产前超声诊断单脐动脉与胎儿异常的相关性研究

目的探讨超声检测胎儿脐带血管数目预测胎儿先天异常的价值。方法2000年1月至2006年10月在中山大学附属第一医院采用超声检测胎儿脐血管数目，对单脐动脉胎儿行产前超声系统筛查及胎儿染色体检查；分析单脐动脉合并畸形类型，与染色体异常的关系及胎儿结局。结果产前超声诊断胎儿单脐动脉119例，包括左侧72例（60．5％），右侧47例（39．5％）。单纯性单脐动脉59例（49.6％）；合并其他结构畸形60例（50．4％），其中泌尿系统畸形25例（41．7％），心血管系统畸形17例（28.3％），中枢神经系统畸形15例（25.0％），下肢畸形9例（15．0％），前腹壁和消化道畸形各5例（各占8．3％），唇裂或唇腭裂畸形3例（5．0％），其他畸形3例（5．0％）。行胎儿染色体检查41例，发现染色体异常8例，包括18-三体综合征3例、13-三体综合征1例、21．三体综合征1例、染色体片段异常3例，均合并其他畸形。结论胎儿单脐动脉左侧发生率高于右侧，约50％合并其他畸形；合并畸形时，染色体异常发生率较高；大部分单纯性单脐动脉胎儿结局良好。     

Single umbilical artery and its siding in the second trimester of pregnancy: relation to chromosomal defects

OBJECTIVES: To determine the possible association between single umbilical artery (SUA) in the second trimester of pregnancy and the incidence of chromosomal abnormalities. To determine whether the presence of chromosomal defects in fetuses with SUA is related to the side of the missing artery. METHODS: Color flow imaging of the fetal pelvis was used to determine the number of umbilical arteries in 2147 fetuses immediately before amniocentesis for karyotyping in the second trimester of pregnancy. RESULTS: SUA was diagnosed in 102/2147 (4.8%) cases. The left umbilical artery was absent in 60/102 (58.8%) fetuses, compared with the 42/102 (41.2%) for the right artery. The rate of chromosome abnormalities was significantly higher among fetuses with SUA than among those with 2 umbilical arteries (19/102 or 18.6% versus 109/2045 or 5.3%; OR = 4.1, 95% CI 2.3-7.1, p < 0.0001). Among fetuses with SUA, there was no significant difference in the rate of chromosome abnormalities between those with absence of the left versus the right artery (11/60 or 18.3% versus 8/42 or 19.0%, p = 0.93). There was an SUA in 5/39 (12.8%) cases with trisomy 21, 8/16 (50%) with trisomy 18, 1/4 (25%) with trisomy 13 and 5/69 (7.2%) with other chromosomal defects. There were no chromosome abnormalities in fetuses where a single umbilical artery was an isolated sonographic finding. All fetuses with SUA and chromosomal defects had associated abnormalities detected by ultrasound. CONCLUSION: A single umbilical artery (SUA) in the second trimester of pregnancy has a high association with trisomy 18, 13, 21 and other chromosomal defects, but all chromosomally abnormal fetuses had associated malformations detected by ultrasound. The absence of the left artery is more frequent than the absence of the right artery. The association with chromosomal abnormalities seems to be equal on each side.     

Antenatal sonographic detection of single umbilical artery.

The absence of one umbilical artery of single umbilical artery (SUA) is one of the most common congenital malformations in man. This vascular anomaly of the umbilical cord is frequently associated with other congenital malformations as well as some adverse perinatal events such as intrauterine growth retardation (IUGR), premature delivery, and increased perinatal mortality. Five cases of SUA detected prenatally by ultrasound are reported here in detail, including the first reported case in a twin gestation. None of the 5 affected infants had associated anomalies, but 2 cases of intrauterine growth retardation (IUGR) and 1 stillborn infant were noted in this series. An umbilical vein/umbilical artery ratio less than 2 was invariably found in all cases, making this observation another useful sonographic characteristic to use in the antenatal detection of SUA. Since the umbilical cord can be easily seen prenatally by ultrasound, and SUA is recognized as an important index for detecting congenital malformations, examination of the umbilical cord for the absence of one umbilical artery is an extremely valuable tool in prenatal diagnosis. The prenatal detection of SUA demands an extensive search for associated anomalies and a close surveillance of fetal well-being, since these fetuses have a high risk of fetal death or IUGR. Sonologists and sonographers should be aware of the possibility of SUA, especially in those cases associated with congenital malformations or IUGR.     

