Ultrasound examination is the most modern way to determine abnormalities in the development of the fetus and problems with bearing. At 20 weeks, an ultrasound scan is performed to analyze the most vital organs of the fetus and identify malformations. If possible problems are not identified in time, then abortion after 21 weeks will be contraindicated.
Ultrasound fetal development (20 weeks): normal
The sixth month of pregnancy marks the active development of the fetal organs, the most intensively developing the reproductive system and skin. As well as:
- the fetus forms the rudiments of molars;
- already have a full four-layer skin;
- subcutaneous fatty tissue is fully formed;
- the process of hair and nail growth is activated;
- the skin is very wrinkled, it is covered with protective grease, in the eyebrow area the layer is the thickest;
- the surface of the body of the fetus is covered with a fluff called lanugo; its function is to enable primordial lubrication to be fixed on the epidermis;
- the formation of the brain ends, it already has a furrowed structure with convolutions;
- the fetal eyes begin to open slightly, he can grab the umbilical cord with his hands or suck a finger;
- the child’s immunity is already formed;
- periods of activity are formed in the child, he can differentiate the time of day, depending on this, be calm or excited, tactile or sound stimuli can influence the activity of the baby;
- the fetal reproductive system is formed: in boys, the testicles descend into the scrotum, and the ultrasound of the girl at week 20 shows the degree of ovarian maturity.
Ultrasound at week 20 is the most important examination of a pregnant woman, as it allows you to more fully analyze the development of the fetus and the condition of the mother.
What parameters are examined in 20 weeks
Each ultrasound screening has its purpose. During an ultrasound scan (20 weeks), all fetal bones are measured and the degree of development of the entire organs is analyzed. The most important indicators are:
- BDP - (biparietal size of the skull) is measured between the right and left parietal bones of the skull;
- LZR - distance from the frontal to the occipital bone of the skull;
- LDH - chest diameter;
- SJ - diameter of the abdomen;
- hip bone length;
- the thickness of the placenta and others.
In addition to these indicators, special attention is paid to the heart rate (should be in the range of 130-160 beats / min) and heart size (18-20 mm). The presence of four heart chambers and partitions between them is also checked.
Norm indicators
On ultrasound (20 weeks), the sex of the child can be determined most accurately. To independently analyze the results, you can use the table.
Basic norms of ultrasound indicators at 20 weeksParameter | 18-19 weeks | 19-20 weeks | 20-21 week |
BPR, mm | 42-45 | 45-48.5 | 48.5-56 |
LZR, mm | 51-55 | 55-60 | 60-64 |
SDHC, mm | 37.5-40 | 40-43 | 43-46.5 |
CJ, mm | 43-45.5 | 45.5-49 | 49-52.5 |
Thigh length mm | 23-28 | 28-33 | 33-35.3 |
Placenta, mm | 24.2-25.1 | 25.1-25.6 | 25.6-25.8 |
Amniotic fluid, mm | 30-70 | 30-70 | 30-70 |
Important! The table is not a reason for premature conclusions, only the attending physician is able to decipher the ultrasound correctly.
Preparation and conduct of ultrasound
At 20 weeks, an ultrasound scan can be performed without special training. A pregnant woman does not need to follow a diet and wait for the bladder to fill.
Ultrasound is based on the transabdominal method (the sensor is located on the front wall of the abdomen). If you carry out an ultrasound scan with a vaginal probe at 20 weeks, there is a chance of a premature miscarriage.
A pregnant woman can lie on her left side or on her back. So that an ultrasonic wave can penetrate the uterus, a special gel on a water-soluble basis is applied to the stomach. It can be easily removed with a regular paper towel and does not cause inconvenience.
Ultrasound Protocol
Filling in the data on the fetus, the state of the amniotic fluid and the placenta is carried out according to a clear protocol:
- The number of fruits is indicated.
- The presentation of the fetus is evaluated, which part of the body is located in close proximity to the exit of the uterus. The best option is a head presentation, it is also possible presentation of the fetus by the pelvic region. Ultrasound (20 weeks) allows any fetal location, but by 30 weeks it should stabilize so that the baby can be born unhindered and without complications.
- The presence or absence of cord entanglement is indicated.
- The state of the uterine lining (myometrium) is described, which may affect the possibility of miscarriage.
- The quantity and condition of the amniotic fluid is assessed, the presence of low or high water, suspensions is indicated (at this time, any suspensions in the amniotic fluid are a pathology).
- The length of the cervix is indicated. On ultrasound (20 weeks), the norm of this indicator is at least 3 cm.
- The state of the internal and external pharynx is described. At this time, it should be closed.
- The condition of the placenta is also evaluated. It should be placed approximately seven centimeters from the internal pharynx. The presence of any damage requires urgent hospitalization of the pregnant woman.
Such a detailed analysis allows you to see the whole picture of the condition of the fetus and prevent premature miscarriage.
Features of the second prenatal screening
Most often, the ultrasound of the child at week 20 is carried out in conjunction with a Dopplerometric study. This allows you to detect the presence of chromosomal or genetic abnormalities of the fetus or to confirm that the child is completely healthy.
Dopplerometry determines the presence in the blood of certain substances and their content. Only the attending physician and geneticist can analyze the full picture and draw conclusions about the condition of the fetus.
At 20 weeks, ultrasound is the safest and most informative study, which shows the general condition of the fetus and the degree of development of all vital organs.
Sex determination
At 20 weeks, ultrasound can most accurately show the gender of the unborn child. Defining it is easy. In boys, the genitals are immediately visible, and in girls there are no bulges.
Difficulties in determining sex can arise due to the location of the fetus. In this case, you can re-examine after 15 minutes. Pregnant women are advised to eat some chocolate so that the baby becomes active.
When a child is placed on his stomach, it is also difficult to determine his gender. Some babies turn away or hide during ultrasound, because the sex of the child remains a mystery to parents until birth.
Even when using modern ultrasound equipment, errors with sex determination are possible, everyone should be prepared for this.
Pregnant condition
At this time, toxicosis already passes, but a pregnant woman can often feel a feeling of heaviness in the abdomen or heartburn. Common side effects include spasms of the calf muscles and headaches. To minimize these sensations, you need to fully relax, eat right and eat enough vitamins.
It is important to monitor the swelling and condition of the discharge. If puffiness causes discomfort, you should consult your doctor. If the amount or condition of the discharge changes, it is also worth urgently consulting a gynecologist to prevent infection of the fetus.
With an ultrasound scan (20 weeks), the fetal photo can be saved and placed on the family album. This image will remind you of the wonderful waiting time for the baby.
A study at 20 weeks is the most important analysis of the condition of the fetus, so you should not pull and neglect it. Otherwise, at the right time, any developmental defects or deviations may not be detected.