Obstetric ultrasonography
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Obsteric_ultrasonograph.jpg
Obstetric ultrasonography is the application of medical ultrasonography to obstetrics. Here, ultrasound is used to visualize the embryo or fetus in its mother's uterus (womb). In some countries, routine pregnancy ultrasound scans are performed to detect developmental defects before birth, the perhaps most promising method uses a measurement of the nuchal translucency thickness ("NT-test").
Current evidence indicates that diagnostic ultrasound is safe for the unborn child, unlike radiographs, which employ ionizing radiation, although no randomized controlled trials have been undertaken to test the safety of the technology.
The sex of the baby can usually be determined any time after 16 weeks, often at the dating scan around 20 weeks into the pregnancy. This is also the best time to have a ultrasound done as most infants are the same size at this stage of development. Depending on the skill of the sonographer, ultrasound may suffer from a high rate of false negatives and false positives, that means care has to be taken in interpreting the accuracy of the scan.
External links
- A comprehensive guide to Obstetric Ultrasound (http://www.ob-ultrasound.net/)
- Nuchal Translucency test information page (http://www.obstetrics.co.nz/nuchal-translucency.html)he:בדיקת אולטרה סאונד להריון