Combining early (<11 weeks' gestation) ultrasound features and maternal factors to predict small-for-gestational age neonates.

OBJECTIVES: Placental related adverse pregnancy outcomes such as fetal growth restriction have significant short- and long-term implications for both mother and fetus. This study aimed to determine if conventional and novel early first trimester ultrasound measures are associated with small for gestational age (SGA) neonates. In addition, we aimed to assess whether a combination of ultrasound measures, maternal characteristics and biochemistry improved the prediction of this adverse pregnancy outcome. METHODS: This was a prospective cohort study including ultrasound measurements: trophoblast thickness (TT), trophoblast volume (TV), mean uterine artery pulsatility index, crown-rump length, fetal heart rate, mean sac diameter (MSD) and yolk sac diameter. Biochemical markers considered in the analysis were placental growth factor (PIGF), pregnancy - associated plasma protein A (PAPP-A), beta human chorionic gonadotropin and alpha fetoprotein. Regression models were fitted for ultrasound parameters using multiples of the median (MoM). All measures were compared with normal birthweight (BW) ≥10th centile and SGA (BW < 10th centile). Logistic regression analysis was used to create a clinical prediction model for SGA based on maternal characteristics, ultrasound measurements at <11 weeks gestational age and maternal biochemistry collected at 10-14 weeks. RESULTS: As compared to pregnancies delivered of babies with normal BW (n = 1068), MoM values for TT, TV, MSD, PAPP-A and PIGF were significantly reduced (P < 0.05) in pregnancies delivered of SGA babies (n = 73). The proposed logistic regression model includes maternal height, TV and PIGF resulting in an area under the receiver operator curve 0.70 (95% CI 0.63-0.76) for the prediction of SGA. CONCLUSION: A significantly decreased TV, measured <11 weeks gestation, is predictive of BW < 10th centile. With addition of maternal height and PIGF, this three-marker algorithm provided a reasonable predictive value for the development of SGA later in pregnancy.

Normative ultrasound data of the fetal transverse thalamic diameter derived from 18 to 22 weeks of gestation in routine second-trimester morphology examinations.

INTRODUCTION: The thalamus is important for a wide range of sensorimotor and neuropsychiatric functions. Departure from normal reference values of the thalamus may be a biomarker for differences in neurodevelopment outcomes and brain anomalies perinatally. Antenatal measurement of thalamus is not currently included in routine fetal ultrasound as differentiation of thalamic borders is difficult. The aim of this work was to present a method to standardise the thalamus measure and provide normative data of the fetal transverse thalamic diameter between 18 and 22 weeks of gestational age. METHODS: Transverse thalamic diameter was measured by two sonographers on 1,111 stored ultrasound images at the standard transcerebellar plane. A 'guitar' shape representative structure is presented to demarcate the thalamic diameter. The relationship of the transverse thalamic diameter with gestational age, head circumference and transcerebellar diameter using linear regression modelling was assessed, and the mean of the thalamic diameter was calculated and plotted as a reference chart. RESULTS: Transverse thalamic diameter increased significantly with increasing gestational age, head circumference, and transcerebellar diameter linearly, and normal range thalamic charts are presented. The guitar shape provided good reproducibility of thalamic diameter measures. CONCLUSION: Measuring thalamus size in antenatal ultrasound examinations with reference to normative charts could be used to assess midline brain structures and predict neurodevelopment disorders and potentially brain anomalies.

Ultrasound parameters to identify and diagnose carpal tunnel syndrome. A review of the literature.

Numerous works of literature have assessed the use of ultrasound to detect carpal tunnel syndrome, suggesting various techniques and cut-off values. Currently, an effective parameter and cut-off value are still debated. The aim of this review is to determine if these parameters have sufficient rigour to allow their use in clinical practice. Twenty-one studies using sonographic parameters to identify carpal tunnel syndrome in comparison with electrodiagnostic testing (EDx) were selected for review. Methodological differences were found between studies in the use of EDx criteria, scanning and recruitment protocols, with participant biometrics often not reported. Parameters including the cross-sectional area of the median nerve at the level of the pisiform bone in addition to the wrist-to-forearm difference demonstrated high diagnostic utility for set cut-off values. Doppler techniques and mobility are promising, and further research is required to understand the effectiveness of these techniques.

