Obstetric ultrasound is the use of medical ultrasonography in pregnancy, where sound waves are used to create real-time visual images of developing embryos or fetuses in the womb of their mother (womb). This procedure is part of the standard of prenatal care in many countries, as it can provide various information about maternal health, the timing and development of pregnancy, and the health and development of embryo or fetus.
The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) recommends that pregnant women have routine obstetric ultrasounds between 18 weeks and 22 weeks' gestation (anatomical scan) to ensure pregnancy time, to measure the fetus so that growth abnormalities can be recognized rapidly in pregnancy, and to assess congenital malformations and multiple pregnancies (ie twins). In addition, ISUOG recommends that pregnant women have obstetric ultrasound between 11 weeks and 13 weeks 6 days in countries with resources to perform them (nukal scan). Doing ultrasound in the early stages of pregnancy can be more accurate in determining the time of pregnancy and can also assess for multiple fetuses and major congenital abnormalities at an early stage. Research has shown that routine obstetric ultrasound before 24 weeks' gestation can significantly reduce the risk of failing to recognize multiple pregnancies and may increase pregnancy dating to reduce the risk of labor induction for postdate pregnancy. But there is no difference in perinatal death or poor outcome for the baby.
Video Obstetric ultrasonography
Terminology
Below are useful terms about ultrasound:
- Echogenicà ¢ â,¬â € thus raising the reflection (echo) of ultrasound waves
- HyperechoicÃ, â € "more echogenic (brighter) than usual
- HypoechoicÃ, - less echogenic (darker) than usual
- Isoechoic - same echogenicity with other networks
- Transvaginal ultrasonography - Ultrasound is performed via the vagina
- Transabdominal ultrasound - ultrasound is performed on the abdominal wall or through the abdominal cavity
Under normal circumstances, any type of body tissue, such as liver, spleen or kidney, has a unique echogenicity. Fortunately, the gestational sac, yolk sac and embryo are surrounded by hyperechoic (brighter) tissue.
Maps Obstetric ultrasonography
Type
Traditional midwifery sonogram is performed by placing the transducer on the belly of the pregnant woman. One variant, transvaginal sonography, is performed with a probe placed in the woman's vagina. Transvaginal examination usually gives a clearer picture during early pregnancy and in obese women. Also used is Doppler sonography that detects the fetal heart rate. Doppler sonography can be used to evaluate pulsation in the fetal heart and blood vessels for signs of abnormality.
​​â € <â € <3D ultrasound
Modern 3D ultrasound images provide greater detail for prenatal diagnosis than older 2D ultrasound technology. While 3D is popular with parents who want prenatal photos as mementos, both 2D and 3D are not recommended by the FDA for non-medical use, but there is no definitive study that connects ultrasound with adverse medical effects. The following 3D ultrasound images were taken at different stages of pregnancy:
Medical use
Early pregnancy
A pregnancy sac can be seen reliably on transvaginal ultrasound with 5 weeks' gestation (about 3 weeks after ovulation). The embryo should be seen at the time of the 20 mm pregnancy sac, about five and a half weeks. Heartbeat is usually seen in transvaginal ultrasound when the embryo is 5 mm in size, but may not be visible until the embryo reaches 7 mm, around 7 weeks' gestation. Incidentally, most miscarriages also occur at 7 weeks' gestation. The rate of miscarriage, threatened with miscarriage, drops significantly if a normal heart rate is detected.
