research day - University of Toronto Department of Obstetrics and ...

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ABSTRACT #P-C1
EARLY TRANSVAGINAL ULTRASOUND AT 13-15 WEEKS IS HIGHLY EFFECTIVE
IN DETECTION OF FETAL ANOMALIES.
Erika Frasca [M](1), Ants Toi (2), David Chitayat (3), Dan Farine (4), Karen Chong (3), Katherine
Fong K. (2), Ori Nevo (5). (1) Faculty of Medicine, University of Toronto, (2) Department of Medical
Imaging, Mount Sinai Hospital, (3) Prenatal Diagnosis and Medical Genetics Program, Mount Sinai
Hospital (4) Maternal Fetal Medicine, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, 5)
Maternal-Fetal Medicine, Department of Obstetrics and Gynaecology, Sunnybrook Health Sciences Centre.
University of Toronto.
Objectives: Transabdominal fetal ultrasound at 19-21 weeks is currently the most accepted
practice for fetal anomaly detection, even in women at high risk for having a baby with major
anomalies. However, earlier detection of fetal anomalies may enable sufficient time for further
tests and safer management. The objective of this study was to compare the detection rate of fetal
anomalies and completeness of transvaginal early anatomy ultrasound (TEAU) at 13-15 weeks to
the standard 19-21 week transabdominal ultrasound (TAS).
Methods: Data from women who had a TEAU at Sunnybrook Health Sciences Centre at 13-15
weeks between April 2007 and August 2008 was collected. TEAU included detailed fetal anatomy
examination comparable to the standard ultrasound at 19-21 weeks. Women with higher risk for
fetal anomalies due to an elevated nuchal translucency, previous fetal anomalies, maternal
conditions or other risk factors, and obese women (BMI ≥ 30 kg/m 2 ) were included. Standard TAS
was performed at 19-21 weeks. TEAU was performed by a single highly skilled physician, and
TAS was performed by qualified technologists in a university facility. Detection rate of fetal
anomalies and complete ability to assess the various fetal organs during the scan were compared
between the TEAU and the standard TAS, and to the outcome at delivery.
Results: 156 women were included with a mean maternal age of 33.2±4.5 years. The indications
for a TEAU were an elevated nuchal translucency (25%), fetal anomaly in previous pregnancy
(44%), maternal conditions (18%) and other risk factors (12%). 17% of the women were obese.
TEAU was performed at a mean gestational age of 14.8±0.8 weeks and TAS was performed at a
mean gestational age of 19.3±0.8 weeks. A total of 27 fetal abnormalities were observed, 23 of
which had ultrasonographically detectable anomalies. There was no significant difference in the
anomaly detection rate between TEAU versus a later TAS. TEAU detected 22/23 (95.6%)
anomalies; one undetected abnormality was a late onset skeletal dysplasia. 16 pregnancies were
terminated before the second scan. All abnormalities (100%) were detected in fetuses of women
who completed a TAS. Increased BMI was associated with more complete images using TEAU
(73% vs. 59%). 9/39 (23%) fetuses with elevated nuchal translucency had fetal anomalies that were
detected by TEAU and 3 additional fetuses had anomalies that were not ultrasonographically
detectable. At the time of the TEAU, soft markers for Down syndrome (elevated nuchal
translucency, echogenic bowel, pleural effusion) were detected in 39 women. In 23 cases, the soft
markers were not seen at the TAS. 20/23 had normal outcomes, while 3 had abnormal outcomes.
Conclusions: Early transvaginal ultrasound performed at 13-15 weeks is highly effective in
detecting fetal anomalies and is comparable to the standard ultrasound at 19-21 weeks.
Additionally, TEAU improves the completeness of scans in obese women compared to the
standard ultrasound. TEAU has an important role in the management of women with high risk for
fetal anomalies and in obese women and should be offered to patients.