Reduced uterine perfusion pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis.

The reduced uterine perfusion pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype. We performed a systematic review and meta-analysis by searching Medline and Embase (until 28 March, 2023) for RUPP studies in murine. Primary outcomes included maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump length, fetal reabsorptions, or antiangiogenic factors. We aimed to identify influential factors by meta-regression analysis. We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD = 24.1 mmHg; [22.6; 25.7]; n = 148), proteinuria (SMD = 2.3; [0.9; 3.8]; n = 28), fetal reabsorptions (MD = 50.4%; [45.5; 55.2]; n = 42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD = 2.6; [1.7; 3.4]; n = 34), and lower fetal weight (MD = -0.4 g; [-0.47; -0.34]; n = 113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1. The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Because of underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

Long-Term Neurologic Consequences following Fetal Growth Restriction: The Impact on Brain Reserve.

BACKGROUND: Fetal growth restriction (FGR) corresponds to the fetus's inability to achieve an adequate weight gain based on genetic potential and gestational age. It is an important cause of morbidity and mortality. SUMMARY: In this review, we address the challenges of diagnosis and classification of FGR. We review how chronic fetal hypoxia impacts brain development. We describe recent advances on placental and fetal brain imaging using magnetic resonance imaging and how they offer new noninvasive means to study growth restriction in humans. We go on to review the impact of FGR on brain integrity in the neonatal period, later childhood, and adulthood and review available therapies. KEY MESSAGES: FGR consequences are not limited to the perinatal period. We hypothesize that impaired brain reserve, as defined by structure and size, may predict some concerning epidemiological data of impaired cognitive outcomes and dementia with aging in this group of patients.

Pregnancy in antiphospholipid syndrome: what should a rheumatologist know?

This review focuses on the management of reproductive issues in women who have antiphospholipid syndrome (APS) or are carriers of antiphospholipid antibodies (aPL). The importance of aPL detection during preconception counselling relies on their pathogenic potential for placental insufficiency and related obstetric complications. The risk of adverse pregnancy outcomes can be minimized by individualized risk stratification and tailored treatment aimed at preventing placental insufficiency. Combination therapy of low-dose acetylsalicylic acid and heparin is the mainstay of prophylaxis during pregnancy; immunomodulation, especially with hydroxychloroquine, should be considered in refractory cases. Supplementary ultrasound surveillance is useful to detect fetal growth restriction and correctly tailor the time of delivery. The individual aPL profile must be considered in the stratification of thrombotic risk, such as during assisted reproduction techniques requiring hormonal ovarian stimulation or during the follow-up after pregnancy in order to prevent the first vascular event.

Placental, maternal, fetal, and technical origins of false-positive cell-free DNA screening results.

The introduction of noninvasive prenatal testing has resulted in substantial reductions to previously accepted false-positive rates of prenatal screening. Despite this, the possibility of false-positive results remains a challenging consideration in clinical practice, particularly considering the increasing uptake of genome-wide noninvasive prenatal testing, and the subsequent increased proportion of high-risk results attributable to various biological events besides fetal aneuploidy. Confined placental mosaicism, whereby chromosome anomalies exclusively affect the placenta, is perhaps the most widely accepted cause of false-positive noninvasive prenatal testing. There remains, however, a substantial degree of ambiguity in the literature pertaining to the clinical ramifications of confined placental mosaicism and its potential association with placental insufficiency, and consequentially adverse pregnancy outcomes including fetal growth restriction. Other causes of false-positive noninvasive prenatal testing include vanishing twin syndrome, in which the cell-free DNA from a demised aneuploidy-affected twin triggers a high-risk result, technical failures, and maternal origins of abnormal cell-free DNA such as uterine fibroids or unrecognized mosaicisms. Most concerningly, maternal malignancies are also a documented cause of false-positive screening results. In this review, we compile what is currently known about the various causes of false-positive noninvasive prenatal testing.

Doppler ultrasound of umbilical and middle cerebral artery in third trimester small-for-gestational age fetuses to decide on timing of delivery for suspected fetal growth restriction: A cohort with nested RCT (DRIGITAT).