Quistes de plexos coroideos y riesgo de cromosomopatía

IntroductionSince they were first described in 1984, the presence of choroid plexus cysts during pregnancy have stimulated considerable debate concerning their possible relationship with chromosomal anomalies, mainly trisomy 18. Even today, the controversy persistsObjectiveTo identify which associated factors (cyst characteristics, associated anomalies and maternal age at diagnosis) should be considered to justify invasive karyotyping, bearing in mind that these techniques carry a risk of fetal lossMaterial and methodsWe analyzed data from one decade (January 1991-December 2000) corresponding to 26,500 fetuses who underwent ultrasound examination between weeks 14 and 22 of gestation. Choroid plexus cysts were considered as an ultrasound-negative formation of at least 3 mm in diameter located within the choroid plexusResultsChoroid plexus cysts were found in 366 fetuses (1.38%). Of these, eight fetuses presented chromosomal anomalies: six presented trisomy 18, one presented trisomy 21 and one showed chromosomal deletion at 6p. In all eight patients, choroid plexus cysts were bilateral and associated anomalies were detected. Mean maternal age was 36.5 yearsConclusionsWhen choroid plexus cysts are detected in the second trimester, detailed fetal investigation must be performed to find other possible markers of chromosomal anomalies even though some are difficult to detect ultrasonographically. Because the risk of fetal loss after amniocentesis is estimated at 1%, when other markers are absent, our results suggest that invasive karyotyping does not seem justified in pregnant women without additional risk factors     

Chromosomal microarray analysis in fetuses with high-risk prenatal indications: A retrospective study in China

ObjectiveThe present study aimed to determine the diagnostic value of prenatal chromosomal microarray analysis (CMA) for fetuses with several indications of being at high risk for various conditions.Materials and methodsThis retrospective analysis included 1256 pregnancies that were prenatally evaluated due to high-risk indications using invasive CMA. The indications for invasive prenatal diagnosis mainly included ultrasound anomalies, high-risk for maternal serum screening (MSS), high-risk for non-invasive prenatal tests (NIPT), family history of genetic disorders or birth defects, and advanced maternal age (AMA). The rate of clinically significant genomic imbalances between the different groups was compared.ResultsThe overall prenatal diagnostic yield was 98 (7.8%) of 1256 pregnancies. Clinically significant genomic aberrations were identified in 2 (1.5%) of 132 patients with non-structural ultrasound anomalies, 36 (12.7%) of 283 with structural ultrasound anomalies, 2 (4.5%) of 44 at high-risk for MSS, 38 (26.6%) of 143 at high-risk for NIPT, 11 (3.8%) of 288 with a family history, and 7 (2.1%) of 328 with AMA. Submicroscopic findings were identified in 29 fetuses, 19 of whom showed structural ultrasound anomalies.ConclusionThe diagnostic yields of CMA for pregnancies with different indications greatly varied. CMA could serve as a first-tier test for structural anomalies, especially multiple anomalies, craniofacial dysplasia, urinary defects, and cardiac dysplasia. Our results have important implications for genetic counseling.     