First trimester
In the first trimester, standard ultrasound examinations usually include:
- The sacred size, location, and bag number
- Identify the embryo and/or yolk sacs
- Fetal length measurement (known as head-butt)
- Fetal numbers, including number of amniotic sacs and chorionic sacs for multiple pregnancies
- Embryonic/fetal heart activity
- An appropriate embryo/fetal anatomy assessment for the first trimester
- Evaluation of the mother's uterus, tubes, ovaries, and surrounding structures
- Evaluation of the fetal nuchal fold, taking into account the fetal nuchal translucency
Second and third trimesters
In the second trimester, standard ultrasound examinations usually include:
- Fetal numbers, including the number of amniotic sacs and chorionic sacs for multiple pregnancies
- Fetal heart activity
- The position of the fetus relative to the uterus and cervix
- Placental location and view, including umbilical cord insertion when possible
- Amnion fluid volume
- Pregnancy check
- Estimated fetal weight
- Fetal anatomy survey
- Evaluation of the mother's uterus, tube, ovaries, and surrounding structures where appropriate
Dating and growth monitoring
The age of pregnancy is usually determined by the last woman's menstrual date, and assuming ovulation occurs on the fourteenth day of the menstrual cycle. Sometimes a woman may be unsure about her last menstrual date, or there may be a reason to suspect ovulation significantly earlier or later than the fourteenth day of her cycle. Ultrasound scanning offers an alternative method for estimating gestational age. The most accurate measurement for dating is the length of the fetal crown-ass, which can be performed between 7 and 13 weeks of pregnancy. After 13 weeks of pregnancy, fetal age can be estimated using a biparietal diameter (transverse diameter of the head, crossing two parietal bones), head circumference, femur length, crown-heel length, and other fetal parameters. Example: Medical quotes Dating that has been installed is more accurate when done early in pregnancy; if the next scan provides a different estimate of gestational age, the estimated age does not usually change but it is assumed the fetus does not grow at the expected rate.
Not useful for dating, fetal abdominal circumference can also be measured. It provides an approximate fetal weight and size and is important when performing a serial ultrasound to monitor fetal growth.
Fetal sex acuity
The sex of the fetus can be seen with ultrasound as early as 11 weeks' gestation. Accuracy is relatively inaccurate when attempted earlier. After 13 weeks gestation, high accuracy between 99% and 100% is possible if the fetus does not display intersex external characteristics.
The following is accurate data from two hospitals:
Influencing factor
The accuracy of fetal sex depends on:
- Gestational age
- Precision sonography machine
- Operator skills
- Fetal posture
Cervical ultrasonography
Obstetric sonography has become useful in cervical assessment in women at risk for preterm delivery. Short cervical prefixes are undesirable: In 24-week pregnancies, cervical lengths less than 25 mm define the risk group for preterm delivery, further, the shorter the cervix the greater the risk. It has also helped to use ultrasonography in women with premature contractions, since those with a cervical length exceeding 30 mm are unlikely to deliver within the next week.
Filtering abnormality
In most countries, routine sonographic scanning of pregnancy is performed to detect developmental defects before birth. This includes checking the status of limbs and vital organs, as well as (sometimes) special tests for abnormalities. Some abnormalities detected by ultrasound can be treated by medical care in utero or with perinatal care, although other indications of abnormality may lead to a decision regarding abortion.
Perhaps the most common test uses the measurement of nuchal translucency thickness ("NT-test", or "Nuchal Scan"). Although 91% of fetuses affected by Down syndrome show this defect, 5% of fetuses marked by the test do not have Down syndrome.
Ultrasound can also detect fetal organ anomalies. Usually the scan for this type of detection is performed about 18 to 23 weeks of gestation (called "anatomy scan", "anomaly scan," or "level 2 ultrasound"). Some resources indicate that there is a clear reason for this and that the scan is also clearly useful because ultrasound allows clear clinical advantages to assess developing fetuses in terms of morphology, bone form, skeletal features, fetal heart function, volume evaluation, lung maturity fetus, and general fetal welfare.
Second trimester ultrasound screening for aneuploi- dies is based on finding soft markers and some predefined structural abnormalities. Soft markers are a variation of normal anatomy, which is more common in aneuploid fetus compared with euploid. These markers are often not clinically significant and do not cause adverse pregnancy outcomes.