OBJECTIVE: To assess the association of the umbilicocerebral ratio (UCR) with adverse perinatal outcome in late preterm small-for-gestational age (SGA) fetuses and to investigate the effect on perinatal outcomes of immediate delivery. DESIGN: Multicentre cohort study with nested randomised controlled trial (RCT). SETTING: Nineteen secondary and tertiary care centres. POPULATION: Singleton SGA pregnancies (estimated fetal weight [EFW] or fetal abdominal circumference [FAC] <10th centile) from 32 to 36+6 weeks. METHODS: Women were classified: (1) RCT-eligible: abnormal UCR twice consecutive and EFW below the 3rd centile at/or below 35 weeks or below the 10th centile at 36 weeks; (2) abnormal UCR once or intermittent; (3) never abnormal UCR. Consenting RCT-eligible patients were randomised for immediate delivery from 34 weeks or expectant management until 37 weeks. MAIN OUTCOME MEASURES: A composite adverse perinatal outcome (CAPO), defined as perinatal death, birth asphyxia or major neonatal morbidity. RESULTS: The cohort consisted of 690 women. The study was halted prematurely for low RCT-inclusion rates (n = 40). In the RCT-eligible group, gestational age at delivery, birthweight and birthweight multiple of the median (MoM) (0.66, 95% confidence interval [CI] 0.59-0.72) were significantly lower and the CAPO (n = 50, 44%, p < 0.05) was more frequent. Among patients randomised for immediate delivery there was a near-significant lower birthweight (p = 0.05) and higher CAPO (p = 0.07). EFW MoM, pre-eclampsia, gestational hypertension and Doppler classification were independently associated with the CAPO (area under the curve 0.71, 95% CI 0.67-0.76). CONCLUSIONS: Perinatal risk was effectively identified by low EFW MoM and UCR. Early delivery of SGA fetuses with an abnormal UCR at 34-36 weeks should only be performed in the context of clinical trials.

Placental T2* and BOLD effect in response to hyperoxia in normal and growth-restricted pregnancies: multicenter cohort study.

OBJECTIVES: Blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI) facilitates the non-invasive in-vivo evaluation of placental oxygenation. The aims of this study were to identify and quantify a relative BOLD effect in response to hyperoxia in the human placenta and to compare it between pregnancies with and those without fetal growth restriction (FGR). METHODS: This was a prospective multicenter study (NCT02238301) of 19 pregnancies with FGR (estimated fetal weight (EFW) on ultrasound < 5th centile) and 75 non-FGR pregnancies (controls) recruited at two centers in Paris, France. Using a 1.5-Tesla MRI system, the same multi-echo gradient-recalled echo (GRE) sequences were performed at both centers to obtain placental T2* values at baseline and in hyperoxic conditions. The relative BOLD effect was calculated according to the equation 100 × (hyperoxic T2* - baseline T2*)/baseline T2*. Baseline T2* values and relative BOLD effect were compared according to EFW (FGR vs non-FGR), presence/absence of Doppler anomalies and birth weight (small-for-gestational age (SGA) vs non-SGA). RESULTS: We observed a relative BOLD effect in response to hyperoxia in the human placenta (median, 33.8% (interquartile range (IQR), 22.5-48.0%)). The relative BOLD effect did not differ significantly between pregnancies with and those without FGR (median, 34.4% (IQR, 24.1-48.5%) vs 33.7% (22.7-47.4%); P = 0.95). Baseline T2* Z-score adjusted for gestational age at MRI was significantly lower in FGR pregnancies compared with non-FGR pregnancies (median, -1.27 (IQR, -4.87 to -0.10) vs 0.33 (IQR, -0.81 to 1.02); P = 0.001). Baseline T2* Z-score was also significantly lower in those pregnancies that subsequently delivered a SGA neonate (n = 23) compared with those that delivered a non-SGA neonate (n = 62) (median, -0.75 (IQR, -3.48 to 0.29) vs 0.35 (IQR, -0.79 to 1.05); P = 0.01). CONCLUSIONS: Our study confirms a BOLD effect in the human placenta and that baseline T2* values are significantly lower in pregnancies with FGR. Further studies are needed to evaluate whether such parameters may detect placental insufficiency before it has a clinical impact on fetal growth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Maternal serum biomarkers of placental insufficiency at 24-28 weeks of pregnancy in relation to the risk of delivering small-for-gestational-age infant in Sylhet, Bangladesh: a prospective cohort study.

BACKGROUND: Small-for-gestational-age (SGA), commonly caused by poor placentation, is a major contributor to global perinatal mortality and morbidity. Maternal serum levels of placental protein and angiogenic factors are changed in SGA. Using data from a population-based pregnancy cohort, we estimated the relationships between levels of second-trimester pregnancy-associated plasma protein-A (PAPP-A), placental growth factor (PlGF), and serum soluble fms-like tyrosine kinase-1 (sFlt-1) with SGA. METHODS: Three thousand pregnant women were enrolled. Trained health workers prospectively collected data at home visits. Maternal blood samples were collected, serum aliquots were prepared and stored at -80℃. Included in the analysis were 1,718 women who delivered a singleton live birth baby and provided a blood sample at 24-28 weeks of gestation. We used Mann-Whitney U test to examine differences of the median biomarker concentrations between SGA (< 10th centile birthweight for gestational age) and appropriate-for-gestational-age (AGA). We created biomarker concentration quartiles and estimated the risk ratios (RRs) and 95% confidence intervals (CIs) for SGA by quartiles separately for each biomarker. A modified Poisson regression was used to determine the association of the placental biomarkers with SGA, adjusting for potential confounders. RESULTS: The median PlGF level was lower in SGA pregnancies (934 pg/mL, IQR 613-1411 pg/mL) than in the AGA (1050 pg/mL, IQR 679-1642 pg/mL; p < 0.001). The median sFlt-1/PlGF ratio was higher in SGA pregnancies (2.00, IQR 1.18-3.24) compared to AGA pregnancies (1.77, IQR 1.06-2.90; p = 0.006). In multivariate regression analysis, women in the lowest quartile of PAPP-A showed 25% higher risk of SGA (95% CI 1.09-1.44; p = 0.002). For PlGF, SGA risk was higher in women in the lowest (aRR 1.40, 95% CI 1.21-1.62; p < 0.001) and 2nd quartiles (aRR 1.30, 95% CI 1.12-1.51; p = 0.001). Women in the highest and 3rd quartiles of sFlt-1 were at reduced risk of SGA delivery (aRR 0.80, 95% CI 0.70-0.92; p = 0.002, and aRR 0.86, 95% CI 0.75-0.98; p = 0.028, respectively). Women in the highest quartile of sFlt-1/PlGF ratio showed 18% higher risk of SGA delivery (95% CI 1.02-1.36; p = 0.025). CONCLUSIONS: This study provides evidence that PAPP-A, PlGF, and sFlt-1/PlGF ratio measurements may be useful second-trimester biomarkers for SGA.