Uterine Artery Pulsatility Index Assessment at <11 Weeks' Gestation: A Prospective Study.

OBJECTIVE: Mean uterine artery pulsatility index (meanUAPI) is commonly measured at 11-13+6 weeks to predict adverse pregnancy outcomes including hypertensive disorders and small-for-gestational age. The aims of this study were to establish a population-specific reference range for meanUAPI at <11 weeks, to determine if an abnormal meanUAPI at <11 weeks was associated with adverse pregnancy outcome, and to assess changes in meanUAPI between <11 weeks and 11-13+6 weeks. METHODS: A prospective cohort was examined at <11 weeks and at 11-13+6 weeks to develop reference ranges for meanUAPI. Based on these regression models, meanUAPI Z-scores were compared between outcome groups using a two-sample t test. Longitudinal changes in the meanUAPI between <11 and 11-13+6 weeks were assessed by two-way mixed ANOVA. RESULTS: Prior to 11 weeks, there was no significant difference in meanUAPI between normal (n = 622) and adverse (n = 80) outcomes (mean [95% CI]: 2.62 [2.57-2.67] and 2.67 [2.50-2.84], respectively; p = 0.807). At 11-13+6 weeks, meanUAPI was significantly higher in the adverse (n = 66) compared with the normal (n = 535) outcome group (mean [95% CI]: 1.87 [1.70-2.03] and 1.67 [1.63-1.72], respectively; p = 0.040). There was a statistically significant decrease (p < 0.0001) in meanUAPI between the two time points. CONCLUSION: MeanUAPI measured at <11 weeks' gestation does not appear to be a useful marker for the prediction of placental-related adverse pregnancy outcomes, supporting an argument for the prediction of risk at 11-13+6 weeks' gestation.

First-trimester ultrasound features associated with subsequent miscarriage: A prospective study.

BACKGROUND: First-trimester miscarriage is common, with women increasingly offered an ultrasound scan early in the first trimester to assess the status of their pregnancy. Ultrasound is uniquely situated to significantly impact the clinical management of these women. AIMS: This study aims to determine whether there were any differences in the early ultrasound appearances of pregnancies that continued to be viable or resulted in miscarriage before 12 weeks gestation. MATERIALS AND METHODS: This was a prospective cohort study including ultrasound measurements: mean sac diameter (MSD), yolk sac diameter (YSD), crown-rump length (CRL), fetal heart rate (FHR), trophoblast thickness, trophoblast volume (TTV) and mean uterine artery pulsatility index (meanUAPI). Regression models were fitted for each parameter and Z-scores compared between cohorts that progressed or miscarried after the scan but before 12 weeks gestation. Logistic regression analysis was used to create a prediction model for miscarriage prior to 12 weeks gestation based on the standardised ultrasound measurements recorded during the early first-trimester scan. RESULTS: Comparison of Z-Scores for meanUAPI, TTV, FHR and MSD demonstrated significant variation between the two groups. The proposed logistic regression model resulted in an area under the receiver operator curve of 0.81. At a false-positive rate of 30%, the model resulted in a sensitivity of 76% (95% CI 64-89%). CONCLUSION: The combination of FHR, meanUAPI, TTV in a prediction model for miscarriage may prove to be of value for ongoing pregnancy management in the first trimester.

Impaired fetal thymic growth precedes clinical preeclampsia: a case-control study.

