The value of urine screening for glucose at each prenatal visit

To determine whether chemical (dipstick) urinalysis for glucose at each prenatal visit predicts gestational outcomes such as gestational diabetes, abruptio placentae, preterm delivery, fetal heart rate abnormality, cesarean delivery for dystocia, fetal macrosomia, and shoulder dystocia.

We retrospectively evaluated each of the 3217 women who were delivered at St. Joseph's Hospital between July 1, 1990, and September 1, 1993, and who had received all prenatal care at Marshfield Clinic. Study subjects had complete urinalyses at the first prenatal visit, blood glucose diabetes screening at 24-28 weeks, and dipstick urinalysis for glucose at each prenatal visit. Women were excluded because of preexisting diabetes, multiple gestation, glucosuria at the first prenatal visit, or failure to complete the recommended blood screening at 24-28 weeks. The remaining 2965 women were grouped according to whether their dipstick urine tests were positive for glucose. Then the two groups were compared with regard to relevant pregnancy outcomes.

Women with glucosuria in the first two trimesters had a significantly higher incidence of gestational diabetes (12.8 versus 2.9%, P = .003). For women without evidence of gestational diabetes, there were no clinically important differences in the measured pregnancy outcomes between the two groups.

Routine dipstick urinalysis for glucose can identify gravidas at increased risk for gestational diabetes, possibly allowing certain women with gestational diabetes to be diagnosed earlier than 24-28 weeks. However, most glucosuria testing is performed after a patient has completed routine blood screening for gestational diabetes. This third-trimester testing is not predictive of any clinically important pregnancy outcome.