Prenatal diagnosis of tracheo-oesophageal fistula and oesophageal atresia

OBJECTIVES: To assess the accuracy of the prenatal ultrasound finding of subjectively small/absent stomach bubble in the prenatal diagnosis of tracheo-oesophageal fistula and oesophageal atresia (TOF/OA). METHODS: A retrospective study of prenatal ultrasound scans showing small/absent stomach bubble was carried out between 1st January 1994 and 31st December 2003. RESULTS: There were 62 cases with prenatally suspected (n = 40) and/or post-natally diagnosed (n = 22) TOF/OA. Among the 40 cases of prenatally suspected TOF/OA 15 were thought to be isolated and 25 non-isolated. Of the 15 suspected isolated cases, 7 were normal and 8 had TOF/OA (5 isolated + 3 TOF/OA with another anomaly) at delivery. Among the 25 cases of prenatally suspected non-isolated TOF/OA, there was confirmation in only two cases, in the remaining 23 cases other anomalies were confirmed but TOF/OA was not present.Twenty-two babies with TOF/OA were identified in whom there had been no prenatal ultrasound suspicion on ultrasound scanning. Six had isolated TOF/OA and 16 had non-isolated TOF/OA. CONCLUSION: Of the 32 cases of confirmed TOF/OA,10 (31%) were suspected prenatally. If the TOF/OA was an isolated anomaly (11 cases), the prenatal detection rate was 45%. Interpretation of ultrasound findings suspicious of TOF/OA requires caution, particularly, when there are associated multiple anomalies on scan.     

Perinatal results following the prenatal ultrasound diagnosis of single umbilical artery

OBJECTIVE. To study the perinatal results in our population, following the prenatal ultrasound diagnosis of a single umbilical artery (SUA), as this alteration is associated with fetal malformations, chromosomal abnormality, and poor perinatal results. MATERIALS AND METHODS. A retrospective review of all obstetric ultrasounds carried out between October 2000 and December 2003 in our service, obtaining the postnatal results of the fetuses diagnosed with an SUA. RESULTS. From a total of 5,987 pregnant patients examined by ultrasound scan at 20th week, an SUA was found in 40 cases, representing an incidence of 0.7%. Of these, 84.6% were normal pregnancies at birth and 15.4% presented other malformations and/or chromosomal abnormalities. No aneuploidy was found in pregnancies where there were no other associated findings in the ultrasound scan at 20 weeks. All cases with serious congenital malformations accompanying the SUA were diagnosed prenatally. There was a 5% of perinatal mortality rate among our fetuses with SUA, which represents a mortality rate 10 times greater than the overall rate among our patients. CONCLUSIONS. The ultrasound discovery of an SUA implies the meticulous search for other associated malformations, and in the absence of these, the risk of a chromosomal abnormality is very low, unless it is a high-risk patient. However, the growth and wellbeing of the fetus must be carefully monitored in the last 3 months, although the ultrasound scan does not show any other associated alterations.     

Chromosomal anomalies and additional sonographic findings in fetuses with open neural tube defects

Objective

To evaluate the results and the necessity of chromosome analysis in fetuses prenatally detected with a neural tube defect and to determine the significance of ultrasonographic evaluation for the identification of underlying or accompanying chromosomal anomalies.

Methods

Ninety fetuses that underwent prenatal and/or postnatal chromosome analysis after being diagnosed with open neural tube defects (NTD) between the years 2006 and 2010 in the Department of Obstetrics and Gynecology at Ondokuz Mayis University School of Medicine were included in this study. Detailed fetal ultrasonography was performed in all cases in order to investigate any additional anomalies. Karyotype was determined in the prenatal period by amniocentesis in 72 (80?%) of the 90 fetuses, and by cordocentesis in 5 (5.5?%). In 13 (13.3?%) fetuses, karyotype was determined in the postnatal period by blood sampling.

Results

Fourteen (15.5?%) of the 90 fetuses were diagnosed with acrania/anencephaly, 14 (15.5?%) with encephalocele, 2 (2.2?%) with iniencephaly, 60 (66.6?%) with open spina bifida. None of the 90 fetuses with open NTD who had undergone chromosome analysis was diagnosed with chromosomal anomalies. None of the 19 (21.1?%) fetuses diagnosed with additional ultrasound findings had a chromosomal abnormality, either. Seventy-one (78.9?%) fetuses having sonograhically isolated NTD were also isolated in postmortem examination.

