Gestational dating ultrasound whos dating usher
Most patients find the examination much more tolerable when compared to a cervical PAP smear.
During the scan the sonographer may need to gently press on the abdomen to move bowel out of the way and bring the ovaries and other pelvic structures into view.
If the sex chromosome option is ordered, results will be reported as either low or high probability.
The individual bands of each chromosome are examined in detail for subtle genetic abnormalities such as 1) insertion of genetic material into a chromosome , 2) deletion of genetic material from a chromosome and 3) exchanging of genetic material between chromosomes (translocation).
It takes about 30 seconds to draw up the 20m L of straw coloured fluid required for analysis.
The volume of fluid aspirated is about 1/6th of that present around the fetus and this is naturally replaced over the next 24 hours. An amniocentesis is usually performed between 15 and 18 weeks gestation.
This test excludes not only Down syndrome, but a wide variety of subtle and major chromosome abnormalities What is to be expected after the test?
It is advisable for someone to take you home after the test and that you rest for the remainder of the day.