The aetiology of preterm birth and risks of cerebral palsy and cognitive impairment: A systematic review and meta-analysis.

AIM: The associations between the aetiology of preterm birth and later neurodevelopmental outcomes are unclear. A systematic review and meta-analysis examined the existing evidence. METHODS: The PubMed and Embase databases were searched for papers published in English from inception to 16 December 2020. We included original papers on the causes of preterm birth and the risks of cerebral palsy (CP) and suboptimal cognitive development. Two reviewers independently evaluated the studies and extracted the data. RESULTS: The literature search yielded 5472 papers and 13 were selected. The aetiology of preterm birth was classified under spontaneous or medically indicated delivery. A meta-analysis was performed, comprising 104 902 preterm infants from 11 papers on CP. Preterm infants born after a medically indicated delivery had a lower CP risk than infants born after spontaneous delivery, with a pooled odds ratio of 0.59 (95% confidence interval 0.40-0.86). This result was robust in the subgroup and sensitivity analyses. Cognitive development was reported in three papers, which suggested that worse outcomes were associated with medically indicated deliveries. CONCLUSION: The aetiology of preterm delivery may contribute to the risk of CP and cognitive delay. Further research is needed, using individual-level meta-analyses to adjust for possible confounders, notably gestational age.

Dysfunctional Postnatal Mitochondrial Energy Metabolism in a Patient with Neurodevelopmental Defects Caused by Intrauterine Growth Restriction Due to Idiopathic Placental Insufficiency.

We report the case of a four-year-old male patient with a complex medical history born prematurely as the result of intrauterine growth restriction due to placental insufficiency. His clinical manifestations included severe neurodevelopmental deficits, global developmental delay, Pierre-Robin sequence, and intractable epilepsy with both generalized and focal features. The proband's low levels of citrulline and lactic acidosis provoked by administration of Depakoke were evocative of a mitochondrial etiology. The proband's genotype-phenotype correlation remained undefined in the absence of nuclear and mitochondrial pathogenic variants detected by deep sequencing of both genomes. However, live-cell mitochondrial metabolic investigations provided evidence of a deficient oxidative-phosphorylation pathway responsible for adenosine triphosphate (ATP) synthesis, leading to chronic energy crisis in the proband. In addition, our metabolic analysis revealed metabolic plasticity in favor of glycolysis for ATP synthesis. Our mitochondrial morphometric analysis by transmission electron microscopy confirmed the suspected mitochondrial etiology, as the proband's mitochondria exhibited an immature morphology with poorly developed and rare cristae. Thus, our results support the concept that suboptimal levels of intrauterine oxygen and nutrients alter fetal mitochondrial metabolic reprogramming toward oxidative phosphorylation (OXPHOS) leading to a deficient postnatal mitochondrial energy metabolism. In conclusion, our collective studies shed light on the long-term postnatal mitochondrial pathophysiology caused by intrauterine growth restriction due to idiopathic placental insufficiency and its negative impact on the energy-demanding development of the fetal and postnatal brain.

The medullary serotonergic centres involved in cardiorespiratory control are disrupted by fetal growth restriction.

