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.     

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.     

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.     

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.     

Reference range for the fetal intracranial translucency measurement between 11 and 14 + 2 weeks of gestation in a Brazilian population

Objective: To establish a reference range for the fetal intracranial translucency (IT) measurement between 11 and 14?+?2 weeks in a Brazilian population.

Methods: A retrospective cross-sectional study was performed with 199 low-risk singleton pregnancies during the first trimester ultrasound exam. The IT (fourth ventricle width) measurement was performed in a mid-sagittal view of fetal profile defined by two echogenic borders – the dorsal part of the brain stem anteriorly and the choroid plexus of the fourth ventricle posteriorly. Polynomial regression was used to obtain the best fit using fetal IT measurements and crown-rump length (CRL). Percentiles 5th, 50th and 95th were determined for each gestational age.

Results: The mean of fetal IT ranged from 1.6 mm at CRL 45 to 2.0 mm at CRL 84 mm. A best fit curve was a first-degree polynomial regression: IT measurement?=?1.001?+?0.0124?×?CRL (R²=0.09).

Conclusion: Reference range for the fetal IT measurement between 11 and 14?+?2 weeks of gestation in a Brazilian population was established.     

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.     

Fetal frontomaxillary facial angle between 11 and 13 + 6 weeks of gestation in a Brazilian population: influence of different races

Abstract

Objective: To evaluate the influence of different races over the measurement of the frontomaxillary facial angle between 11 and 13?+?6 weeks of pregnancy in a Brazilian population.

Methods: A cross-sectional study was conducted with 332 healthy pregnant women, with a crown-rump length (CRL) between 47 and 84?mm. Such measurements were taken abdominally, using the mid-sagittal plane, and the angle was measured by tracing a line over the palate and a line from the anterosuperior maxillary angle all the way to the external part of the forehead. As for the reference intervals, a simple linear regression between the frontomaxillary facial angle and the CRL was used, as well as Pearson’s correlation coefficient (r). To evaluate the difference between races, a variance analysis was used (ANOVA). To calculate reproducibility, the intraclass correlation coefficient (ICC) was used.

Results: The means for the fetal frontomaxillary facial angle in white, black and mixed races were 81.8?±?6.6; 82.2?±?6.1 and 81.4?±?6.2?mm, respectively. There was no statistical difference between races (p?=?0.713). A decreasing correlation between the frontomaxillary facial angle and the CRL was observed for the black (r?=??0.450) and mixed (r?=??0.212) races. Excellent intraobserver reproducibility was observed, as well as a satisfactory interobserver reproducibility, with ICC of 0.858 and 0.605, respectively.

Conclusion: There were no significative statistical differences in the measurement of the fetal frontomaxillary facial angle between 11 and 13?+?6 weeks of pregnancy in the different races in a Brazilian population.     

Reference range for the pulsatility index ductus venosus Doppler measurement between 11 and 13 + 6 weeks of gestation in a Brazilian population

Objective: To establish reference range for the pulsatility index (PI) ductus venosus (DV) Doppler measurement between 11 and 13?+?6 weeks of gestation in a Brazilian population.

Methods: A retrospective cross-sectional study was performed with 430 singleton pregnancies. The PI DV Doppler measurement was performed as routine during the first trimester screening. DV was identified by color Doppler and the pulsed Doppler gate was placed in the distal portion of the umbilical sinus. When at least three typical DV waveforms were obtained, PI DV was measured manually in one waveform. Polynomial regression was used to obtain the best fit using PI DV Doppler measurement and crown-rump length (CRL) with adjustments by the determination coefficient (R²). 5th, 50th and 95th percentiles for the PI DV Doppler measurements at each gestational were determined.

Results: The mean of PI DV Doppler measurement was 1.1?±?0.2 (range 0.8–3.7). The linear regression was the best fit: PI DV measurement?=?1.288–0.0034*CRL (R^2?=?0.03).

Conclusions: Reference range for the PI DV Doppler measurement between 11 and 13?+?6 weeks of gestation in a Brazilian population was established.     

Maternal cardiovascular profiling in the first trimester of pregnancies complicated with gestation-induced hypertension or fetal growth retardation: a pilot study

Abstract

Objective: In this study, we determine whether maternal cardiovascular (CV) profiling can detect first trimester differences between women with uncomplicated pregnancies (UP) and those who will develop gestational hypertensive disorders (GHD) or normotensive fetal growth retardation (FGR).

Methods: Cardiac, arterial, and venous function were evaluated in 242 pregnant women around 12 weeks of gestation, using impedance cardiography (ICG) and combined electrocardiogram – Doppler ultrasonography. After postnatal determination of gestational outcome, first trimester measurements were compared between groups using Mann–Whitney U test for continuous data or Fisher’s Exact test for categorical variables (SPSS 20.0).

Results: Compared to UP, first trimester aortic flow velocity index [71?±?0.96 versus 61?±?4.91 1/1000/s (p?=?0.016)], acceleration index [133?±?2.25 versus 106?±?11.26 1/100/s² (p?=?0.023)] and Heather index [23.1?±?0.35 versus 19.2?±?1.70?Ω/s² (p?=?0.019)] were lower in GHD pregnancies, and first trimester stroke volume [77?±?1.16 versus 67?±?3.97?ml (p?=?0.033)] and cardiac output [7.3?±?0.10 versus 6.2?±?0.31?l/min (p?=?0.025)] were lower in FGR pregnancies.

Conclusions: Maternal CV function in the first trimester of pregnancy differs between UP and those destined to develop GHD or FGR. This can be assessed with non-invasive maternal CV profiling, opening perspectives for the application of this technique in early gestational screening for GHD and FGR.     

Unconditional reference values for the amniotic fluid index measurement between 26w0d and 41w6d of gestation in low-risk pregnancies

Objective: To establish reference values for the amniotic fluid index (AFI) measurement between 26w0d and 41w6d of gestation in a Brazilian population.

Methods: We performed a cross-sectional study with 1984 low-risk singleton pregnant women between 26w0d and 41w6d of gestation. AFI was measured according to the technique proposed by Phelan et al. Maternal abdomen was divided into four quadrants using the umbilicus and linea nigra as landmarks. Single vertical pocket in each quadrant was measured and the AFI was generated by the sum of these four values without umbilical cord or fetal parts. All ultrasound exams were performed by only two experienced examiners. AFI was expressed as median, interquartile range, mean and ranges in each gestational age (GA) interval. Polynomial regressions were performed to obtain the best fit with adjustment by the determination coefficient (R²).

Results: Mean of AFI ranged from 14.0?±?4.1?cm (range, 9.7–14.0) at 26w0d to 8.3?±?4.7?cm (range, 1.9–16.5) at 41w6d, respectively. The best polynomial regression fit curve was a first-degree: AFI?=?16.29–0.125*GA (R²?=?0.01). According the scatterplot, AFI values practically did not vary with advancing GA.

Conclusion: Reference values for the AFI measurement between 26w0d and 41w6d of gestation in a low-risk Brazilian population were established.     

Pessary versus cerclage versus expectant management for cervical dilation with visible membranes in the second trimester

Objective: We evaluated pessary for dilated cervix and exposed membranes for prolonging pregnancy compared to cerclage or expectant management.

Methods: Multicenter retrospective cohort study of women, 15–24 weeks, singleton pregnancies, dilated cervix ≥2?cm and exposed membranes. Women received pessary, cerclage or expectant management. Primary outcome was gestational age (GA) at delivery. Secondary outcomes were time until delivery, preterm premature rupture of membranes (PPROM) and neonatal survival.

Results: About 112 women met study criteria; 9 – pessary, 85 – cerclage and 18 – expectant management. Mean GA at delivery was 22.9?±?4.5 weeks with pessary, 29.2?±?7.5 weeks with cerclage and 25.6?±?6.7 weeks with expectant management (p?=?0.015). Time until delivery was 16.1?±?18.9 days in the pessary group, 61.7?±?48.2 days in the cerclage group and 26.8?±?33.4 days in the expectant group (p?<?0.001). PPROM occurred less frequently and neonatal survival increased in women with cerclage. There was a significant difference in all the perinatal outcomes with cerclage compared with either pessary or expectant management.

Conclusions: Perinatal outcomes with pessary were not superior to expectant management in women with dilated cervix with exposed membranes in the second trimester in this small retrospective cohort.     

Duration of labor by gestational week in nulliparous women

Abstract

Objectives: To assess whether labor length differs by week of gestation.

Methods: In this observational cross-sectional study, we compared duration of labor by gestational age (36?+?0 through 40?+?6 weeks) in primiparous singleton parturients with vertex presentation. Data were acquired for a period of 24 months (2010–2011).

Results: In general, the rate of change in cervical dilatation decreased as gestational week at delivery advanced: 1.8?±?1.0?cm/h, 1.5?±?0.9?cm/h, 1.3?±?0.8?cm/h, 1.6?±?1.5, and 1.3?±?1.0?cm/h at 36th, 37th, 38th, 39th and 40th gestational week, respectively (p?=?0.040). Concurrently, the total labor duration (1st?+?2nd?+?3rd stages) increased as gestational age advanced: 423.6?±?180.9?min, 496.5?±?212.6?min, 545.9?±?247.1?min, 483.8?±?256.3?min, and 568.2?±?273.8?min at 36th, 37th, 38th, 39th and 40th gestational week, respectively (p?=?0.013).

Conclusions: Gestational week of pregnancy may alter the duration of labor, specifically, the length of labor increases as gestational week at delivery advances.     

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.     

Assessment of nitrite oxide and maternal–fetal Doppler parameters during pregnancy

Objective: The objective was to evaluate and compare the whole blood nitrite concentration in the three trimesters of pregnancy. Additionally, we investigate whether there is any relation between nitrite concentrations and Doppler ultrasound analysis of some maternal and fetal vessels.

Methods: Thirty-three healthy pregnant women were examined at the first (11–14 weeks), second (20–24 weeks) and third trimester (34–36 weeks) of pregnancy. In the three exams, we determined the maternal whole blood nitrite concentration and uterine arteries Doppler analysis to determine pulsatility index (PI), and resistance index (RI). In the second and third trimester we also performed fetal umbilical and middle cerebral arteries PI and RI. We compared the concentrations of nitrite in three trimesters and correlated with Doppler parameters.

Results: No difference was observed in the whole blood nitrite concentrations across trimesters: 151.70?±?77.90?nmol/ml, 142.10?±?73.50?nmol/ml and 147.10?±?87.30?nmol/ml; first, second and third trimesters, respectively. We found no difference in correlation between whole blood nitrite concentration and Doppler parameters from the evaluated vessels.

Conclusions: In healthy pregnant women, the nitrite concentrations did not change across gestational trimesters and there was also no strong correlation with Doppler impedance indices from maternal uterine arteries and fetal umbilical and middle cerebral arteries.     

Low-dose vaginal misoprostol in the management of intrauterine fetal death

Objectives.?To assess the effectiveness and side effects of vaginal misoprostol (Vagiprost® tablet) termination of second and third trimester pregnancy complicated with intrauterine fetal death (IUFD).

Design.?A prospective observational cohort study.

Setting.?Tanta University Hospital.

Patients.?The study carried out on 324 women with fetal demise in the second and third trimesters, from January 2008 to December 2009.

Intervention.?All patients were subjected to history taking, physical examination, and the Bishop Scoring. Application of 25?μg misoprostol in the posterior fornix of the vagina, this was repeated every 4 h over 24 h. We assessed the adverse effects, progress, and outcomes.

Results.?The success rate was 90% and 45% in women in the third and second trimesters, respectively. The mean induction-termination interval was 8.95?±?2.63 and 15.3?±?5.37 h for women in the third and second trimesters, respectively. The induction termination interval correlated negatively with the duration of gestation. Approximately, 90% of second trimester and 55% of third trimester women required oxytocin augmentation. The mean value of total required dose of misoprostol was 166.3?±?7.5 and 120?±?28.79?μg for women in the second and third trimesters, respectively.

Conclusion.?Vagiprost appears to be a safe, effective, practical, and inexpensive method for termination of third trimester pregnancy complicated with of IUFD.     

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.     