Conclusion

In fetuses with open NTD, we could not find the chromosomal anomaly rate as high as reported in previous literature. The necessity of fetal karyotyping should be questioned especially in isolated cases.     

Right ductus arteriosus: facts and theory

ObjectiveTo report fetal right-sided persistent ductus arteriosus (RPDA) in association with right aortic arch (RAA).Study designExtensive sonographic fetal anatomical scans were consecutively performed on 19,874 private, self-referred pregnant women who wanted early sonographic detection of fetal anomalies.ResultsOf 19,874 transvaginal (TVS) sonographic examinations 40 fetuses had right aortic arch (RAA) and four of them (10%) had RPDA. We also diagnosed seven cases of RPDA with involvement of the left aortic arch where a right-curving pattern (“L” shape) parallel to the right pulmonary artery was suggestive of Rt. DA with left aortic arch. Only one (9%) of the RPDA cases was associated with a cardiac anomaly (double outlet right ventricle). None of the other eight RPDA cases had any discernible anomalies, and all of the fetuses with RPDA had normal karyotypes.ConclusionsIn 10% of the fetuses with right aortic arch the ductal arch was also on the right side. An unusual-looking DA may be a RPDA associated with the left aortic arch.In most cases, the RPDA is a normal variant not associated with other anomalies.     

Role of fetal autopsy as a complementary tool to prenatal ultrasound

Abstract

Aim: To correlate and compare prenatal ultrasound with fetal autopsy examination to detect structural births defects and provide specific diagnoses.

Methods: 141 second trimester fetuses (<20 weeks and <500?g) where pregnancy was terminated for structural birth defects and/or severe intra-uterine growth restriction (IUGR) or intra-uterine death, referred to our tertiary care private, teaching hospital were examined by a team of experienced pathologist and clinical geneticist. Findings of pathology examination were compared to those provided by ultrasound examination.

Results: A total of 301 structural abnormalities were noted. Specific etiology was identified or syndromic diagnosis was possible in 57/141 (40.4%) cases. The maximum number of systemic anomalies (45/301, 14.95%) was noted in the central nervous system (CNS). CNS anomalies were most commonly associated with facial dysmorphism including cleft lip/palate etc. There was a complete agreement between ultrasound and autopsy findings in 41/141 (29.07%) cases, additional information that did not influence the final diagnosis and/or counseling was obtained by autopsy in 65/1416 (46.09%) cases, while additional information that influenced the final diagnosis and/or counseling was provided by autopsy in 35/141 (24.82%) cases.

Conclusion: Fetal autopsy serves as a complementary tool to fetal ultrasound due to its ability to pick up minor anomalies and/or anomalies that were missed on ultrasound. It may be routinely performed as an attempt to reach a specific diagnosis and offer appropriate counseling to couples, following pregnancy termination for fetal anomalies.     

Pregnancy and perinatal outcomes of first-trimester crown−rump length discordant IVF dichorionic twin pregnancies – a retrospective cohort study

