The article was consulted professionally by Master, Dr Ta Quoc Tau – Obstetrician and Gynecologist, Obstetrics and Gynecology Department – Share99 Da Nang International Health Hub.
Doppler ultrasound technique is one of the most important and essential methods of pregnancy ultrasound in obstetrics and gynecology. Pregnancy Doppler ultrasound helps monitor and assess the normal, healthy growth rate of the baby while in the womb.
1. What is an ultrasound of the pregnancy Doppler?
Ultrasonic Doppler,also known as color ultrasound, is the leading ultrasonic technique that is quite widely applied today. Doppler ultrasound techniques use continuous waves to detect the directions as well as the velocity of the flow in the body. Therefore, an ultrasound of the pregnancy doppler in obstetrics and gynecology measures the flow of blood vessels, fetal heart surveys and some functions that other fetal ultrasound techniques do not perform. Specifically, Doppler ultrasound also helps to measure the impedance index of the umbilical artery, the middle cerebral artery in the fetus.
Because Doppler ultrasound uses high-frequency waves that are not in nature, the diagnostic value is very high. From each frequency signal obtained, the machine will synthesize and display to the screen in different colors or systographs, sometimes even audio signals.
Similar to all other types of ultrasound, fetal Doppler ultrasound is considered safe, painless and does not endanger the health of the fetus if conducted as prescribed by a doctor in the last 3 months of pregnancy. However, there are still some cases where the doctor will ask to perform doppler ultrasound earlier and the frequency of doing it more times. If an early pregnancy doppler ultrasound is required, it should be done with the lowest energy level (thermal index TI ≤ 1.0) and the contact time should be the shortest (not longer than 5 -10 minutes and not > 60 minutes).
2. Types of Pregnancy Doppler Ultrasound
Ultrasonic Doppler is usually divided into 2 main types: Continuous Doppler and Pulsed Doppler. However, Doppler is constantly not commonly used in obstetrics, except in some cases pregnancy with aortic stenosis or tricyclic valve opening. At this time, Continuous wave doppler (CW Doppler) can be useful in determining the maximum velocity of a very high velocity flow, limiting the crossing of the threshold.
Meanwhile, pulsed Doppler pregnancy ultrasound can distinguish signals at different depths. The doctor will use a crystal as both play and recording tasks, in which sound waves are played in pulse sequences and along the direction of scanning of the probe. The size and depth of the sampling area are also adjustable on the machine.
In addition, to evaluate the medley-pregnancy duct ring there are other modes such as Doppler Spectrum, Energy Doppler (Power wave Doppler – PW Doppler) and flow color spectrum, or Dual Doppler (Duplex Doppler).
3. The Role of Ultrasonic Doppler
In general, asking the mother to perform an ultrasound of fetal Doppler in obstetrics will help:
- Measure blood flow in each part of the fetal body(umbilicalcord, brain and fetal heart) to determine the baby's ability to absorb enough oxygen and nutrients;
- Observe and assess the flow of blood through the arteries – veins to diagnose the normal condition, as well as the healthy development of the fetus;
- Screen for certain conditions (e.g., congenital heart)and fetal birth defects to provide the earliest remedy;
- Monitor and detect abnormal signs in the fetus if any, preventing the birth of a child with a light weight;
- Assess when it is appropriate to take the baby out.
Depending on the condition as well as doubts about the pregnancy of the maternity, the doctor will specify the specific area and part that needs a Doppler ultrasound. However, in cases where both mother and child are healthy, it is not recommended to abuse this ultrasound technique.
3.1. Ultrasound Doppler Arterial Uterus
The arteries of the uterus play a very important role, responsible for leading blood to the uterus of the maternity to provide oxygen and nutrients to the fetus to develop healthy in the womb . Therefore, an ultrasound of the arterial uterus muscle doppler will help the doctor to check whether the placenta is given enough blood. Because if the placenta does not receive the necessary amount of blood, it means that the fetus also cannot receive enough oxygen and nutrients through the umbilical cord.
Ultrasound of the arterial arterial uterus muscle doppler can be performed by probe through abdominal wall fall or vaginal fall, and only applied in women with normal uterus anatomy (no congenital malformations in the uterus)
3.2. Ultrasonic Doppler Umbilical Arteries
The umbilical cord is a bridge to provide oxygen and nutrients to the fetus. To check the flow of blood from the placenta to the navel, doctors can apply the technique of ultrasound of the umbilical artery Doppler. Commonly prescribed cases of an ultrasound of the umbilical artery Doppler include:
- Delayed fetal growth (small pregnancy different from gestational age);
- The fetus is affected by incompatable Rh antibodies;
- Pregnant women (twins with eggs), have too high / low BMI, or suffer from diseases such as hypertension, diabetes ..
- There is a history of mild childbirth, late-stage miscarriages or infant deaths immediately after birth.
If the pregnancy develops early onculation (before 34 weeks) there will be signs of impaired function such as increased umbilical artery impedance and decreased resistance to the flow of the middle cerebral artery. Cons, late onculation delayed pregnancy (after 34 weeks) will show signs of blood acidification or multiple risk of pregnancy death, manifestations of loss/reversal of umbilical artery waves and intravenous doppler abnormalities.
In summary, umbilical artery Doppler is the standard parameters for identifying early onced delayed pregnancy (before 34 weeks), but is not a valuable one for detecting cases of late onc onculation after 34 weeks. Most late-onced delayed pregnancies with bad results have normal umbilical artery Doppler.
3.3. Middle cerebral artery and vein tube
In case of detection of abnormal signs after conducting an ultrasound of the umbilical artery Doppler (increased impedance, loss of waves or reversal of the mesenterous wave), the doctor will likely prescribe further blood flow survey by ultrasound of the Doppler pulsed veins or middle cerebral arteries. In particular, the vein tube is a source of blood rich in nutrient oxygen to the brain and heart of the fetus. When the pregnancy is severely hypoxia or blood acidification will appear the redistribution of oxygen-rich blood from the umbilical vein to the vein.
Ultrasound of fetal doppler helps to examine, diagnose and evaluate the health of the fetus. In particular, the function of checking the necessary nutrients and oxygen is something that ordinary pregnancy ultrasounds cannot perform. In general, pregnant mothers who are pregnant for the last 3 months can conduct an ultrasound of the pregnancy Doppler during a regular pregnancy examination at the request of a doctor, to ensure that the baby is developed in the best way.
Share99 International Health Hub has a full range of expertise and technical means to effectively perform pregnancy examination methods, including pregnancy Doppler ultrasound. There is a team of highly trained and experienced obstetrician and gynecologist, a complete and modern medical equipment system, professional service quality, bringing high diagnosis and treatment efficiency, contributing to protecting the health of pregnancy for both mother and baby.
Master. Dr Ta Quoc Original is a Lecturer in Obstetrics and Gynecology at Thai Nguyen University of Medicine and Pharmacy, Obstetrician and Gynecologist of Thai Nguyen Tw General Health Hub, Deputy Dean of Obstetrics and Gynecology Department of University of Medicine. The doctor has a full range of practice certificates in the field of obstetrics and gynecology such as ultrasound, laparoscopic surgery, endoscopy and cervical incul burning, artificial insefining (IUI) …
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