Sunday, May 5, 2013

Ultrasound in pregnancy

The story of ultrasound in pregnancy begins in the month of July in 1955. when Ian Donald, an obstetrician in Scotland, lent industrial ultrasonic device that is used for error detection in metal and tried it on some tumors previously removed, koisteći beef control. Ian Donald discovered that different tumors produce different echoes. Shortly after that he began to use ultrasound not only for abdominal tumors in women, but also in pregnant women. Articles about it have appeared in medical journals and its use quickly spread throughout the world. (A. Oakley, The Captured Womb; Oxford, England: Blackwell Publishing, 1984). 

How Ultrasound Works?

Ultrasonic device actually transmits sound signals at very short intervals. Then receives an echo (echo).Here's an example: You are in a big, empty room. Windows, and then listen. You can hear the echo when the sound bounces off the walls. In other words, when transmitting a sound signal (your voice) and then you hear, what you hear is the echo. What is the wall farther than you need more time to sound and refuses to come to you in the form of an echo. You closer to the wall, before you hear the echo.

Ultrasound machine is doing the same thing. And more than that! He uses sound to create receives the image you see on your monitor. How? Each time it receives the echo of the sound signal is sent, he records a point (usually gray tones from black to white) on the monitor. The position of each point depends on how long it takes the echo to "reach" machine, ie. how long the device must wait until it receives a response.Shade of gray is determined by the strength of echo machine registers.

Think of it this way. The echo from the wall with a hard, smooth surface will be louder than the echo from the wall with rough and smooth surface.

Therefore, a strong echo from deep inside the womb will be brighter and closer to the bottom of your monitor. Weak echo, which is closer to the surface, there will be more gray and nearing the top of your monitor.

Ultrasound machine sends sound signals and registers the reverberations very high speed to create the image on the monitor. High frequency sound waves, which are commonly used for this purpose, is 3.5-7.0 MHz, ie. 3.5 to 7 million times (hertz) per second. (American Institute of Ultrasound in Medicine, October 1982).

What comprises the ultrasound equipment?

There are three main components that make up the ultrasound: a transducer, and monitor the appliance.

Probe - Transducer - is part of the gynecologist in the hand while performing inspection. It is a crystal that emits ultrasonic waves and receives their echo. Gynecologist moves the probe to focused ultrasound waves to examine the area you want. There are several different forms of the probe.

Monitor - This is probably the most interesting part of both parents. Monitor the screen which shows the image created by the camera.

Ultrasound machine - it uses a computer program that converts the echoes, which registers the probe, the images that you see a gynecologist, and the monitor.

How is ultrasound performed?

There are two methods commonly used in ultrasound.

Transabdominal metda is the oldest and therefore the method is known to all pregnant women. After placing the gel gynecologist puts a probe on the abdomen. The gel is applied to enable easier transfer of sound waves from the transducer to the skin. Gel is not sticky, but moist and slightly cooled. This search is performed when a pregnant woman has "optimal full" bladder. The reason why pregnant women in early pregnancy must have a full bladder is because the ultrasonic wave does not pass well through the gas in the intestines. A full bladder helps to gut "out of the way." Therefore, your doctor will ask you to drink plenty of fluids prior to the examination and that you do not go to the bathroom until an inspection.

Sometimes there can be too much urine in the bladder, so your doctor may ask you to just something izmokrite. This is called a "useful discharge" and it can affect a huge difference in the final outcome between excellent and bad shots. Maybe it sounds hard to do, but most women make it work smoothly. Although not all gynecologists believe in "useful discharge", it is one of the most important techniques used in performing high quality ultrasound examinations.

Transvaginal ultrasound is usually performed with an empty bladder and with a specially designed probe that is inserted into the vagina. In this way, the doctor can clearly see the general structure with a higher resolution for watching more closely than transabdominal method. The only limitation of this approach is distance. For technical reasons, the ultrasonic waves from the transducer transvaginale not travel so deep into the body as transabdominal ultrasound waves from the transducer. Thus, while the uterus is very enlarged, transvaginal ultrasound is limited to the first trimester, but can be used in late pregnancy. The heartbeat of the fetus can be seen clearly already in the sixth week of pregnancy.

There is another ultrasound technique used in gynecology. It could be considered a transition between the two methods given above, called transperinelani ultrasound. It is performed by placing a transabdominal probe to the part just below the vagina - crotch. It's usually done with an empty bladder, and used to view the cervix. It can also be used to view structures inside the uterus that are close to the cervix. This method is very useful in certain special cases. (American Institute of Ultrasound in Medicine, October 1982).

