Objective To investigate the clinical feature,treatment and prognosis of both themother and the fetus with gestational diabetes insipidus.Methods A total of 7 cases of gestational diabetes insipidus collected in the First Affiliated Hospital of Wenzhou Medical College,Wen'zhou Combination ofTraditional Chinese Medicine with Western Medicine Hospital,and Zhejiang Taizhou Hospital from June 1993to June 2006 were analyzed retrospectively.Resuits Seven cases symptoms all characterized by excessive thirst polydipsia and polyuria.The average 24 h urinary output was between 11 L to 13 L and manifested of hypobaricuria.After effective treatment(three cases were treated with 1-deamino-8-D-arginine vasopressin,another three patients were managed with hydrochlorothiazide,and the last one was cured with antisterone),seven patients with gestational diabetes insipidus did not have any severe consequences.Their symptoms of excessive thirst,polyuria,and polydypsia disappeared from 7 days to 3 months after parturition.Urinary volume returned to normal standard of 1000-2000 ml during 24 hours.Specific gravity of urine recovered normally between a range 1.015-1.025 and serum sodium recovered between 135-147 mmol/L Theaverage duration of illness was 52 days.Eight newborn infants survived.Two of them were sent to neonatal intensive care unit for treatment.One was because of premature delivery caused by antepartum eclampsia,and the other case was one of the twins who had hydronephrosis.The baby of the first case left hospital after 3 weeks'treatment.The latter one's symptom disappeared 2 weeks after delivery.No obvious symptom was discovered among all the babies through follow-up telephone calls 42 days after childbirth.Conclusion Gestational diabetes insipidus is a rare endocrinopathy complicating pregnancy.This disorder is characterized by excessive thirst,polydypsia,polyuria,hypobaric urine and electrolyte disturbances usually manifesting in the third trimester of pregnancy or puerperium.This is a transient syndrome.The first treatment of choice in patients with gestational diabetes insipidus is 1-deamino-8-D-arginine vasopressin and the second-choice is hydrochlorothiazide.Early diagnosis and appropriate management of the disease may reduce the hazard forboth the mother and the fetus during perinatal period.