A new analysis has found that some second trimester markers for
Down’s syndrome that are detected by ultrasound are more telling than
others (Agathokleous M et al Ultrasound Obstet Gynecol. 2012 Dec 3).
Screening for Down’s syndrome is offered to all pregnant women in most
Western countries, starting out with a background risk based on age.
Certain features detected during a second trimester ultrasound exam are
potential markers for Down’s syndrome, including dilated brain
ventricles, absent or small nose bone, increased thickness of the back
of the neck, an abnormal artery to the upper extremities, bright spots
in the heart, ‘bright’ bowels, mild kidney swelling, and shortening of
an arm bone or thigh bone.To determine how these markers affect risk,
Kypros Nicolaides’s group at the Research Centre for Fetal Medicine at
King’s College London in UK analyzed all published studies that reported
results on second trimester markers for Down’s syndrome between 1995
and 2012. The team found that a few markers carry increased risks.
Dilated brain ventricles, increased thickness of the back of the neck,
and an abnormal artery to the upper extremities increase the risk by
three- to four-fold, and an absent or small nose bone increases the risk
by six- to seven-fold.