sFlt-1/PlGF ratio for the prediction of the time of delivery

A point-of-care urine test to predict adverse maternal and neonatal outcomes in Asian women with suspected preeclampsia

OBJECTIVES

To assess clinical utility of the urine Congo red dot test (CRDT) in predicting composite adverse maternal and neonatal outcomes in women with suspected preeclampsia (PE).

METHODS

CRDT result and pregnancy outcomes were prospectively documented in women with new onset or pre-existing hypertension, new or pre-existing proteinuria, PE symptoms and suspected PE-related fetal growth restriction or abnormal Doppler presenting from 20 weeks' gestation between January 2020 and December 2022. Participants and clinicians were blinded to the CRDT result and managed according to internally agreed protocols. Composite maternal outcome was defined as PE, postpartum hemorrhage, intensive care unit admission, and maternal death. Composite neonatal outcome was defined as small for gestational age, preterm birth, 5-min Apgar score < 7, neonatal intensive care unit admission, and neonatal death.

RESULTS

Two hundred and forty-four women out of two hundred and fifty-one (97.2%) had a negative CRDT. All seven women with positive CRDT had both adverse maternal and neonatal outcomes, giving positive predictive values (PPV) of 100%. Rates of composite adverse maternal and neonatal outcomes in CDRT negative women were 103/244 [42.2%, 95% confidence interval (CI) 36.2%-48.5%] and 170/244 (69.7%, 95% CI 63.6%-75.1%), respectively. CRDT negative predictive values (NPV) for adverse maternal and neonatal outcomes were, respectively, 141/244 (57.8%, 95% CI 48.6%-68.2%) and 74/244 (30.3%, 95% CI 23.8%-38.1%).

CONCLUSION

CRDT had low NPV but high PPV for adverse maternal and neonatal outcomes in women with suspected PE. Its role in clinical management and triage of women with suspected PE is limited as it cannot identify those at low risk of developing adverse outcomes.

Prediction of preterm birth in growth-restricted and appropriate-for-gestational-age infants using maternal PlGF and the sFlt-1/PlGF ratio-A prospective study

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.

Trends in antenatal corticosteroid administration: did our timing improve?

OBJECTIVES

We aimed to analyze trends in the rate of effective antenatal corticosteroid prophylaxis (ACS) administrations across a spectrum of typical diagnoses associated with preterm birth.

METHODS

In this retrospective study we utilized delivery data after ACS from 2014 to 2020 at Charité Berlin, Germany. We evaluated the rate of effective ACS administrations defined as ≤10 days between last dose of ACS and delivery as well as the rate of post-ACS births on/after 37 + 0 weeks. We explored conditions associated with high rates of ineffective ACS administrations (>10 days before delivery). We analyzed the trend of ACS-effectiveness during the study period in the overall cohort and in placental dysfunction and cervical insufficiency diagnoses.

RESULTS

The overall rate of effective ACS administrations was 42 % (709/1,672). The overall percentage of deliveries after/at 37 + 0 weeks following ACS administration was 19 % (343). Placenta previa, twin pregnancy and isthmocervical insufficiency were associated with ineffective ACS (19-34 % effective i.e. ≤10 days before delivery). The overall ratio of effective ACS applications rose over time (p=0.002). Over the course of this study ACS effectiveness increased in placental dysfunction and isthmocervical insufficiency diagnoses (p=0.028; p=0.001).

CONCLUSIONS

Compared to a previous publication we found a decrease of post-ACS deliveries after/at 37 + 0 weeks (19 vs. 27 %). Ineffective ACS administrations are still frequent in patients with placenta previa, twin pregnancy and isthmocervical insufficiency. It remains to be investigated in future trials if the introduction of new diagnostic tools such as soluble Fms-like tyrosinkinase-1/placental growth factor (sFlt-1/PlGF) testing and placental alpha-microglobulin-1 (PAMG-1) testing directly led to an increased ACS effectiveness.

