Frontomaxillary facial angle in fetuses with trisomy 13 at 11 + 0 to 13 + 6 weeks.

OBJECTIVE: To investigate the frontomaxillary facial (FMF) angle in fetuses with trisomy 13 at 11 + 0 to 13 + 6 weeks of gestation. METHODS: A three-dimensional (3D) volume of the fetal head was obtained before karyotyping at 11 + 0 to 13 + 6 weeks of gestation in 23 fetuses with trisomy 13. The FMF angle, defined as the angle between the upper surface of the maxilla and the frontal bone in a midsagittal view of the fetal face, was measured and compared to the angle in 500 chromosomally normal fetuses. RESULTS: In 10 of 12 (83.3%) fetuses with trisomy 13 and holoprosencephaly, the FMF angle was above the 95(th) centile of the normal range. In the 11 fetuses with no holoprosencephaly, the FMF angle was not significantly different from normal. There was no significant difference in the FMF angle between the trisomy 13 fetuses with and without facial cleft. CONCLUSIONS: In fetuses with trisomy 13, the FMF angle at 11 + 0 to 13 + 6 weeks of gestation is increased only in cases with associated holoprosencephaly.     

Frontomaxillary and mandibulomaxillary facial angles at 11 + 0 to 13 + 6 weeks in fetuses with trisomy 18.

OBJECTIVE: To define the relative position of the maxilla and mandible in fetuses with trisomy 18 at 11 + 0 to 13 + 6 weeks of gestation. METHODS: A three-dimensional (3D) volume of the fetal head was obtained before karyotyping at 11 + 0 to 13 + 6 weeks of gestation in 36 fetuses subsequently found to have trisomy 18, and 200 chromosomally normal fetuses. The frontomaxillary facial (FMF) angle and the mandibulomaxillary facial (MMF) angle were measured in a mid-sagittal view of the fetal face. RESULTS: In the chromosomally normal group both the FMF and MMF angles decreased significantly with crown-rump length (CRL). In the trisomy 18 fetuses the FMF angle was significantly greater and the angle was above the 95(th) centile of the normal range in 21 (58.3%) cases. In contrast, in trisomy 18 fetuses the MMF angle was significantly smaller than that in normal fetuses and the angle was below the 5(th) centile of the normal range in 12 (33.3%) cases. CONCLUSIONS: Trisomy 18 at 11 + 0 to 13 + 6 weeks of gestation is associated with both mid-facial hypoplasia and micrognathia or retrognathia that can be documented by measurement of the FMF angle and MMF angle, respectively.     

Frontomaxillary facial angle at 11 + 0 to 13 + 6 weeks: effect of plane of acquisition.

OBJECTIVE: To determine the range of positions of the fetal head in which a three-dimensional (3D) volume is acquired for subsequent successful assessment of the frontomaxillary facial (FMF) angle. METHOD: We obtained 3D volumes of the fetal head at 11 + 0 to 13 + 6 weeks. The volumes were acquired with the head in different positions and reconstructed to obtain a mid-sagittal section and demonstrate the maxilla, palate and frontal bone, which constitute the landmarks for the assessment of the FMF angle. RESULTS: In the reconstructed mid-sagittal sections, it was possible to demonstrate the landmarks that define the FMF angle in most of the cases when the 3D volume acquisition plane was: (a) mid-sagittal, with the angle between the face of the transducer and the direction of the fetal nose being about 0-99 degrees, 150-199 degrees and 330-359 degrees; (b) transverse at the level of the biparietal diameter when the angle between the transducer and the midline echo of the brain was 0-29 degrees; and (c) oblique around the crown-rump axis when the angle from the mid-sagittal plane was 0-49 degrees. However, the measurement of the FMF angle was artificially increased when in the mid-sagittal plane the angle was 40-99 degrees and 150-199 degrees. CONCLUSION: Successful assessment of the FMF angle by 3D ultrasound is dependent on the plane and angle of the volume acquisition.     

Frontomaxillary facial angle at 11+0 to 13+6 weeks' gestation-reproducibility of measurements.

