suggested that endogenous antidiuretic hormone was released during lactation. Intravenous infusions of small doses of vasopressin had a pronounced antidiuretic effect on the third and twenty-eighth days of the menstrual cycle, a distinctly smaller effect during pregnancy, and a possibly smaller effect on the eighteenth day of the menstrual cycle.