Screening for Glycosuria During Pregnancy

Abstract

It is currently recommended that every pregnant woman have a blood glucose screening test for gestational diabetes at 24 to 28 weeks' gestation. Random urine samples are also tested for glucose at each prenatal visit. In 500 consecutive pregnant women, random urine glucose screening values from each prenatal visit were compared with a serum glucose test done at 28 weeks' gestation after ingestion of a 50 gm glucose-containing beverage. Twenty-two patients (4.4%) subsequently were identified as having gestational diabetes. Eighty-five (17%) had some degree of glycosuria, and 19 (3.8%) had severe glycosuria. Only six (27%) of the 22 women with gestational diabetes had any glycosuria. As a screening test for gestational diabetes, glycosuria had a 27% sensitivity and a positive predictive value of only 7.1%. Severe glycosuria, although increased in women with gestational diabetes (P = .0071), occurred in only 18% of cases. Detection of severe glycosuria before 24 weeks' gestation is an indication to do earlier blood glucose screening. After blood glucose screening is done, routinely screening the urine for glycosuria at each prenatal visit does not appear to be clinically useful.