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

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.