Research QuestionThis study aimed to evaluate the association between discordance in crown–rump length (CRL) and adverse pregnancy and perinatal outcomes in dichorionic twin pregnancies.DesignThis was a retrospective cohort study of dichorionic twin pregnancies after IVF that showed two live fetuses at the first ultrasound scan between 6 ⁺⁵ and 8 weeks gestational age from 1 January 2015 to 31 December 2016. Study groups were defined by the presence or absence of 20% or more discordance in CRL. The primary outcomes were early fetal loss of one or both fetuses before 12 weeks and birthweight discordance. Secondary outcomes included fetal anomalies, fetal loss between 12 and 28 weeks, stillbirth, small for gestational age (SGA) at birth, low birthweight (LBW), very low birthweight (VLBW), admission to the neonatal intensive care unit (NICU) and preterm delivery (PTD).ResultsCRL-discordant twin pregnancies were more likely to end in the loss of one fetus before 12 weeks’ gestation (odds ratio [OR] 15.877, 95% confidence interval [CI] 10.495–24.019). Discordant twin pregnancies with twin deliveries had a significantly higher risk of birthweight discordance (OR 1.943, 95% CI 1.032–3.989). There was no significant difference in perinatal outcomes including fetal anomalies, PTD, LBW, VLBW, SGA, neonatal death and admission to NICU between singleton or twin deliveries.ConclusionsDiscordant twin pregnancies were at increased risk of one fetal loss prior to 12 weeks’ gestation. Except for birthweight discordance, there was no significant difference between CRL discordance and other adverse perinatal outcomes.     

Progression of Doppler changes in early-onset small for gestational age fetuses. How frequent are the different progression sequences?

Objective: To evaluate the progression of Doppler abnormalities in early-onset fetal smallness (SGA).

Methods: A total of 948 Doppler examinations of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV), belonging to 405 early-onset SGA fetuses, were studied, evaluating the sequences of Doppler progression, the interval examination-labor at which Doppler became abnormal and the cumulative sum of Doppler anomalies in relation with labor proximity.

Results: The most frequent sequences were that in which only the UA pulsatility index (PI) became abnormal (42.1%) and that in which an abnormal UA PI appeared first, followed by an abnormal MCA PI (24.2%). In general, 71.3% of the fetuses followed the classical progression sequence UA→MCA→DV, mostly in the early stages of growth restriction (84.1%). In addition, the UA PI was the first parameter to be affected (9?weeks before delivery), followed by the MCA PI and the DV PIV (1 and 0?weeks). Finally, the UA PI began to sum anomalies 5?weeks before delivery, while the MCA and DV did it at 3 and 1?weeks before the pregnancy ended.

Conclusions: In early-onset SGA fetuses, Doppler progression tends to follow a predictable order, with sequential changes in the umbilical, cerebral and DV impedances.     

Umbilical artery blood flows among pregnancies with single umbilical artery: a prospective case-control study

Objectives: To evaluate peak systolic velocity (PSV) in the umbilical artery (UA) among patients with single umbilical artery (SUA) as compared with patients with three vessel cords.

Methods: A prospective case-control study was performed. UA blood flow velocimetry was obtained from fetuses with SUA and from a control group with three vessel cord. PSV and pulsatility index (PI) were measured. Patients’ characteristics were compared for statistical differences and a linear regression model was constructed for the different groups.

Results: UA Doppler velocimetry measurements were obtained from 29 patients with SUA and from 29 controls matched for gestational age. The differences between UA PI with and without SUA were significant (F?=?3.471; p?=?0.0379) showing a lower PI in the SUA group. However, no significant statistical difference was found in PSV between these two groups (F?=?0.149; p?=?0.86).

Conclusions: While the impedance in the UA of patients with a SUA was lower compared with patients with a normal umbilical cord, the PSV did not differ.     

Single umbilical artery: what does it mean for the fetus?

Single umbilical artery (SUA) is the most common anomaly of the umbilical cord which affects between 0.5 and 2.5% of all pregnancies. AIM: Our purpose was to determine whether there was a significant relationship between SUA and other anatomical anomalies. MATERIAL AND METHODS: All cases of fetal single umbilical artery identified in our hospital between 2002-2005 were reviewed for other ultrasound detected abnormalities. RESULTS: 18 cases of single umbilical artery were diagnosed on the basis of initial sonograms. 17 cases formed the study population (in 10 cases the left artery and in 7 the right artery was absent). In one case we diagnosed an umbilical cord tumor. 33.3% had other anatomical anomalies. The mean of women in the study was 30.5 years, the mean gestational age at examination was 28 weeks. CONCLUSIONS: In most cases the SUA occurs to be an isolated anomaly. In cases of SUA, the detailed ultrasound examination should be performed. Left artery absence is more common and also in these cases other anatomical anomalies are more likely to be observed as well. In our study we did not find a correlation between SUA and IUGR.     