Maternal Serum Angiogenic Profile and Its Correlations with Ultrasound Parameters and Perinatal Results in Normotensive and Preeclamptic Pregnancies Complicated by Fetal Growth Restriction

FGR is a complication of pregnancy in which the fetus does not reach its programmed growth potential due to placental reasons and it is the single largest risk factor of stillbirth. Babies with FGR are at increased risk of mortality and morbidity not only in the perinatal period, but also in later life. FGR presents a huge challenge for obstetricians in terms of its detection and further monitoring of pregnancy. The ultrasound is the gold standard here; apart from assessing fetal weight, it is used to measure Doppler flows in maternal and fetal circulation. It seems that additional tests, like biochemical angiogenic factors measurement would be helpful in diagnosing FGR, identifying fetuses at risk and adjusting the surveillance model. The study aimed to assess the potential relationship between the concentration of sEng, sFlt-1, PlGF, and the sFlt-1/PlGF ratio in maternal serum at delivery and maternal and fetal Doppler flow measurements as well as perinatal outcomes in pregnancies complicated by FGR with and without PE, isolated PE cases and normal pregnancies. The use of angiogenic markers is promising not only in PE but also in FGR. Numerous correlations between ultrasound and Doppler studies, perinatal outcomes and disordered angiogenesis marker levels in maternal serum suggest that biochemical parameters have a great potential to be used as a complementary method to diagnose and monitor pregnancies with FGR. The, PlGF in particular, could play an outstanding role in this regard.

Performance of sFlt-1/PIGF Ratio for the Prediction of Perinatal Outcome in Obese Pre-Eclamptic Women

Obese women are at high risk of developing pre-eclampsia (PE). As an altered angiogenic profile is characteristic for PE, measurement of soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PIGF) ratio in the maternal serum can be helpful for PE diagnosis, as well as for adverse perinatal outcome (APO) prediction. There is growing evidence that obesity might influence the level of sFlt-1/PIGF and, therefore, the aim of the study was the evaluation of sFlt-1/PIGF as an APO predictor in obese women with PE. Pre-eclamptic women who had an sFlt-1/PIGF measurement at the time of diagnosis were retrospectively included. Women were classified according to their pre-pregnancy body mass index (BMI) as normal weight (BMI < 25 kg/m2), overweight (BMI > 25−29.9 kg/m2) or obese (BMI ≥ 30 kg/m2). APO was defined as the occurrence of one of the following outcomes: Small for gestational age, defined as a birthweight < 3rd centile, neonatal mortality, neonatal seizures, admission to neonatal unit required (NICU) or respiratory support. A total of 141 women were included. Of them, 28 (20%) patients were obese. ROC (receiver operating characteristic) analysis revealed a high predictive value for sFlt-1/PIGF and APO across the whole study cohort (AUC = 0.880, 95% CI: 0.826−0.936; p < 0.001). However, the subgroup of obese women showed a significantly lower level of sFlt-1 and, therefore, the performance of sFlt-1/PIGF as APO predictor was poorer compared to normal or overweight PE women (AUC = 0.754, 95% CI: 0.552−0.956, p = 0.025). In contrast to normal or overweight women, a ratio of sFlt-1/PIGF < 38 could not rule out APO in women with obesity.

Course of the sFlt-1/PlGF ratio in fetal growth restriction and correlation with biometric measurements, feto-maternal Doppler parameters and time to delivery

Purpose

The study aimed to assess the course of the soluble Fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio in pregnant women with fetal growth restriction (FGR) and to evaluate potential associations between the sFlt-1/PlGF ratio and feto-maternal Doppler parameters, fetal biometric measurements and the time between study inclusion and birth (“time to delivery”).

Methods

This was a retrospective longitudinal single center study including 52 FGR cases. The serum levels of sFlt-1 and PlGF were measured by using the BRAHMS Kryptor Compact PLUS. Fetal biometric and Doppler parameters, as well as the sFlt-1/PlGF ratio, were obtained both upon study inclusion and upon birth.

Results

Various associations between the levels of the biomarkers in maternal blood upon study inclusion and upon birth and sonographic parameters were observed in FGR cases: umbilical artery (p < 0.01), uterine arteries (p < 0.01), ductus venosus (p < 0.05), cerebroplacental ratio (CPR) (p < 0.01), femur length (p < 0.01) and birth weight (p < 0.01). The higher the sFlt-1/PlGF ratio upon study inclusion, the shorter the “time to delivery” (p < 0.01). The multivariate regression analysis showed that the greater the daily percentage increase of the angiogenic markers, the shorter the “time to delivery” (p < 0.01).

Conclusion

The fetal well-being, as measured by feto-maternal Doppler parameters such as CPR and the severity of the placental dysfunction, as measured by the urgency of birth and birth weight, is reflected by the level of the sFlt-1/PlGF ratio in the maternal serum. A rapid daily increase of the sFlt-1/PlGF ratio is significantly associated with the clinical progression of the disease.

