The utility of cervical elastosonography in prediction of cervical insufficiency: cervical elastosonography and cervical insufficiency

Objective: To evaluate the utility of cervical elastosonography (ES) in prediction of cervical insufficiency (CI).

Methods: A total of 40 women, of which 20 who had previously received the diagnosis of CI and 20 healty women were included in the study. None of the women were pregnant. All subjects underwent sonographic evaluation including cervical length measurement and ES of uterine cervix. Adjacent muscular tissue was the reference point for elastosonography evaluation. Tissue strain ratio values were obtained from all the patients.

Results: The area around the internal cervical os of the group with CI was found to be significantly softer as compared to the control group (higher SR rate, p?<?0.05). Furthermore, the outer parts of the cervix (sites A and D) were also found harder in the group that had CI (lower SR rate, p?<?0.05).

Conclusions: According to our knowledge, this is preliminary study to evaluate the predictive value of cervical ES in CI and we concluded that ES can be used as reliable method to determine CI but it is necessary to be studied in different cohort groups.     

Fetal growth cessation in late pregnancy: its impact on predicted size parameters used to classify small for gestational age neonates

Objective: To evaluate the impact of late 3rd trimester fetal growth cessation on anatomical birth characteristic predictions used in classifying SGA neonates.

Methods: A prospective longitudinal study was performed in 119 pregnancies with normal neonatal growth outcomes. Seven biometric parameters were measured at 3–4 weeks intervals using 3D ultrasonography. Rossavik size models were determined to predict birth characteristics at different ages. Percent Differences (% Diff) were calculated from predicted and measured birth characteristics. Growth Cessation Ages (GCA) were identified when no systematic change in % Diff values occurred after specified prediction ages. Systematic and random prediction errors were compared using different assumptions about the GCA. Predicted and measured size parameters were used to determine six new Growth Potential Realization Index (GPRI) reference ranges. Five were used to sub-classify 34 SGA neonates (weight?<?10th percentile) based on the number of abnormal GPRI values.

Results: Growth cessation ages were 38 weeks for HC, AC, mid-thigh circumference, estimated weight and mid-arm circumference. Crown-heel length GCA was 38.5 weeks. At GCA, birth characteristics had prediction errors that varied from 0.08?±?3.4% to 15.7?±?9.1% and zero % Diff slopes after 38 weeks. Assuming growth to delivery gave increased systematic and random prediction errors as well as positive % Diff slopes after 38 weeks, MA. Seventeen of the SGA neonates had 0 or 1 abnormal GPRI values [Subgroup 1] and 17 others had 2 or more abnormal values [Subgroup 2]. In Subgroup 1, 4/85 (4.7%) of GPRI's were abnormal while in Subgroup 2, 43/85 (50.6%) were abnormal. Use of only one type of GPRI for SGA subclassification resulted in substantial false negative and some false positive rates when compared to subclassification based on all five GPRI values.

Conclusions: Growth cessation occurred at approximately 38 weeks for all six birth characteristics studied. SGA neonates can be separated into normal and growth restricted subgroups based on the frequency of abnormal GPRI values (GPRI Profile Classification).     

Doppler reference values of the fetal vertebral and middle cerebral arteries,at 19–41 weeks gestation

Objectives: Blood flow to the fetal brain is supplied by two vascular systems: the vertebral artery (VA) and the internal carotid artery with its anatomical continuation, the middle cerebral artery (ICA/MCA). In this work, our aim was to establish consistent reference values for the comparative study of both arterial systems.

Methods: The study group consisted of 2323 Doppler examinations of the VA, MCA and UA performed on 2323 single pregnancies between 19 and 41 weeks. These values were afterwards used to calculate the pulsatility index (PI), peak systolic velocity (PSV) and cerebro-placental ratio (CPR) percentiles.

Results: The VA and MCA PI reached maximum values at the end of the second trimester and decreased afterwards due to an increase in the diastolic flow. Conversely, the VA and MCA PSV increased progressively until the end of pregnancy. Regarding the VA and MCA CPR values, they were higher in the middle of the third trimester and decreased afterwards.

Conclusions: In both arterial systems, Doppler reference values have been calculated for the PI, PSV and CPR, being available for future comparative studies.     

Does the level of amniotic fluid have an effect on the accuracy of sonographic estimated fetal weight at term?

Objective: Controversy exists concerning the impact of amniotic fluid index (AFI) on the accuracy of sonographic estimation of fetal weight (EFW). Thus, we aimed to evaluate whether differences in AFI has an influence on the accuracy of sonographic EFW.

