At each visit of a pregnant woman to the doctor leading her pregnancy, the height of the fundus of the uterus is measured. In the exchange card, the doctor designates this parameter as WDM or WDM. This article will tell you what such a measurement is, why it is carried out and how this height changes throughout the entire period of the baby's intrauterine life.
What it is?
The female reproductive organ, which becomes a safe haven for a growing baby during pregnancy, resembles a bag. Its lower part is like the tied part of this bag, it is the narrowest. This is the cervix, which is a round muscle. The widest part of the uterus, domed, is called the fundus. The word “bottom” should not be embarrassing, because for a growing baby who will leave the womb during childbirth, this domed part will really be the bottom. The entrance to the exit hole inside the reproductive organ is one - this is the cervical canal inside the cervix, and it is located below.
The height of the bottom of the uterus is a special dimension that reflects the height to which the bottom has risen relative to the pubis... Until the end of the first trimester, the parameters of the uterus are small (by the eighth week - no more than a goose egg), and it fits perfectly in the pelvic space.
But the genital organ grows rapidly, the number of muscle fibers increases, and by the start of the second trimester, the uterus ceases to fit in the small pelvis and goes beyond it, into the abdominal cavity, gradually rising up and supporting the diaphragm. It is for these good reasons that the abdomen grows, its visual increase in a woman who is preparing for imminent motherhood.
Uterine fundus height shows how her height corresponds to the gestational age, and to a certain extent, this size indicates that is everything all right with the lady "in position" and her child. That is why at each visit to the consultation during all months of pregnancy, starting from 12-14 weeks, the doctor measures the WDM (WDM) and the circumference (girth) of the expectant mother's abdomen along the navel. By the ratio of these two values according to obstetric formulas, it is even possible to calculate the estimated weight of the fetus. Until a certain time, while ultrasound did not exist, this was the only way to find out if a large, normal or miniature baby was about to be given to a woman.
Today, specialists pay less attention to VCDM than before, because there are much more diagnostic tools at the obstetrician's disposal, and their accuracy is much higher. But this parameter in pregnant women was not removed from the protocols of the Ministry of Health and obstetric practice.
Determination of WDM can be carried out both independently and with the help of an obstetrician-gynecologist. This is not difficult.
Measurement technique
The actual term of the "interesting position" according to the state of the uterus, doctors establish earlier, before the genital organ rises from the small pelvis. In the first trimester of pregnancy, palpation is used for this purpose - a bimanual method of gynecological examination (one hand is inserted into the genital tract, and the other is pressed on the lower abdomen to determine the boundaries of the organ). You can't feel anything outside. This method does not give very accurate information, but an experienced obstetrician can establish a pregnancy with a two-handed method with an accuracy of up to a week.
You can measure how much the bottom of the uterus has risen using a centimeter tape, a pelvis meter, and the width of the fingers located transversely. Definition of VSDM by anatomical landmarks is acceptable.
To measure correctly, you need the pregnant woman to take a lying position. She is asked to sit on the couch on her back, her legs are asked to bend slightly at the knees. It is important that before the measurement, the woman visits the toilet and be sure to empty the bladder from its natural contents.
Next, the obstetrician-gynecologist needs to establish in what position the baby is located, where is the bottom of the uterus, and also what part of the baby's body is adjacent to it. The doctor places both palms on the stomach, and directs the tips of the fingers to each other (Leopold's first obstetric technique). This sets the most distant point of the bottom of the reproductive organ relative to the line of the pubic bone. Then they apply a measuring tape to this point and simply determine the numerical value, which expresses the height of the uterine fundus.
If the doctor is a big fan of the old obstetric school, then he can use the finger method. He presses his fingers together (middle and index), they should be located transversely on the stomach. The height is determined in the fingers, and then converted into centimeters (2 transverse fingers = 3-4 centimeters)
Why define this parameter?
