The basic examination that most of us associate with pregnancy is ultrasound. For parents-to-be, it is an opportunity to 'get a sneak peek' of their little one, and for the doctor, it is an excellent method of assessing the baby's development and an opportunity to look for any indication of an increased risk of various defects. How often during pregnancy should one undergo a Medical US examination? Is it safe for the developing foetus?
Table of contents:
- What is the Medical US examination and is it safe?
- How often are Medical US tests performed during pregnancy?
- Medical US in the first trimester of pregnancy
- Medical US in the 2nd and 3rd trimester of pregnancy
- Medical US in the perinatal period
What does the Medical US examination consist of and is it safe?
Anultrasound examination, known as Medical US for short, is one of the imaging techniques. Unlike examinations such as X-rays or CT scans, it does not use X-rays but a much safer ultrasound wave. The probe sends the wave towards the tissues, where it is reflected at the boundary of the media and returns to the receiver, which we can simultaneously observe on the screen. In gynaecology and obstetrics, internal, vaginal and external transabdominal probe examination is used.
Ultrasound is the most commonly performed imaging examination during pregnancy, which is primarily associated with its high safety for the developing foetus. It does not increase the risk of its damage, but it is nevertheless recommended that they be performed as infrequently as possible, i.e. according to the recommended schedule. Technological advances ensure that the examinations performed are increasingly accurate. Modern imaging systems, such as Medical US 4D, allow parents to see in detail the arms, legs or profile of the developing baby, and doctors to identify any abnormalities with great precision.
How often are Medical US examinations performed during pregnancy?
Many mothers-to-be would like to "peep" at their baby as often as possible. Others, on the other hand, prefer not to have any examinations at all due to unfounded fears. However, during the course of each normal pregnancy, three examinations are obligatory: between 11 and 13 (+6 days). week of pregnancy, between the 18th and 22nd week of pregnancy and between the 28th and 32nd week of pregnancy.
For most mothers-to-be, an additional examination is carried out even before the 10th week of pregnancy. At that time, they suspect they are pregnant and visit the doctor to confirm it. Additional examinations between these dates are carried out on patients with multiple pregnancies. It must be remembered that every multiple pregnancy is a high-risk pregnancy and complications can occur that are dangerous not only to the health and life of the fetuses, but also of the mother, so in this case, observation of the development of the children is particularly important.
Of course, additional examinations are carried out in the event of symptoms indicating various pathologies. These are carried out in the event of abdominal pain, bleeding and haemorrhage from the genital tract, premature outflow of amniotic fluid or changes in the child's previous motor activity.
Medical US in the first trimester of pregnancy
As already mentioned, in most cases the 1st examination is carried out even before the 10th week of pregnancy is completed. As a rule, it is performed using the transvaginal method, which is much more accurate at this stage. The purpose of the examination is to confirm the pregnancy and to assess whether the embryo has implanted in the correct location, i.e. the uterine cavity. Otherwise, we are dealing with an ectopic pregnancy, i.e. an ectopic pregnancy, which poses a threat to the patient's health and life. The gynaecologist also assesses the number of gestational follicles, i.e. whether it is a single or multiple pregnancy.
1. of the compulsory Medical US during pregnancy, performed between 11. and 13(+6 days). week of pregnancy, serves to assess the anatomy of the foetus, especially for changes indicating the risk of certain genetic diseases in the baby. Signs indicating such a risk, the so-called chromosome aberration markers, are an increase in nuchal translucency, underdevelopment or absence of the nasal bone or abnormalities in the blood flow through the ductus venosus and tricuspid valve of the heart. In addition, the doctor verifies that the gestational age, calculated on the basis of the date of the last menstrual period, is correct on the basis of the fetal parietal length measurements (CRL). At the beginning of pregnancy, there may be bleeding that the patient misinterprets as menstruation, which may be the cause of the discrepancy.
Medical US examination in pregnancy, photo: panthermedia
Medical US in the 2nd and 3rd trimester of pregnancy
Medical US performed later in pregnancy, i.e. between the 18th and 22nd week of pregnancy and between the 28th and 32nd week of pregnancy, are aimed at assessing the development of the foetus and picking up any abnormalities. The doctor carries out a thorough assessment of the baby's successive organs, starting with the brain, the heart and other internal organs. Basic biometric measurements are also taken, such as head circumference, abdominal circumference or length of the humerus or femur. On this basis, the doctor assesses whether the baby is developing at a normal rate according to gestational age. The gynaecologist can also determine the estimated weight of the foetus. Around the middle of pregnancy, i.e. at the 2nd compulsory examination, the sex of the baby can be determined in most cases. This moment is delayed if, during the examination, the foetus is arranged in a way that makes it difficult to assess the external genitalia. During the Medical US, the gynaecologist also assesses the condition of the placenta, the umbilical vessels and the amount of amniotic fluid. The accuracy of the examination depends on the precision of the equipment, the experience of the doctor, but also the intrauterine position of the foetus.
Early intrauterine diagnosis of certain defects and abnormalities makes it possible to take therapeutic measures even before the baby is born. Firstly, the pregnant woman can be transferred to a specialised centre, where the further management of the pregnancy, the course of the birth and the care of the newborn child will be handled by professionals experienced in the relevant diseases. In other cases, e.g. when thrombocephaly is diagnosed, missing fluid can be supplemented and, in the opposite case, excess fluid can be removed, which significantly improves the condition of the foetus. In addition, intrauterine surgery of the foetus has been developing in recent years, mainly in western countries and, unfortunately, to a lesser extent in Poland. Surgery to remove meningo-spinal hernias or to correct certain heart defects at this stage significantly improves the prognosis and increases the chance of the child functioning normally after birth.
Medical US in the perinatal period
Some centres also carry out an additional examination before the birth. This is to ascertain the position of the foetus in the uterus and its dimensions, as well as its estimated weight. If the babies are too large, there may be a problem during natural childbirth and the pregnancy may have to be terminated by caesarean section. Of course, it is safer for the foetus and the mother to anticipate this eventuality before pushing and complications such as shoulder dystocia occur. It is then possible to plan a date for the procedure, which does not have to take place urgently in a life-threatening condition.
Sometimes additional examinations are also carried out during the birth itself. These are aimed at assessing the length of the dilating cervix, as well as determining the exact location of the progenitor (usually the head) in the birth canal indicating the progress of the labour.