OBJECTIVE: To assess the intra- and interobserver reproducibility in the measurement of the frontomaxillary facial (FMF) angle at 11+0 to 13+6 weeks' gestation and to investigate the effect of deviations from the exact mid-sagittal view on these measurements. METHODS: Three-dimensional (3D) volumes of the fetal face were used by two operators to measure the FMF angle in 50 chromosomally normal and 50 trisomy 21 fetuses. The measurements were taken in the exact mid-sagittal view and repeated after lateral rotation of the head by 5 degrees, 10 degrees and 15 degrees away from the vertical position of the occipitofrontal diameter axis. Mean difference and 95% limits of agreement between paired measurements of FMF angle by the same and by two different sonographers were determined. RESULTS: In the mid-sagittal plane the maxillary bone was rectangular shaped. Rotation away from this plane became easily recognizable because at a mean of 7 degrees (range, 4-10 degrees) the shape of the maxilla changed with the appearance of the zygomatic process of the maxilla and at a mean of 8 degrees (range, 4-12 degrees) the tip of the nose became invisible. In both the normal and trisomy 21 fetuses the FMF angle measured at 5-15 degrees was not significantly different from the one measured in the mid-sagittal plane. In 95% of the cases, the difference between paired measurements of the FMF angle by the same sonographer at the mid-sagittal plane was between -2.3 degrees and 3.0 degrees and at 15 degrees it was -1.0 degrees to 6.8 degrees. At the mid-sagittal plane, the difference in measurements between two sonographers was -3.1 to 3.0 degrees. CONCLUSION: The landmarks that define the mid-sagittal plane of the fetal face are the tip of the nose and the rectangular shaped maxilla. Measurement of the FMF angle is highly reproducible.     

Aberrant right subclavian artery at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal and abnormal fetuses.

OBJECTIVES: To establish the feasibility of examining the subclavian artery at 11 + 0 to 13 + 6 weeks of gestation, and to determine the prevalence of aberrant right subclavian artery (ARSA) in chromosomally normal and chromosomally abnormal fetuses. METHODS: Fetal echocardiography was performed prospectively in 516 patients before chorionic villus sampling at 11 + 0 to 13 + 6 weeks of gestation. Transabdominal sonography was carried out, and color flow mapping was used to identify the right subclavian artery and determine whether this was normal or aberrant (ARSA). Second-trimester fetal echocardiography was also carried out in a subgroup of 183 fetuses. RESULTS: The median gestational age was 12 weeks and the median crown-rump length was 68 mm. Successful assessment of the right subclavian artery was achieved in 425/516 (82.4%) cases and the rate of failure to do so was significantly associated with decreasing fetal crown-rump length (r = 0.174, P < 0.001) and increasing maternal body mass index (r = 0.275, P < 0.001). An ARSA was observed in 2/353 (0.6%) fetuses with a normal karyotype, in 4/51 (7.8%) cases with trisomy 21 and in 2/20 (10.0%) with other chromosomal defects. In a subgroup of 183 fetuses examined in both the first and second trimester there were three cases of ARSA observed at both scans and an additional case in which ARSA was detected only at the second scan. CONCLUSIONS: Assessment of the position of the right subclavian artery is feasible at the 11 + 0 to 13 + 6-week scan and ARSA is more common in chromosomally abnormal than normal fetuses. However, ARSA in the first trimester is unlikely to be a useful marker of trisomy 21.     