Fetal growth restriction (FGR) is associated with cardiovascular and respiratory complications after birth and beyond. Despite research showing a range of neurological changes following FGR, little is known about how FGR affects the brainstem cardiorespiratory control centres. The primary neurons that release serotonin reside in the brainstem cardiorespiratory control centres and may be affected by FGR. At two time points in the last trimester of sheep brain development, 110 and 127 days of gestation (0.74 and 0.86 of gestation), we assessed histopathological alterations in the brainstem cardiorespiratory control centres of the pons and medulla in early-onset FGR versus control fetal sheep. The FGR cohort were hypoxaemic and asymmetrically growth restricted. Compared to the controls, the brainstem of FGR fetuses exhibited signs of neuropathology, including elevated cell death and reduced cell proliferation, grey and white matter deficits, and evidence of oxidative stress and neuroinflammation. FGR brainstem pathology was predominantly observed in the medullary raphé nuclei, hypoglossal nucleus, nucleus ambiguous, solitary tract and nucleus of the solitary tract. The FGR groups showed imbalanced brainstem serotonin and serotonin 1A receptor abundance in the medullary raphé nuclei, despite evidence of increased serotonin staining within vascular regions of placentomes collected from FGR fetuses. Our findings demonstrate both early and adaptive brainstem neuropathology in response to placental insufficiency. KEY POINTS: Early-onset fetal growth restriction (FGR) was induced in fetal sheep, resulting in chronic fetal hypoxaemia. Growth-restricted fetuses exhibit persistent neuropathology in brainstem nuclei, characterised by disrupted cell proliferation and reduced neuronal cell number within critical centres responsible for the regulation of cardiovascular and respiratory functions. Elevated brainstem inflammation and oxidative stress suggest potential mechanisms contributing to the observed neuropathological changes. Both placental and brainstem levels of 5-HT were found to be impaired following FGR.

Placental insufficiency and heavier placentas in sheep after suppressing CXCL12/CXCR4 signaling during implantation†.

During implantation, trophoblast cell invasion and differentiation is predominantly important to achieving proper placental formation and embryonic development. The chemokine, C-X-C motif chemokine ligand 12 (CXCL12) working through its receptor C-X-C motif chemokine receptor 4 (CXCR4) is implicated in implantation and placentation but precise roles of this axis are unclear. Suppressing CXCL12/CXCR4 signaling at the fetal-maternal interface in sheep reduces trophoblast invasion, disrupts uterine remodeling, and diminishes placental vascularization. We hypothesize these negative impacts during implantation will manifest as compromised fetal and placental growth at midgestation. To test, on day 12 postbreeding, osmotic pumps were surgically installed in 30 ewes and delivered intrauterine CXCR4 inhibitor or saline for 7 or 14 days. On day 90, fetal/maternal tissues were collected, measured, weighed, and maternal (caruncle) and fetal (cotyledon) placenta components separated and analyzed. The objectives were to determine if (i) suppressing CXCL12/CXCR4 during implantation results in reduced fetal and placental growth and development and (ii) if varying the amount of time CXCL12/CXCR4 is suppressed impacts fetal/placental development. Fetal weights were similar; however greater placental weight and placentome numbers occurred when CXCL12/CXCR4 was suppressed for 14 days. In caruncles, greater abundance of fibroblast growth factor 2, vascular endothelial growth factor A, vascular endothelial growth factor A receptor 1 (FLT-1), and placental growth factor were observed after suppressing CXCL12/CXCR4. Similar results occurred in cotyledons except less vascular endothelial growth factor in 7 day group and less fibroblast growth factor in 14 day group. Our data underscore the importance of CXCL12/CXCR4 signaling during placentation and provide strong evidence that altering CXCL12-mediated signaling induces enduring placental effects manifesting later in gestation.

Association of Prenatal Placental Function with Anthropometry and Body Composition through 2 years of Age in South African Infants: The UmbiBaby Study.

BACKGROUND: Placental insufficiency negatively impacts fetal growth and body composition (BC), potentially affecting lifelong health. Placental insufficiency, detectable as an abnormal umbilical artery resistance index (UmA-RI) on Doppler ultrasonography, is highly prevalent in otherwise healthy South African pregnant women. Appropriate intervention reduces stillbirth and perinatal death, but research on long-term outcomes of surviving infants is lacking. OBJECTIVES: This study aimed to describe and compare anthropometry and BC during the first 2 y of life in a cohort of term-born infants with normal and abnormal prenatal UmA-RI. METHODS: Term-born infants (n = 81; n = 55 normal, n = 26 abnormal UmA-RI on third trimester Doppler screening) were followed up at 8-time points until age 2 y. Anthropometric measurements were taken, and FFM and FM were assessed by deuterium dilution. Age- and sex-specific z-scores were calculated for anthropometric indices, FM, FFM, FM index (FMI), and FFM index (FFMI) using appropriate reference data. Anthropometry and BC of infants with normal and abnormal UmA-RI were compared using an independent t-test or Mann-Whitney test. RESULTS: At most ages, group mean z-scores were <0 for length-for-age and FM and >0 for weight-for-length and FFM. Compared with infants with normal UmA-RI, infants with abnormal UmA-RI had significantly lower weight-for-age z-scores at birth (-0.77 ± 0.75 compared with -0.30 ± 1.10, P = 0.026), ages 10 wk to 9 mo (-0.4 ± 0.87 to -0.2 ± 1.12 compared with 0.3 ± 0.85 to 0.6 ± 1.09; P = 0.007-0.017) and 18 mo (-0.6 ± 0.82 compared with 0.1 ± 1.18; P = 0.037); length-for-age z-scores at ages ≤14 wk (-1.3 ± 1.25 to -0.9 ± 0.87 compared with -0.2 ± 1.04 to -0.1 ± 1.00; P = 0.004-0.021); and FFM-for-age z-scores at ages ≤9 mo (-0.1 ± 0.82 to 0.7 ± 0.71 compared with 0.7 ± 1.00 to 1.3 ± 0.85; P = 0.002-0.028). FFMI, percentage FFM, FM, percentage FM, and FMI showed no consistent significant differences. CONCLUSIONS: Infants with abnormal UmA-RI had lower weight-for-age and length-for-age z-scores, particularly at younger ages, with proportionally lower FFM but no consistent differences in percentage FFM and FFMI. These findings merit further investigation in larger cohorts.

