Reference range of fetal cisterna magna volume by three-dimensional ultrasonography using the VOCAL method

Abstract

Objective: To determine reference values for the fetal cisterna magna volume by three-dimensional ultrasonography (3DUS) using the virtual organ computer-aided analysis (VOCAL) method.

Methods: A cross-sectional study was conducted with 224 healthy pregnant women between 17 and 29 completed weeks. Measurement of the fetal cisterna magna volume was performed in the standard axial plane of the transverse diameter of the cerebellum through the VOCAL method with a 30° angle. For the determination of reference values, polynomial regressions with adjustments by the coefficient of determination (R²) were held. The reliability and agreement were made by the intra-class correlation coefficient (ICC) and limits of agreement of the Bland-Altman graph.

Results: The average of the fetal cisterna magna volume ranged from 0.73?±?0.25 to 3.79?±?1.10?cm³ between 17 and 29 weeks, respectively. Correlation was observed between the fetal cisterna magna volume and the gestational age (GA), best represented by a quadratic equation: ?1.918+0.0284?×?GA + 0.0065?×?GA² (R^2?=?0.67). It was observed good reliability and intra-observer agreement, with ICC?=?0.92 and 95% limits of agreement (?49.7; 48.4). There was low inter-observer reliability and agreement, with ICC?=?0.58 and 95% limits of agreement (?114.0; 80.2).

Conclusion: Reference values for the fetal cisterna magna volume by 3DUS using the VOCAL method were determined and showed good agreement and intra-observer reliability.     

Fetal thymus: visualization rate and volume by integrating 2D- and 3D-ultrasound during 2nd trimester echocardiography

Objective: To assess the visualization rate and transverse diameter of fetal thymus by two-dimensional ultrasound (2DUS) as well as the fetal thymus volume by three-dimensional ultrasound (3DUS) during the 2nd trimester echocardiography.

Methods: A prospective cross-sectional study involving 100 normal fetuses between 18w0d and 23w6d was performed. The identification of fetal thymus and peri-thymic vessels was realized at level of three vessels and trachea (3VT). The transverse diameter was obtained placing a line cursor perpendicular to the line connecting the sternum and the spine. The fetal thymus volume was obtained by virtual organ computer-aided analysis (VOCAL) with 30° of rotation. We used the percentage of visualization rate of 2D structures and means and 95% confidence intervals (CI) for fetal thymus transverse diameter and volume.

Results: The visualization rate of fetal thymus by 2DUS was of 100% in all gestational ages using the 3VT view. Addition of color Doppler ultrasound facilitates identification of the thy-box and enhanced the calculation of both fetal thymus transverse diameter and volume. The mean fetal thymus transverse diameter by 2DUS ranged from 11?mm at 18 weeks to 19?mm at 23 weeks of gestation. The mean fetal thymus volume by 3DUS ranged from 1.25?cm³ at 18 weeks to 2.61?cm³ at 23 weeks of gestation.

Conclusion: We demonstrated a high visualization rate of fetal thymus and peri-thymic vessels by 2DUS during the 2nd trimester echocardiography. The measurements of transverse diameter by 2DUS and the volume by 3DUS also showed a high success rate.     

Fetal thigh and upper-arm volumes by three-dimensional ultrasound to predict low postnatal body mass index

Objective: To assess the usefulness of estimating fetal upper arm and thigh volumes as predictors of low postnatal body mass index (BMI) using three-dimensional ultrasonography (3DUS) with extended imaging virtual organ computer-aided analysis (XI VOCAL).

Methods: This prospective cross-sectional study analyzed 300 singleton pregnancies between 33 and 41 weeks of gestation. The Hadlock 4 formula was used to estimate fetal weight. The XI VOCAL 10 planes method was used to assess fetal upper arm and thigh volumes. After delivery, the newborns’ BMI was evaluated and considered low (≤10th percentile) or normal (>10th percentile). We determined receiver operating characteristics (ROC) curves and respective areas under the curves for the percentiles of fetal weight and fetal thigh and upper arm volumes.

