Elsevier Trophoblast Research Award Lecture: Searching for an early pregnancy 3-D morphometric ultrasound marker to predict fetal growth restriction

Influence of maternal psychological distress during COVID-19 pandemic on placental morphometry and texture

The Coronavirus Disease 2019 (COVID-19) pandemic has been accompanied by increased prenatal maternal distress (PMD). PMD is associated with adverse pregnancy outcomes which may be mediated by the placenta. However, the potential impact of the pandemic on in vivo placental development remains unknown. To examine the impact of the pandemic and PMD on in vivo structural placental development using advanced magnetic resonance imaging (MRI), acquired anatomic images of the placenta from 63 pregnant women without known COVID-19 exposure during the pandemic and 165 pre-pandemic controls. Measures of placental morphometry and texture were extracted. PMD was determined from validated questionnaires. Generalized estimating equations were utilized to compare differences in PMD placental features between COVID-era and pre-pandemic cohorts. Maternal stress and depression scores were significantly higher in the pandemic cohort. Placental volume, thickness, gray level kurtosis, skewness and run length non-uniformity were increased in the pandemic cohort, while placental elongation, mean gray level and long run emphasis were decreased. PMD was a mediator of the association between pandemic status and placental features. Altered in vivo placental structure during the pandemic suggests an underappreciated link between disturbances in maternal environment and perturbed placental development. The long-term impact on offspring is currently under investigation.

Ultrasonographic evaluation of feto-placental tissues at different intrauterine locations in rabbit

The main purpose of examining multiparous species with real-time ultrasonography is to determine the gestational age and make various fetal measurements for early diagnosis of growth anomalies and sibling mismatches. This study investigated changes in fetometric measurements, obstetric Doppler indices and placental image analysis results based on gestational age and fetal location in fetuses located cranially and caudally between 16 and 24 days gestation in 22 healthy pregnant New Zealand rabbits. The first study group consisted of fetuses positioned at the cranial end (n = 22) while the second group consisted of fetuses positioned at the caudal end (n = 22) in each pregnancy. Fetal biparietal head diameter (BPD) and trunk diameter (TD) were measured, and mean grayness values (MGV) were determined from placental image analysis of each fetus. Using Doppler USG, the pulsatile (PI) and resistance (RI) indices of the uterine artery (UtA) and umbilical artery (UmA) were recorded. By the end of the study, BPD and TD values for cranial and caudal fetuses had significantly increased with gestational age (P < 0.001). The MGV values of caudal fetuses were significantly higher (except for the 16th day) (P < 0.05). The UtA PI value of the caudal fetuses was significantly higher (except for the 18th day) (P < 0.01). The UtA RI values of caudal fetuses were significantly higher than cranial ones on the 16 and 24th days (P < 0.05). The PI of the UmA increased until the 20th day before decreasing significantly in both study groups (P < 0.001). The UmA RI value decreased according to the gestational age in both groups (P < 0.001). It was significantly higher in the caudal fetuses on the 20th day (P < 0.05). The somatic rate of all fetuses peaked at the end of the second trimester, although caudal fetuses had higher fetometric values, and this location difference also affected placental echotexture. In both vessels of caudal fetuses, pulsatility and resistance values were higher. The 20th day of pregnancy was a threshold for the Doppler exam results. In conclusion, growth and metabolic status of fetuses located in different uterine locations in healthy pregnant New Zealand rabbits vary. Based on the these growth curves and hemodynamic data, more comprehensive studies of intrauterine life may be possible.

Second-Trimester 3-Dimensional Placental Sonography as a Predictor of Small-for-Gestational-Age Birth Weight

OBJECTIVES

We previously reported the association between first-trimester 3-dimensional (3D) placental measurements and small-for-gestational-age (SGA) neonates. In this study, we sought to determine whether second-trimester measurements further contribute to the antenatal detection of SGA and preeclampsia.