Each obstetrician considers it his duty to measure the BMR, not only because the instructions provide for it, but also because this method is one of the most accessible in order to understand whether the course of pregnancy is normal. VSDM, despite the fact that the size is associated with errors, is among the indicators of the gravidogram (general table of indicators of a pregnant woman). This is a special table that displays the entire course of the gestation period in the form of graphs: there is a graph of weight gain, a graph of pressure, a graph of abdominal circumference and a graph of VSDM.
Almost during all weeks of gestation, the height of the fundus of the uterus is in accordance with the term in a numerical equivalent, and only before childbirth, when the abdomen drops, the fetus shifts lower and begins to press the internal cervical os with its head, helping it to mature and prepare for disclosure during labor, VSDM decreases. The belly also becomes visually lower, and it becomes somewhat easier for the expectant mother to breathe and move.
According to the VSDM, the doctor can assume without an ultrasound machine how much the fetus is supposed to weigh, whether it is full-term. After childbirth, or rather, after the birth of the placenta, this size helps specialists determine how well the uterus contracts.
Timeline and table
If the girth of a pregnant woman's abdomen is a rather individual and subjective value (the abdomens of women and before the onset of an "interesting position" have different sizes), then the VSDM depends little on how thin or lush, tall or short the lady is. This value is more constant, and therefore we can talk about the average norms of the height of the bottom point of the reproductive organ for different periods of pregnancy.
Anatomical landmarks help in clarifying the timing:
- by week 16 pregnancy, the upper part of the uterus is located midway from the womb to the navel;
- by week 20 pregnancy, the high point of the bottom is located approximately 2 transverse fingers below the navel;
- by 24-25 weeks - the bottom line is compared with the line of the navel;
- by 28-29 weeks - 2 transverse fingers above the navel;
- by 31-32 weeks - the bottom of the uterus is located exactly in the middle between the navel and the xiphoid sternum;
- by 36 weeks - the bottom of the uterus, if it has not yet descended, is located almost at the xiphoid process at the level of the ribs;
- by 40 weeks - the sagging uterus is again in the middle between the navel and the xiphoid process.
The height is considered the minimum at the end of the first and the beginning of the second trimester, and the fundus reaches its maximum by 35–36 weeks.
If the values do not meet the standards
The domed part of the female reproductive organ grows at the same time as the baby, increasing over the weeks of pregnancy, in fact, that is why VDM is measured so diligently. Until the 27th week of pregnancy, the height increases by about a centimeter or two per week, after 28 weeks, the rate decreases slightly, and the bottom rises by about 1.5 cm per week, and after 36 weeks, the growth rate decreases to a minimum of 0.2-0, 5 cm per week. If, for several measurements, the growth of WDM is not observed or, on the contrary, the growth is too fast, they speak of a mismatch with the terms.
The lag from the standard values by 2 centimeters or more may be due to one of the following reasons:
- erroneously established terms of pregnancy, late ovulation;
- a healthy baby, but with a low body weight (genetic inherited constitution);
- IUGR - intrauterine growth retardation;
- small amount of water;
- transverse or oblique position of the fetus in the uterine cavity;
- wide pelvis of the expectant mother.
An excess of the VSDM by 2 centimeters or more from the standard values can indicate:
- erroneously established gestational age;
- incorrect measurement (for example, with a full bladder);
- the narrowness of the woman's pelvis;
- multiple pregnancy;
- a healthy baby, but with a large body weight (hereditary factor);
- if a woman has diabetes, including its gestational type;
- polyhydramnios;
- breech presentation of the fetus, in which the legs or buttocks of the crumbs are directed forward.
You should not immediately start to worry and get nervous - this is generally superfluous in such a situation. In addition, according to medical statistics, the most common cause of deviations of the VSDM from real indicators is a banal error in determining the gestational age or incorrect counting. This is possible with an irregular female cycle, when a woman does not remember the date of her last menstrual period after IVF.
The second most popular reason is the weight of the fetus. You need to understand that the baby does not always have to weigh exactly as much as indicated in the tables with the norms. There is a genetic predisposition, and after 10 weeks of pregnancy, all children grow up according to their own genetic program, which his parents laid in him.
