The capacity in the first trimester to predict the later development of pre-eclampsia is potentially of significant clinical utility, as doing so may allow the initiation of aspirin or other prophylactic therapies that might prevent the onset of disease, and would permit appropriate triaging of antenatal care.1 Maternal history alone can identify only a limited number of antenates destined to develop pre-eclampsia, especially among primigravidae, who are at highest risk of this complication.2 As a consequence, a wide range of biophysical and biochemical markers has been studied with respect to their utility in predicting pre-eclampsia, including maternal mean arterial pressure, uterine artery Doppler parameters, and various serum markers such as placental growth factor (PlGF) and pregnancy-associated plasma protein A (PAPP-A). None has demonstrated sufficient predictive capacity in isolation to merit introduction into clinical practice.3 Indeed, it is only through the combination of these markers in multiparametric algorithms that such testing approaches adequate screening performance.4
The first such multiparametric regimen was published in 2009, and demonstrated a detection rate of 93.1% for early pre-eclampsia, 35.7% for late pre-eclampsia, and 18.3% for gestational hypertension, at a false positive rate of 5%.5 Variations on this approach have been devised for and validated in different populations, although none has achieved the detection rates of the original study, and most operate using a 10% false positive rate.6 Although the implementation of a pre-eclampsia screening program in a single centre has demonstrated a favourable impact on rates of early pre-eclampsia,7 whether it is appropriate for such testing to be introduced into broader clinical practice remains controversial. Concern has been expressed that these screening tests perform inadequately in the prediction of later-onset pre-eclampsia, wherein the bulk of the disease burden lies, and that there is insufficient evidence that interventions applied to those deemed at high risk are of sufficient benefit.8 This latter issue is being addressed by the aspre trial, results of which are keenly awaited.