Prediction of Adverse Pregnancy Outcome Related to Placental Dysfunction Using the sFlt-1/PlGF Ratio: A Narrative Review

The sFlt-1 (soluble fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio is a helpful tool for the prediction and diagnosis of preeclampsia (PE). Current data even show that the ratio has the potential to predict adverse pregnancy outcomes (APO) caused by placental pathologies. The aim of this article is to give a brief overview of recent findings on APO predictions based on the sFlt-1/PlGF ratio. The focus is on obstetric pathologies related to placental dysfunction (PD) such as PE and/or fetal growth restriction (FGR). New uses of the sFlt-1/PlGF ratio as a predictor of APO demonstrate its potential with regard to planning hospitalization and corticosteroid administration and the optimal timing of delivery. However, prospective interventional studies are warranted to define the exact role of the sFlt-1/PlGF ratio as a predictor of adverse pregnancy outcomes caused by placental pathologies.

Prediction of adverse perinatal outcome and the mean time until delivery in twin pregnancies with suspected pre-eclampsia using sFlt-1/PIGF ratio

PURPOSE

An elevated soluble fms-like tyrosine kinase-1 (sFlt-1) / placental growth factor (PlGF) ratio is associated with adverse perinatal outcome (APO) and the mean time until delivery (MTUD) in singleton pregnancies complicated by pre-eclampsia (PE). Data on APO and MTUD prediction in twin pregnancies using sFlt-1/PlGF ratio are scarce. We evaluated the predictive value of the sFlt-1/PIGF ratio regarding APO and MTUD in twin pregnancies with suspected PE and/or HELLP syndrome.

METHODS

This is a single center retrospective cohort study. All twin pregnancies with suspected PE/HELLP and determined sFlt-1/PIGF were included. Composite APO (CAPO) was defined as the presence of at least one of the following outcomes: respiratory distress syndrome (RDS), intubation, admission to neonatal intensive care unit (NICU) and arterial umbilical cord pH value < 7.10. Selective fetal growth restriction (s-FGR) was analyzed separately.

RESULTS

For final analysis, 49 twin pregnancies were included. Median sFlt-1/PIGF ratio was not significantly different in patients with CAPO compared to those without (89.45 vs. 62.00, p = 0.669). MTUD was significantly negative correlated with sFlt-1/PIGF ratio (r = -0.409, p < 0.001). For the whole study cohort, ROC analysis revealed no predictive value for sFlt-1/PIGF and CAPO (AUC = 0.618, 95% CI: 0.387-0.849, p = 0.254). However, sFlt-1/PIGF ratio showed a predictive value for s-FGR (AUC = 0.755, 95% CI: 0.545-0.965, p = 0.032).

CONCLUSION

In twin pregnancies with PE and/or HELLP, sFlt-1/PIGF ratio may be helpful for s-FGR prediction and decision-making regarding close monitoring of high-risk patients. However, further prospective studies are warranted to define the role of sFlt-1/PlGF ratio as outcome predictor in twin pregnancies.

Role of sFlt-1/PIGF ratio and uterine Doppler in pregnancies with chronic kidney disease suspected with Pre-eclampsia or HELLP syndrome

PURPOSE

Pregnancies of women with chronic kidney disease (CKD) are at higher risk of experiencing adverse perinatal (APO) and maternal outcome (AMO). Mean uterine artery pulsatility index (mUtA-PI) as well as the ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are helpful tools in diagnosing pre-eclampsia (PE) in women with CKD. The aim of the study was to evaluate the role of sFlt-1/PIGF ratio and mUtA-PI as predictors for APO, AMO, preterm delivery and decline of kidney function in CKD pregnancies.

METHODS

A total of 28 CKD pregnancies with suspected PE/HELLP syndrome were retrospectively included, in whom both sFlt-1/PIGF and mUtA-PI were determined during the third trimester. APO was defined as fetal growth restriction, respiratory distress syndrome, intubation, admission to NICU, 5 min Apgar <7 and intracerebral hemorrhage. AMO was defined as the development of PE, HELLP syndrome or resistant hypertension. Decline of kidney function was defined as a 25% increase of creatinine level after delivery.

