Pregnant women should be screened for preeclampsia with blood pressure measurements taken throughout their pregnancy, according to a draft recommendation statement published by the U.S. Preventive Services Task Force (USPSTF).
The task force gave a B grade to the recommendation, noting that obtaining blood pressure measurements could result in earlier diagnosis of the condition. The task force added that testing protein in the urine with a dipstick test has a low diagnostic accuracy for proteinuria detection in pregnancy.
Women have an increased risk of preeclampsia if they have a history of eclampsia or preeclampsia, a previous adverse pregnancy outcome, maternal comorbid conditions, or multifetal gestation. Additional risk factors may include nulliparity, obesity, African American race, low socioeconomic status, and older maternal age.
The task force noted that blood pressure measurements should be obtained during each prenatal care visit throughout the pregnancy, and if a patient has a high blood pressure reading, the reading should be confirmed with additional measurements.
The revised criteria for the diagnosis of preeclampsia include high blood pressure ≥140 mm Hg or ≥90 mm Hg diastolic pressure on 2 occasions, at least 4 hours apart, after 20 weeks of gestation, and either proteinuria, thrombocytopenia, renal insufficiency, impaired liver function, pulmonary edema, or cerebral visual symptoms.
Treatment options for diagnosed preeclampsia include close fetal and maternal monitoring, antihypertension medications, and magnesium sulfate. The potential harms of treating preeclampsia include preterm delivery, neonatal complications, cesarean delivery, and side effects from magnesium sulfate. To prevent preeclampsia in women who have an increased risk, the USPSTF recommends the use of low-dose aspirin after 12 weeks of gestation.
Overall, the USPSTF found substantial evidence that measuring blood pressure has few potential harms. However, there is limited evidence regarding the harms of screening for preeclampsia and risk prediction of preeclampsia.
The task force concluded that, “Given the evidence that treatment can reduce poor maternal and perinatal health outcomes and the well-established accuracy of blood pressure measurements, the USPSTF found adequate evidence that screening for preeclampsia results in a substantial benefit for the mother and infant.” The USPSTF also noted that there is also adequate evidence to suggest that the harms of screening and treatment are small.
“Studies are needed to further develop and validate tools for risk prediction using rigorous methodology, including appropriate calibration statistics and validated models that use parameters available in routine care,” the study authors wrote. “Large studies are needed to compare different approaches to screening and effects on maternal and perinatal health outcomes, as well as long-term health outcomes.”
- Preeclampsia: screening [draft recommendation statement]. U.S. Preventive Services Task Force. Published September 2016. Accessed September 28, 2016.