Amount of polyhydramnios attributable to diabetes may be less than previously reported.

Aim: To evaluate the frequency and the quantity of polyhydramnios attributable to diabetes in pregnancy.

Methods: The charts of patients with a four-quadrant amniotic fluid index (AFI) ≥ 20 cm and either a diagnosis of diabetes or a diabetes screening test during the index pregnancy were retrospectively reviewed. AFI was stratified into 5 categories and the frequency of diabetes was evaluated for each group. The frequency of polyhydramnios attributable to diabetes was compared to the frequency of polyhydramnios in the setting of fetal anomalies or no known cause.

Results: One thousand five hundred and forty-five patients were included in the study. Eight point five percent ( = 131) had diabetes and no other cause for polyhydramnios. Eleven point two percent (173) had antenatally diagnosed anomalies. For all categories of AFI except the largest (> 40.9 cm) the most common cause of polyhydramnios was idiopathic. In patients with diabetes the AFI was most likely to be between 26 cm and 35.9 cm.

Conclusion: The rate of polyhydramnios in this study is 8.5%. Patients with diabetes most commonly have mild polyhydramnios between 26 and 35.9 cm of fluid on a four-quadrant AFI.