Gestational cholestasis induced intrauterine growth restriction through triggering IRE1α-mediated apoptosis of placental trophoblast cells.

Epidemiological and animal experimental studies suggest an association between gestational cholestasis and intrauterine growth restriction (IUGR). Here, we explored the mechanism through which gestational cholestasis induced IUGR. To establish gestational cholestasis model, pregnant mice were subcutaneously injected with 17α-Ethynylestradiol (E2) on gestational day 13 (GD13)-GD17. Some pregnant mice were intraperitoneally injected with 4µ8C on GD13-GD17. The results found that the apoptosis of trophoblast cells was elevated in placentas of mice with gestational cholestasis and in deoxycholic acid (DCA)-treated human trophoblast cell lines and primary mouse trophoblast cells. Correspondingly, the levels of placental cleaved caspase-3 and Bax were increased, while placental Bcl2 level was decreased in mice with gestational cholestasis and in DCA-treated trophoblast cells. Further analysis found that placental IRE1α pathway was activated in mice with gestational cholestasis and in DCA-treated trophoblast cells. Interestingly, 4µ8C, an IRE1α RNase inhibitor, significantly inhibited caspase-3 activity and apoptosis of trophoblast cells in vivo and in vitro. Importantly, 4µ8C rescued gestational cholestasis-induced placental insufficiency and IUGR. Furthermore, a case-control study demonstrated that placental IRE1α and caspase-3 pathways were activated in cholestasis cases. Our results provide evidence that gestational cholestasis induces placental insufficiency and IUGR may be via triggering IRE1α-mediated apoptosis of placental trophoblast cells.

Maternal serum levels of soluble fms-like tyrosine kinase-1 and placental growth factor at 20 and 28 weeks of gestational age and the risk of spontaneous preterm birth.

BACKGROUND: Spontaneous preterm birth is the endpoint of multiple different pathophysiological pathways. Fetal growth restriction, assessed by serial ultrasonic fetal biometry, has been shown to predict both preterm and early-term spontaneous labor. The soluble fms-like tyrosine kinase-1 to placental growth factor ratio is predictive of early-term spontaneous labor, but its association with spontaneous preterm birth is unclear. OBJECTIVE: This study aimed to determine whether maternal serum levels of soluble fms-like tyrosine kinase-1, placental growth factor, and the soluble fms-like tyrosine kinase-1: placental growth factor ratio at 20 and 28 weeks' gestation, and the rate of change in these biomarkers between 20 and 28 weeks were predictive of risk of spontaneous preterm birth. STUDY DESIGN: The biomarkers were measured in maternal serum at 20- and 28-weeks' gestation in women recruited to a prospective cohort of unselected nulliparous women as part of the Pregnancy Outcome Prediction study in Cambridge, United Kingdom. The risk of spontaneous preterm birth was assessed using Cox regression and competing-risks regression. Associations from Cox regression were quantified by the adjusted hazard ratio for a 1 standard deviation higher level of a given biomarker or a 1 standard deviation increase in the marker between 20 and 28 weeks' gestation. A previously identified risk factor, slow femur length growth, was used as an additional predictor of spontaneous preterm birth for the purpose of risk stratification. RESULTS: Of the 3763 participants in the analysis, 95 (2.5%) had spontaneous preterm birth and 54 (1.4%) had medically indicated preterm birth. At 20 weeks' gestation, higher levels of soluble fms-like tyrosine kinase-1 and the soluble fms-like tyrosine kinase-1:placental growth factor ratio were associated with reduced risk of spontaneous preterm birth (adjusted hazard ratio [95% confidence interval], 0.75 [0.61-0.92]; P=.006 and 0.71 [0.59-0.87]; P=.0009, respectively). At 28 weeks' gestation, there was no association between either soluble fms-like tyrosine kinase-1 or placental growth factor and the risk of spontaneous preterm birth, but there was a U-shaped relation with the soluble fms-like tyrosine kinase-1:placental growth factor ratio. However, when the biomarkers were quantified as the rate of increase between 20 and 28 weeks' gestation, there were strong positive associations between spontaneous preterm birth and rate of increase in soluble fms-like tyrosine kinase-1 (1.36 [1.13-1.63]; P=.001) and the soluble fms-like tyrosine kinase-1:placental growth factor ratio (1.50 [1.30-1.73]; P<.0001), and a strong negative association with the rate of increase in placental growth factor (0.71 [0.61-0.82]; P<.0001). Women who were in the highest decile of increase in the soluble fms-like tyrosine kinase-1:placental growth factor ratio and the lowest decile of femur length growth between 20 and 28 weeks' gestation had approximately 9-fold risk of spontaneous preterm birth (9.27 [4.21-20.37]; P<.0001). Competing-risks regression yielded similar results. CONCLUSION: Changing levels of soluble fms-like tyrosine kinase-1 and placental growth factor are indicative of placental dysfunction and are strongly associated with the risk of spontaneous preterm birth, especially when combined with slower fetal femur length growth.