Psychological and emotional side ultrasound

For medical ultrasound is an important diagnostic tool. For parents it may be of greater personal significance. Some people think that a woman tied with a child if he sees his earlier ultrasound, says Ella A.Kazerooni, an assistant professor of radiology at the University of Michigan Medical Center, Ann Arbor. Its survey of 318 women showed that 83% of women said they would be less worried if the ultrasound findings were normal. When pregnant women are satisfied that all is well, less care, and the whole physical and emotional images can affect their condition. Then, 97% of women stated that they plan napravititi ultrasound, and 44% are willing to pay the same if their insurance does not cover. There's something about when you see a child and took home the first picture and show everyone adds Dr.. Kazeronni.

But what if not? When ultrasound is made and its result is questionable, it can be a real emotional abyss.Gynecologists who perform ultrasound mistakes as much as they are right and when the family is told that their unborn child has some kind of defect, they will spend the rest of pregnancy care, cry, and in some cases even abort a child because they are convinced that there is an abnormality. The few tests were conducted on the physical safety of ultrasound, but it is often forgotten that he carries some very serious emotional and psychological consequences.

The famous French obstetrician Michel Odent says that the ultrasound attribute almost magical properties and it is believed that it will solve all kinds of problems. Zacjelo, ultrasound examination can give a large amount of information and equally satisfy the curiosity of both parents and physicians. However, in the final sense, they rarely give more details of the diagnosis of a skilled physician. Even when such a question says something that we have not discovered by other methods, rarely leads to a change in procedure.

It is important to remember that at this time we do not have yet the knowledge that exposure to ultrasound, even in a very short period of time can affect the mother - or a fetus. While many doctors and nurses believe that this procedure is safe, there are ongoing studies that explore the broad of his work on the genetic structure, fetal development, hematology and vascular conditions, the immune system and so on.Since this research has just begun, it is too early to draw final conclusions. We can only wait and wonder what we will see for forty years, you will have one or two generations to be literally in utero soothed by ultrasonic waves.

The first ultrasound is usually done at the beginning of pregnancy, and from the 18th and 22 weeks, and between 32 and 36 weeks of pregnancy. There are many reasons given for the performance of ultrasound in pregnancy.

Diagnosis and confirmation of early pregnancy - gestational sac (GV) can be seen earliest around 4.5 weeks of pregnancy, and the "yolk" bags around 5 weeks. The embryo can be seen and measured about 5.5 weeks.Ultrasound can also confirm that the pregnancy is within the uterus.

Bleeding in early pregnancy - the ability of the fetus to maintain the life proof in cases of vaginal bleeding in early pregnancy. Visible heartbeat could be seen and detected by Doppler ultrasound around the sixth week and is usually clearly visible in the seventh week. If the beats are there, the likelihood of continued pregnancy is greater than 83 percent. Spontaneous abortions and anembrijska bags will usually give a typical picture of a deformed gestational sac (LV) and the absence of fetal heart rate (CDS).

With the occurrence of bleeding in the first trimester, ultrasound is also very important in the early diagnosis of ectopic pregnancies and molar pregnancies.

Determination of gestational age and fetal sizing - fetal body measurements reflect his gestational age. This is particularly reliable in early pregnancy. Women who are not sure about the duration of the last menstrual cycle, such measurements should be made as soon as possible, in order to obtain an approximate date of conception and birth as well.

But, again, when a woman had irregular menstruation, experienced doctor can almost always also accurately determine the approximate date, asking the right questions and look on the woman in early pregnancy, writes in his book Revival birth etc.. Michel Odent.

In late pregnancy, the measurement of physical parameters of the fetus demonstrates its size and development, which may possibly indicate intrauterine growth retardation (IUGR). There are tables and curves by which compares the gestational age of the child, however, to consider how the values ​​in the tables only average, which means that deviations from these values ​​is quite normal for every child especially in its growth. Most measurements were made: femur length (FL), abdominal range (AC), Biparietal diameter (BPD), transthoracic diameter (TTD) and the Crown Rumph length (CRL).

Diagnosis of fetal malformation - many structural abnormalities in the fetus can be diagnosed by ultrasound, and before 20 weeks. These are: hydrocephalus, anencephaly, meningomijelokela, achondroplasia, spina bifida, egzomfalus, gastroscizis, duodenal artrezija and hydrops fetalis.

However, to make this discovery was of particular importance, said Dr.. Michel Odent, must occur early enough to permit voluntary interruption of pregnancy. Ultrasound can never be 100 percent sure of the diagnosis such as the issue of abortion or even more problematic. In addition, he adds that many babies with neural tube defects are doomed to die of natural causes in utero or within a few days after birth.(Rebirth of birth)

With the recent equipment, conditions such nesrasle lip / palate and congenital heart defects can be detected even at very early gestational age. The tests in the first trimester associated with chromosomal abnormalities such as the absence of fetal nasal bone and increased nuchal translucency (NH - an area at the back of fruit), now reliably detect Down syndrome in the fetus.

