Reduced placental volume and flow in severe growth restricted fetuses

MRI assessed placental volume and adverse pregnancy outcomes: Secondary analysis of prospective cohort study

INTRODUCTION

Our goal was to evaluate the potential utility of magnetic resonance imaging (MRI) placental volume as an assessment of placental insufficiency.

METHODS

Secondary analysis of a prospective cohort undergoing serial placental MRIs at two academic tertiary care centers. The population included 316 participants undergoing MRI up to three times throughout gestation. MRI was used to calculate placental volume in milliliters (ml). Placental-mediated adverse pregnancy outcome (cAPO) included preeclampsia with severe features, abnormal antenatal surveillance, and perinatal mortality. Serial measurements were grouped as time point 1 (TP1) <22 weeks, TP2 22 0/7-29 6/7 weeks, and TP3 ≥30 weeks. Mixed effects models compared change in placental volume across gestation between cAPO groups. Association between cAPO and placental volume was determined using logistic regression at each TP with discrimination evaluated using area under receiver operator curve (AUC). Placental volume was then added to known clinical predictive variables and evaluated with test characteristics and calibration.

RESULTS

59 (18.7 %) of 316 participants developed cAPO. Placental volume growth across gestation was slower in the cAPO group (p < 0.001). Placental volume was lower in the cAPO group at all time points, and alone was moderately predictive of cAPO at TP3 (AUC 0.756). Adding placental volume to clinical variables had moderate discrimination at all time points, with strongest test characteristics at TP3 (AUC 0.792) with sensitivity of 77.5 % and specificity of 75.3 % at a predicted probability cutoff of 15 %.

DISCUSSION

MRI placental volume warrants further study for assessment of placental insufficiency, particularly later in gestation.

Ultrasonographic placental parameters at 11-13+6 weeks' gestation in the prediction of complications in pregnancy after assisted reproductive technology

OBJECTIVE

To evaluate the performance of maternal factors, biophysical and biochemical markers at 11-13 + 6 weeks' gestation in the prediction of gestational diabetes mellitus with or without large for gestational age (GDM ± LGA) fetus and great obstetrical syndromes (GOS) among singleton pregnancy following in-vitro fertilisation (IVF)/embryo transfer (ET).

MATERIALS AND METHODS

A prospective cohort study was conducted between December 2017 and January 2020 including patients who underwent IVF/ET. Maternal mean arterial pressure (MAP), ultrasound markers including placental volume, vascularisation index (VI), flow index (FI) and vascularisation flow index (VFI), mean uterine artery pulsatility index (mUtPI) and biochemical markers including placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were measured at 11-13 + 6 weeks' gestation. Logistic regression analysis was performed to determine the significant predictors of complications.

RESULTS

Among 123 included pregnancies, 38 (30.9%) had GDM ± LGA fetus and 28 (22.8%) had GOS. The median maternal height and body mass index were significantly higher in women with GDM ± LGA fetus. Multivariate logistic regression analysis demonstrated that in the prediction of GDM ± LGA fetus and GOS, there were significant independent contributions from FI MoM (area under curve (AUROC) of 0.610, 95% CI 0.492-0.727; p = 0.062) and MAP MoM (AUROC of 0.645, 95% CI 0.510-0.779; p = 0.026), respectively.

CONCLUSION

FI and MAP are independent predictors for GDM ± LGA fetus and GOS, respectively. However, they have low predictive value. There is a need to identify more specific novel biomarkers in differentiating IVF/ET pregnancies that are at a higher risk of developing complications.

Ex-Vivo MRI of the Normal Human Placenta: Structural-Functional Interplay and the Association With Birth Weight

BACKGROUND

Advanced magnetic resonance imaging (MRI) methods are increasingly being used to assess the human placenta. Yet, the structure-function interplay in normal placentas and their associations with pregnancy risks are not fully understood.

PURPOSE

To characterize the normal human placental structure (volume and umbilical cord centricity index (CI)) and function (perfusion) ex-vivo using MRI, to assess their association with birth weight (BW), and identify imaging-markers for placentas at risk for dysfunction.

STUDY TYPE

Prospective.

POPULATION

Twenty normal term ex-vivo placentas.

FIELD STRENGTH/SEQUENCE

3 T/ T₁ and T₂ weighted (T₁ W, T₂ W) turbo spin-echo, three-dimensional susceptibility-weighted image, and time-resolved angiography with interleaved stochastic trajectories (TWIST), during passage of a contrast agent using MRI compatible perfusion system that mimics placental flow.