Effect of pentaerythritol tetranitrate (PETN) on the development of fetal growth restriction in pregnancies with impaired uteroplacental perfusion at midgestation-a randomized trial.

BACKGROUND: Fetal growth restriction is strongly associated with impaired placentation and abnormal uteroplacental blood flow. Nitric oxide donors such as pentaerythritol tetranitrate are strong vasodilators and protect the endothelium. Recently, we demonstrated in a randomized controlled pilot study a 38% relative risk reduction for the development of fetal growth restriction or perinatal death following administration of pentaerythritol tetranitrate to pregnant women at risk, identified by impaired uterine perfusion at midgestation. Results of this monocenter study prompted the hypothesis that pentaerythritol tetranitrate might have an effect in pregnancies with compromised placental function as a secondary prophylaxis. OBJECTIVE: This study aimed to test the hypothesis that the nitric oxide donor pentaerythritol tetranitrate reduces fetal growth restriction and perinatal death in pregnant women with impaired placental perfusion at midgestation in a multicenter trial. STUDY DESIGN: In this multicenter, randomized, double-blind, placebo-controlled trial, 2 parallel groups of pregnant women presenting with a mean uterine artery pulsatility index >95th percentile at 19+0 to 22+6 weeks of gestation were randomized to 50-mg Pentalong or placebo twice daily. Participants were assigned to high- or low-risk groups according to their medical history before randomization was performed block-wise with a fixed block length stratified by center and risk group. The primary efficacy endpoint was the composite outcome of perinatal death or development of fetal growth restriction. Secondary endpoints were neonatal and maternal outcome parameters. RESULTS: Between August 2017 and March 2020, 317 participants were included in the study and 307 were analyzed. The cumulative incidence of the primary outcome was 41.1% in the pentaerythritol tetranitrate group and 45.5% in the placebo group (unadjusted relative risk, 0.90; 95% confidence interval, 0.69-1.17; adjusted relative risk, 0.90; 95% confidence interval, 0.69-1.17; P=.43). Secondary outcomes such as preterm birth (unadjusted relative risk, 0.73; 95% confidence interval, 0.56-0.94; adjusted relative risk, 0.73; 95% confidence interval, 0.56-0.94; P=.01) and pregnancy-induced hypertension (unadjusted relative risk, 0.65; 95% confidence interval, 0.46-0.93; adjusted relative risk, 0.65; 95% confidence interval, 0.46-0.92; P=0.01) were reduced. CONCLUSION: Our study failed to show an impact of pentaerythritol tetranitrate on the development of fetal growth restriction and perinatal death in pregnant women with impaired uterine perfusion at midgestation. Pentaerythritol tetranitrate significantly reduced secondary outcome parameters such as the incidence of preterm birth and pregnancy-induced hypertension in these pregnancies.

Copy number variants and fetal growth in stillbirths.

BACKGROUND: Fetal growth abnormalities are associated with a higher incidence of stillbirth, with small and large for gestational age infants incurring a 3 to 4- and 2 to 3-fold increased risk, respectively. Although clinical risk factors such as diabetes, hypertension, and placental insufficiency have been associated with fetal growth aberrations and stillbirth, the role of underlying genetic etiologies remains uncertain. OBJECTIVE: This study aimed to assess the relationship between abnormal copy number variants and fetal growth abnormalities in stillbirths using chromosomal microarray. STUDY DESIGN: A secondary analysis utilizing a cohort study design of stillbirths from the Stillbirth Collaborative Research Network was performed. Exposure was defined as abnormal copy number variants including aneuploidies, pathogenic copy number variants, and variants of unknown clinical significance. The outcomes were small for gestational age and large for gestational age stillbirths, defined as a birthweight <10th percentile and greater than the 90th percentile for gestational age, respectively. RESULTS: Among 393 stillbirths with chromosomal microarray and birthweight data, 16% had abnormal copy number variants. The small for gestational age outcome was more common among those with abnormal copy number variants than those with a normal microarray (29.5% vs 16.5%; P=.038). This finding was consistent after adjusting for clinically important variables. In the final model, only abnormal copy number variants and maternal age remained significantly associated with small for gestational age stillbirths, with an adjusted odds ratio of 2.22 (95% confidence interval, 1.12-4.18). Although large for gestational age stillbirths were more likely to have an abnormal microarray: 6.2% vs 3.3% (P=.275), with an odds ratio of 2.35 (95% confidence interval, 0.70-7.90), this finding did not reach statistical significance. CONCLUSION: Genetic abnormalities are more common in the setting of small for gestational age stillborn fetuses. Abnormal copy number variants not detectable by traditional karyotype make up approximately 50% of the genetic abnormalities in this population.

