Shanthi Sairam

Maternal ethnic origin and fetal nasal bones at 11–14 weeks of gestation

Objectives  Failure to visualise the fetal nasal bones at 11–14 weeks of gestation is associated with a significant increase in the risk for trisomy 21. However, it is not known whether the ethnic origin of the mother has any effect on the fetal profile and the prevalence of this marker.

Screening for aneuploidy in the first trimester by assessment of blood flow in the ductus venosus

Objective To assess the role of ductus venosus Doppler assessment in screening for fetal aneuploidy in pregnancies at 11–14 weeks of gestation.

Evaluation of fetal arrhythmias from simultaneous pulsed wave Doppler in pulmonary artery and vein

Objective: To evaluate the clinical application of simultaneous recordings of pulsed wave Doppler (PWD) signals in pulmonary artery and vein as alternative sampling site for assessment of arrhythmias in the fetus. Design: Prospective, cross-sectional study. Setting: Tertiary referral centre for fetal cardiology. Patients and methods: From July 1999 to July 2005 PWD was used in pulmonary vessels to assess fetal arrhythmias at 15–40 weeks’ gestation. Sample volume placement in the peripheral lung vessels was guided by colour flow mapping on a four-chamber section of the fetal heart. Atrial and ventricular systoles were identified from the pulmonary venous and arterial signals respectively. M-mode recordings were used for comparison. Outcome measures: Diagnosis of fetal arrhythmias. Results: Of 129 cases, 15 had supraventricular tachycardia, 12 with 1:1 atrioventricular conduction and 3 with atrial flutter and 2:1 block. There were 96 cases of atrial and 7 of ventricular premature beats, 2 of sinus bradycardia, 8 of variable degree heart block and 1 of ventricular tachycardia. PWD was diagnostic in 119 cases. PWD was better than M mode for diagnosis of premature beats and added information about mechanisms of tachycardia. Both methods facilitated interpretation of all arrhythmia patterns, although PWD was of less practical value in cases of complete heart block. Conclusion: Simultaneous PWD recording of pulmonary vessels in the fetus allows accurate diagnosis of arrhythmias. It is easily obtained with standard ultrasound equipment and adds to the armamentarium of diagnostic techniques for assessment of rhythm abnormalities prenatally.

Effect of parity on second‐trimester uterine artery Doppler flow velocity and waveforms

To investigate the relationship between second‐trimester uterine artery Doppler findings and parity in a large pregnant population.

Effectiveness of prenatal chromosomal analysis using multicolour fluorescent in situ hybridisation

Objective To evaluate the clinical effectiveness of multicolour fluorescent in situ hybridisation (FISH) analysis in routine prenatal diagnosis.

First-trimester ductus venosus, nasal bones, and Down syndrome in a high-risk population.

OBJECTIVE: Assessing the role of fetal ductus venosus and nasal bones evaluation in first-trimester screening for Down syndrome. METHODS: This was a prospective cohort study in a tertiary referral fetal medicine unit involving 628 consecutive fetuses undergoing chorionic villus sampling. The indication for chorionic villus sampling was an increased risk (more than 1:300) for trisomy 21 based on maternal age and nuchal translucency screening in 313 cases (54.7%), increased maternal age in 195 (34.1%), and other in 64 (11.2%). Immediately before chorionic villus sampling, an ultrasound examination was performed. The pattern of blood flow in the ductus venosus and the presence or absence of the nasal bones was noted. RESULTS: A satisfactory examination of both ductus venosus and nasal bones was possible in 572 fetuses. Of these, 497 (86.9%) had a normal karyotype, and 47 (8.2%) were affected with Down syndrome. The likelihood ratio for trisomy 21 was 7.05 (95% confidence interval 4.27–11.64) in the case of abnormal ductus venosus flow and 6.42 (95% confidence interval 3.86–10.67) in the case of absent nasal bones. CONCLUSION: In addition to increased fetal nuchal translucency, Down syndrome is significantly associated with first-trimester abnormal flow velocity patterns in the ductus venosus and hypoplasia of the nasal bones. LEVEL OF EVIDENCE: II-2

Ultrasound-guided interstitial laser therapy for the treatment of placental chorioangioma

BACKGROUND Placental chorioangioma is a relatively rare malformation with potential to cause fetal hydrops and even death. We describe ultrasound-guided interstitial laser as a modality for treating chorioangiomas of the placenta. CASE The patient presented at midgestation with placental chorioangioma resulting in fetal cardiomegaly. Interstitial laser was performed under local anesthesia on two occasions and resulted in arrest of flow through the tumor feeder vessel. CONCLUSION Interstitial laser therapy in a patient with placental chorioangioma resulted in a successful outcome.

Ultrasound diagnosis of fetal renal abnormalities

Development of the urogenital system in humans is a complex process; consequently, renal anomalies are among the most common congenital anomalies. The fetal urinary tract can be visualised ultrasonically from 11 weeks onwards, allowing recognition of megacystis at 11-14 weeks, which warrants comprehensive risk assessment of possible underlying chromosomal aneuploidy or obstructive uropathy. A mid-trimester anomaly scan enables detection of most renal anomalies with higher sensitivity. Bilateral renal agenesis can be confirmed ultrasonically, with empty renal fossae and absent bladder filling, along with severe oligohydramnios or anhydramnios. Dysplastic kidneys are recognised as they appear large, hyperechoic, and with or without cystic spaces, which occurs within the renal cortex. Presence of dilated ureters without obvious dilatation of the collecting system needs careful examination of the upper urinary tract to exclude duplex kidney system. Sonographically, it is also possible to differentiate between infantile type and adult type of polycystic kidney diseases, which are usually single gene disorders. Upper urinary tract dilatation is one of the most common abnormalities diagnosed prenatally. It is usually caused by transient urine flow impairment at the level of the pelvi-ureteric junction and vesico-ureteric junction, which improves with time in most cases. Fetal lower urinary tract obstruction is mainly caused by posterior urethral valves and urethral atresia. Thick bladder walls and a dilated posterior urethra (keyhole sign) are suggestive of posterior urethral valves. Prenatal ultrasounds cannot be used confidently to assess renal function. Liquor volume and echogenicity of renal parenchyma, however, can be used as a guide to indirectly assess the underlying renal reserve. Renal tract anomalies may be isolated but can also be associated with other congenital anomalies. Therefore, a thorough examination of the other systems is mandatory to exclude possible genetic disorders.

The sensitivity of antenatal ultrasound for predicting renal tract surgery in early childhood

To establish the sensitivity of antenatal ultrasound for identifying the need for renal tract surgery in infancy and early childhood.

Isolated fetal echogenic intracardiac foci or golf balls: is karyotyping for Down's syndrome indicated?

Objective To determine the prevalence of isolated echogenic intracardiac foci and the subsequent risk for Downs syndrome at 18–23 weeks in an unselected obstetric population.