Sensitivity of prenatal ultrasound for detection of trisomy 18

Objectives: To evaluate the sensitivity of prenatal ultrasound (US) for trisomy (T18) diagnosis and describe US findings in a large tertiary care institution in the USA.

Materials and methods: This was a retrospective cohort of all T18 cases diagnosed at our institution from October 2004 to October 2014 based on prenatal or postnatal genetic diagnostic testing. We included all women with a fetus affected by T18 who had a comprehensive US by a maternal–fetal medicine specialist performed at our institution. US findings were reviewed, classified by organ system, and categorized as an anomaly or soft marker. Chi-square or t-test was used for statistical analysis.

Results: We included 128 cases of T18 with confirmed cytogenetic analysis ?110 (86%) of which were diagnosed prenatally or suspected by cell-free DNA and confirmed postnatally, and 18 of which underwent neonatal blood sampling alone. One hundred and twenty-one (95%) had at least one abnormal US finding. Anomalies were more frequently identified on US at ≥20 weeks as compared with <20 weeks (93% versus 76%; p?=?.004). The mean number of findings detected per fetus was 5.1?±?3.0. Fetuses diagnosed by postnatal sampling alone had a similar number of US exams performed and number of abnormal findings compared to those diagnosed prenatally.

Conclusion: Ninety-five percent of fetuses with T18 had at least one abnormal US finding. This sensitivity of is higher than reported in most prior studies, but is not 100%, and should be considered when counseling women regarding prenatal diagnosis of T18.

Rationale: Historical detection rates for abnormal sonographic findings in trisomy 18 fetuses range from 70% to 100%. These studies are limited by small sample sizes. This is a contemporary study of ultrasound findings in a large group of women with confirmed trisomy 18 by prenatal or postnatal genetic diagnosis. We provide expansive detail on soft markers and anomalies broken down by organ-system and gestational age.     

4D ultrasound study of fetal facial expressions in the third trimester of pregnancy

Objective: To evaluate the frequencies of fetal facial expressions in the third trimester of pregnancy, when fetal brain maturation and development are progressing in normal healthy fetuses.

Methods: Four-dimensional (4?D) ultrasound was used to examine the facial expressions of 111 healthy fetuses between 30 and 40?weeks of gestation. The frequencies of seven facial expressions (mouthing, yawning, smiling, tongue expulsion, scowling, sucking, and blinking) during 15-minute recordings were assessed. The fetuses were further divided into three gestational age groups (25 fetuses at 30–31?weeks, 43 at 32–35?weeks, and 43 at ≥36?weeks). Comparison of facial expressions among the three gestational age groups was performed to determine their changes with advancing gestation.

Results: Mouthing was the most frequent facial expression at 30–40?weeks of gestation, followed by blinking. Both facial expressions were significantly more frequent than the other expressions (p?p?=?.031). Other facial expressions did not change between 30 and 40?weeks. The frequency of yawning at 30–31?weeks was significantly higher than that at 36–40?weeks (p?Conclusions: Our results suggest that 4D ultrasound assessment of fetal facial expressions may be a useful modality for evaluating fetal brain maturation and development. The decreasing frequency of fetal yawning after 30?weeks of gestation may explain the emergence of distinct states of arousal.     

Outcome of small-for-gestational-age fetuses according to umbilical artery Doppler: Is there any yield from additional middle cerebral artery Doppler?

Abstract

Objective.?To investigate the outcome of small-for-gestational-age (SGA) fetuses in relation to the features of umbilical artery (UA) Doppler and to explore the prognosticator of middle cerebral artery (MCA) Doppler in SGA fetuses with normal UA impedance.

