MOM during pregnancy by week

, medical expert
Last reviewed: 19.10.2021

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A woman who is expecting the birth of a child needs to visit a doctor often and take laboratory tests. Of course, the results of such tests are always clear to the medical specialist, but not to the patient herself. But what if the treasured sheet with the indicators is already in hand, and it’s still a long way from receiving a doctor? How to understand that everything is good with a child? What the abbreviation HCG is talking about, many women know. But what does MOM mean during pregnancy?

International MoM Standards for Pregnancy

The letters MoM, which are incomprehensible to patients, mean Multiple of Median, which means “multiple median” in English. The median in this situation is an average indicator corresponding to a certain period of pregnancy. Speaking about MOM, gynecologists have in mind the coefficient by which it is possible to determine the degree of deviation of any indicators in one direction or another from the average value.

MoM is calculated using the following formula: the indicator obtained in the analyzes is divided by the average accepted value corresponding to a given gestational age. [1]

For MoM, there is no specific unit of measure, and its values are individual. It turns out that if this value is close to unity, then the results of the woman's analyzes are as similar as possible to the average. For example, if you evaluate the standard indicator of pregnancy - hCG - then the indicators of MOM during pregnancy should be from 0.5 to 2, depending on the term.

The calculation is carried out using special programs that can not only determine the necessary figure, but also compare the indicator taking into account the characteristics of a particular patient (presence of bad habits, excess weight, etc.). Since such programs are different and there are many, the values of MOM during pregnancy obtained in different diagnostic institutions may vary slightly. Strong deviations from normal parameters often indicate the presence of serious problems affecting both the unborn baby and the pregnant patient.

HCG in MoM by week of pregnancy

During pregnancy, chorionic gonadotropin, commonly known as the hormonal substance hCG, plays a special role. It is he who stimulates the mechanisms that are necessary for the normal bearing of the fetus, and also prevents the reverse development of the corpus luteum, activates the production of estrogen and progesterone at the pre-placental stage.

HCG includes α and β units, the latter being the most important in diagnosis. β-units appear in the bloodstream immediately after the introduction of the egg into the thickness of the endometrium, and this occurs approximately on the ninth day after ovulation. In the normal course of pregnancy, the hCG indicator tends to double twice every couple of days, and the peak of its increase falls on the tenth week. Starting from this period, its values begin to decrease within two months, and then stabilize. In some women, a new growth spurt is also recorded in the late stages of gestation: a high MoH of hCG in this case is able to indicate the development of placental insufficiency.

In what cases can a doctor prescribe a study of My HCG to a pregnant patient?

  • As part of the general diagnosis at the initial stage of pregnancy.
  • During the current diagnosis throughout pregnancy.
  • If you suspect an ectopic development of pregnancy, fetal freezing.
  • With the existing threat of spontaneous abortion.
  • When conducting the so-called "triple analysis" (estriol, ACE) in order to identify malformations in the unborn child.

Normal HCG MoM for pregnancy by week

As we have already said, the reference values of MOM during pregnancy in different diagnostic institutions may differ, but they never leave the range of 0.5-2. [2], [3]

The hCG value can be determined in IU / ml or in mMU / ml. Its normal values in IU / ml are:

The period of gestation from the day of the last menstruation

Estimated hCG

Second week


Third to fourth week


Fourth to Fifth Week


Fifth to sixth week


Sixth to seventh week


Seventh to eighth week


Eighth to ninth week


Ninth to tenth week


Tenth to eleventh week


Eleventh to twelfth week


Thirteenth to Fourteenth Week


Fifteenth to sixteenth week


Seventeenth to twenty first week


After fixing the hCG results, the MoM is calculated - the ratio of the obtained indicator to the median. Physiologically normal values during pregnancy, recall, is considered a range of 0.5-2.

AFP in MOM during pregnancy

AFP reads as alpha-fetoprotein. It is a protein substance produced in the liver and digestive system of the embryo. An AFP study for pregnant patients is performed to determine developmental defects in the unborn baby. [4]

AFP indicators are dependent on many factors - for example, on the applied diagnostic methods. To avoid misunderstandings, it is customary to consider the deviation of the degree of AFP content from normal values using the same MoM - the degree of multiplicity of the median.

The normal indicator of MoM when taking ACE is considered to be a range of 0.5-2.

These numbers are found to be elevated in such situations:

  • with multiple pregnancy;
  • with necrosis of the liver tissue in the fetus;
  • with a disorder of the formation of the neural tube of the fetus, congenital aplasia of the anterior abdominal wall;
  • with umbilical hernia or kidney disease of the fetus.

The decrease in the MoM AFP is observed:

  • with trisomy 18, 21 (connection with Down syndrome);
  • with developmental delay;
  • with intrauterine death, spontaneous interruption;
  • with cystic drift.

In addition, a low level can only be the result of an error in calculating the gestational age (meaning that the true conception took place later than previously assumed).

Norm AFP MoM during pregnancy by week

The AFP content in the bloodstream of a pregnant woman gradually begins to increase, starting from 14 weeks. Continued increase is observed until about 32-34 weeks, after which the level begins to decline. [5]

The norm is calculated by the following values:

  • a period of 13-15 weeks - 15-60 U / ml (0.5-2 MoM);
  • a period of 15-19 weeks - 15-95 U / ml (0.5-2 MoM);
  • the period of 20-24 weeks is 27-125 U / ml (0.5-2 MoM).

It should be noted that the AFP or MoM indicator alone is not sufficiently informative during pregnancy. The results of the analyzes should be compared with the conclusion of an ultrasound, the study of the level of placental hormones, the values of hCG and free estriol. Only a comprehensive assessment of the results allows us to determine the risk of malformations in the fetus.

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