Results: Of the 300 newborns, BMI was ≤10th percentile for 21 and >10th percentile for 279 newborns. The area under the ROC curve for fetal weight, obtained using the Hadlock formula, and fetal upper arm and thigh volumes, obtained by 3DUS, were 0.801, 0.930 and 0.924, respectively. We determined the sensitivity and specificity of the three parameters for predicting low postnatal BMI and found values of 85.70% and 65.60%, respectively, for fetal weight, 90.48% and 88.17%, respectively, for fetal thigh volume, and 76.19% and 92.47%, respectively, for fetal upper arm volume.

Conclusion: Fetal upper arm and thigh volumes estimated using 3DUS with XI VOCAL were effective predictors of low postnatal BMI.     

Reference ranges of fetal adrenal gland and fetal zone volumes between 24 and 37 + 6 weeks of gestation by three-dimensional ultrasound

Objective: To establish reference ranges of the fetal adrenal gland (AG) and fetal zone (FZ) volumes using three-dimensional ultrasound (3DUS).

Methods: We performed a prospective cross-sectional study with 204 normal singleton pregnancies between 24 and 37?+?6 weeks of gestation. The fetal AG and FZ volumes were obtained using the virtual organ computer-aided analysis method with a 30° rotation. To establish reference ranges as the function of gestational age (GA), quantile regression was performed with the adjusted coefficient of determination (R²). Intra- and inter-observer repeatability was performed using the intraclass correlation coefficient (ICC).

Results: The mean results of fetal AG and FZ values were 0.42?cm³ (0.04–1.22) and 0.10?cm³ (0.02–0.47), respectively. The best-fit quantile regression models for fetal AG and FZ volumes as the function of GA were in first-degree models: AG = ?0.937?+?0.041 × GA (R^2?=^?0.124) and FZ = ?0.201?+?0.009 × GA (R^2?=^?0.127), respectively. We observed good intra-observer repeatability of fetal AG and FZ volumes, with an ICC of 0.996 and 0.989, respectively. We also observed good inter-observer repeatability, with an ICC of 0.972 and 0.966 for AG and FZ, respectively.

Conclusion: The reference ranges of AG and FZ volumes using 3DUS between 24 and 37?+?6 weeks of gestation were established and exhibited good repeatability.     

Fetal cerebral ventricle volumetry: comparison between 3D ultrasound and magnetic resonance imaging in fetuses with ventriculomegaly

Objectives.?The aim of this study was to evaluate feasibility of fetal lateral ventricle (LV) volumetry in fetuses with ventriculomegaly and to compare measurements performed by 3D sonographic method virtual organ computer-aided analysis (VOCAL) with those obtained by magnetic resonance imaging (MRI).

Methods.?This cross-sectional study evaluated 30 fetuses with atrial width (AW) between 10 and 30?mm, from 20 to 36 gestational weeks. Fifty-nine ventricles were measured by two observers. Sonographic volumetric measurements using VOCAL 30° were performed with an ACCUVIX XQ machine (Medison, Korea) and MRI assessments with a Sonata system using ARGUS software (Siemens, Germany). Agreement between both techniques was assessed by intraclass correlation coefficient (ICC) calculation, and proportionate Bland–Altman plots were constructed.

Results.?A high degree of reliability was observed between VOCAL and MRI measurements (ICC 0.928, 95%CI [0.876;0.958]). Bland–Altman plots confirmed the high correlation (mean of differences: 1.62 cm³ and standard deviation:?±?8.41 cm³).

Conclusion.?Three-dimensional volumetry of fetal LVs by VOCAL method has good agreement with fetal MRI in fetuses with ventriculomegaly and may be used as an additional tool in patient counseling and prognosis prediction.     

