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.
Repetitive arrays of ultrasound beams scan the fetus in thin slices and are reflected back onto the same transducer.
Very high frequency sound waves of between 3.5 to 7.0 megahertz (i.e.
), fossils formed in the early post-flood period would give radiocarbon ages older than they really are.
boltwood used this method, called radioactive dating, to obtain a very accurate measurement of the age of earth.
ABSTRACT: Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative.
As soon as data from the last menstrual period, the first accurate ultrasound examination, or both are obtained, the gestational age and the estimated due date (EDD) should be determined, discussed with the patient, and documented clearly in the medical record.