Fetal head-to-trunk volume ratio in chromosomally abnormal fetuses at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To determine the pattern of early growth disturbance in chromosomally abnormal fetuses by comparing the volume of the fetal head to that of the trunk. METHODS: The fetal trunk and head volume was measured using three-dimensional (3D) ultrasound in 145 chromosomally abnormal fetuses at a median gestational age of 12 (range, 11 + 0 to 13 + 6) weeks. The head volume was measured separately and then subtracted from the total head and trunk volume to obtain the volume of the fetal trunk. The head-to-trunk ratios were then calculated and the Mann-Whitney U-test was used to determine the significance of differences from 500 chromosomally normal fetuses. RESULTS: The fetal head volume for crown-rump length (CRL) was significantly smaller than normal in trisomy 21, trisomy 13 and Turner syndrome (P < 0.001, P < 0.001 and P = 0.001, respectively), whereas no significant differences were found in trisomy 18 and triploidy (P = 0.139 and P = 0.070, respectively). The fetal trunk volume for CRL was significantly smaller in all chromosomal abnormalities (P < 0.001) except Turner syndrome (P = 0.134). The head-to-trunk ratio for CRL was significantly larger in trisomy 18, trisomy 13 and triploidy (P < 0.001), but normal in trisomy 21 (P = 0.221) and Turner syndrome (P = 0.768). CONCLUSIONS: In trisomy 21 and Turner syndrome, the growth deficit was symmetrical with the head and trunk being equally affected, whereas in triploidy and trisomies 18 and 13 there was asymmetrical growth restriction with the trunk being more severely compromised than the head.     

Fetal trunk and head volume in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation.

OBJECTIVE: To examine the pattern of growth in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation and compare the trunk and head volume to crown-rump length (CRL) in defining the growth deficit in such fetuses. METHODS: The fetal trunk and head volume was measured using three-dimensional (3D) ultrasound in 140 chromosomally abnormal fetuses at 11+0 to 13+6 (median 12) weeks of gestation, and the values were compared to 500 chromosomally normal fetuses. In each chromosomally abnormal fetus, the observed fetal trunk and head volume was subtracted from the expected mean (delta value) of the chromosomally normal fetuses of the same gestational age, and this difference was expressed as a percentage of the appropriate normal mean. The Mann-Whitney U-test was used to determine the significance of differences between the chromosomally normal and abnormal groups. RESULTS: In trisomy 21 (n=72) and Turner syndrome (n=14) fetuses, compared to chromosomally normal fetuses, the CRL for gestation was similar (P=0.335 and P=0.317, respectively), but the fetal trunk and head volume was about 10-15% lower (P<0.001 and P=0.004, respectively). In trisomy 18 (n=29), trisomy 13 (n=14) and triploidy (n=11), the deficit in volume was about 45% (P<0.001), whereas the deficit in CRL was less than 15% (P<0.001). CONCLUSIONS: In the quantification of the degree of early growth impairment in chromosomally abnormal fetuses, measurement of the fetal trunk and head volume using 3D ultrasound may be better than measurement of CRL.     

Metopic suture in fetuses with holoprosencephaly at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To investigate the development of the metopic suture in fetuses with holoprosencephaly at 11 + 0 to 13 + 6 weeks of gestation. METHODS: Three-dimensional (3D) ultrasound was used to measure the height and gap between the frontal bones in 200 normal fetuses and in nine fetuses with holoprosencephaly at 11 + 0 to 13 + 6 (median, 12) weeks of gestation. RESULTS: In the 200 normal fetuses, the height of the frontal bones increased significantly with gestation from a mean of 2.5 mm (5(th) and 95(th) centiles: 1.9 mm and 3.3 mm) at 11 weeks to 6.1 mm (5(th) and 95(th) centiles: 4.6 mm and 8.1 mm) at 13 + 6 weeks. The gap between the two frontal bones did not change significantly with gestation (mean: 1.5 mm; 5(th) centile: 1.0 mm; 95(th) centile: 2.0 mm). In fetuses with holoprosencephaly, the height of the frontal bones was significantly larger (mean difference, 5.6 SDs; range, 3.9-7.7 SDs; P < 0.0001) and the gap was significantly smaller (mean 0.2 mm, range 0-0.8 mm; P < 0.0001) than those in normal fetuses. CONCLUSIONS: Holoprosencephaly is associated with an accelerated development of the frontal bones and premature closure of the metopic suture.     

