ImportanceAspirin reduces the incidence of preterm preeclampsia by 62% in pregnant individuals at high risk of preeclampsia. However, aspirin might be associated with an increased risk of peripartum bleeding, which could be mitigated by discontinuing aspirin before term (37 weeks of gestation) and by an accurate selection of individuals at higher risk of preeclampsia in the first trimester of pregnancy.ObjectiveTo determine whether aspirin discontinuation in pregnant individuals with normal soluble fms-like tyrosine kinase–1 to placental growth factor (sFlt-1:PlGF) ratio between 24 and 28 weeks of gestation was noninferior to aspirin continuation to prevent preterm preeclampsia.Design, Setting, and ParticipantsMulticenter, open-label, randomized, phase 3, noninferiority trial conducted in 9 maternity hospitals across Spain. Pregnant individuals (n = 968) at high risk of preeclampsia during the first-trimester screening and an sFlt-1:PlGF ratio of 38 or less at 24 to 28 weeks of gestation were recruited between August 20, 2019, and September 15, 2021; of those, 936 were analyzed (intervention: n = 473; control: n = 463). Follow-up was until delivery for all participants.InterventionsEnrolled patients were randomly assigned in a 1:1 ratio to aspirin discontinuation (intervention group) or aspirin continuation until 36 weeks of gestation (control group).Main Outcomes and MeasuresNoninferiority was met if the higher 95% CI for the difference in preterm preeclampsia incidences between groups was less than 1.9%.ResultsAmong the 936 participants, the mean (SD) age was 32.4 (5.8) years; 3.4% were Black and 93% were White. The incidence of preterm preeclampsia was 1.48% (7/473) in the intervention group and 1.73% (8/463) in the control group (absolute difference, −0.25% [95% CI, −1.86% to 1.36%]), indicating noninferiority.Conclusions and RelevanceAspirin discontinuation at 24 to 28 weeks of gestation was noninferior to aspirin continuation for preventing preterm preeclampsia in pregnant individuals at high risk of preeclampsia and a normal sFlt-1:PlGF ratio.Trial RegistrationClinicalTrials.gov Identifier: NCT03741179 and ClinicalTrialsRegister.eu Identifier: 2018-000811-26

Introduction Increased soluble fms‐like tyrosine kinase to placental growth factor ratio (sFlt‐1/PlGF) has been demonstrated in early‐onset fetal growth restriction (FGR) and small for gestational age (SGA). sFlt‐1/PlGF cut‐offs have been described to assess preeclampsia severity; however, sFlt‐1/PlGF values present in early‐onset SGA and different FGR severity stages remain unknown. Hence, the objective of this study was to describe and compare the sFlt‐1/PlGF values and pregnancy outcomes among early‐onset SGA/FGR stages. Material and methods This is a prospective case‐control study conducted at Vall d’Hebron University Hospital. Singleton pregnancies with estimated fetal weight <10th centile and a control group of uncomplicated pregnancies between 20+0 and 31+6 weeks of gestation were enrolled. Study women were classified at diagnosis into different stages, according to estimated fetal weight centile and Doppler ultrasound. sFlt‐1/PlGF serum concentrations were measured at diagnosis and, together with pregnancy outcomes, were compared among FGR severity stages, SGA, and controls. Finally, correlations between sFlt‐1/PlGF values and time to delivery, gestational age at delivery, days of neonatal admission, and birthweight z‐scores were investigated. Results Among the 207 women enrolled, 32 (15.4%) had uncomplicated pregnancies, 49 (23.7%) pregnancies showed SGA, and 126 (60.9%) involved FGR (92 being stage I, 17 stage II, and 17 stage III). SGA and controls had similar median sFlt‐1/PlGF values (25.7 vs 27.1, P > .05) and pregnancy outcomes. However, all FGR stages had significantly poorer outcomes and greater sFlt‐1/PlGF values than those of SGA and controls. Furthermore, median values differed significantly among all FGR severity stages (9.76 for stage I; 284.3 for stage II, and 625.02 for stage III, P < .05) increasing with FGR severity as well as the frequency of adverse pregnancy outcomes. Additionally, a significant correlation was found between greater sFlt‐1/PlGF ratio values and gestational age at delivery, time from diagnosis to delivery, birthweight z‐scores, and time in neonatal intensive care unit (r = −.637, r = −.576, r = −.161, and r = .311, respectively). Conclusions Values of sFlt‐1/PlGF at diagnosis permit early‐onset FGR/SGA severity classification with good correlation with Doppler ultrasound findings and the occurrence of adverse outcomes. Thus, sFlt‐1/PlGF could aid in early‐onset FGR/SGA severity classification and clinical management when Doppler assessment is not feasible.

What are the novel findings of this work? The performance of combined first-trimester screening in predicting early-onset and preterm pre-eclampsia (PE) is similar when serum levels of pregnancy-associated plasma protein-A and placental growth factor are measured before or after 11 weeks' gestation. What are the clinical implications of this work? Measurement of serum biomarkers for both PE and aneuploidy screening before the first-trimester scan permits risk calculation for both screening tests at the time of the scan without compromising PE screening performance.

The aim of this study was to assess the added value of the soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) ratio for adjusting the periodicity of ultrasound examinations in early-onset fetal growth restriction (FGR) and small for gestational age (SGA).

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