A Case of Central Diabetes Insipidus: Evaluation in Pregnancy

A 20 years old woman, admitted in our Centre at the 6th week of pregnancy, was affected by Central Diabetes Insipidus and since the age of 10 years old she assumed desmopressin at a dose of 30 mg/nostril/day. She was primigravida, with normal past medical history. Fasting blood levels were normal; specific gravity of the urine: 1006; no glucosuria or proteinuria was present. Urinary and plasma osmolality were 245 and 287 mOsm/l; water intake about 2700 mL/day; diuresis 2000 mL/day. On the basis of the value of urine output and osmolality the dose of desmopressin was increased at 40 mg/nostril/day. Patient was evaluated every month with fluid balance, urine volume, osmolality, and serum electrolytes. Daily dosage of desmopressin was 40 mg/nostril for all the duration of pregnancy according to a trend of an adequate fluid and electrolytes balance and in absence of symptoms. Mean blood Pressure was 100/60 mmHg; coagulation, liver, renal function were normal. Fetal monitoring with periodic ultrasound detected a normal intrauterine growth. Patient had an uncomplicated labor of a healthy male baby at the 39th week. Because of an insufficient dilatation of the cervical canal caesarian section was chosen. Despite a previous Central Diabetes Insipidus may worsen in a pregnant with impaired reserve of Antidiuretic Hormone because of the changes in osmoregulatory system and increased levels of vasopressinasis in middle and late pregnancy, our patient required a slightly higher dose of desmopressin in the first trimester. Contrary to expectations the need of desmopressin did not increase during the weeks.