Fetal cardiac interventricular septum: volume assessment by 3D/4D ultrasound using spatio-temporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL)

Objective: To determine reference values for fetal interventricular septum (IVS) volume by 3D/4D ultrasound using spatio-temporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL).

Methods: A prospective cross-sectional study was conducted on 200 consecutive normal low-risk pregnant women at a gestational age ranging from 18w0d to 33w6d. The volume data sets of the fetal heart were acquired by applying STIC to a four-chamber plane. IVS volume was calculated offline using VOCAL with rotation of 30° (six planes). To assess the correlation of fetal IVS volume as a function of gestational age (GA), Pearson’s correlation coefficient (r) and polynomial regression models with adjustments through the coefficient of determination (R²) were calculated. The intra-class coefficient (ICC) was used to evaluate intra- and inter-observer reproducibility.

Results: A good correlation between GA and fetal IVS volume (r?=?0.827) was observed. The mean fetal IVS volume ranged from 0.13?±?0.03?cm³ (0.08–0.18?cm³) at 18wd0 of gestation to 1.33?±?0.37?cm³ (0.41–1.98?cm³) at 33w6d. The best correlation between fetal IVS volume and GA was exponential: fetal IVS volume?=?0.11e^0.139×GA (R^2?=?0.785). A good intra- and inter-observer reliability were observed, with ICC?=?0.999 and 0.991, respectively.

Conclusions: Reference values for fetal IVS volume using STIC and VOCAL by 3D/4D ultrasound between 18w0d and 33w6d of gestation were determined and showed to be reliable and concordant.     

Influence of gestational age and fetal heart rate on the fetal mechanical PR interval

Objective: The fetal mechanical PR interval obtained via pulsed Doppler has previously been demonstrated to correlate with electrocardiographic PR interval measured in the neonate. We sought to further analyze the influence of fetal heart rate and gestational age upon the fetal mechanical PR interval.

Methods: We searched our database for mechanical PR intervals, which were obtained during fetal echocardiography performed in our antenatal diagnostic unit. We included fetuses with a normal cardiac structural survey. The mechanical PR interval is measured from the A wave of the mitral valve to the beginning of ventricular systole corresponding to the opening of the aortic valve. Linear regression curves were generated to examine the correlation of mechanical PR interval with gestational age and fetal heart rate. Analysis of variance was used to compare the mean variation across three gestational age groups: 17–21.9 weeks (n?=?24), 22–25.9 weeks (n?=?52) and 26–38 weeks (n?=?20).

Results: Mechanical PR intervals were measured in 96 fetuses with normal fetal echocardiography. The mechanical PR interval was 123.9?±?10.3?ms (mean?±?SD), with a range of 90–150?ms. Linear regression curves correlating mechanical PR interval with fetal heart rate and gestational age demonstrated a flat slope with R²?=?0.016, p?=?0.22 and R²?=?0.0004, p?=?0.85, respectively. The mechanical PR interval measured over the three gestational ages was as follows (mean?±?SD): 122.3?±?10.5?ms for 17–21.9 weeks; 125.0?±?9.6?ms for 22–25.9 weeks; and 123.1?±?11.9?ms for 26–38 weeks. Analysis of variance revealed no difference among the mechanical PR interval means measured over the three gestational age groups (p?=?0.53).

Conclusions: Fetal mechanical PR interval ranges from 90 to 150?ms in fetuses with sonographically normal fetal cardiac structure and rate. The mechanical PR interval appears to be independent of gestational age and fetal heart rate.     

Reference values for the volumes of foetal heart atrial wall by three-dimensional ultrasound using STIC and VOCAL methods between 20w0d and 33w6d weeks of gestation

Objective: To establish reference values for the volumes of foetal heart atrial wall by three-dimensional (3D) ultrasound using spatio-temporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL) methods.

