During pregnancy, the doctor obstetrician-gynecologist necessarily sends the pregnant woman to a pregnancy ultrasound examination. And it is done three times: at the end of each trimester. At each stage, doctors will receive their own, inestimably important information about the condition of the fetus.
There have been many clinical trials showing that ultrasound during pregnancy is completely safe. Pregnancy ultrasound is done solely to study the development of the fetus and does no harm the baby.
Ultrasound for a future mother is not only a possibility to get acquainted with the baby, but also a diagnosis of the baby’s health. Therefore, it is important to conduct ultrasound on time, with a qualified specialist and with modern equipment.
Features of Pregnancy Ultrasound
How does the child develop before birth and is everything fine? This question always bothers future parents. Pregnancy ultrasound is one of the ways to find the answer out. This is a universal, non-invasive, safe and convenient method for the study of the fetus and the uterus. Its mechanism is based on the analysis of differences in the reflection of ultrasonic waves from structures of different densities. During the procedure, ultrasound is used in the frequency range from 2 to 10 MHz.
Air, water and body tissues have different acoustic resistance. When ultrasound passes through them, they either absorb it to a different extent or completely reflect it. At pregnancy inspection is made by means of the special sensing device. It doesn’t cause pain or discomfort to the future mum, or to the fetus.
Pregnancy ultrasound includes the study of the anatomy of the developing fetus, as well as the placenta, umbilical cord, amniotic fluid, uterus and appendages. The goal of ultrasound is to assess the general condition of the future child and the mother, as well as the diagnosis of possible hereditary and congenital abnormalities of the fetus at various stages of pregnancy.
Pregnancy ultrasound is especially important when there is a genetic predisposition to the occurrence of congenital anomalies and syndromes incompatible with life. With the help of ultrasound doctors determine the condition and size of the fetus, the amount of amniotic fluid, the degree of placental aging, the integrity of the placenta, and the place of its attachment to the wall of the uterus. The results of ultrasound research can give an idea of the size of the uterus and fetus, can help with the preparation for childbirth, and can determine the conformity of the passage of the fetus along the birth canal of a woman.
Effect of Pregnancy Ultrasound on the Fetus
Most doctors say that pregnancy ultrasound is harmless. However, the effect of ultrasound on the fetus is still there. The uterus is a very sensitive to external influences organ. During the procedure it can come in tonus. In a normal course of pregnancy, there is no danger. But if there is a threat of interruption in the early stages, often this study is refrained until the tonus of the uterus normalizes.
Time of the Procedure
A woman expecting a child needs to undergo three ultrasounds at different times of pregnancy. The first study is conducted in a period of 10-14 weeks. The next is in the period from the 20th to the 24th week. And the last one, the third ultrasound, is done at the time of 32-34 weeks. However, a doctor can appoint an unscheduled ultrasound at any time of pregnancy. A future mother should not get scared. Additional pregnancy ultrasound is usually needed to clarify the diagnosis and take timely measures to maintain the health of the woman and the fetus. An additional examination will not harm.
Planned Pregnancy Ultrasound
The first ultrasound scan: the 10th-14th Week
The first ultrasound study can determine or clarify the duration of pregnancy, as well as learn about the position of the fetus and the status of the uterus, the presence of fibroids, and various neoplasms. The doctor will measure the embryo and compare the indicators with the rates appropriate to the term of your pregnancy.
All future mothers are prescribed ultrasound at the end of the first trimester of pregnancy at a period of 10-14 weeks. At this time, you can determine whether there are any serious abnormalities in the development of the fetus. The doctor measures the distance from the coccyx to the crown of the embryo (this indicator is called parietal-coccygeal length), studies the anatomical structure of the fetus. By this indicator, one can judge about the development of the fetus and whether its size corresponds to the norm.
Nuchal translucency thickness is also estimated. Due to this indicator it is possible to understand whether the fetus has chromosomal abnormalities. In the first place there is the probability of development of a fetal Down syndrome. If the doctor suspected a threat, you will also have to pass a blood test to determine the state of health of the future baby.
By 12-14 weeks, almost all organs of the fetus can already develop. Therefore, you can see the most obvious congenital pathologies of the brain, the heart, and the presence of unwanted formations. In the case of severe pathologies, it is not too late to terminate pregnancy due to medical conditions.
The Second Ultrasound: the 20th-24th Week
A Boy or A Girl
Theoretically, the sex of the fetus can be determined already starting from the 12th week of pregnancy. However, it is best seen at 16-20 weeks. By this time, the fetus’s genitalia noticeably increase in size and are easier to see. So if you want to find out the baby’s gender, it is better to do it at the second pregnancy ultrasound. However, you will not get a one-hundred-percent guarantee. The position of the child may simply not allow the doctor to see genitalia.