Methods: All term, singleton pregnancies which underwent a sonographic EFW and measurement of AFI within a week from delivery were included. Cases were stratified into three categories according to AFI: (1) Normal AFI (51–249?mm), (2) Oligohydramnios (AFI?≤?50?mm) and (3) Polyhydramnios (AFI?≥?250?mm). Inaccurate EFW was defined if there was more than 15% difference between sonographic EFW and actual birthweight.

Results: Overall, 1746 pregnancies were identified (1096 with normal AFI, 455 with oligohydramnios and 195 with polyhydramnios). Mean AFI was 115.8?±?60?mm, 28.1?±?13?mm and 293?±?35?mm, p?<?0.001, and mean sonographic EFW was 3182.5?±?573?g, 3118.8?±?517?g and 3713.2?±?461?g, p?<?0.001, respectively. Demographic data and gestational age at delivery were similar. Mean birthweight was 3221.7?±?535?g, 3132.5?±?505?g and 3654.1?±?480?g, p?<?0.001, respectively. The rate of inaccurate EFW was similar between the groups (8.4%, 8.7% and 9.7%, p?=?0.19, respectively). On multivariate analysis, AFI was not associated with EFW inaccuracy (OR 1.01, 95% C.I 0.67–1.54, p?=?0.93).

Conclusion: AFI has limited impact on the percentage of errors in sonographic fetal weight estimation a week prior delivery.     

Maternal and umbilical cord copeptin levels in pregnancies complicated by fetal growth restriction

Objective: The aim of this study was to compare maternal and fetal serum copeptin concentrations in pregnancies complicated by isolated fetal growth restriction (FGR), and uncomplicated pregnancies, and to investigate relationships between copeptin levels and clinical parameters.

Methods: Maternal and fetal serum copeptin levels were measured in 21 women with pregnancies complicated by isolated FGR and 20 women with normal pregnancies (control group). Doppler assessment of the uterine and umbilical arteries was performed in each patient.

Results: Maternal serum copeptin levels were significantly higher in women with isolated FGR compared to controls (p?=?0.042). In addition, maternal copeptin levels were inversely correlated with the uterine artery pulsatility and resistance indices and positively correlated with neonatal birth weight. Umbilical vein copeptin levels were significantly increased in neonates with adverse outcomes (p?=?0.001).

Conclusions: Increased maternal copeptin concentration may reflect a response to stress, thus serving as a compensatory mechanism in pregnancies complicated by FGR.     

Impact of amniotic fluid “sludge” on the risk of preterm delivery

Objective: To evaluate the impact of amniotic fluid “sludge” (AFS) on the risk of preterm delivery and to describe the effect of antibiotic treatment in that situation.

Methods: Case–control study including singleton pregnancies with or without AFS, between 15–32 weeks of gestation. Factors associated with preterm delivery before 32 weeks, 34 weeks and 37 weeks were evaluated with univariate and multivariate logistic regression. Since all women with AFS in this study were treated with antibiotics, a historical comparison was performed with similar patients with AFS found before 2007 and not treated with antibiotics.

Results: AFS was observed in 90/1220 patients (7.4%). AFS was associated with shorter cervical length, greater body mass index, cervical cerclage and preterm birth before 28 weeks. However, after adjustment, AFS did not remain associated with preterm delivery before 32 or 34 weeks. The historical comparison suggested that azithromycin could significantly reduce the risk of preterm delivery before 34 weeks (odds ratio: 0.2; 95% CI: 0.04–0.92).

Conclusions: AFS, treated with azithromycin, was associated with a higher risk of prematurity, but not independently after adjustment for cervical length and second trimester vaginal bleeding. Further studies need to evaluate the effect of antibiotics in pregnancies with AFS.     

Three-dimensional versus two-dimensional ultrasound for fetal nasal bone evaluation in the second trimester

Objectives: To compare two-dimensional with three-dimensional ultrasound evaluation of the fetal nasal bone in the second trimester.

Methods: A prospective, non-interventional study was conducted, in 55 singleton fetuses, between 18 and 24 weeks’ gestation. Fetal nasal bone length was measured in the midsagittal plane by two-dimensional imaging and in the midsagittal and coronal plane with three-dimensional ultrasound. All three measurements were compared with one another using one-way repeated samples-measures ANOVA and paired samples t-test.

Results: The average fetal nasal bone length (mean?±?SD) as determined by the three methods was 7.01?±?0.94?mm for the two-dimensional midsagittal, 6.96?±?1.34?mm for the three-dimensional midsagittal, and 6.98?±?1.32?mm for the three-dimensional coronal plane; comparisons between one another were not statistically significant. Unilateral hypoplasia and bifid shape of the fetal nasal bone were detected in 8.2% and 20.4% of cases, respectively, by three-dimensional ultrasound, whereas all cases evaded detection with two-dimensional ultrasound (p?<?0.001 and p?=?0.001, respectively).