Methods: We performed a retrospective cross-sectional study with 170 normal singleton pregnancies between 20 weeks?+?0 days (20w0d) and 33 weeks?+?6 days (33w6d) of gestation. Foetal heart atrial wall volume was obtained by VOCAL method with 30-degree rotation (six planes) subtracting the internal volume from the atrium volume. Polynomial regression with adjustments by determination coefficient (R²) was performed. To calculate the interobserver reproducibility, concordance correlation coefficient (CCC) was applied.

Results: The mean?±?standard deviation (SD) for the left atrium wall volume (cm³) ranged from 0.54?±?0.21 at 20w0d–20w6d to 2.17?±?0.30 at 33w0d–33w6d. The mean?±?SD for the right atrium wall volume (cm³) ranged from 0.45?±?0.16 at 20w0d–20w6d to 2.17?±?0.62 at 33w0d–33w6d. We observed a satisfactory interobserver reproducibility with CCC?=?0.69 and 0.58 for the left and right volumes of foetal heart atrial wall, respectively. The best-fit models were first-degree: volume for the left atrium wall?=??2.194?+?0.139*GA (R^2?=^?0.41) and volume for the right atrium wall?=??2.757?+?0.155*GA (R^2?=^?0.37).

Conclusion: Reference values for the volumes of foetal heart atrial wall by 3D ultrasound using STIC and VOCAL methods between 20w0d and 33w6d weeks of gestation were established.     

Reference intervals of embryos/fetuses heart rate between 6 and 14 weeks of pregnancy

Abstract

Objective: To determine reference intervals for the embryos/fetuses heart rate (HR) between 6 and 14 weeks of pregnancy.

Methods: A retrospective cross-sectional study was carried in a single center with singleton pregnancies of embryos/fetuses with a crown-rump length (CRL) between 5 and 85?mm. The HR was assessed by real time M-mode or spectrum Doppler ultrasound. To evaluate the correlation between embryo/fetal HR and CRL, polynomial equations were calculated, with adjustment by the determination coefficient (R²).

Results: A total of 5867 pregnancies were assessed. The mean gestational age was 10.37?±?2.12 weeks. The mean maternal age was 26.41?±?6.78 years. The mean embryo/fetal HR (bpm) for the CRL (mm) intervals 5├15; 15├25; 25├35; 35├45; 45├55; 55├65; 65├75; 75├85 was 145.1?±?18.7; 167.2?±?10.1; 166.9?±?8.7; 165.5?±?6.9; 162.2?±?6.8; 159.2?±?6.4; 157.1?±?6.4; 154.9?±?7.3; respectively. The following third-order equation best represented the correlation between embryo/fetal HR and CRL: HR?=?119.25?+?3.596*CRL-0.07954*CRL^2?+?0.00051*CRL³ (R^2?=?0.36).

Conclusion: Reference intervals of HR in embryos/fetuses in a large sample were determined. These reference intervals can be used in high-risk early pregnancy losses.     

Five-dimensional long bones biometry for estimation of femur length and fetal weight at term compared to two-dimensional ultrasound: a pilot study

Background/objective: This study aimed to evaluate accuracy of five-dimensional long bones (5D LB) compared to two-dimensional ultrasound (2DUS) biometry to predict fetal weight among normal term women.

Methods: Fifty six normal term women were recruited at Ain Shams Maternity Hospital, Egypt from 14 May to 30 November 2015. Fetal weight was estimated by Hadlock’s IV formula using 2DUS and 5D LB. Estimated fetal weights (EFW) by 2DUS and 5D LB were compared with actual birth weights (ABW).

Results: Mean femur length (FL) was 7.07?±?0.73?cm and 6.74?±?0.67?cm by 2DUS and 5D LB (p?=?.02). EFW was 3309.86?±?463.06?g by 2DUS and 3205.46?±?447.85?g by 5D LB (p?=?.25). No statistical difference was observed between ABW and EFW by 2DUS (p?=?.7) or 5D LB (p?=?.45). Positive correlation was found between EFW by 2DUS, 5D LB, and ABW (r?=?0.67 and 0.7; p?p?=?.15).