METHODS

We prospectively collected 3D sonographic volume sets and uterine artery pulsatility indices of singleton pregnancies at 18 to 24 weeks. Placental volume, placental quotient (placental volume/gestational age), mean placental diameter and chorionic diameter, placental morphologic index (mean placental diameter/placental quotient), placental chorionic index (mean chorionic diameter/placental quotient), and placental growth (volume per week) were assessed and evaluated as predictors of SGA and preeclampsia as a composite and alone.

RESULTS

Of 373 pregnancies, the composite outcome occurred in 67 (18.0%): 36 (9.7%) manifested SGA alone; 27 (7.2%) developed preeclampsia alone, and 4 (1.1%) developed both. The placental volume, placental quotient, mean placental diameter, mean chorionic diameter, and volume per week were significantly smaller, whereas the placental morphologic index and chorionic index were significantly larger in pregnancies with the composite outcome (P < .01). Further analyses revealed that the significant associations with placental parameters were limited to the SGA outcome. Each placental measure remained significantly associated with SGA after adjusting for confounders. The mean uterine artery pulsatility index was not associated with either outcome. Placental parameters were moderately predictive of SGA, with adjusted areas under the curve ranging from 0.72 to 0.76. Sensitivity for detection of SGA ranged from 32.5% to 45.0%, with positive predictive values ranging from 17.3% to 22.7%.

CONCLUSIONS

Second-trimester 3D placental measurements can identify pregnancies at risk of SGA. However, there appears to be no significant improvement compared to those obtained in the first trimester.

Three-Dimensional Power Doppler Ultrasonography for Diagnosing Abnormally Invasive Placenta and Quantifying the Risk

OBJECTIVE

To test an objective ultrasound marker for diagnosing the presence and severity of abnormally invasive placenta.

METHODS

Women at risk of abnormally invasive placenta underwent a three-dimensional power Doppler ultrasound scan. The volumes were examined offline by a blinded observer. The largest area of confluent three-dimensional power Doppler signal (Area of Confluence [Acon], cm) at the uteroplacental interface was measured and compared in women subsequently diagnosed with abnormally invasive placenta and women in a control group who did not have abnormally invasive placenta. Receiver operating characteristic curves were plotted for prediction of abnormally invasive placenta and abnormally invasive placenta requiring cesarean hysterectomy.

RESULTS

Ninety-three women were recruited. Results were available for 89. Abnormally invasive placenta was clinically diagnosed in 42 women; 36 required hysterectomy and had abnormally invasive placenta confirmed histopathologically. Median and interquartile range for Acon was greater for abnormally invasive placenta (44.2 [31.4-61.7] cm) compared with women in the control group (4.5 cm [2.9-6.6], P<.001) and even greater in the 36 requiring hysterectomy (46.6 cm [37.2-72.6], P<.001). Acon rose with histopathologic diagnosis: focal accreta (32.2 cm [17.2-57.3]), accreta (59.6 cm [40.1-89.9]), and percreta (46.6 cm [37.5-71.5]; P<.001 analysis of variance for linear trend). Receiver operating characteristic analysis for prediction of abnormally invasive placenta revealed that with an Acon of 12.4 cm or greater, 100% sensitivity (95% confidence interval [CI] 91.6-100) could be obtained with 92% specificity (95% CI 79.6-97.6); area under the curve is 0.99 (95% CI 0.94-1.0). For prediction of abnormally invasive placenta requiring hysterectomy, 100% sensitivity (95% CI 90.3-100) can be obtained with an Acon of 17.4 cm or greater with 87% specificity (95% CI 74.7-94.5; area under the curve 0.98 [0.93-1.0]).

CONCLUSION

The marker Acon provides a quantitative means for diagnosing abnormally invasive placenta and assessing severity. If further validated, subjectivity could be eliminated from the diagnosis of abnormally invasive placenta.

LEVEL OF EVIDENCE

II.