"Usually, a 20-gauge spinal needle is inserted under direct sonographic guidance towards the umbilical vein. A typical sampling site would be where the segment of the umbilical cord is closest to the placenta where the cord is relatively fixed. The presence of a posterior placenta increases the difficulty of the procedure and in such cases, a muscle relaxant may be required prior to the procedure to immobilise the intervening fetus."
"further investigation of an in utero infection"
Expected headings
"Technique"
"There is a higher complication rate if performed prior to 20 weeks. An associated fetal loss rate as high as 4% has been reported 2."