Methods.?Two hundred ninety-seven patients were classified into Group 1 with normal UA and MCA pulsatility index (PI), Group 2 with normal UA but abnormal MCA PI and Group 3 with abnormal UA PI/absent or reversed end diastolic flow. Neonatal outcomes were compared between each group.

Results.?Neonatal intensive care unit (NICU) admission, duration of hospital stay and perinatal mortality were higher in Group 3 as compared to the others. Group 2 had a lower birth weight and more fetuses with 5-min Apgar score <7 than Group 1; NICU admission and need for ventilators were also significantly higher than Group 1.

Conclusions.?SGA fetuses with abnormal UA Doppler suffered more morbidity and mortality compared to those with normal UA Doppler. SGA fetuses with normal UA PI but abnormal MCA PI had worse outcomes compared to those with normal UA and MCA PI.     

The role of fetal echocardiography in the prenatal diagnosis of aneuploidy based upon prenatally diagnosed patau syndrome fetuses (case analysis)

OBJECTIVE: Assessment of usefulness of the fetal echocardiography and genetic sonography in prenatal diagnosis trisomy 13 (retrospective analysis). MATERIAL AND METHOD: Between 1994-1999 at the Department for Diagnosis of Congenital Malformation at the Institute of PPMH in 11 fetuses with Patau Syndrome ultrasound and echocardiography examination were performed. In our study the most of cases come from low risk of pregnant women. RESULTS: Fetal heart defect was the most common anomaly diagnosed prenatally in fetuses with Patau Syndrome (7/11), the second one were central nervous system anomalies (6/11) and genitourinary system anomalies (6/11).     

Hyperechogenic fetal bowel and Down syndrome. Results of a French collaborative study based on 680 prospective cases

Hyperechogenic fetal bowel is prenatally detected by ultrasound during the second trimester of pregnancy in 0.1% to 1.8% of foetuses. It has been described as a normal variant and has often been associated with severe diseases, notably Down syndrome. The aim of the present study was to determine the risk of trisomy 21 in a prospective study of 680 fetuses with hyperechogenic foetal bowel. Karyotyping was performed on amniotic cells in 632 cases, and outcome was known in 655 cases. A 2.5% risk of Down syndrome and a 1% risk of other severe chromosomal anomalies were observed. Hyperechogenicity was isolated in 11/17 Down syndrome cases, and associated with other ultrasound anomalies in all seven cases of severe chromosomal anomalies. In conclusion, fetal bowel hyperechogenicity indicates a risk of chromosomal anomalies ten-fold higher than that expected on the basis of maternal age, therefore justifying invasive procedures.     

Isolated absent or hypoplastic nasal bone in the second trimester fetus: is amniocentesis necessary?

Objective.?To elucidate the significance of isolated absent or hypoplastic nasal bone in the second trimester ultrasound scan.

Methods.?All cases of absent or hypoplastic nasal bone (length?<?5th percentile) encountered during 2007–2009 were retrieved from database and all the ultrasound findings including structural abnormalities and soft markers for Down syndrome and fetal karyotype were reviewed. The cases were categorized into a study group with isolated absent or hypoplastic nasal bone and a comparison group with additional ultrasound findings. The incidence of Down syndrome confirmed by karyotyping was compared between the two groups.

Results.?Among 14 fetuses with absent or hypoplastic nasal bone identified, six (42.9%) had Down syndrome and eight (57.1%) were normal. All (100%) of the six fetuses with isolated absent or hypoplastic nasal bone (Study Group) had normal karyotype, while six (75%) of the other eight fetuses with additional ultrasound findings (Comparison Group) had Down syndrome (p?=?0.010).

Conclusions.?The use of isolated absent or hypoplastic nasal bone in the second trimester ultrasound scan for Down syndrome screening may not be effective. Amniocentesis, however, is indicated for fetuses with structural abnormality or additional soft marker which should be carefully searched by an experienced ultrasonographer.