Risk of adverse perinatal outcomes in pregnancies with "small" fetuses not meeting Delphi consensus criteria for fetal growth restriction.

BACKGROUND: Previous research endeavors examining the association between clinical characteristics, sonographic indices, and the risk of adverse perinatal outcomes in pregnancies complicated by fetal growth restriction have been hampered by a lack of agreement regarding its definition. In 2016, a consensus definition was reached by an international panel of experts via the Delphi procedure, but as it currently stands, this has not been endorsed by all professional organizations. OBJECTIVE: This study aimed to assess whether an independent association exists between estimated fetal weight and/or abdominal circumference of <10th percentile and adverse perinatal outcomes when consensus criteria for growth restriction are not met. STUDY DESIGN: Data were derived from a passive prospective cohort of singleton nonanomalous pregnancies at a single academic tertiary care institution (2010-2022) that fell into 3 groups: (1) consecutive fetuses that met the Delphi criteria for fetal growth restriction, (2) small-for-gestational-age fetuses that failed to meet the consensus criteria, and (3) fetuses with birthweights of 20th to 80th percentile randomly selected as an appropriately grown (appropriate-for-gestational-age) comparator group. This nested case-control study used 1:1 propensity score matching to adjust for confounders among the 3 groups: fetal growth restriction cases, small-for-gestational-age cases, and controls. Our primary outcome was a composite: perinatal demise, 5-minute Apgar score of <7, cord pH of ≤7.10, or base excess of ≥12. Pregnancy characteristics with a P value of <.2 on univariate analyses were considered for incorporation into a multivariable model along with fetal growth restriction and small-for-gestational-age to evaluate which outcomes were independently predictive of adverse perinatal outcomes. RESULTS: Overall, 2866 pregnancies met the inclusion criteria. After propensity score matching, there were 2186 matched pairs, including 511 (23%), 1093 (50%), and 582 (27%) patients in the small-for-gestational-age, appropriate-for-gestational-age, and fetal growth restriction groups, respectively. Moreover, 210 pregnancies (10%) were complicated by adverse perinatal outcomes. None of the pregnancies with small-for-gestational-age OR appropriate-for-gestational-age fetuses resulted in perinatal demise. Twenty-three of 511 patients (5%) in the small-for-gestational-age group had adverse outcomes based on 5-minute Apgar scores and/or cord gas results compared with 77 of 1093 patients (7%) in the appropriate-for-gestational-age group (odds ratio, 0.62; 95% confidence interval, 0.39-1.00). Furthermore, 110 of 582 patients (19%) with fetal growth restriction that met the consensus criteria had adverse outcomes (odds ratio, 3.08; 95% confidence interval, 2.25-4.20), including 34 patients with perinatal demise or death before discharge. Factors independently associated with increased odds of adverse outcomes included chronic hypertension, hypertensive disorders of pregnancy, and early-onset fetal growth restriction. Small-for-gestational age was not associated with the primary outcome after adjustment for 6 other factors included in a model predicting adverse perinatal outcomes. The bias-corrected bootstrapped area under the receiver operating characteristic curve for the model was 0.72 (95% confidence interval, 0.66-0.74). The bias-corrected bootstrapped area under the receiver operating characteristic curve for a 7-factor model predicting adverse perinatal outcomes was 0.72 (95% confidence interval, 0.66-0.74). CONCLUSION: This study found no evidence that fetuses with an estimated fetal weight and/or abdominal circumference of 3rd to 9th percentile that fail to meet the consensus criteria for fetal growth restriction (based on Doppler waveforms and/or growth velocity of ≥32 weeks) are at increased risk of adverse outcomes. Although the growth of these fetuses should be monitored closely to rule out evolving growth restriction, most cases are healthy constitutionally small fetuses. The management of these fetuses in the same manner as those with suspected pathologic growth restriction may result in unnecessary antenatal testing and increase the risk of iatrogenic complications resulting from preterm or early term delivery of small fetuses that are at relatively low risk of adverse perinatal outcomes.

SARS-CoV-2 placentitis, stillbirth, and maternal COVID-19 vaccination: clinical-pathologic correlations.