Conclusions: 2DUS and 5D LB had same accuracy for fetal weight estimation at normal term pregnancy.     

The assessment of placental volume and mean gray value in preeclamptic placentas by using three-dimensional ultrasonography

Objectives: We aimed to evaluate the placental volume and placental mean gray value in preeclampsia and healthy placentas by using three-dimensional (3D) ultrasonography and Virtual Organ Computer-aided AnaLysis (VOCAL).

Methods: This case–control prospective study consisted of 27 singleton pregnancies complicated by preeclampsia and 54 healthy singleton pregnancies matched for gestational age, maternal age and parity. Placental volume and placental volumetric mean gray values were evaluated. The placental volume (cm³) was analyzed using the VOCAL imaging program, and 3D histogram was used to calculate the volumetric mean gray value (%).

Results: Preeclamptic and control group consisted of 27 (mean age: 28.90?±?5.95 years, mean gestation: 32.0?±?4.55 weeks) and 54 (mean age: 29.48?±?5.78 years, mean gestation: 32.61?±?4.23 weeks) singleton pregnancies, respectively. Placental volume was significantly smaller in preeclampsia (250.62?±?91.69 versus 370.98?±?167.82?cm³; p?=?0.001). Volumetric mean gray value of the placenta was significantly higher in preeclampsia (38.24?±?8.41 versus 33.50?±?8.90%; p?=?0.043). Placental volume was significantly correlated with the estimated fetal weight (r?=?0.319; p?=?0.003). There was negative significant relation between placental volume and umbilical artery pulsatility index, resistance index and systolic/diastolic ratio (r?=?–0.244, p?=?0.024; r?=?–0.283, p?=?0.005; r?=?–0.241, p?=?0.024, respectively).

Conclusions: Placental volume diminishes significantly in preeclampsia, whereas volumetric mean gray values increases. This may reflect the early alterations in preeclamptic placentas, which may help to understand the pathophysiology better.     

Doppler study of the embryonic heart in normal pregnant women

Objective.?To describe normal fetal cardiac and hemodynamic development in normal early first trimester pregnancies.

Materials and methods.?Eighty-eight women with singleton, uncomplicated pregnancies were prospectively studied with transvaginal ultrasound, pulsed and color Doppler. Heart diameter, heart rate, and inflow and outflow waveforms with valve signals were documented. The proportion of the cardiac cycle of isovolumetric relaxation time (IRT%) and isovolumetric contraction time (ICT%) as well as Tei index were calculated.

Results.?Ninety-one percent of studies were successful. Heart diameter and the fetal heart rate showed a positive correlation with increasing gestational age: R = 0.80 (p < 0.000001), R = 0.76 (p < 0.000001), respectively. Mean heart diameter at 6 weeks was 1.28 ± 0.26 mm and mean fetal heart rate was 117 ± 6 bpm compared to 3.88 ± 0.54 mm and 171 ± 6 bpm at 10 weeks. The inflow waveform was monophasic (atrial contraction) in all cases from 6 to 9 weeks. Eight pregnancies (9%) miscarried between 6 and 12 weeks of gestation and the heart exams were characterized by increased IRT% compared with the survivors. In survivors, IRT% decreased between 7 and 8 weeks, from 32.9 ± 10.7% to 20.8 ± 5.7% (p < 0.0001). ICT% decreased from 18.6 ± 4.4% of the cardiac cycle at 8 weeks to 12.6 ± 4.4% at 9 weeks (p < 0.0008) (after heart development period).

Conclusions.?Doppler examination of the fetal cardiac function is possible after 5 weeks of gestation. After 8 weeks of gestation, the fetal heart is morphologically mature but has not yet achieved effective myocardial compliance. The embryonic human heart is dependent on the atrial contraction for ventricular filling throughout the period of cardiac development. Non-survivors manifest myocardial dysfunction.     

Three-dimensional ultrasound using the VOCAL technique for estimation of reference values of fetal thigh volume in normally grown Egyptian fetuses from 20 to 41 weeks

Objective: To establish the normal reference values for the fetal thigh volume (FTV) of normally grown Egyptian fetuses using three-dimensional (3D) virtual organ computer aided analysis (VOCAL) method.

Patients and methods: A total of 334 Egyptian pregnant women carrying a singleton living normally grown fetus between the 20th and the 41st weeks of gestation were enrolled in this cross-sectional study. FTV was measured using the 3D VOCAL method with 30° rotation. Estimated fetal weight (EFW) was calculated based on Hadlock formula.

Results: FTV correlated strongly with gestational age (r = 0.921, p?<?0.001) and EFW (r?=?0.891, p?<?0.001). For clinical application, a nomogram of growth percentiles of FTV was produced.

Conclusion: Reference values of FTV between 20th and 41st weeks of gestation in normally grown Egyptian fetuses were provided using the 3D VOCAL method. These data may be helpful to assess fetal growth and to diagnose deviation from normal.     

Reproducibility of echocardiographic measurements of human fetal left ventricular volumes and ejection fractions using four-dimensional ultrasound with the spatio-temporal image correlation modality

Objectives

To determine the reproducibility, both reliability and agreement, of measurements of fetal left ventricular parameters from volumes obtained by spatio-temporal image correlation (STIC) acquisition applying virtual organ computer-aided analysis (VOCAL) and Simpson's rule (method of discs). Furthermore the success rate of STIC acquisition was determined.

Study design

In 84 pregnancies between 20 and 34 weeks of gestation the fetal heart was scanned using the STIC modality. An optimal four-chamber view in end-diastole and end-systole was obtained. Left ventricular end-diastolic volume, left ventricular end-systolic volume, stroke volume and ejection fraction were determined. For calculations based on Simpson's rule only one plane was traced, whereas for VOCAL six planes were traced. To quantify the reliability intraclass correlation coefficients were calculated for both intra- and inter-observer measurements. Agreement of measurements was evaluated by Bland-Altman plots.

Results

The STIC volumes of 54 women (64%) were excluded from the study because of poor quality, leaving 30 volumes for further analysis. Intraclass correlation coefficients for intra-observer reliability for VOCAL and Simpson were 0.99 and 0.99 for left ventricular end-diastolic volume, 0.95 and 0.92 for left ventricular end-systolic volume, 0.98 and 0.97 for stroke volume, 0.76 and 0.77 for ejection fraction, respectively. Intraclass correlation coefficients for inter-observer reliability for VOCAL and Simpson were 0.97 and 0.86 for left ventricular end-diastolic volume, 0.97 and 0.86 for left ventricular end-systolic volume, 0.95 and 0.81 for stroke volume, 0.68 and 0.63 for ejection fraction, respectively. According to Bland-Altman plots, the mean percentage difference and 95% limits of intra- and inter-observer agreement for left ventricular stroke volume measurements using VOCAL were −0.2 (−25.1, 24.7)% and 2.8 (−34.2, 39.8)%, respectively. For left ventricular stroke volume measured with Simpson versus VOCAL the mean percentage difference and 95% limits of agreement were −1.8 (−22.1, 18.5)%.

Conclusions

4D STIC enables reproducible measurements of left ventricular volumes. Reliability of the VOCAL mode is not essentially different from the single-plane method used in Simpson's rule. The large percentage of poor quality STIC volumes and the wide limits of inter-observer agreement would create obstacles for the clinical applicability of this technique.     