In preeclampsia the maternal adaptive immune system undergoes specific changes, which are different from the physiological processes associated with healthy pregnancy. Whether preeclampsia also affects the fetal immune system is difficult to investigate, due to limited access to the fetus. We hypothesized that if preeclampsia affects the fetal adaptive immune system this might be associated with early changes in thymic growth. In this case-control study, 53 preeclamptic and 120 healthy control pregnancies were matched for maternal age, gestational age and smoking. Fetal thymus diameter was measured as the greatest width perpendicular to a line connecting sternum and spine based on ultrasound images taken at 17-21 weeks gestation. Independent of fetal and maternal anthropometric measures, thymuses were found to be smaller in preeclamptic pregnancies than healthy controls (16.2 mm versus 18.3 mm, respectively, mean difference=2.1 mm, 95% CI: 0.8-3.3, p<0.001), and the odds of developing preeclampsia was estimated to be 0.72 (95% CI: 0.60-0.86, p<0.001) lower for each 1 mm increase in thymus diameter. There was no correlation between the onset of preeclampsia and fetal thymus size. This is the first study to suggest that fetal thymus growth is reduced before the clinical onset of preeclampsia and precedes any described fetal anomalies or maternal immunological changes associated with preeclampsia. We propose that the fetal adaptive immune system is either passively affected by maternal processes preceding clinical preeclampsia or is actively involved in initiating preeclampsia in later pregnancy.

Flow-mediated dilatation assessment in women with preeclampsia compared to women with gestational hypertension.

OBJECTIVES: To assess flow-mediated dilatation (FMD) in women with preeclampsia (PE) versus gestational hypertension (GH) and to determine if results of this ultrasound method vary with modifications to the technique. METHODS: Pregnant women with hypertension (BP ≥ 140/90 mmHg) were recruited. Women were allocated to the PE group if they had proteinuria ≥300 mg/24 h. FMD(o) was calculated from the percentage difference in baseline and post-occlusion (PO) diameter at 45-60 s and FMD(max) from baseline and maximum diameter between 45 and 90 s. FMD(max) was adjusted for hematocrit and shear rate. RESULTS: FMD(o) (m ± SD) was similar (p = 0.83) in the no medication GH (5.3 ± 3.2; n = 15) and the PE (6.5 ± 4.1; n = 13) groups. FMD(o) was reduced (p < 0.001) in the medication GH (3.7 ± 2.8; n = 23) versus the PE (8.8 ± 4.3; n = 25) groups. For FMD(max) the interaction between group and medication was not significant (both p = 0.08) in unadjusted analysis or analysis adjusted for covariates hematocrit (p = 0.023) and shear rate (p = 0.007). Means averaged over medication are presented. FMD(max) was reduced (p < 0.0001) in the GH (5.7 ± 4.0; n = 38) versus the PE group (9.2 ± 4.0; n = 38). Of the PE women, 79% (30/38) reached maximum dilatation by 90 s compared with 63% (24/38) of the GH women (chi-square, p = 0.16). CONCLUSIONS: The FMD(max) analysis revealed reduced FMD in GH women compared with PE women. We therefore hypothesize that PE may be a different disease to GH. Our work demonstrates differing results in FMD(o) and FMD(max) because of modifications in the technique. Previous work on PE and FMD may not be definitive due to this evolving technique.

A longitudinal study using ultrasound to assess flow-mediated dilatation in normal human pregnancy.

OBJECTIVE: To develop normal ranges of endothelial function in normal human pregnancy to use as a screening test for preeclampsia. METHODS: In this longitudinal study, women were studied five times during pregnancy and once postpartum using flow-mediated dilatation (FMD). FMD is a noninvasive ultrasound technique used to assess endothelial function. Healthy nonpregnant women were controls. RESULTS: FMD increased non-significantly in pregnancy until 32 weeks, when it decreased significantly at 36+ weeks (n = 47). CONCLUSION: The fall in FMD in the third trimester has not been previously reported. This indicates the importance of gestational age when assessing FMD as a screening test for preeclampsia.