One is destined to be large, and the other - miniature. Moreover, he and the other will be perfectly healthy children. Look closely at yourself, at your partner, at your own and his parents. Assess height, weight, physique. Perhaps this is your case.
If a developmental delay is suspected, an ultrasound scan with a Doppler is prescribed, from 30-31-32 weeks - CTG, this allows you to know how well the baby's heart beats, whether he is receiving enough nutrition from the bloodstream. Examination for intrauterine infections is carried out. With IUGR, there are a lot of methods of providing assistance, and in most cases, doctors manage to quickly, by eliminating the cause that negatively affects the child, to normalize the rate of its growth.
The width of the pelvis plays an important role. In women with a narrow pelvis, the abdomen becomes noticeable much faster, because the uterus leaves the cramped pelvis faster and rises higher ahead of the average. A wide pelvis is more spacious, and small deviations of the WDM to the smaller side are possible.
A survey on the case of deviations of VDM from the norms is appointed in any case, because it is better, as they say, to play it safe. It includes a woman's blood donation for sugar and infections, ultrasound and Doppler ultrasound.
But even if the reasons are not found and the genetic characteristics of the child are assumed, then the woman will be monitored more closely, it may be necessary to visit the doctor more often, as well as to take tests.
How to calculate the weight of a child using WDM?
To determine the estimated weight of a baby, today they increasingly resort to ultrasound diagnostics, since its results are much more accurate. But obstetric formulas, which have already become history, women can easily apply on their own, at least to satisfy their own curiosity. There are several ways.
By Lankowitz
You need to take the last two sizes indicated on the date of the last visit to the antenatal clinic: woman's abdominal circumference and WDM. You also need to know your height and weight.
The algorithm is as follows: (VSDM + coolant + height + weight) x10.
Example: gestational age 30 weeks, coolant = 115, VSDM = 30, height - 170 cm, weight - 75 kg. (115 + 30 + 170 + 75) X10 = 3900. The error of the formula is about half a kilogram, both in plus and minus.
According to Bublchenko
For such a calculation, you need to know the exact weight of the expectant mother. It is divided by 200 and multiplied by 10. For example, a pregnant woman who weighs 80 kilograms, the baby will weigh about 4 kilograms. The error is about a kilogram in either direction.
According to Yakubova
This method is more accurate than the previous two, but in many ways loses in the accuracy of ultrasound. Formula: ((WDM + coolant) / 4) x100.
If a woman's BMR is 30, and the abdominal circumference is 115, then the estimated weight of the baby in the womb at the current time is 3625 grams. It is important to understand that the formula only applies to women with no excess fat in the abdomen.
By Jordania
The formula is simple: OzhhVDM, which usually means multiplying one indicator from an exchange card to another. With a BMD of 30 cm and a coolant of 100 cm, the estimated weight of the baby in the womb is 3300 grams.
Important! Of all the formulas, the Jordania method is considered the most accurate.
Self measurements
Self-measurement of the height of the rise of the domed part of the uterus above the bosom is much easier than decoding measurements. At home, a woman may well do this without outside help. Knowing how doctors do it (described above), you can similarly use a measuring tape, and if it is not at hand, then using the method of two folded fingers. It is important to visit the toilet, empty the bladder, and take a comfortable horizontal position with your knees slightly bent.
A bed with a soft mattress is not suitable for measurements - the surface on which the expectant mother will be located must be hard. The self-determination algorithm is quite simple:
- determine the location of the pubic bone, its upper border;
- gently feel the bottom of the reproductive organ, smoothly rising from the edge of the pubic bone to the navel and above (the bottom feels like a comb with uneven contours to the touch);
- using any of the above methods, measure the distance from the edge of the pubis to the high basement point.
Do not allow errors, try to apply the zero mark of the centimeter tape to the edge of the pubic bone. Remember that WDM is measured not in mm, but in cm.
Be sure to take into account the peculiarities of your pregnancy, in particular the position of the fetus (the doctor informs about it at the appointment), the number of children, with twins, the weight of the fetus will be less, and the size of the uterus due to stretching of the walls will be larger.