Evaluation of Placental Volume at 7–10 + 6 Weeks of Pregnancy by 3D-Sonography

The aim of the study was to establish normative data for placental volume (PV) at 7–10 + 6 weeks of gestation using three-dimensional ultrasound (3DUS). The cross-sectional study involved 70 healthy pregnancies between 7 and 11 weeks. The VOCAL (Virtual Organ Computer-aided Analysis) method with a 30° rotation angle and six planes was used for volumetric calculations. Regression models were constructed to assess the correlation between PV and crown–rump length (CRL) adjusted by the determination coefficient (R²). The method proposed by Royston and Wright was used to establish the 2.5th; 10th; 50th; 90th and 97.5th percentiles (percentile = mean + K × SD). The intraclass correlation coefficient (ICC), Bland–Altman graphs and Student’s paired t-tests were used to assess intra- and interobserver variability. PV ranged from 1.7 to 42.6 cm³, with a mean of 13.6 cm³ (±9.4 cm³). There was a strong correlation between PV and CRL; the exponential equation was the model that best expressed the correlation between them (R² = 0.76). For CRL between 9 and 40 mm, the mean PV increased 10.5 times, while CRL increased only 4.4 times. Inter- and intraobserver correlation were excellent (ICC = 0.979 and 0.971, respectively). Bland–Altman graphs indicated a good reproducibility with a mean intraobserver and interobserver difference of 0.2 cm³ (95% CI: ?0.7–1.2 cm³) and ?0.2 cm³ (95% CI: ?1.3–0.9 cm³), respectively. Reference limits were generated for first trimester PV assessed by 3DUS using the VOCAL method. There is a strong correlation between PV and CRL. Placental volume obtained through this method was highly reproducible.     

Fetal nuchal fold thickness measurement between 18 and 24 weeks of pregnancy: reference intervals for a Brazilian population

Objective: To determine reference intervals of fetal nuchal fold (NF) thickness measurement in the second trimester of pregnancy in a Brazilian population.

Methods: This was a retrospective cross-sectional study with 2559 normal singleton pregnancies between 18 and 24 weeks of pregnancy. The fetal NF was obtained in the axial plane of fetal head at level of lateral ventricles including the cavum septum pellucidum, third ventricle, thalamus and transverse cerebellar diameter. The NF was measured posterior to the occipital bone, from the bone surface to the skin, including only soft tissue. To assess the correlation between fetal NF and gestational age (GA), polynomial equations were calculated and adjusted to determination coefficient (R²).

Results: The mean fetal NF ranged from 3.98?±?1.14?mm at 18???18?+?6 to 4.83?±?0.93?mm at 24???24?+?6 weeks of gestation. A good correlation was observed between fetal NF and GA, which is better represented by a linear equation: NF?=?1.055?+?0.158*GA (R²?=?0.06).

Conclusion: Reference intervals of fetal NF thickness measurement in the second trimester of pregnancy were determined for a Brazilian population.     

Reference range of fetal nasal bone length between 18 and 24 weeks of pregnancy in an unselected Brazilian population: experience from a single service

Abstract

Objective: To determine reference range of fetal nasal bone length (NBL) during the second trimester of pregnancy in a Brazilian population.

Methods: This was a retrospective cross-sectional study with 2681 normal singleton pregnancies between 18 and 24 weeks of gestation. The NBL was obtained in the mid-sagittal plane of the fetal face profile using the following landmarks: nasal bone, overlying skin and the tip of the nose. The NBL was measured by placing the calipers in the out-to-out position. To assess the correlation between NBL and gestational age (GA), polynomial equations were calculated, with adjustments by coefficient of determination (R²).

Results: The mean of NBL ranged from 5.72?±?0.87?mm at 18–18?+?6 weeks to 7.45?±?1.23?mm at 24–24+6 weeks of pregnancy. We observed a good correlation between NBL and GA, best represented by a linear equation: NBL?=?0.080+0.276*GA (R^2?=?0.16).

Conclusion: We established a reference range of fetal NBL in the second trimester of pregnancy in a Brazilian population.     

Decision-to-delivery interval in suspected placental abruption – association with pregnancy outcome

Abstract

Objective: To determine the association between decision to delivery interval (DDI) and short-term perinatal outcome in cases of suspected placental abruption delivered by cesarean section (CS).