Ultrasound is also used with other diagnostic procedures in prenatal diagnosis such as amniocentesis, chorionic villus sampling (CVS), and cordocentesis for fetal therapy.

Localizing the placenta - ultrasound can reliably determine the position of the placenta and its lower edges, and so dijagnosticitati or exclude placenta dressed. Other possible abnormalities can be identified in conditions such as diabetes, maternal Rh sensitization, which can cause hydrops fetalis and certain intrauterine growth retardation.

Suppose that early ultrasound examination showed that the placenta attached to the uterus too low. This finding may cause great concern to women, and yet the doctor until delivery can not intervene, describes al. Michel Odent. Moreover, it makes no sense to worry about that because the position of the placenta becomes important only near the end of pregnancy when the placenta anyway most of these have a tendency to move away from the cervix. Dr.. Michel Odent points out that even during labor skilled gynecologist can easily manually check if the placenta is on the way. If you really cover the entire opening, contractions may continue, keeping in reserve intervention as an option if the mother lose too much blood or if the child is in any way threatened. (Rebirth of birth)

Multiple pregnancy-in this case, ultrasound is very valuable in detecting the number of fetuses, the number of chorionic bags, the existence of the fetus, evidence of growth retardation and fetal anomalies, placenta previa, and the existence of any indication twin transfusion.

Hidramnion and oligohydramnios - increased or decreased amount of amniotic fluid can be clearly established by ultrasound. Both conditions can have adverse effects on the fetus. In both cases, careful ultrasound examination should be made to exclude intrauterine growth retardation and congenital malformations in the fetus as intestinal atresia, hydrops fetalis or renal dysplasia.

Other reasons - ultrasound is of great value in other obstetric conditions such as confirmation of intrauterine death, fetal confirm the presence of uncertain cases, the evaluation of fetal movement, tone, amniotic fluid and fetal breathing (BPP), the diagnosis of uterine and pelvic abnormalities during pregnancy eg . fibromyomata and ovarian cyst.

Doppler and 3-D ultrasound

Doppler has been used for a long time to detect fetal cardiac error. Recent developments in technology in recent years has enabled the proliferation and use in obstetrics, especially in the area that includes the well-monitoring and diagnosis of fetal cardiac malformations. Doppler ultrasound has been recently widely used in the detection of fetal heart rate and pulse in different blood vessels of the fetus.

Using color Doppler can clearly see the blood flow in the blood vessels of the fetus in the period and direction of which is represented in different colors. Blood flow (BF) indicates the flow rate of blood and fetal blood vessels and thus it is estimated that the amount of nutrients and oxygen through them. And that includes measurements in the umbilical artery (AU), middle cerebral artery (MCA), fetal aorta (AO) and some of the veins, such as the umbilical vein (VU), ductus venosis (DV) and the like. Color-Doppler is particularly important in the diagnosis and assessment of congenital heart defects.

3-D ultrasound quickly out of the research and development phase and is widely used in clinical settings. A good 3-D picture often leaves a strong impression on the parents. However, to make a good 3-D image, it is often a lot depends on the skill of the person who performed it, then the amount of amniotic fluid surrounding the fetus, its position and the degree of maternal obesity, so that a good image can not always be achieved.

More recently, the 4-D or dynamic 3-D on the market and the ability to watch faces and movements of the child before birth enthusiastic crowd of people. This news was published with great enthusiasm in parenting and health magazines.

Most experts believe that 3-D and 4-D ultrasound will not replace the existing usage is conventional two-dimensional ultrasound. They may be only part of his new accessories, such as the color Doppler.

The World Health Organization (WHO / WHO) on the use of ultrasound

The World Health Organization points out that the medical-technology equipment must be thoroughly and fully evaluated before their widespread use. A routine ultrasound during pregnancy is now in widespread use, and without the necessary assessments. Research has shown its effectiveness for certain complications of pregnancy, but the published material does not justify the routine use of ultrasound on pregnant women.There is also little information regarding the safe use of ultrasound in pregnancy. Then, there is still no comprehensive, multidisciplinary assessment of ultrasound used during pregnancy, including its: clinical effectiveness, psychosocial effects, ethical importance, legal involvement, financial convenience and safety for the mother and child.

The World Health Organization has strongly emphasized the principle of informed choice regarding the use of technology. Health workers have full moral responsibility: fully to inform the public about knowledge and what is known about routine ultrasound during pregnancy to fully inform each woman primarily on ultrasound examination as well as the clinical indications for ultrasound, its, hopefully, benefits, potential risk and possible alternatives, if any. ("Diagnostic Ultrasound in Pregnancy: WHO View on Routine Screening", Lancet, 2, 1984, P.361).

(Dr. M. Odent: Rebirth of birth) 

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