At the second ultrasound, the doctor measures the abdominal circumference, the length of the femur, the intertemporal size of the fetal head. Based on these indicators, you can judge whether there is a lag in the development of the future baby. In addition, an ultrasound specialist evaluates such indicators as blood flow in the vessels of the placenta, its location, degree of the maturity and structure. This is very important, as premature detachment of the placenta is very dangerous and may be the reason for hospitalization. A thickening of the placenta is often a sign of infection, diabetes and other diseases that can harm the fetus.
The study of amniotic fluid can provide additional information on the development of fetal kidneys. Hydramnios can indicate Rh-conflict or an infection. In both cases, special therapy and supervision of a doctor will be required.
Investigation of the cervix allows you to clarify whether there is an isthmic-cervical insufficiency. This is a pathology in which the cervix begins to open before the 37th week, which can lead to the threat of premature birth.
The Third Ultrasound: the 32th-34th Week
By this time, the fetus already usually has time to occupy the final position inside the uterus and settle head or pelvic end “to the exit.” Therefore, the obstetrician-gynecologist can decide in advance how to lead childbirth. Using an ultrasound machine, you can determine the approximate weight of the fetus, its size, and calculate the approximate date of delivery.
Also doctors assess the placenta position, because by 32-34 weeks its migration is already over. Normally, the placenta is attached at the very top of the uterus, away from the cervix. But sometimes, for various reasons, it moves down to the cervix and blocks it. This is the so-called placenta previa, which leads to a cesarean section, because the placenta blocks the child from leaving the uterus.
In addition, doctors assess the degree of maturity of the placenta. If it ripens prematurely, it is necessary to give birth on time or a little earlier. Prolonged pregnancy leads to a risk of hypoxia in the fetus. During this period, the expert again examines the umbilical cord on the presence of a cord entanglement. This is important for doctors who will lead delivery.
The third ultrasound allows you to assess the condition and position of the child before childbirth. It is important for the doctor to understand what the baby’s presentation is: cephalic or pelvic. It is also necessary to find out whether there is no cord entanglement, whether there are developmental defects manifested in late pregnancy. On the third planned pregnancy ultrasound you can already see the face of the baby on the monitor. Usually the third pregnancy ultrasound is performed in conjunction with Doppler velocimetry. This is a kind of ultrasound diagnosis, in which blood flow in the vessels of the fetus, umbilical cord and uterus are assessed.
Unscheduled Pregnancy Ultrasound
Unplanned pregnancy ultrasound may be needed at any time. Indications for it can be very different. The most common are complaints of a woman (pain in the lower abdomen, spotting, mismatch of the size of the uterus during pregnancy). Also, the doctor will necessarily send you to an unscheduled examination if there are reasons to assume leakage of amniotic fluid or you need to clarify the position of the fetus, the condition of the cervix. In the event that the doctor worries about the inadequate activity of the fetus in the second and third trimester of pregnancy, ultrasound is also necessary. Do not refuse this examination. Thus, your doctor will have a full picture of all the nuances of your pregnancy.
Indications for Pregnancy Ultrasound
The study is considered compulsory in the following cases:
- there is a suspicion of a missed miscarriage
- if there are signs of ectopic development of the fetus
- a woman or her close relatives have already experienced the death of the fetus before birth, miscarriages, malformations
- suspicion of placental abruption, a threat of premature birth
- with chronic diseases of the mother and the father: diabetes, blood diseases
- with gestosis
- in case of conflict over the blood group or Rh factor
- diagnosis of multiple pregnancies
- with closely related marriages
- if there was rubella, or a woman was taking “forbidden” medications during pregnancy, or had to take an X-ray (e.g., lung) during pregnancy
- if there are diseases that are transmitted to the family of the husband or wife by inheritance
- a mother works in the chemical, radiology service.
Types of Pregnancy Ultrasound
Modern technology allows you to make ultrasound of different types. In state maternity welfare centers, 2D ultrasound is usually done. That is, a study in two dimensions: width and height. The result is a black and white flat image resembling a photo. This ultrasound is performed at any time of pregnancy and gives the doctor basic information about the future child.
Three-dimensional (3D) pregnancy ultrasound of the fetus is a more advanced and modern method of diagnostics, in which a voluminous color holographic image is displayed on the screen. 3D ultrasound during pregnancy allows you to see facial features and even the facial expressions of the baby. The main advantage of 3D research is the reception of a high-quality image of the fetus. At the same time, the power, frequency and intensity of ultrasonic waves remain at the same level as in the standard form of pregnancy ultrasound. The difference is only in the duration of the procedure. 2D pregnancy ultrasound takes 15-20 minutes. 3D pregnancy ultrasound takes at least 50 minutes.
4D pregnancy ultrasound resembles a three-dimensional one. The difference is in the connection of the fourth dimension – real time. In the process of 4D ultrasound, there is a unique opportunity not only to examine the fetus in motion, but also to record its movement. After such an ultrasound, future parents get not just a picture of the baby, but a video.
3D and 4D pregnancy ultrasound is better done on the second planned examination, when the future child already has a facial expression. Most private clinics offer these kinds of ultrasound.