Study design: A retrospective cohort study of all cases of placental abruption delivered by CS (2010–2012) in a single university affiliated tertiary center. Composite adverse neonatal and maternal outcome were assessed.

Results: The rate of placental abruption was 0.5% (140/27 677 deliveries) and 65/140 (46%) were delivered by CS. Indications for CS were non-reassuring fetal heart rate (NRFHR) in 32/65 (49.3%), maternal bleeding 20/65 (30.7%) and other indications in 13/65 (20%). Obstetrical and labor characteristics were similar unrelated to the indication for CS. Gestational age at delivery was higher in the group operated due to NRFHR (36?±?4.3, 34?±?3.7 and 32?±?4.1 weeks, respectively, p?=?0.03). DDI was shortest when CS was due to NRFHR followed by CS due to maternal bleeding or other indications (23?±?19, 30?±?16, 50?±?40?min, respectively, p?=?0.001). The umbilical artery PH was lower in those who operated due to NRFHR (7.17?±?0.17, 7.23?±?0.06 and 7.30?±?0.09, respectively, p?=?0.002). The overall rate of neonatal and maternal composite outcome was 66% and 40%, respectively with no significant difference in relation to indication for CS.

Conclusion: In cases of suspected placental abruption, fetal short-term morbidity is probably related to the indication for CS and not only to DDI.     

First-trimester crown-rump length as a predictor of fetal LGA and SGA at term

Objective.?To determine whether first-trimester crown-rump length (CRL) is associated with birthweight extremes at term.

Methods.?Included in this study were all term, small for gestational age (SGA), and large for gestational age (LGA) neonates with no other obstetric complications and no abnormal outcomes of pregnancy. CRL at 12.0 to 12.6 weeks of estimated gestational age obtained during nuchal translucency screening was selected as an estimate of early fetal growth. Mean first-trimester CRL of the LGA noenates at term was compared via student’s t-test with mean first-trimester CRL of SGA neonates at term.

Results.?In all, 121 neonates were included in the study. Mean first-trimester CRL of the 63 LGA-term neonates was 62.7?±?6.0 mm (95% confidence interval, ±1.49 mm; range, 61.21–64.19), while that of the 58 SGA-term neonates was smaller at 58.8?±?6.9 mm (95% confidence interval, ±1.79 mm; range, 57.01–60.59 mm). This 3.9 mm difference between the means was statistically significant (P?=?0.01).

Conclusion.?We found that birthweights of LGA and SGA neonates at term were associated with their first-trimester CRL measurements, thus, indicating that fetal growth patterns apparent early in pregnancy continue through term.     

Reference values for the fetal lateral ventricle atrium measurement in the second and third trimesters of pregnancy in a Brazilian population

Objective: To establish reference values for the fetal atrium lateral ventricle measurements in the second and third trimesters of pregnancy in a Brazilian population.

Methods: A retrospective cross-sectional study was performed with low-risk pregnant women who underwent ultrasound examination at 16–41 weeks of gestation. The atrium of lateral ventricle measurement was performed in the transventricular plane at the end of choroid plexus. We assessed reference curves (percentiles 5th, 50th and 95th) for the atrium of lateral ventricle measurement with gestational age (GA), using the best-fit polynomial equation, and determination coefficient (R²) and modeling the variability.

Results: The fetal atrium of lateral ventricle measurements was assessed in 519 singleton pregnancies. However, seven fetuses were excluded because of central nervous system malformations, and therefore data from 512 pregnancies were included in the analysis. The mean?±?standard deviation (range) of the fetal atrium lateral ventricle measurement (mm) was 5.1?±?1.4 (1.6–9.7). A best-fit curve was a first-degree polynomial regression: atrium lateral ventricle?=?6.455???0.049?×?GA (R²?=?0.05).

Conclusion: Reference values for the fetal atrium lateral ventricle measurements in the second and third trimesters of pregnancy in a Brazilian population were established.