M. Bakker

Low uptake of the combined test in the Netherlands : which factors contribute?

The aim of this study was to evaluate which of the following factors affect the uptake of the combined test (CT) in the Netherlands: womens socio‐demographic background, attitude towards Down syndrome, attitude towards termination of pregnancy, counseling process, reimbursement policy, and knowledge on the aim of the CT.

Increased nuchal translucency with normal karyotype and anomaly scan: What next?

Over the years, it has become clear that increased nuchal translucency is a marker for chromosomal abnormalities, and it is also associated with a wide spectrum of structural anomalies, genetic syndromes, a higher risk of miscarriage, and intrauterine fetal death. These risks are all proportionally related to the degree of nuchal translucency enlargement. After the initial assessment of increased nuchal translucency, parents should be counselled by the fetal medicine specialist about the possible outcomes and the value of additional karyotyping and array comparative genomic hybridisation. A detailed late first-trimester and subsequent 20-week scan should aim at identifying structural anomalies, with special focus on the fetal heart and subtle dysmorphic features. In the absence of structural anomalies or markers, the chance of a favourable outcome is high.

Nasal bone length, prenasal thickness, prenasal thickness-to-nasal bone length ratio and prefrontal space ratio in second- and third-trimester fetuses with Down syndrome

To evaluate nasal bone length (NBL), prenasal thickness (PT), prenasal thickness‐to‐nasal bone length (PT‐NBL) ratio and prefrontal space ratio (PFSR) as markers for Down syndrome in the second and third trimesters.

Facial profile markers in second- and third-trimester fetuses with trisomy 18

To evaluate nasal bone length (NBL), maxilla–nasion–mandible (MNM) angle, fetal profile (FP) line, prenasal thickness (PT), prenasal thickness to nasal bone length (PT:NBL) ratio and prefrontal space ratio (PFSR) as markers of trisomy 18 in the second and third trimesters of pregnancy.

Premaxillary protrusion assessment by the maxilla–nasion–mandible angle in fetuses with facial clefts

The aim of the study was to measure the degree of premaxillary protrusion in fetuses with orofacial clefts of various severities.

Prenasal Thickness, Prefrontal Space Ratio and Other Facial Profile Markers in First-Trimester Fetuses with Aneuploidies, Cleft Palate, and Micrognathia.

Objective: To investigate the feasibility and reproducibility of the prenasal thickness (PNT)/nasal bone length (NBL) ratio, maxilla-nasion-mandible (MNM) angle, facial profile line, profile line distance, and prefrontal space ratio (PFSR) in the first trimester of pregnancy, develop normal ranges, and evaluate these markers in abnormal fetuses. Methods: All measurements were performed on stored images by two operators. Feasibility, interoperator agreement, and prediction intervals were calculated for all measurements. Results: Feasibility was the highest for the NBL (74.3-79.7%) and the MNM angle (75.7-79.05%). Correlation was good for the NBL, the PNT, and the MNM angle (intraclass correlation coefficient 0.706-0.835). Mean difference between operators was the lowest for the PNT and PFSR (0.03-0.08). Measurements in abnormal fetuses showed that the majority of trisomy 21 fetuses had either an absent nasal bone or a shorter NBL. The PNT and PNT/NBL ratio were above the 97.5th centile in one third of the cases. Fetuses with facial clefts or micrognathia showed on average a large MNM angle (multiple of the median 0.96-5.15). Conclusion: First-trimester facial markers are feasible. The PNT and PNT/NBL ratio were increased in one third of the trisomic fetuses, and the MNM angle in the majority of fetuses with micrognathia and facial clefts.

Is 3D technique superior to 2D in Down syndrome screening? Evaluation of six second and third trimester fetal profile markers

The objective of this article is to investigate whether in the clinical setting of second trimester ultrasound (US) investigations, 3D multiplanar correction prior to the measurement of Down syndrome (DS) facial markers (nasal bone length, prenasal thickness, fetal profile line, maxilla‐nasion‐mandible angle, prenasal thickness to nasal bone length ratio, and prefrontal space ratio) is superior to subjective judgment of a correct midsagittal plane by 2D technique.

Trends in Serial Measurements of Ultrasound Markers in Second and Third Trimester Down Syndrome Fetuses

Objectives: To evaluate trends of nasal bone length (NBL), prenasal thickness (PT), nuchal fold (NF), prenasal thickness to nasal bone length (PT-NBL) ratio, and prefrontal space ratio (PFSR), measured serially in second- and third-trimester Down syndrome (DS) fetuses. Methods: Prenatal databases were searched for cases of continuing DS pregnancies with serial measurements, taken at least two weeks apart. Trends were plotted on previously reported normal ranges. Results: Serial measurements were available in 25 Down syndrome fetuses. Median gestational age (GA) was 25 weeks; average number of visits per case was 2.44, with a median interval of 39 days between investigations. In DS fetuses, NBL and PT showed fairly stable trends with gestation. PFSR, but especially NF, had a more unpredictable trend. The PT-NBL ratio was the most stable marker, remaining unchanged in 95% of cases. NBL, PT, and NF showed more deviance from the normal range with advancing gestation, but MoM values remained stable. All but two fetuses had ultrasound markers or structural anomalies, especially heart defects. Conclusions: The PT-NBL ratio is the most constant DS marker throughout gestation, following a predictable trend.

Intra-operator and inter-operator reliability of manual and semiautomated measurement of fetal nuchal translucency: a cross sectional study.

The goal of this study was to examine the intra‐operator and inter‐operator differences of the manual and semiautomated nuchal translucency (NT) measurements and to evaluate if these differences alter womens risk status.

OP12.03: To see or not to see anomalies: the nuchal translucency as a magnifying glass?

Failed visualisation of the fetal nasal bone is strongly associated with aneuploidies (T21, 13, and 18). It may also rarely be observed in euploid fetuses, mostly of Afro-Caribbean and Asian ethnicities. Absent nasal bone can be the presenting sign for cleidocranial dysplasia. Case report: A 42-year-old pregnant woman was referred at 24 weeks for an absent nasal bone (Fig 1). In addition to this finding, the fontanelles were large with wide sutures (Fig 2), the brain parenchyma was unusually clearly visible, and the clavicles were hypoplastic (Fig 3). Fetal growth was normal. The child’s father had two children from a previous relationship who had missing clavicles. The diagnosis of cleidocranial dysplasia was made and confirmed by amniocentesis with detection of RUNX2 gene mutation. Discussion: Cleidocranial dysplasia is an autosomal dominant skeletal dysplasia characterised by abnormal bone and dental development with normal cognitive function. 80% of cases are caused by a mutation in the RUNX2 gene. Prenatal genetic testing for this mutation is available. The prenatal sonographic diagnosis is primarily based on clavicular hypoplasia or aplasia and insufficient ossification of the cranium. In the few published cases, there are occasional references to the absence of the nasal bone, yet in most cases this is retrospective. Absent nasal bone may help to establish the prenatal diagnosis. Prenatal diagnosis is important, since the abnormal ossification of the skull and chest may expose the fetal brain and lungs to potential damage during natural birth. In conclusion, in absence of fetal nasal bone and low risk for fetal aneuploidies or if aneuploidies are excluded, consider cleidocranial dysplasia and check the clavicles.