Cut-off values for Gaussian first-trimester screening for early-onset preeclampsia with maternal history, biochemical markers and uterine artery Doppler

Introduction: Several algorithms for first-trimester screening for preeclampsia are available; however, the Gaussian model algorithm is more likely to match the characteristics of different populations. It is recommended to validate a screening strategy before being implemented in clinical practice; unfortunately, the validation process might not be feasible in all settings. Thus, the aim of this study was to provide cut-off values for the Gaussian model for its use in clinical practice.

Material and methods: This prospective cohort study was conducted at Vall d'Hebron University Hospital (Barcelona) from October 2015 to September 2017. A total of 2641 women with singleton pregnancies were recruited. Recorded at the first-trimester scan were demographic characteristics, maternal obstetric history, maternal history, uterine artery Doppler and arterial blood pressure. Serum concentrations of pregnancy-associated plasma protein-A and placental growth factor were assessed from the first-trimester blood test. Detection rates and cut-off values for fixed 5%, 10 %, 15 %, 20 %, 25 % and 30 % false-positive rates were calculated for all combinations of markers.

Results: Ninety (3.41 %) of the 2641 women developed preeclampsia, which was early-onset in 11 (0.42 %). The cut-off values and their respective detection rates, for the screening of early-onset PE by all possible combinations of markers involved in this model, are provided.

Discussion: When external validation of first-trimester screening for preeclampsia before its clinical implementation is not feasible, the cut-off values from the Gaussian model algorithm provided in this study could be used and median values corrected prospectively if necessary.