Metopic suture in fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To investigate the development of the frontal bones and metopic suture in fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation. METHODS: Three-dimensional (3D) ultrasound was used to measure the height of and gap between the frontal bones in 75 fetuses with trisomy 21 and these were compared to the measurements in 200 normal fetuses at 11 + 0 to 13 + 6 (median, 12 + 6) weeks of gestation. RESULTS: In the fetuses with trisomy 21, compared to the normal fetuses, there was no significant difference in either the height of the frontal bones (mean difference 0.16 SD, range -1.78 to 2.17 SD; P = 0.369) or the gap between them (mean difference 0.012, 95% CI -0.073 to 0.097; P = 0.780). Additionally, within the group of trisomy 21 fetuses there were no significant differences in the development of the frontal bones and metopic suture between those with absent (n = 46) and those with present (n = 29) nasal bone. CONCLUSIONS: In trisomy 21 the development of the frontal bones and metopic suture is as normal and is independent from the development of the nasal bones.     

Fetal trunk and head volume measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal pregnancies.

OBJECTIVE: To establish the relationship between fetal trunk and head volume measured by three-dimensional (3D) ultrasound and gestational age at 11 + 0 to 13 + 6 weeks of gestation. METHODS: The fetal trunk and head volume were measured using 3D ultrasound in 417 chromosomally normal fetuses from singleton pregnancies at 11 + 0 to 13 + 6 (median, 12 + 0) weeks of gestation. Regression analysis was used to determine the significance of the association between fetal volume and gestational age. The Bland-Altman analysis was used to compare the measurement agreement and bias for a single examiner and between different examiners. RESULTS: The fetal trunk and head volume increased linearly with gestation from a mean of 5.8 mL at 11 + 0 weeks to 33.3 mL at 13 + 6 weeks and 1 SD was 4.4 mL. There was also a significant linear association between fetal volume and crown-rump length (CRL), from a mean of 5.1 mL at a CRL of 45 mm to 37.5 mL at a CRL of 84 mm and 1 SD was 2.7 mL. However, within this gestational range, a doubling in CRL, from a mean of 48 mm at 11 + 0 weeks to 79 mm at 13 + 6 weeks, was associated with a 5-6-fold increase in fetal volume. The mean difference in fetal volume between paired measurements by the same sonographer was -0.87 mL (95% limits of agreement, -2.31 to 4.05 mL) and the mean difference between paired measurements by two sonographers was -1.09 mL (-5.49 to 3.32 mL). CONCLUSIONS: 3D ultrasound can provide a reproducible measurement of the fetal trunk and head volume in early pregnancy. At between 11 + 0 and 13 + 6 weeks there is a 5-6-fold increase in fetal volume but only a doubling in CRL.     

Brachycephaly and frontal lobe hypoplasia in fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks.

OBJECTIVE: To investigate the incidence of brachycephaly and frontal lobe hypoplasia in fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation. METHODS: A three-dimensional (3D) volume of the fetal head was obtained before fetal karyotyping at 11 + 0 to 13 + 6 (median, 12 + 5) weeks of gestation in 100 fetuses that were subsequently found to have trisomy 21 and in 300 fetuses subsequently found to be chromosomally normal. The multiplanar mode was used to obtain a sequence of transverse views of the fetal head and to demonstrate the biparietal and suboccipitobregmatic views. We measured the biparietal diameter (BPD), the occipitofrontal diameter (OFD) and the frontothalamic distance (FTD) between the inner table of the frontal bone and the posterior thalami. RESULTS: In the chromosomally normal group the BPD, OFD and FTD increased linearly with crown-rump length (CRL) from 16.7 mm, 19.0 mm and 12.1 mm at a CRL of 45 mm to 26.7 mm, 31.7 mm and 18.7 mm, respectively, at a CRL of 84 mm. In the trisomy 21 fetuses, compared to normal fetuses, there was shorter BPD (mean difference = -0.63 mm; 95% CI, -0.97 to -0.30 mm, P < 0.0001), OFD (mean difference = -1.41 mm; 95% CI, -1.75 to -1.07 mm, P < 0.0001) and FTD (mean difference = -0.77 mm; 95% CI, -1.02 to -0.54 mm; P < 0.0001) and higher BPD to OFD ratio (mean difference = 0.022; 95% CI, 0.012 to 0.032, P < 0.0001) but no significant difference in the FTD to OFD ratio (mean difference = 0.004; 95% CI, -0.006 to 0.013, P = 0.448). CONCLUSIONS: In fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation there is evidence of brachycephaIy but not of frontal lobe hypoplasia.     