Stillbirth is a recognized complication of COVID-19 in pregnant women that has recently been demonstrated to be caused by SARS-CoV-2 infection of the placenta. Multiple global studies have found that the placental pathology present in cases of stillbirth consists of a combination of concurrent destructive findings that include increased fibrin deposition that typically reaches the level of massive perivillous fibrin deposition, chronic histiocytic intervillositis, and trophoblast necrosis. These 3 pathologic lesions, collectively termed SARS-CoV-2 placentitis, can cause severe and diffuse placental parenchymal destruction that can affect >75% of the placenta, effectively rendering it incapable of performing its function of oxygenating the fetus and leading to stillbirth and neonatal death via malperfusion and placental insufficiency. Placental infection and destruction can occur in the absence of demonstrable fetal infection. Development of SARS-CoV-2 placentitis is a complex process that may have both an infectious and immunologic basis. An important observation is that in all reported cases of SARS-CoV-2 placentitis causing stillbirth and neonatal death, the mothers were unvaccinated. SARS-CoV-2 placentitis is likely the result of an episode of SARS-CoV-2 viremia at some time during the pregnancy. This article discusses clinical and pathologic aspects of the relationship between maternal COVID-19 vaccination, SARS-CoV-2 placentitis, and perinatal death.

Death and severe morbidity in isolated periviable small-for-gestational-age fetuses.

OBJECTIVE: This study aims to predict perinatal death or severe sequelae in isolated small-for-gestational-age fetuses, diagnosed at a periviable gestational age, based on ultrasound and Doppler parameters at diagnosis. DESIGN: Observational study. SETTING: A tertiary perinatal centre. POPULATION: A cohort of singleton non-malformed fetuses suspected to be small for gestational age (estimated fetal weight, EFW, <10th centile) diagnosed at 22.0-25.6 weeks of gestation. The following parameters were recorded at diagnosis: severe smallness (<3rd centile); absent or reversed end-diastolic velocity in umbilical artery; abnormal middle cerebral artery Doppler; abnormal cerebroplacental ratio; abnormal uterine artery Doppler; and absent or reversed end-diastolic velocity in the ductus venosus. METHODS: Logistic regression analysis. MAIN OUTCOME MEASURES: Predictive performance of EFW and Doppler parameters for short-term adverse outcome of perinatal morbimortality and composite serious adverse outcomes (death, neurological impairment or severe bronchopulmonary dysplasia). RESULTS: A total of 155 pregnancies were included. There were 13 (8.4%) intrauterine and 11 (7.7%) neonatal deaths. A short-term adverse perinatal outcome occurred in 40 (25.8%) pregnancies. There were 31 (20%) cases of serious adverse outcomes. For the prediction of serious adverse outcomes, the combination of absent or reversed end-diastolic velocity in the umbilical artery and impaired middle cerebral artery detected by Doppler evaluation achieved a detection rate of 87%, with a false-positive rate of 14% (accuracy 86%). CONCLUSION: In periviable isolated small-for-gestational-age fetuses, a Doppler evaluation of the umbilical and fetal brain circulation can accurately predict short-term adverse perinatal complications and serious adverse outcomes.

Prediction of fetal and neonatal outcomes after preterm manifestations of placental insufficiency: systematic review of prediction models.

OBJECTIVES: To identify all prediction models for fetal and neonatal outcomes in pregnancies with preterm manifestations of placental insufficiency (gestational hypertension, pre-eclampsia, HELLP syndrome or fetal growth restriction with its onset before 37 weeks' gestation) and to assess the quality of the models and their performance on external validation. METHODS: A systematic literature search was performed in PubMed, Web of Science and EMBASE. Studies describing prediction models for fetal/neonatal mortality or significant neonatal morbidity in patients with preterm placental insufficiency disorders were included. Data extraction was performed using the CHARMS checklist. Risk of bias was assessed using PROBAST. Literature selection and data extraction were performed by two researchers independently. RESULTS: Our literature search yielded 22 491 unique publications. Fourteen were included after full-text screening of 218 articles that remained after initial exclusions. The studies derived a total of 41 prediction models, including four models in the setting of pre-eclampsia or HELLP, two models in the setting of fetal growth restriction and/or pre-eclampsia and 35 models in the setting of fetal growth restriction. None of the models was validated externally, and internal validation was performed in only two studies. The final models contained mainly ultrasound (Doppler) markers as predictors of fetal/neonatal mortality and neonatal morbidity. Discriminative properties were reported for 27/41 models (c-statistic between 0.6 and 0.9). Only two studies presented a calibration plot. The risk of bias was assessed as unclear in one model and high for all other models, mainly owing to the use of inappropriate statistical methods. CONCLUSIONS: We identified 41 prediction models for fetal and neonatal outcomes in pregnancies with preterm manifestations of placental insufficiency. All models were considered to be of low methodological quality, apart from one that had unclear methodological quality. Higher-quality models and external validation studies are needed to inform clinical decision-making based on prediction models. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.