An early obstetric ultrasonography can determine the age of the pregnancy fairly accurately.

The diagnosis is made in asymptomatic pregnant women by obstetric ultrasonography.

Obstetric ultrasonography may also be used to detect pregnancy.

More exact measurements can be performed with obstetric ultrasonography.

Velocity measurements of blood flow are also used in other fields of medical ultrasonography, such as obstetric ultrasonography and neurology.

Patients with abnormal MSAFP need to undergo detailed obstetric ultrasonography.

Early obstetric ultrasonography exams sometimes reveal an "extra" fetus, which fails to develop and instead disintegrates and vanishes.

Trisomy 9 can be detected prenatally with chorionic villus sampling and cordocentesis, and can be suggested by obstetric ultrasonography.

Obstetric ultrasonography is the application of medical ultrasonography to obstetrics, in which sonography is used to visualize the embryo or fetus in its mother's uterus (womb).

Instead, obstetric ultrasonography is the imaging method of choice in the first trimester and throughout the pregnancy, because it emits no radiation, is portable, and allows for realtime imaging.

Obstetric ultrasonography was first practiced in the 1960s; the first home test kit for hCG was invented in 1968 by Margaret (Meg) Crane in New York.

Sonicaid Ltd was involved in an early venture in the development of a 3D multiplanar scanner in the mid 1970s, building on the pioneering obstetric ultrasonography work by Prof Ian Donald and colleagues.

Although the College recommends obstetric ultrasonography at 18-20 weeks gestation in cases of advanced paternal age "to evaluate fetal growth and development," it notes that this procedure "is unlikely to detect many of the conditions of interest."

Obstetric ultrasonography is routinely used for dating the gestational age of a pregnancy from the size of the fetus, the most accurate dating being in first trimester before the growth of the fetus has been significantly influenced by other factors.

With obstetric ultrasonography the gestational sac sometimes can be visualized as early as four and a half weeks of gestation (approximately two and a half weeks after ovulation) and the yolk sac at about five weeks' gestation.