第11~13周胎儿额上颌角的二维及三维超声测量

目的 比较及评价二维和三维超声在测量胎儿额上颌(FMF)角中的作用.方法 分别应用二维及三维超声方法在颜面正中矢状面测量11～13周正常胎儿的FMF角,比较两种测量方法所得测值的差异及可重复性,分析三维测量的FMF角与胎儿头臀长(CRL)的关系.结果 共37名胎儿测得FMF角.随CRL增大,测量例数增加,而FMF角减小.其中18名(48.65%)得到符合要求的二维测量平面,30名(81.08%)胎儿获得符合要求的三维重建平面.对同一胎儿,二维测量平面两次测值间的平均差异为2.78°±1.95°,明显大于三维重建平面两次测值间的平均差异(1.68°±1.01°,P<0.01).11名胎儿同时应用两种方法进行测量,所得FMF角差异无统计学意义.三维重建平面测得的FMF角随CRL的增加而减小,二者明显相关(r＝-0.540,P<0.01).结论 在 11～13周正常胎儿中,与二维超声相比,应用三维超声可以快速而精确地测量FMF角.     

Three-dimensional evaluation of mid-facial hypoplasia in fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To investigate the mid-facial hypoplasia of fetuses with trisomy 21 at 11 + 0 to 13 + 6 weeks of gestation, by three-dimensional (3D) evaluation of the maxilla and the nasal bones. METHODS: A 3D volume of the fetal head was obtained before fetal karyotyping at 11 + 0 to 13 + 6 (median 12) weeks of gestation in 80 fetuses that were subsequently found to have trisomy 21 and in 862 fetuses subsequently found to be chromosomally normal. The multiplanar mode was used to obtain a sequence of transverse views of the fetal face and to demonstrate the maxilla, the adjacent rami of the mandible and the nasal bones. The maxillary depth, defined as the distance between the alveolus of the maxilla in the midline anteriorly and the midpoint of the line joining the rami posteriorly, was measured. Ossification of the nasal bones was considered to be normal if both bones were more echogenic than the overlying skin. RESULTS: In the chromosomally normal group the maxillary depth increased linearly with crown-rump length (CRL) from 3.1 mm at a CRL of 45 mm to 4.8 mm at a CRL of 84 mm, and in the trisomy 21 fetuses the depth was significantly smaller than normal (mean difference = - 0.3 mm, P < 0.001). There was no significant association between the delta maxillary depth and delta nuchal translucency thickness in either the trisomy 21 or the chromosomally normal fetuses. Impaired ossification of the nasal bones was observed in 3.1% of the chromosomally normal fetuses and in 60.0% of those with trisomy 21. The mean maxillary depth was significantly smaller in fetuses demonstrating impaired ossification than in those with normal ossification of the nasal bones (mean difference = -0.2 mm; 95% CI, -0.3 to -0.1, P = 0.001). CONCLUSIONS: In a high proportion of fetuses with trisomy 21 there is sonographic evidence of mid-facial hypoplasia at 11 + 0 to 13 + 6 weeks of gestation.     

Uterine artery Doppler at 11 + 0 to 13 + 6 weeks in the prediction of pre-eclampsia.

