Can fetal fractions in the cell-free DNA test predict the onset of fetal growth restriction?

Placental elasticity in trisomy 21: prenatal assessment with shear-wave elastography

OBJECTIVES

To quantitatively examine placental tissue elasticity in Trisomy 21 (T21) pregnancies using shear wave elastography (SWE) and to evaluate the potential contribution of placental SWE measurements in predicting T21 fetuses.

METHODS

This prospective case-control study was conducted at tertiary centers between January 2022 and January 2024. The study included 30 pregnant women who underwent invasive prenatal diagnostic testing and were found to have T21, along with 30 pregnant women with a normal karyotype. Central placental elasticity measurements were performed from the middle of the thickest part of the placenta, avoiding vascular areas and lacunae, and peripheral measurements were performed two centimeter (cm) medial to the lateral border of the placenta.

RESULTS

The mean gestational week at measurement was 16 ± 2 weeks. Peripheral placental SWE velocity was significantly higher in the T21 group (7.4 ± 3.7 kPa vs. 4.8 ± 3.6 kPa, p=0.004). Similarly, central placental SWE velocity was also significantly higher in the T21 group (6.5 ± 2.1 kPa vs. 4.1 ± 2.6 kPa, p<0.001). In predicting T21, central placental SWE velocity had 76.7 % sensitivity and 73.3 % specificity with a cut-off value of ≥4.35 kPa (p<0.001), and peripheral had 70 % sensitivity and 66.7 % specificity with a cut-off value of ≥4.65 kPa (p=0.004). When central placental SWE velocity was ≥4.35 kPa, the risk of T21 was increased 6.64-fold, even after adjusting for maternal age, which is a well-known risk factor for T21.

CONCLUSIONS

Placental stiffness was significantly higher in T21 in both central and peripheral areas. Placental elasticity, especially in the central part, may be a potential marker for T21.

Relationship Between Adverse Neonatal Outcomes and Diastolic Deceleration Area on Fetal MCA Doppler in Patients with Late Fetal Growth Restriction

Objectives

This study aimed to assess the predictive value of the Diastolic Deceleration Area (DDA), a novel Doppler ultrasound parameter, in detecting adverse neonatal outcomes in fetuses with late-onset fetal growth restriction (FGR). While Doppler parameters such as cerebroplacental ratio (CPR), umbilicocerebral ratio (UCR), and cerebralplacentaluterine ratio (CPUR) are commonly used for fetal monitoring, their predictive power varies. Given the importance of cerebral blood flow redistribution in fetal adaptation to hypoxia, we investigated whether DDA could serve as a reliable indicator of fetal distress and adverse perinatal outcomes.

Methods

This prospective case-control study was conducted between January 2024 and July 2024, including 90 pregnant women: 45 diagnosed with late-onset FGR and 45 gestational age-matched healthy controls. Doppler ultrasound measurements, including umbilical artery, uterine artery, middle cerebral artery Doppler indices, CPR, UCR, CPUR, and DDA, were performed. The primary outcome was the prediction of adverse neonatal events, such as neonatal intensive care unit (NICU) admission, neonatal sepsis, respiratory distress, low APGAR scores, and low cord blood pH. Receiver Operating Characteristic (ROC) curve analysis was used to determine the predictive ability of the Doppler indices.

Results

DDA values were significantly higher in the FGR group compared to controls (p<0.001). At a cut-off value of >7.23, DDA demonstrated 50% sensitivity and 88% specificity, making it the most specific Doppler parameter for predicting adverse neonatal outcomes. In comparison, CPR (cut-off ≤2.11), UCR (cut-off >0.46) and CPUR (cut-off ≤1.36) had higher sensitivity (96%, 96%, 54%) but lower specificity (32%, 31% and 85% respectively).

Conclusion

DDA is a promising Doppler parameter for identifying fetuses at risk in late-onset FGR. Its high specificity suggests it could be a valuable supplementary tool alongside traditional Doppler indices for better risk assessment and clinical decision-making. Further studies are needed to validate its role in perinatal care.

Association between fetal fraction of cell-free DNA and adverse pregnancy outcomes

PURPOSE

To determine the association between fetal fraction (FF) levels in cell-free fetal DNA (cffDNA) testing and adverse pregnancy outcomes.

METHODS

This retrospective cohort study, conducted at a single center, involved 2063 pregnant women with normal 1st and 2nd trimester non-invasive prenatal test (NIPT) results between 2016 and 2021. Pregnancy outcomes were examined by determining the  < 4% and  < 5th percentile (3.6%) cut-off values for low fetal fraction (LFF). Pregnancy outcomes were also examined by dividing the FF into population-based quartiles. Adverse pregnancy outcomes were pregnancy-induced hypertensive diseases (PIHD), gestational diabetes mellitus (GDM), spontaneous preterm birth (PTB), intrahepatic cholestasis of pregnancy (ICP), small for gestational age (SGA), large for gestational age (LGA), low birth weight (LBW), macrosomia, and 1st and 5th minutes low APGAR scores (< 7).

RESULTS

PIHD was significantly higher in LFF (< 4% and  < 5th percentile) cases (p = 0.015 and p < 0.001, respectively). However, in population-based quartiles of FF, PIHD did not differ significantly between groups. Composite adverse maternal outcomes were significantly higher in the FF < 4% group (p = 0.042). When analyzes were adjusted for maternal age, BMI, and gestational age at NIPT, significance was maintained at  < 4%,  < 5th percentile LFF for PIHD, and  < 4% LFF for composite adverse maternal outcomes. However, there was no significant relationship between LFF with GDM, ICP and PTB. Additionally, there was no significant association between low APGAR scores, SGA, LGA, LBW, macrosomia, and LFF concerning neonatal outcomes.

CONCLUSION

Our study showed that LFF in pregnant women with normal NIPT results may be a predictor of subsequent PIHD.

Circulating biomarkers associated with placental dysfunction and their utility for predicting fetal growth restriction

Fetal growth restriction (FGR) leading to low birth weight (LBW) is a major cause of neonatal morbidity and mortality worldwide. Normal placental development involves a series of highly regulated processes involving a multitude of hormones, transcription factors, and cell lineages. Failure to achieve this leads to placental dysfunction and related placental diseases such as pre-clampsia and FGR. Early recognition of at-risk pregnancies is important because careful maternal and fetal surveillance can potentially prevent adverse maternal and perinatal outcomes by judicious pregnancy surveillance and careful timing of birth. Given the association between a variety of circulating maternal biomarkers, adverse pregnancy, and perinatal outcomes, screening tests based on these biomarkers, incorporating maternal characteristics, fetal biophysical or circulatory variables have been developed. However, their clinical utility has yet to be proven. Of the current biomarkers, placental growth factor and soluble fms-like tyrosine kinase 1 appear to have the most promise for placental dysfunction and predictive utility for FGR.

Analysis of Causes and Results of Fetal Growth in Utero Caused by Genetic Factors Detected by Ultrasound

In order to investigate the value of the ultrasonic monitoring of maternal and fetal vascular parameters, serum vitamin D, and placental growth factor (PLGF) in predicting fetal growth restriction (FGR), a method of ultrasonic detection of genetic factors causing fetal growth in utero was proposed. 125 pregnant women with FGR diagnosed in our hospital from June 2018 to June 2021 (the FGR group) and 125 pregnant women with a normal prenatal examination (the control group) were collected retrospectively. The systolic/diastolic blood flow ratio (S/D), pulsatile index (PI), and resistance index (RI) of the fetal umbilical artery (UA), middle cerebral artery (MCA), and maternal uterine artery (UtA) were monitored by ultrasound at 20 to 24 weeks of gestation, and the levels of serum vitamin D and PLGF were detected. The receiver operating characteristic curve (ROC curve) was used to evaluate the predictive value of FGR. The results showed that the S/D, PI, and RI of UA in the FGR group were higher than those in the control group, the areas under the curve (AUC) were 0.866, 0.817, and 0.849, and the sensitivity and specificity were (72.8%, 91.2%), (50.4%, 100%), and (72.8%, 91.2%), respectively. The S/D, PI, and RI of MCA were lower than those of the control group. The AUC was 0.882, 0.869, and 0.834, respectively; the sensitivity and specificity were (92.0%, 74.4%), (88.8%, 81.6%), and (90.4%, 72%), respectively. The S/D, PI, and RI of UtA were higher than those of the control group; the AUC was 0.768, 0.729, and 0.732; the sensitivity and specificity were (91.2%, 52%), (48%, 90.4%), and (48.8%, 90.4%), respectively. The serum levels of vitamin D and PLGF were lower than those of the control group (AUC 0.784 and 0.807), and the sensitivity and specificity were (54.4%, 91.2%) and (99.2%, 52%), respectively. It was concluded that the ultrasound monitoring of UA, MCA, and UtA in pregnant women in the middle of pregnancy and detection of serum vitamin D and PLGF levels had a certain predictive value for FGR. Moreover, the comprehensive evaluation could reduce the occurrence of FGR in high-risk pregnant women.