Competing Risks Model in Early Screening for Preeclampsia by Biophysical and Biochemical Markers

Abstract

Objective: To develop models for prediction of preeclampsia (PE) based on maternal characteristics, biophysical and biochemical markers at 11–13 weeks’ gestation in which the gestation at the time of delivery for PE is treated as a continuous variable. Methods: This was a screening study of singleton pregnancies at 11–13 weeks including 1,426 (2.4%) that subsequently developed PE and 57,458 that were unaffected by PE. We developed a survival time model for the time of delivery for PE in which Bayes’ theorem was used to combine the prior information from maternal characteristics with uterine artery pulsatility index (PI), mean arterial pressure (MAP), serum pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PLGF) multiple of the median (MoM) values. Results: In pregnancies with PE, there was a linear correlation between MoM values of uterine artery PI, MAP, PAPP-A and PLGF with gestational age at delivery and therefore the deviation from normal was greater for early than late PE for all four biomarkers. Screening by maternal characteristics, biophysical and biochemical markers detected 96% of cases of PE requiring delivery before 34 weeks and 54% of all cases of PE at a fixed false-positive rate of 10%. Conclusions: A new model has been developed for effective first-trimester screening for PE.

Diagnosis, Evaluation, and Management of the Hypertensive Disorders of Pregnancy: Executive Summary

“…Combining clinical, biochemical, and/or ultrasonographic risk markers may better identify women at increased preeclampsia risk (see "Prediction"); however, no intervention trial has used such an approach to evaluate preventative therapy. 33 *Women at increased risk (who should be considered for specialty referral) are those with one of the bolded factors, or two or more of the unbolded markers. †First antenatal visit, usually early in pregnancy.…”

Metabolic profiles of placenta in preeclampsia using HR-MAS MRS metabolomics

“…18,34,58 Another link between preeclampsia and cardiovascular disease is elevated homocystein levels, which is found in women with preeclampsia and is a risk factor for CVD. 59 Homocysteine levels can accumulate through de ciency of B vitamins and folate.…”

Re: Longitudinal changes in maternal soluble endoglin and angiopoietin‐2 in women at risk for pre‐eclampsia. A. Khalil, N. Maiz, R. Garcia‐Mandujano, M. Elkhouli and K. H. Nicolaides. Ultrasound Obstet Gynecol 2014; 44: 402–410

“…A host of studies has shown that a combination of maternal history and biophysical and biochemical markers at 11-14 weeks of gestation is able to detect with high accuracy the subsequent onset of pre-eclampsia 1 . Moreover, meta-analysis has revealed that intervention is possible: low-dose aspirin prevents onset of the condition when started before 16 weeks of gestation 2 .…”