Obstetric dating scan
The conducting gel is non-staining but may feel slightly cold and wet.
There is no sensation at all from the ultrasound waves.
Fetal body measurements reflect the gestational age of the fetus. In patients with uncertain last menstrual periods, such measurements must be made as early as possible in pregnancy to arrive at a correct dating for the patient. In the latter part of pregnancy measuring body parameters will allow assessment of the size and growth of the fetus and will greatly assist in the diagnosis and management of intrauterine growth retardation (IUGR).
(Chart and further comments) Dating using the BPD should be done as early as is feasible.3.5 to 7 million cycles per second) are generally used for this purpose.They are emitted from a transducer which is placed in contact with the maternal abdomen, and is moved to "look at" (likened to a light shined from a torch) any particular content of the uterus.The diagnosis of missed abortion is usually made by serial ultrasound scans demonstrating lack of gestational development.
For example, if ultrasound scan demonstrates a 7mm embryo but cannot demonstrable a clearcut heartbeat, a missed abortion may be diagnosed.
Currently used equipments are known as real-time scanners, with which a continous picture of the moving fetus can be depicted on a monitor screen.