Conclusions: Fetal nasal bone length measured with two-dimensional ultrasound does not differ significantly from three-dimensional measurements. However, three-dimensional ultrasound is superior in detecting unilateral nasal bone hypoplasia or absence and in assessing fetal nasal bone shape. Hence, fetal nasal bone examination in the second trimester should include three-dimensional ultrasound evaluation.     

The utility of ultrasound in late pregnancy compared with clinical evaluation in detecting small and large for gestational age fetuses in low-risk pregnancies

Objective: To determine the utility of ultrasound (US) in late pregnancy for identifying fetuses with growth disturbances.

Methods: This study was designed as a retrospective study of birth weights over a 12-month period at the Royal Hobart Hospital (RHH) and Barwon Health (BH). Data were collected from the discharge summaries and medical records at both hospitals targeting abnormal fetal weight below 10th percentile (small for gestational age – SGA) and above 90th percentile (large for gestational age – LGA).

Results: There were 4079 study patients from both hospitals. After weight adjustment by gender and gestational age, an abnormal fetal weight was detected in 741 cases (babies over the 90th percentile or below 10th percentile). One hundred and twenty-eight patients with high-risk pregnancies were excluded. Therefore, a total of 613 patients remained that were considered to be low-risk pregnancies with abnormal foetal growth; 305 patients from RHH and 308 from BH. The antenatal detection rate for LGA was 35.9%, at RHH by combination of US and clinical evaluation, while for BH it was 34.8% by clinical evaluation alone (p?=?0.910). The antenatal detection rate for SGA was 36.8% via US and clinical evaluation at RHH and 54.5% by clinical evaluation alone at BH (p?=?0.006).

Conclusion: This study shows no benefit in the use of routine US for the antenatal diagnosis of LGA compared with clinical evaluation in low-risk pregnancies. US evaluation was inferior to clinical evaluation in the antenatal diagnosis of SGA in low-risk pregnancies.     

New technique for assessing fetal heart growth using three-dimensional ultrasonography: description of the technique and reference curves

Objective: To describe a new technique for assessing fetal growth using three-dimensional ultrasonography (3DUS) using the extended imaging virtual organ computer-aided analysis (XI VOCAL) software and its respective reference curves.

Methods: We conducted a cross-sectional study on 303 normal singleton pregnancies between their 20th and 34th weeks. To assess fetal heart growth, we used the XI VOCAL software with 10 planes in which the reference lines (beginning and end) were placed at the cardiac apex, the output level of the vessels and the base above the diaphragm, respectively. To assess the correlation between distance and interval, polynomial regressions were performed with adjustments using the coefficient of determination (R²). To assess the inter-observer reproducibility, we used the intraclass correlation coefficient (ICC).

Results: The mean distance between the apex and the base of the fetal heart ranged from 14.41?±?1.24?mm to 26.24?±?2.62?mm between the 20th and 34th weeks, respectively. The mean interval between the apex and the base of the fetal heart ranged from 1.56?±?0.13?mm and 2.94?±?0.30?mm between the 20th and 34th weeks, respectively. We observed good correlation of distance and interval with the gestational age, with R²?=?0.73 and 0.74, respectively. We observed a good inter-observer to the interval and distance with ICC?=?0.983 and 0.996, respectively.

Conclusion: We described a new technique for assessing fetal heart growth using 3DUS and determined reference curves for the distance and interval between the 20th and 34th weeks of pregnancy.     

Ultrasound evaluation of cortical brain development in fetuses with intrauterine growth restriction

Objective: We evaluated the ultrasound appearance of brain volume and cortical development in fetuses with early growth restriction and placental insufficiency.

Methods: We examined a cohort of 20 fetuses with severe intrauterine growth restriction (IUGR) and evidence of placental insufficiency by three-dimensional (3D) ultrasound between 24 and 34 weeks. We graded cortical development and measured the supratentorial intracranial volume. The cortical grading and volume were compared to data obtained from a reference population of 28 adequate for gestational age (AGA) fetuses.

Results: Ultrasound examinations were performed in 20 fetuses with IUGR. The biometry and brain volume were significantly reduced in IUGR fetuses. There was evidence of accelerated cortical development in IUGR fetuses.

Conclusion: This study confirms that the smaller brain volume in IUGR fetuses, with normal or accelerated cortical maturation as previously depicted with postnatal MRI examination, can be demonstrated by prenatal 3D ultrasound.