Obstetric ultrasonography Totally Explained

Everything about Obstetric Ultrasonography totally explained

Obstetric sonography (ultrasonography) is the application of medical ultrasonography to obstetrics, in which ultrasound is used to visualize the embryo or fetus in its mother's uterus (womb). The procedure is often a standard part of prenatal care, as it yields a variety of information regarding the health of the mother and of the fetus, as well as regarding the progress of the pregnancy.

Types

Traditional obstetric ultrasounds are done by placing a transducer (a probe that emits high frequency sound waves) on the abdomen of the pregnant woman. One variant is a transvaginal ultrasound is done with a probe placed in the woman's vagina. Transvaginal scans usually provide clearer pictures during early pregnancy and in obese women. Also used is doppler ultrasound which detects the heartbeat of the fetus. Doppler ultrasound can be used to evaluate the pulsations in the fetal heart and bloods vessels for signs of abnormalities.

Early pregnancy

The gestational sac can sometimes 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. The embryo can be observed and measured by about five and a half weeks. The heartbeat may be seen as early as 6 weeks, and is usually visible by 7 weeks gestation.

Dating and growth monitoring

Gestational age is usually determined by the date of the woman's last menstrual period, and assuming ovulation occurred on day fourteen of the menstrual cycle. Sometimes a woman may be uncertain of the date of her last menstrual period, or there may be reason to suspect ovulation occurred significantly earlier or later than the fourteenth day of her cycle. Ultrasound scans offer an alternative method of estimating gestational age. The most accurate measurement for dating is the crown-rump length of the fetus, which can be done between 7 and 13 weeks of gestation. After 13 weeks gestation, the fetal age may be estimated by the biparietal diameter (the diameter of the head) and the length of the femur (the longest bone in the body). Dating is more accurate when done earlier in the pregnancy; if a later scan gives a different estimate of gestational age, the estimated age isn't normally changed but rather it's assumed the fetus isn't growing at the expected rate. This was the start of the most popular design in the history of ultrasound scanners.
Obstetric ultrasound has played a significant role in the development of diagnostic ultrasound technology in general. Much of the technological advances in diagnostic ultrasound technology are due to the drive to create better obstetric ultrasound equipment. Acuson Corporation's pioneering work on the development of Coherent Image Formation helped shape the development of diagnostic ultrasound equipment as a whole.

Safety issues

Current evidence indicates that diagnostic ultrasound is safe for the unborn child, unlike radiographs, which employ ionizing radiation. However, no randomized controlled trials have been undertaken to test the safety of the technology, and thus ultrasound procedures are generally not done repeatedly unless medically called for.
   A 2006 study on mice exposed to ultrasound showed neurological changes in the exposed fetuses. Some of the rodent brain cells failed to migrate to their proper position and remained scattered in incorrect parts of the brain.
   It has been shown that Low Intensity Pulsed Ultrasound does have a localized effect on growth in human beings. The 1985 FDA-allowed maximum power of 180 milliwatts per square cm is well under the 30-80 milliwatts per square cm range of the Statison V veterinary LIPUS device. LIPUS has been shown to effect tissue growth in as little as 20 minutes of time with repeated daily applications. Adding to the similarity, LIPUS and medical ultrasound both operate in the 1 to 10MHz range.
   While the benefits of medical ultrasound probably outweigh any risks, vanity uses such as making 3D ultrasound movies without a doctors order present an obviously unnecessary but unknown risk to a developing fetus. Clinical guidelines produced by the Society of Obstetricians and Gynaecologists of Canada recommend against the non-medical use of fetal ultrasound.

Further Information

Get more info on 'Obstetric Ultrasonography'.

External Link Exchanges

Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:

<a href="http://obstetric_ultrasonography.totallyexplained.com">Obstetric ultrasonography Totally Explained</a>

Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned.