Ultrasound Quality Clinical Trial
Official title:
Can Increased Body Mass Index Prevent Adequate Ultrasound Examination for Trisomy 21 Risk Assessment?
Determine Cutoff BMI at which transabdominal sonography (TAS) is not satisfactory for aneuploidy risk assessment.
Obesity is a common public health problem which is increasing worldwide at an alarming rate.
According to National nutrition survey statistics of 2007, the prevalence of obesity in the
kingdom of Saudi Arabia was 23.6% in women and 14% in men. Also the prevalence of overweight
in the Saudi community was determined to be 30.7% for men as compared to 28.4% for the
women.
First trimester screening between 11-14 weeks gestation is known to be an effective and
reliable screening test for Down syndrome and trisomy 18.First trimester screening allows
earlier identification of the pregnancy at risk for fetal aneuploidy and anatomic defects,
particularly, cardiac anomalies, therefore, providing an option of earlier diagnosis by
chorionic villus sampling and analysis of amniocytes.
The well-known association of obesity during pregnancy with a variety of maternal and fetal
complications increases the importance of early aneuploidy screening.
Fetal aneuploidy risk assessment is based on a combination of maternal age, prior affected
pregnancy or family history, maternal serum biochemical tests and fetal ultrasound markers.
The impact of obesity on the quality of prenatal ultrasound examination is well established
with a greater risk for suboptimal visualization, in particular, the fetal cardiac
structures and the craniospinal structures only when body mass index above the 90th
percentile.
The quality of prenatal screening for aneuploidy via nuchal translucency thickness
measurement is significantly limited among obese pregnant women, thus, increased risk of
fetal anomalies.
Gandhiet al, have noted that increased BMI is not associated with suboptimal visualization
of nuchal translucency, but it is associated with a longer time to perform the
first-trimester ultrasound examination for aneuploidy risk assessment, increased need for
transvaginal ultrasound examination for optimum nuchal translucency visualization.
There is evidence suggesting that fetal anatomic evaluation in the low-risk gravida can be
better accomplished in the first trimester using the transvaginal route, providing a
valuable option for obese patients.
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Observational Model: Case Control, Time Perspective: Prospective