OBJECTIVE: To determine the performance of screening for pre-eclampsia (PET) by maternal characteristics and uterine artery pulsatility index (PI) at 11 + 0 to 13 + 6 weeks' gestation. METHODS: In women with singleton pregnancies attending for routine care at 11 + 0 to 13 + 6 weeks' gestation we recorded maternal variables and measured the uterine artery PI. We identified 107 cases that subsequently developed PET and 5041 that were unaffected by PET, gestational hypertension or delivery of newborns with birth weight below the 10(th) centile. A multivariate Gaussian model was fitted to the distribution of log multiples of the median (MoM) PI in the PET and unaffected groups. Likelihood ratios for log MoM PI were computed and used together with maternal variables to produce patient-specific risks for each case. Predicted detection rates (DR) and false-positive rates (FPR) were calculated by taking the proportions with risks above a given risk threshold. RESULTS: In the unaffected group log MoM PI was influenced by maternal ethnic origin, body mass index, previous history of PET and fetal crown-rump length. In the prediction of PET significant contributions were provided by log MoM PI, ethnic origin, body mass index and previous and family history of PET. For an FPR of 10% the DRs of all PET and PET leading to delivery before 34 weeks' gestation by log MoM PI and maternal variables were 61.7% and 81.8%, respectively. CONCLUSION: Maternal variables together with uterine artery PI at 11 + 0 to 13 + 6 weeks' gestation provide sensitive prediction of the development of PET, especially of severe early-onset PET.     

Uterine artery Doppler at 11-14 weeks of gestation in chromosomally abnormal fetuses.

OBJECTIVE: To determine whether the major chromosomal abnormalities are associated with impaired placentation in the first trimester of pregnancy. METHODS: This was a prospective study of 692 singleton pregnancies undergoing fetal karyotyping at 11-14 weeks of gestation. Uterine artery Doppler was carried out and the mean pulsatility index was calculated just before chorionic villus sampling. RESULTS: The fetal karyotype was normal in 613 pregnancies and abnormal in 79, including 39 cases of trisomy 21, 11 of trisomy 18, 11 of trisomy 13, eight of Turner syndrome and 10 with other defects. There were no significant differences in the median value of uterine artery mean PI between any of the individual groups. Although in the combined group of trisomy 18, trisomy 13 and Turner syndrome fetuses, the median pulsatility index (1.60) was significantly higher than in the chromosomally normal group (median pulsatility index, 1.51; P = 0.021), in the majority of abnormal fetuses (24 of 30) mean pulsatility index was below the 95th centile of the normal group (mean pulsatility index, 2.34). There was no significant association between uterine artery mean pulsatility index and fetal nuchal translucency thickness or fetal growth deficit. CONCLUSIONS: The high intrauterine lethality and fetal growth restriction associated with the major chromosomal abnormalities are unlikely to be the consequence of impaired placentation in the first trimester of pregnancy.     

Dilemmas in the management of twins discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To help develop an evidence-based approach to the best management of twin pregnancies discordant for anencephaly. METHODS: We retrospectively examined the management and outcome of 18 pregnancies discordant for anencephaly diagnosed at 11 + 0 to 13 + 6 weeks of gestation in our center. We combined these data with those from other publications. In total, there were 44 dichorionic pregnancies that were managed expectantly (n = 35) or by selective feticide (n = 9) and 19 monochorionic pregnancies that were managed expectantly. We also reviewed the literature to ascertain the outcome of monochorionic twin pregnancies undergoing cord occlusion. RESULTS: In the 35 dichorionic pregnancies that were managed expectantly, 20 (57.1%) developed polyhydramnios at 25-31 weeks; 13 were managed expectantly, five had amniodrainage and two had selective feticide. In 34 of the 35 cases the non-anencephalic twin was liveborn at a median gestation of 36 (range, 28-39) weeks and in six (17.6%) of these it was born before 33 weeks. In the dichorionic pregnancies that had selective feticide, there was one miscarriage and eight (88.9%) live births at a median gestation of 37 (range, 30-40) weeks and in one (12.5%) of these it was born before 33 weeks. In the monochorionic pregnancies, four (21.1%) anencephalic fetuses died at 20-32 weeks and in three of these the normal co-twin also died. In the 16 (84.2%) cases resulting in the live birth of the normal twin, delivery occurred at a median gestation of 33 (range, 27-39) weeks and in six (37.5%) of these it was before 33 weeks. Ultrasound-guided bipolar cord coagulation in 92 pregnancies, mostly complicated by twin reversed arterial perfusion sequence or severe twin-to-twin transfusion syndrome, was associated with a survival rate of 77.2% and early preterm delivery rate of 31.0%. CONCLUSION: Dichorionic twins discordant for anencephaly are best managed with serial ultrasound examinations for early diagnosis of polyhydramnios, which can then be treated either by amniodrainage or selective feticide. In monochorionic twins it is uncertain whether the best management is expectant or by cord occlusion.     