Security issues
Current evidence suggests that diagnostic ultrasound is safe for unborn babies, unlike radiographs, which use ionizing radiation. Randomized controlled trials have followed children up to age 8-9, with no significant differences in vision, hearing, school performance, dyslexia, or speech and neurological development with ultrasound exposure. In one randomized trial, children with greater exposure to ultrasound had a decline in perinatal mortality, and were associated with anomalous detection rates in the ultrasound group.
The maximum power of 1985 authorized by the US Food and Drug Administration (FDA) 180 miliwatt per square cm is also below the level used in therapeutic ultrasound, but still higher than 30-80 milliwatts per square cm range of the Statison V animal LIPUS tool.
Doppler ultrasound examination has a thermal index (TI) about five times that of routine ultrasonography (B-mode). Several randomized controlled trials have reported no association between Doppler exposure and birth weight, Apgar score, and perinatal mortality. One randomized controlled trial, however, came to a higher perinatal mortality rate than a normal-born infant after 24 weeks of Doppler ultrasonography (RR 3.95, 95% CI 1.32-11.77), but this not the main result of learning, and has been speculated by chance rather than the dangerous effects of Doppler itself.
The FDA prohibits its use for non-medical purposes such as fetal memento videos and photos, even though it is the same technology used in hospitals.
The American Institute of Ultrasound in Medicine recommends the Doppler spectral only if M-mode sonography does not work, and even then only briefly, due to the acoustic intensity sent to the fetus.
History
Scottish physician Ian Donald is one of the pioneers of medical ultrasound use. His article "Mass Pulmonary Investigation by Ultrasound Pulsed" was published in The Lancet in 1958. Donald is a Regius Professor of Midwifery at the University of Glasgow.
In 1962, after about two years of work, Joseph Holmes, William Wright, and Ralph Meyerdirk developed the first B-mode contact compound scanner. Their work has been supported by the U.S. Public Health Service and University of Colorado. Wright and Meyerdirk left the university to form Physionic Engineering Inc., which launched the first commercially articulated art of contact compound B-mode scanner in 1963. This was the beginning of the most popular design in the history of ultrasound scanners.
Ultrasound obstetrics has played an important 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 ultrasound obstetric devices. The pioneering efforts of Acuson Corporation on the development of the Coherent Image Formation helped shape the development of ultrasound diagnostic equipment as a whole.
In March and April 2015, a post by a pregnant woman named Jen Martin (nÃÆ' Â © e Cardinal) and her husband to YouTube, who has been seen at least 2 million times and has a lot to like, shows a 14 week-old fetus clapping repeatedly to the song , sung by parents, "If You're Happy and You Know It." It was later revealed that the video-while not a fake-had been edited to show more applause. It is unprecedented for the fetus at that age to make a momentary movement that can be repeated once or twice outside the initial movement, according to experts, but to repeat such a movement more than that - especially on purpose - is unlikely to be feasible at that time..
Social and cultural
The widespread use of ultrasound technology in monitoring pregnancy has had a major impact on the way in which women and society are at large concepts and experience pregnancy and childbirth. The spread of ultrasound obstetrics technology worldwide and the incorporation of its use by creating a 'safe' pregnancy as well as the ability to see and determine features such as the sex of the fetus influence the way pregnancy is experienced and conceptualized. This "technocratic" adoption of pregnancy is not limited to western or advanced countries but also affects the conceptualization and experience in developing countries and is an example of increasing the health of pregnancy, a phenomenon that has social and technological consequences. Ethnographic research related to the use of ultrasound technology in monitoring pregnancy can show us how it has changed the experience realized from pregnant women around the world.
See also
- 3D Ultrasound
- Doppler fetal monitor
- Global Women's Medical Library
- Gynecological ultrasonography
References
External links
- RadiologyInfo: Obstetric Ultrasound Imaging
- AIUM statement about using Ultrasound carefully
- Global Library of Women's Drug Imaging in Obstetrics and Gynecology links
Source of the article : Wikipedia
0 Comments