Dating scan accuracy
The sound waves bounce off bones and tissue returning back to the transducer to generate black and white images of the fetus.
Ultrasounds may be performed at any point during pregnancy, and the results are seen immediately on a monitor during the procedure.
Advanced Ultrasound – This exam is similar to the standard ultrasound, but the exam targets a suspected problem and uses more sophisticated equipment.
Doppler Ultrasound – This imaging procedure measures slight changes in the frequency of the ultrasound waves as they bounce off moving objects, such as blood cells.
Heartbeats are best detected with transvaginal ultrasounds early in pregnancy.
Concern typically develops if there is no fetal heart activity in an embryo with a crown-rump length greater than 5mm.
This is used to help assess suspected congenital heart defects.
If there are any questions regarding gestational age, placenta location, or possible complications then more ultrasounds may be scheduled.
Your healthcare provider will use hormone levels in your blood, the date of your last menstrual period and, in some cases, results from an ultrasound to generate an expected date of conception.
Ultrasounds are usually combined with other tests, such as triple tests, amniocentesis, or chorionic villus sampling, to validate a diagnosis.
An ultrasound exam may be performed throughout pregnancy for the following medically-necessary reasons: First Trimester: The ultrasound is a noninvasive procedure which, when used properly, has not demonstrated fetal harm.