No need for routine glycosuria/proteinuria screen in pregnant women
The presence of proteinuria was increased in younger women and those with a greater prepregnant body mass index but not with pregnancy-associated hypertension—preeclampsia, fetal distress, abruption, low birth weight, prematurity, stillbirth, or Apgar scores less than 7 at 5 minutes. The authors concluded that there is no evidence supporting routine urine dipstick protein determinations during uncomplicated prenatal visits.
In another retrospective study of 610 women, 18 % had ≥1+ proteinuria during at least one prenatal visit and 17 (3%) developed preeclampsia.6 Three women with preeclampsia (17%) developed proteinuria before hypertension. But the timing of the appearance of proteinuria was not otherwise specified, and it may have been remote from the hypertension. The sensitivity of proteinuria detected prior to the onset of hypertension for preeclampsia was 71% with a PV–of 99%. The author advised against routine dipstick testing.
TABLE 2
Accuracy of proteinuria for predicting preeclampsia
| DIAGNOSTIC TEST | STUDY QUALITY | N | SENSITIVITY (95% CI) | SPECIFICITY (95% CI) | LR+ (95% CI) | LR–(95% CI) | PV+ | PV— | PREVALENCE OF PREECLAMPSIA | ODDS RATIO (95% CI) |
|---|---|---|---|---|---|---|---|---|---|---|
| Automated read urine dipstick proteinuria ≥1+13 | 2b | 913 | 63% (43%–79%) | 62% (59%–65%) | 1.7 (1.2–2.3) | 0.60 (0.4–1.0) | 5% | 98% | 2.8% | 2.7 (1.2–6.3) |
| Visually read urine dipstick proteinuria ≥30 mg/dL [H]6 | 2b | 610 | 71% (47%–87%) | 84% (80%–86%) | 4.3 (3.0–6.2) | 0.35 (0.17–0.74) | 11% | 99% | 2.8% | 12.3 (4.2–35.6) |
| Visually read urine dipstick proteinuria ≥trace (30 mg/dL)5 | 2b | 2802 | 5% (2%–11%) | 90% (89%–91%) | 0.5 (0.2–1.1) | 1.1 (1.0–1.1) | 2% | 96% | 9.7% | 0.5 (0.2–1.1) |
| LR+, positive likelihood ratio; LR–, negative likelihood ratio; PV+, probability of disease given a positive test; PV–, probability of disease given a negative test; CI, confidence interval. | ||||||||||
Recommendations and practices of others
Routine testing at antenatal visits for proteinuria is not helpful in predicting preeclampsia and should be targeted at women with an increased blood pressure or acute weight gain. ACOG advises that there is no reliable predictive test for preeclampsia.23 The US Preventive Services Task Force advises urine testing for protein only after abnormalities in blood pressure appear.24 The Canadian Task Force on the Periodic Health Examination25 and other groups in Australia26 advise against testing, as does a standard textbook of obstetrics.27 ICSI suggests that prenatal care would be improved by discontinuing routine urine dipstick testing.10
Most groups support further evaluation of proteinuria21,26,30 or glycosuria26 found on the initial urinalysis at the first prenatal visit although there is little evidence to support this course of action.31 Based on the results of these studies and the recommendations of other groups, it is reasonable to reserve urine protein testing (using a more accurate method than a dipstick) for women with an elevated blood pressure.
Acknowledgments
The author wishes to thank Thomas L. Mead and Cora Damon for assisting in the library research of the topic and Colleen Flewelling for technical assistance.
CORRESPONDING AUTHOR
William A. Alto, MD, MPH, 4 Sheridan Drive, Fairfield, ME 04937. E-mail: waalto@dartmouth.edu