Screening performance of different methods defining fetal nasal bone hypoplasia as a single and combined marker for the detection of trisomy 21 in the second trimester

Objective: To evaluate different methods of defining fetal nasal bone hypoplasia in the second trimester for the detection of trisomy 21.

Methods: Prospective study in Greek women undergoing anomaly scan between 18?+?0 and 23?+?6 weeks. The following methods of defining nasal bone hypoplasia were evaluated, either as a single marker or in combination with others: (1) BPD to nasal bone length (NBL) ratio; (2) multiples of the median (MoM) of NBL, according to normal curves from a Greek population; (3–4) NBL?<?2.5 percentile according to normal curves (3) commonly used internationally curves and (4) curves from a Greek population.

Results: In total, 1301 singleton fetuses were evaluated???10 with trisomy 21. The best detection rate of trisomy 21 was achieved when the applied method was nasal bone percentiles adjusted to maternal ethnicity, in combination with other markers (<2.5 percentile according to normal curves from a Greek population; p?<?0.001; sensitivity 50%; specificity 94.8%; false-positive rate 5.2%; positive likelihood ratio 9.6).

Conclusion: Screening performance of fetal nasal bone hypoplasia in detecting trisomy 21 varies according to the method applied. The best screening performance is achieved by using percentiles adjusted to maternal ethnicity in combination with other markers of aneuploidy.     

Facial shape; height and width in the second and third trimester of pregnancy

Objectives: The objective of this study is to calculate on 3D volumes obtained from 16 weeks’ gestation normative data of facial height (FH), facial width (FW) and their ratio and to test these parameters in pathological cases.

Methods: In total, 228 volumes were analyzed: 207 from normal and 21 from pathological cases. After multiplanar correction to the exact midsagittal plane FH was measured from the nasion to the gnathion and FW between the most lateral points on the zygomatic arch.

Results: For both FH and FW the intra- and inter-observer intraclass correlation coefficient variability was 0.99 and the difference between paired measurements was less than 0.3?cm in 95% of the cases. FH increased from 1.48 to 5.08?cm (FH?=??16.10?+?3.78?×?log(GA), R²: 0.93) and FW from 2.20 to 6.42?cm (FW: 4.19–17.18?×?log(GA), R²: 0.85). The ratio increased steadily until about 25 weeks and less thereafter (ratio: (1/GA)?×?26.44?+?0.92, R²: 0.23). In pathological cases 16.6% of measurements were outside the normal range.

Conclusions: This study provides normative data for FH and FW measurements and insight in normal facial growth after 16 weeks’ gestation. FH exceeds FW growth especially before 25 weeks.     

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.     

The effect on the fetal pituitary-adrenal axis of dexamethasone administration early in the second trimester of pregnancy

Objective.?To evaluate the effect of a single dose of dexamethasone to pregnant women at early second trimester on the fetal pituitary-adrenal axis.

Methods.?Thirty-eight women between 13 and 15 weeks' gestation were included in the study. Blood was taken from the mothers and their fetuses for the evaluation of plasma ACTH, cortisol, and free cortisol levels before and after treatment with a single dose of 1?mg of dexamethasone orally at 11 p.m. the night before the termination of pregnancy.

Results.?The mean plasma ACTH was significantly lower following dexamethasone administration (8.5?±?5.1 vs. 18.4?±?10.9 pg/ml). Similarly, plasma cortisol was significantly lower after dexamethasone treatment (208.3?±?168.7 vs. 772.7?±?206.1?nmol/l), as well as plasma free cortisol levels (2.6?±?0.0 vs. 6.1?±?6.1?nmol/l). Mean plasma ACTH levels were not significantly different in the fetuses after dexamethasone treatment (33.6?±?22.7 vs. 42.5?±?21.9 pg/ml). Moreover, mean fetal plasma cortisol was not different before and after treatment (108.2?±?27.2 vs. 94.3?±?47.2?nmol/l), as well as the mean free cortisol levels (7.7?±?5.2 vs. 7.0?±?4.3?nmol/l).

Conclusions.?A single dose of 1?mg of dexamethasone to the mother early in the second trimester of pregnancy does not result in a significant suppression of the fetal pituitary axis.