ASSESSMENT

Placental volume and CI were manually extracted from the T₁ W images by a fetal-placental MRI scientist (D.L., 7 years of experience). Perfusion maps including bolus arrival-time and full-width at half maximum were calculated from the TWIST data. Mean values, entropy, and asymmetries were calculated from each perfusion map, relating to both the whole placenta and volumes of interest (VOIs) within the umbilical cord and its daughter blood vessels.

STATISTICAL TESTS

Pearson correlations with correction for multiple comparisons using false discovery rate were performed between structural and functional parameters, and with BW, with P < 0.05 considered significant.

RESULTS

All placentas were successfully perfused and scanned. Significant correlations were found between whole placenta and VOIs perfusion parameters (mean R = 0.76 ± 0.06, range = 0.67-0.89), which were also significantly correlated with CI (mean R = 0.72 ± 0.05, range = 0.65-0.79). BW was correlated with placental volume (R = 0.62), but not with CI (P = 0.40). BW was also correlated with local perfusion asymmetry (R = -0.71).

DATA CONCLUSION

Results demonstrate a gradient of placental function, associated with CI and suggest several ex-vivo imaging-markers that might indicate an increased risk for placental dysfunction.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.

Effect of delayed cord clamping on stem cell transfusion and hematological parameters in preterm infants with placental insufficiency: a pilot randomized trial

The feasibility of delayed cord clamping (DCC) in preterm infants with placental insufficiency (PI) is questionable. We aimed to study the effect of DCC on stem cell transfusion, hematological parameters, and clinical outcomes in preterm infants born to mothers with PI. Preterm infants, < 34 weeks' gestation, born to mothers with PI were randomized based on the timing of umbilical cord clamping into delayed clamping for 60 s (DCC group) or immediate cord clamping (ICC group) groups at time of birth. CD34 percentage as a marker of stem cell transfusion, early and late-onset anemia, hypothermia, hypotension, polycythemia, hyperbilirubinemia, duration of oxygen therapy, bronchopulmonary dysplasia, intra-ventricular hemorrhage, necrotizing enterocolitis, sepsis, mortality, and length of hospital stay were compared between studied groups. We found that peripheral blood CD34 percentage was significantly higher in DCC compared with that in the ICC group (median (IQR) of 0.5 (0.40-0.7) versus 0.35 (0.20-0.5), p = 0.004). Infants in the DCC group had significantly lower episodes of anemia of prematurity at 2 months, red blood cell transfusion, and shorter duration of oxygen therapy compared with those in the ICC group.Conclusion: In conclusion, DCC compared with ICC increased stem cell transfusion and decreased early- and late-onset anemia in preterm infants with placental insufficiency.Trial registration: NCT03731546 www.clinicaltrials.gov What is Known: • Delayed cord clamping has been recommended by the American Academy of Pediatrics as a standard of care practice during delivery of preterm infants. • The feasibility of DCC in preterm infants with placental insufficiency (PI) is uncertain. What is New: • This randomized controlled trial demonstrated that DCC in the delivery room care of preterm infants born to mothers with placental insufficiency increased stem cell transfusion and decreased early- and late-onset anemia.

Role of diffusion MR imaging (DWI) and three-dimensional ultrasound (3DUS) in the assessment of placental insufficiency in the gestational hypertension

Background

DWI is a non-invasive MR modality that is not contrast-based. In the current study, we aimed to evaluate DWI in correlation with 3DUS in the detection of placental insufficiency in high-risk pregnancies complicated with hypertension.

This prospective analysis included 80 pregnancies; 40 hypertensive and 40 controls, gestational age ranged from 22 to 34 weeks. All cases had undergone 3DUS aided by power Doppler scanning and DWI. There is no given contrast. Data were correlated to histopathology.

Results

Doppler US showed a significant relation between RI of the right uterine artery of cases and control (P = 0.014). There was also a positive correlation between the presence of the diastolic notch and RI value. The mean ADC value in the controls was 1.87 ± 0.26 mm2/s, while in hypertensive was 1.36 ± 0.09 mm2/s. In DWI images, there was a significant difference between patients with normal and those with abnormal placental signals (P value = 0.047). Also, there was a significant difference between the measurement of placental volume by MRI and US among cases and controls (P values ≤0.001 and 0.017, respectively).

Conclusion

Diffusion-weighted imaging can detect early subtle findings and signs of placental dysfunction more than detected with 3DUS, so it can add to the diagnostic accuracy of US in imaging of pregnancies at high risk of placental insufficiency.