The mitral gap at 11 + 0 to 13 + 6 weeks: marker of trisomy 21 or artifact?

OBJECTIVES: To investigate the possible association between a particular pulsed Doppler waveform pattern, mitral gap, and trisomy 21 at 11 + 0 to 13 + 6 weeks. METHODS: We performed two studies. The first was a retrospective analysis of pulsed Doppler velocity waveforms of the mitral valve inflow, recorded during specialist fetal echocardiography in 291 chromosomally normal and 144 trisomy 21 fetuses with a nuchal translucency (NT) thickness of 3.5 mm or more. We examined each waveform in each trace to determine whether there was a gap between the E-wave (early diastolic filling) and A-wave (atrial contraction) in the waveform across the mitral valve. We also examined each trace that contained at least one waveform with a mitral gap and, first, noted the order of waveforms with a mitral gap relative to those without and, second, measured the A-wave peak velocity in a representative waveform with a mitral gap and in one without. The second study was a prospective investigation in which Doppler velocity waveforms of the mitral valve inflow were assessed in 227 singleton pregnancies immediately before chorionic villus sampling. RESULTS: A mitral gap was observed in 16 (5.5%) of the chromosomally normal and in 25 (17.4%) of the trisomy 21 fetuses. The incidence of mitral gap was significantly associated with the presence of cardiac defects but not with thickness of NT. The median number of waveforms per recorded image was 6 (range, 3-7) and in 32 (78%) of the 41 traces with a mitral gap only one or two of the waveforms was abnormal. The abnormal waveforms were in the middle or at the end of the trace in 95% of cases and had a lower mean A-wave peak velocity than did the normal waveforms (mean difference 3.7 cm/s; 95% CI, 0.3-7.0 cm/s; P = 0.03). In a prospective study of 10 normal fetuses we could produce a mitral gap deliberately by moving the sample volume out of the center of flow in the atrioventricular valve. In the prospective study of 227 pregnancies undergoing chorionic villus sampling a mitral gap was observed in 26/197 (13.2%) in which the fetal karyotype was subsequently found to be normal, 4/20 (20%) with trisomy 21 and 1/10 with other chromosomal defects. CONCLUSIONS: At 11 + 0 to 13 + 6 weeks, a mitral gap may be more common in fetuses with trisomy 21 than in fetuses with a normal karyotype. However, it is possible that a mitral gap does not reflect an underlying hemodynamic abnormality, but is rather the result of suboptimal positioning of the Doppler sample volume as the fetus moves during acquisition.     

Placental volume in twin and triplet pregnancies measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation.