RESULTS

Of all included women, eight (28.6%) developed a PE/HELLP syndrome. AMO (28.6%) and APO (32.1%) were frequently observed. ROC analyses revealed a predictive value for AMO and sFlt-1/PIGF or mUtA-PI. Neither sFlt-1/PIGF nor mUtA-PI could predict APO or decline of postnatal kidney function. mUtA-PI was a predictor for preterm delivery.

CONCLUSION

Uterine Doppler and sFlt-1/PIGF are predictors of AMO in CKD pregnancies. Therefore, both markers might be helpful for an improved risk assessment. However, neither sFlt-1/PIGF nor mUtA-PI were able to predict a decline of postnatal kidney function or APO.

Role of sFlt-1/PlGF ratio and feto-maternal Doppler for the prediction of adverse perinatal outcome in late-onset pre-eclampsia

PURPOSE

The sFlt-1 (soluble fms-like tyrosine kinase-1)/PlGF (placental growth factor) ratio and uterine artery Doppler have shown to be helpful in the diagnosis of pre-eclampsia (PE). The predictive value of the cerebroplacental ratio (CPR) regarding adverse perinatal outcome (APO) in low-risk pregnancies is intensively discussed. We evaluated the extent to which sFlt-1/PlGF ratio and feto-maternal Doppler may be useful in predicting APO in singleton pregnancies complicated by late-onset PE and/or HELLP syndrome.

METHODS

This is a retrospective study from 2010 to 2018 consisting of singleton pregnancies with confirmed diagnosis of late-onset (lo ≥ 34 weeks) PE/HELLP syndrome in which sFlt-1/PlGF ratio and feto-maternal Doppler (mUtA-PI: mean uterine artery pulsatility index and CPR) were determined. The ability of sFlt-1/PlGF ratio, mUtA-PI, CPR and their combination to predict APO or SGA was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

67 patients were included in the final analysis. Of these, sFlt-1/PlGF was > 110 (defining angiogenic lo PE) in 40.3% (27/67), mUtA-PI was above the 95th centile in 34.3% (23/67) patients and CPR was lower than the 5th centile in 10.4% (7/67). Abnormal sFlt-1/PlGF and mUtA-PI as well as CPR were associated with a lower birth weight (BW). Late-preterm birth (< 37 weeks) as well as postnatal diagnosis of small for gestational age (SGA: BW < 3rd centile) was significantly more often in angiogenic lo PE cases. Neither sFlt-1/PIGF nor CPR or mUtA-PI were APO predictors. Only for sFlt-1/PlGF, ROC analysis revealed a significant predictive value for postnatal SGA (AUC = 0.856, p = 0.001, 95% CI 0.75-0.97). There was no statistical added value of combined SGA predictors as compared to sFlt-1/PlGF alone.

CONCLUSIONS

In patients with lo PE, adding sFlt-1/PlGF ratio to routine antepartum fetal surveillance may be useful to identify cases of postnatal SGA. However, further prospective studies are warranted to define the role of feto-maternal Doppler and sFlt-1/PlGF ratio as outcome predictors.

The sFlt-1/PlGF ratio values within the <38, 38-85 and >85 brackets as compared to perinatal outcomes

Background Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are used as markers of preeclampsia. The aim of this paper was to assess the correlations between the sFlt-1/PlGF ratio values within the <38, 38-85 and >85 brackets and perinatal outcomes in pregnancies that require determination of these markers. Methods A total of 927 pregnant patients between 18 and 41 weeks' gestation suspected of or confirmed with any form of placental insufficiency (preeclampsia, intrauterine growth restriction [IUGR], gestational hypertension, HELLP syndrome, placental abruption) were included in the study. In each of the patients, the sFlt-1/PlGF ratio was calculated. Patients were divided into three groups according to the sFlt-1/PlGF ratio brackets of <38, 38-85 and >85. Results Significantly worse perinatal outcomes were found in the sFlt-1/PlGF >85 group, primarily with lower cord blood pH, neonatal birth weight and shorter duration of gestation. Statistically significant correlations between the values of these markers and the abovementioned perinatal effects were found. Conclusion An sFlt-1/PlGF ratio value of >85 suggests that either preeclampsia or one of the other placental insufficiency forms may occur, which is associated with lower cord blood pH, newborn weight and earlier delivery. Determining the disordered angiogenesis markers and calculating the sFlt-1/PlGF ratio in pregnancies complicated by placental insufficiency may lead to better diagnosis, therapeutic decisions and better perinatal outcomes.