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Competing-risks model for pre-eclampsia and adverse pregnancy outcomes

Research output: Contribution to journalArticlepeer-review

A. Syngelaki, L. A. Magee, P. von Dadelszen, R. Akolekar, A. Wright, D. Wright, K. H. Nicolaides

Original languageEnglish
Pages (from-to)367-372
Number of pages6
JournalUltrasound in Obstetrics and Gynecology
Issue number3
Accepted/In press14 Jul 2022
Published1 Sep 2022

Bibliographical note

Funding Information: The study was supported by grants from the Fetal Medicine Foundation (UK Charity No: 1037116). Reagents and equipment for the measurement of serum PlGF and sFlt‐1 were provided free of charge by Thermo Fisher Scientific, Hennigsdorf, Germany. These bodies had no involvement in the study design, in the collection, analysis and interpretation of data, in the writing of the report or in the decision to submit the article for publication. Publisher Copyright: © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

King's Authors


Objective: The competing-risks model for assessment of risk for pre-eclampsia (PE) at 35–37 weeks' gestation identifies the majority of women who are at high risk of subsequent delivery with PE. We aimed to examine the incidence and relative risk of adverse pregnancy outcomes in patient groups stratified according to the estimated risk of delivery with PE. Methods: This was a prospective non-interventional, observational study in women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The risk of delivery with PE for each patient in the study population was estimated using the competing-risks model, combining the prior distribution of gestational age at delivery with PE and the likelihood from multiples of the median values of mean arterial pressure, placental growth factor and soluble fms-like tyrosine kinase-1. The patients were assigned to one of the following five risk categories: Group A, ≥ 1 in 2; Group B, 1 in 5 to 1 in 3; Group C, 1 in 20 to 1 in 6; Group D, 1 in 50 to 1 in 21; and Group E, < 1 in 50. The outcome measures were delivery with PE, gestational hypertension (GH), small-for-gestational age (SGA) at birth, delivery by Cesarean section, stillbirth, neonatal death, perinatal death and admission to the neonatal unit (NNU) for at least 48 h. In each risk category, the proportion of women with each adverse outcome was determined and relative risks (RR) were calculated as compared with the lowest-risk Group E. Results: In the study population of 29 035 women, 1.6%, 2.7%, 8.2%, 9.8% and 77.8% were categorized into Groups A, B, C, D and E, respectively. Compared with women in Group E, women in the higher-risk groups were more likely to have an adverse outcome. The RR of delivery with PE in Group A compared with Group E was 65.5 (95% CI, 54.1–79.1) and the respective values were 11.9 (95% CI, 9.1–15.5) for GH, 1.8 (95% CI, 1.5–2.1) for delivery by emergency Cesarean section, 1.5 (95% CI, 1.2–1.8) for delivery by elective Cesarean section, 8.9 (95% CI, 7.4–10.8) for SGA with birth weight < 3rd percentile, 4.8 (95% CI, 4.3–5.4) for SGA with birth weight < 10th percentile, 5.3 (95% CI, 1.4–20.5) for stillbirth and 3.4 (95% CI, 2.8–4.2) for NNU admission for ≥ 48 h. The RR for these pregnancy complications in higher-risk groups (vs Group E) was particularly high for cases with delivery within 2 weeks after assessment. In terms of SGA, both for birth weight < 10th and < 3rd percentiles, the trend in all cases was stronger than that observed when the analysis was confined to normotensive pregnancies. The rates of neonatal death were too small to allow meaningful comparisons between risk groups. Conclusion: Pregnant women identified by the competing-risks model to be at high risk of PE are also at increased risk of GH, Cesarean section, stillbirth, SGA and NNU admission for ≥ 48 h.

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