OBJECTIVE: To compare the placental volume at 11 + 0 to 13 + 6 weeks' gestation between singleton and multiple pregnancies and to examine the possible effect of chorionicity on placental volume. METHODS: The placental volume was measured by three-dimensional (3D) ultrasound using the Virtual Organ Computer-aided AnaLysis (VOCAL) technique in 290 consecutive twin and 37 triplet pregnancies at 11 + 0 to 13 + 6 weeks of gestation. For the comparison of twin, triplet and singleton placental volumes each measurement was expressed as a multiple of the median (MoM) for singletons, previously established from the study of 417 normal fetuses at 11 + 0 to 13 + 6 weeks of gestation. RESULTS: Median twin and triplet placental volumes were 1.66 and 2.28 MoM for singletons, respectively. In twins the placental volumes increased significantly with gestation from a median of 83.6 mL (5th and 95th centiles: 56.0 mL and 124.9 mL) at 11 + 0 weeks to 149.3 mL (5th and 95th centiles: 100.0 mL and 223.1 mL) at 13 + 6 weeks. The median MoM in monochorionic twins was not significantly different from that in dichorionic twins with fused placentas or dichorionic twins with separate placentas. In triplets the placental volumes increased significantly with gestation from a median of 114.9 mL (5th and 95th centiles: 77.6 mL and 170.1 mL) at 11 weeks to 217.9 mL (5th and 95th centiles: 147.2 mL and 322.5 mL) at 13 + 6 weeks. There were no significant differences in total placental volume between monochorionic and dichorionic triplets, monochorionic and trichorionic triplets, or dichorionic and trichorionic triplets. CONCLUSIONS: Placental volume in multiple pregnancies does not depend on chorionicity, and the rate of placental growth between 11 and 13 + 6 weeks is not significantly different between singletons, twins and triplets. Moreover, for a given gestational age the placental volume corresponding to each fetus in twins and triplets is 83% and 76%, respectively, of the placental volume in singletons.     

Cardiac defects in chromosomally normal fetuses with abnormal ductus venosus blood flow at 10-14 weeks.

OBJECTIVE: To assess a possible relationship between ductus venosus blood flow abnormalities and cardiac defects in chromosomally normal fetuses with increased nuchal translucency thickness at 10-14 weeks of gestation. METHODS: Ductus venosus Doppler ultrasound blood flow velocity waveforms were obtained at 10-14 weeks' gestation immediately before fetal karyotyping in 200 consecutive singleton pregnancies with increased nuchal translucency. Fetal echocardiography was subsequently carried out in those with normal fetal karyotype. RESULTS: Reverse or absent flow during atrial contraction was observed in 11 of the 142 chromosomally normal fetuses with increased nuchal translucency. Major defects of the heart and/or great arteries were present in seven of the 11 with abnormal ductal flow and increased nuchal translucency, but in none of the 131 with normal flow. CONCLUSION: These preliminary results suggest that abnormal ductus venosus blood flow in chromosomally normal fetuses with increased nuchal translucency identifies those with an underlying major cardiac defect.     

Frontomaxillary Facial Angle Measurements in Euploid Korean Fetuses at 11 Weeks' to 13 Weeks 6 Days' Gestation

Objective. The purpose of this study was to evaluate the distribution of fetal frontomaxillary facial angles in a euploid Korean population at 11 weeks' to 13 weeks 6 days' gestation. Methods. Three‐dimensional volumes of the fetal head were obtained from women with low‐risk singleton pregnancies at 11 weeks' to 13 weeks 6 days' gestation who consented to this prospective study. Only fetuses with either a normal karyotype confirmed by amniocentesis or no abnormalities after delivery were considered eligible for analysis and were characterized as euploid for the purposes of this study. Women with multiple pregnancies and those who were lost to follow‐up and fetuses with abnormal karyotypes or anomalies diagnosed in utero or postnatally were excluded. The frontomaxillary facial angle was measured twice offline by a single examiner. Cases were categorized by crown‐rump length (CRL) in 10‐mm intervals for analysis of the frontomaxillary facial angle. Results. Among 375 enrolled cases, 158 were eligible for frontomaxillary facial angle analysis. The overall mean frontomaxillary facial angle ± SD was 88.6° ± 9.7°. The mean frontomaxillary facial angle for fetuses with a CRL of 40 to 49 mm (n = 35) was 93.7°; 50 to 59 mm (n = 53), 92.6°; 60 to 69 mm (n = 36), 85.3°; and 70 to 79 mm (n = 34), 81.0°, showing an inverse relationship between the mean frontomaxillary facial angle and CRL (r = ?0.5334; P < .0001). The proportion of cases with frontomaxillary facial angles of 85° or greater was 60.8%, and that of cases with angles of 90° or greater was 37.3%. Conclusions. Ethnic differences in frontomaxillary facial angle measurements should be considered when incorporating the frontomaxillary facial angle in fetal aneuploidy screening in the Korean population.