The added value of the sFlt-1/PlGF ratio in pregnant women with intrauterine growth restriction (IUGR) with or without preeclampsia on adverse pregnancy outcomes and neonatal morbidities: a retrospective study

BACKGROUND The sFlt-1/PlGF (soluble fms-like tyrosine kinase-1/placental growth factor) ratio in the serum of pregnant women is a predictive marker for preeclampsia (PE). PE is often associated with intrauterine growth restriction (IUGR). Overall, growth-restricted fetuses are at increased risk for neonatal morbidities and perinatal death. An increased sFlt-1/PlGF ratio may be valuable for discriminating between different causes of IUGR. The goal of this study was to investigate the added value of the sFlt-1/PlGF ratio in pregnant women with IUGR on adverse pregnancy outcomes, neonatal morbidities and mortality. METHODS This was a retrospective, monocenter, observational study conducted at the University Hospital of Antwerp. All singleton pregnancies with IUGR and known serum levels of sFlt-1/PlGF with a gestational age (GA) of 24 weeks until 37 weeks were included. The results were analyzed over a period of almost three years (January 2022 until October 2024). In total, 85 patients met the inclusion criteria, ten of whom had normal serum levels of sFlt-1/PlGF (values less than 85), whereas the other 75 patients had increased sFlt-1/PlGF ratios. The maternal characteristics, fetal and neonatal mortality rates, adverse pregnancy outcomes and neonatal morbidities of all the patients and their neonates were recorded and analyzed. RESULTS In IUGR fetuses with increased maternal serum sFlt-1/PlGF ratios, aberrant ultrasonic fetal doppler, fetal demise and obstetrical diseases such as PE are more often observed. In the group of neonates from mothers with a high sFlt-1/PlGF ratio, more neonatal morbidities, such as respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, early-onset sepsis, late-onset sepsis and retinopathy of prematurity, are observed. Nevertheless, it is important to correct those results for GA and birth weight since morbidities are more often observed in more premature neonates. CONCLUSION In patients with IUGR due to placental insufficiency, an increased sFlt-1/PlGF ratio is observed.