Britain’s National Institute for Health and Care Excellence (NICE) recommends two new tests for women between the 20th and 35th week of pregnancy in order to rule out pre-eclampsia.
Pre-eclampsia is a complication of pregnancy that typically first manifests as high blood pressure. Left untreated, it can result in serious complications, such as organ damage or diminished blood flow to the placenta, and may require pre-term delivery to avoid death of both mother and baby. NICE reports that pre-eclampsia is the second leading cause of direct maternal deaths in the UK.
Currently, women suspected to have pre-eclampsia must be hospitalized for a period of 24 to 36 hours so a diagnosis can be made. However, with the use of two new blood tests, doctors may be able to rule out pre-eclampsia more quickly and easily in many cases, thus avoiding some unnecessary hospitalizations.
The two new tests, Triage PlGF and Elecsys immunoassay sFlt-1/PlGF ratio, work by measuring levels of placental growth factor (PlGF) in the blood. PlGF is a protein that supports the development of new blood vessels in the placenta. Normally, PlGF levels will rise during pregnancy and peak at approximately 26 to 30 weeks. PlGF levels that do not rise during pregnancy can be a sign of pre-eclampsia. Thus, both tests will assist in identifying pregnancies with normal PIGF, where pre-eclampsia is not a concern.
As a second feature, the Elecsys immunoassay sFlt-1/PlGF ratio test also measures levels of a protein called soluble FMS-like tyrosine kinase-1 (sFlt-1). This protein disables other proteins associated with vessel formation, including PIGF. Women who develop pre-eclampsia have elevated levels of sFlt-1. Thus, where sFlt-1 is normal, pre-eclampsia can again be ruled out.
NICE emphasizes that, at present, the two tests can be used to help rule out pre-eclampsia, but are not sufficiently reliable to positively diagnose that pre-eclampsia is present. The tests are therefore meant to be used in combination with existing practice and guidelines for diagnosing pre-eclampsia.
NICE recommends that the blood tests be administered to pregnant women with high blood pressure newly developing after the 20th week of pregnancy. If the results show high levels of PIGF, pre-eclampsia can be ruled out, and hospitalization is not required. However, women who have low PIGF readings will need to be admitted to hospital for further evaluation to either confirm or rule out a diagnosis of pre-eclampsia.
Written By: Linda Jensen