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Background/Objectives: The utility of shear wave elastography (SWE) as an adjunct to ultrasound biometry and Doppler velocimetry for the examination of placental dysfunction and suboptimal fetal growth is unclear. To date, limited data exist correlating the mechanical properties of placentae with fetal growth. This study aimed to investigate the relationship between placental shear wave velocity (SWV) and ultrasound estimated fetal weight (EFW), and to ascertain if placental SWV is a suitable proxy measure of placental function in the surveillance of small-for-gestational-age (SGA) pregnancies. Methods: This prospective, observational cohort study compared the difference in placental SWV between SGA and appropriate-for-gestational-age (AGA) pregnancies. There were 221 women with singleton pregnancies in the study cohort—136 (61.5%) AGA and 85 (38.5%) SGA. Fetal biometry, Doppler velocimetry, the deepest vertical pocket of amniotic fluid, and mean SWV were measured at 2–4-weekly intervals from recruitment to birth. Results: There was no difference in mean placental SWV in SGA pregnancies compared to AGA pregnancies, nor was there any relationship to EFW. Conclusions: Although other studies have shown some correlation between increased placental stiffness and SGA pregnancies, our investigation did not support this. The mechanical properties of placental tissue in SGA pregnancies do not result in placental SWVs that are apparently different from those of AGA controls. As this study did not differentiate between constitutionally or pathologically small fetuses, further studies in growth-restricted cohorts would be of benefit. [ABSTRACT FROM AUTHOR]

Objective: To assess the utility of placental growth factor (PlGF) levels and the soluble fms‐like tyrosine kinase‐1/placental growth factor (sFlt‐1/PlGF) ratio to predict preterm birth (PTB) for infants with fetal growth restriction (FGR) and those appropriate for gestational age (AGA). Design: Prospective, observational cohort study. Setting: Tertiary maternity hospital in Australia. Population: There were 320 singleton pregnancies: 141 (44.1%) AGA, 83 (25.9%) early FGR (<32+0 weeks) and 109 (30.0%) late FGR (≥32+0 weeks). Methods: Maternal serum PlGF and sFlt‐1/PlGF ratio were measured at 4‐weekly intervals from recruitment to delivery. Low maternal PlGF levels and elevated sFlt‐1/PlGF ratio were defined as <100 ng/L and >5.78 if <28 weeks and >38 if ≥28 weeks respectively. Cox proportional hazards models were used. The analysis period was defined as the time from the first measurement of PlGF and sFlt‐1/PlGF ratio to the time of birth or censoring. Main outcome measures: The primary study outcome was overall PTB. The relative risks (RR) of birth within 1, 2 and 3 weeks and for medically indicated and spontaneous PTB were also ascertained. Results: The early FGR cohort had lower median PlGF levels (54 versus 229 ng/L, p < 0.001) and higher median sFlt‐1 levels (2774 ng/L versus 2096 ng/L, p < 0.001) and sFlt‐1/PlGF ratio higher (35 versus 10, p < 0.001). Both PlGF <100 ng/L and elevated sFlt‐1/PlGF ratio were strongly predictive for PTB as well as PTB within 1, 2 and 3 weeks of diagnosis. For both FGR and AGA groups, PlGF <100 ng/L or raised sFlt‐1/PlGF ratio were strongly associated with increased risk for medically indicated PTB. The highest RR was seen in the FGR cohort when PlGF was <100 ng/L (RR 35.20, 95% CI 11.48–175.46). Conclusions: Low maternal PlGF levels and elevated sFlt‐1/PlGF ratio are potentially useful to predict PTB in both FGR and AGA pregnancies. [ABSTRACT FROM AUTHOR]

Introduction: Small for gestational age (SGA) infants are at increased risk of fetal distress in labour requiring emergency operative birth (by caesarean section (CS), vacuum or forceps). We have previously shown that maternal oral sildenafil citrate (SC) in labour halves the need for operative birth for suspected fetal distress in women with appropriately grown term infants., Methods and Analysis: RidStress 2 is a phase III randomised, double-blinded, placebo-controlled trial of 660 women with an SGA or suboptimally grown fetus (estimated fetal weight or abdominal circumference<10th centile for gestational age) planning a vaginal birth at term. The trial will determine whether oral intrapartum SC (50 mg eight hourly) reduces the relative risk of emergency CS for fetal distress compared with placebo. The primary outcome is CS for fetal distress, and the secondary outcomes are any operative birth for fetal distress, cost-effectiveness of SC treatment and 2-year childhood neurodevelopmental outcomes. To detect a 33% reduction in the primary outcome from 30% to 20% for an alpha of 0.05 and power of 80% with 10% dropout, requires approximately 660 women (330 in each arm). This sample size will also yield >90% power to detect a similar reduction for the secondary outcome of any operative birth (CS or instrumental vaginal birth) for fetal distress., Ethics and Dissemination: Ethics approval was granted by the Mater Misericordiae Limited Human Research Ethics Committee (EC00332) on 11 September 2020. We plan to disseminate the results of this randomised controlled trial through presentations at scientific meetings and peer-reviewed journals, adhering to all relevant reporting guidelines., Trial Registration Number: RidStress 2 is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000354886, 29/03/2021) and the Therapeutic Goods Association of Australia (date registered: 16 March 2021)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)