In the middle of the XIX century Austrian physicist and astronomer HI Opened Doppler effect changes the oscillation frequency of wave motion of the source and the observer with respect to each other. The Doppler effect is used today for research utero-placental blood flow, in which a fetus receives nutrients and oxygen, and the output of toxic products of metabolism
Metabolism: The basis of life of all living things
and carbon dioxide.
What is Fetal Doppler
Doppler (Doppler ultrasound) the fetus relates to additional methods of ultrasound and is carried out to study the nature and speed of blood flow in the mother - placenta - fetus. Held on Doppler ultrasound machine with a special sensor. This study is of great importance to identify placental insufficiency
Placental insufficiency - deviation from the norm
in intrauterine growth retardation (IUGR).
The method is used for almost twenty years, it is simple and highly informative. The essence of the Doppler effect applied in the study of utero-placental circulation, is to ensure that the ultrasonic vibration frequency reference sent to the tissue are reflected by moving red blood cells in the blood vessels and back to the sensor returns to the ultrasound frequency changes. Magnitude changes in the frequency of ultrasound is dependent on the speed and direction of movement of erythrocytes.
Changes to the parameters of the reflected signal is recorded in the form of curves of blood flow rates (MMR), which are then analyzed and detected changes in blood flow in the vessels of the mother and the placenta.
Usually recorded dopplerograms following vessels: the mother and the iliac artery mother, the fetus - umbilical artery, the aorta, and sometimes - the brain vessels, and internal carotid artery.
Depending on the nature of the pregnancy and the rate of blood flow in the uterine arteries and in the aorta of the fetus changes. The rate of blood flow in the umbilical artery is significantly lower than the rate in the aorta, due to the remoteness of the blood vessel from the heart of the fetus. Of particular interest are the data ratio of blood flow in the uterine arteries and fetal umbilical artery, which can detect placental insufficiency, that is a violation of the blood supply to the fetus full, which leads to slow or stop its development. For more information about the features of the fetal circulation can be obtained in the evaluation and comparison of blood flow in the aorta and vessels of the brain of the fetus. Doppler fetal helps to take timely measures to restore the utero-placental blood flow and prevent complications of the fetus.
This is a Doppler fetal
Doppler fetal held for suspected violation of utero-placental blood flow. The risk for this disease are women with late toxicosis of pregnancy, hypertension, pyelonephritis, collagen disease (systemic growth of connective tissue), diabetes mellitus
Diabetes - threatening and incurable disease
, Rh incompatibility of blood between mother and fetus. In addition, the matter of availability of these features in previous pregnancies.
Indications for Doppler there by the fetus, they are detected during ultrasound and cardiotocography (CTG - monitoring of fetal heart rate). This growth retardation, premature maturation of the placenta, expressed oligohydramnios, small-fetal gestational age, congenital heart disease
Heart defects - time heals?
, Abnormal development of fetuses in multiple pregnancies, fetal brain edema, changes kardiotokogrammah, suspected of chromosomal disorders (eg Down syndrome), abnormal development of the umbilical cord.
Doppler is performed, starting with 20 weeks, but sometimes earlier when indicated.
The dependence of intrauterine growth retardation on the severity of vascular disorders
There are several degrees of violation of utero-placental and fetal blood flow:
- I degree - there is an infringement only the mother (A) or only the fruit (B) blood flow;
- Grade II - violates both the mother and fetal blood flow, but critical values of these violations do not reach;
- Grade III - impaired blood flow reaches a critical value.
Here at I A degree of violations of IUGR was observed in one third of cases, and all of them failed to adjust with the help of conservative treatment, and for III degree of IUGR was detected in all the subjects, and some of the children could not be saved. In most cases, severe vascular disorders conservative treatment is ineffective and the only way to help is urgent cesarean delivery.
Doppler allows time to detect and prevent serious complications during pregnancy.