MoM during pregnancy

, medical expert
Last reviewed: 30.07.2022

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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 analyzes are always clear to the medical specialist, but not to the patient herself. But what if the coveted sheet with the indicators is already in your hands, and it’s still a long way before the doctor’s appointment? How to understand that everything is fine with the child? What the abbreviation hCG says, many women know. But what does MoM mean during pregnancy?

International MoM standards during pregnancy

The letters MoM, which are incomprehensible to patients, mean Multiple of Median, which in English means “multiple of the median”. The median in this situation is an average indicator corresponding to a certain gestational age. Speaking of MoM, gynecologists mean 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 taken.

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.

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

The calculation is carried out using special programs that can not only determine the required figure, but also compare the indicator taking into account the characteristics of a particular patient (the presence of bad habits, excess weight, etc.). Since such programs are different and there are many of them, MoM values during pregnancy obtained in various diagnostic institutions may differ 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, a special role is played by chorionic gonadotropin, known to everyone as the hormonal substance hCG. It is he who stimulates the mechanisms that are necessary for the normal bearing of the fetus, and also prevents the regression 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. With a normal pregnancy, the hCG indicator tends to double every couple of days, and the peak of its increase occurs in 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 later stages of gestation: a high HCG MoM in this case can indicate the development of placental insufficiency.

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

  • As part of a general diagnosis at the initial stage of pregnancy.
  • During ongoing diagnostics throughout pregnancy.
  • If you suspect an ectopic development of pregnancy, fetal fading.
  • 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.

The norm of hCG MoM during 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.

The hCG indicator can be determined in IU / ml or in mIu / ml. Its normal indicators in IU / ml are:

Gestation period from the date of the last menstruation

Approximate HCG

Second week


From the third to the fourth week


Fourth to fifth weeks


Fifth to sixth week


Sixth to seventh week


Seventh to eighth week


Eighth to ninth week


Ninth to tenth week


Tenth to eleventh weeks


Eleventh to twelfth week


Thirteenth to fourteenth week


Fifteenth to sixteenth week


Seventeenth to twenty-first weeks


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

AFP in MoM during pregnancy

AFP is read 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 in order to determine developmental defects in the unborn baby.

AFP values are dependent on many factors - for example, on the diagnostic methods used. To avoid misunderstandings, the deviation of the degree of AFP content from normal values is usually considered using the same MoM - the degree of multiplicity of the median.

The normal indicator of MoM during the delivery of ACE is the range of 0.5-2.

These numbers are found elevated in such situations:

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

A decrease in AFP MoM values is observed:

  • with trisomy 18, 21 (associated with Down syndrome);
  • with developmental delay;
  • with intrauterine death, spontaneous interruption;
  • with vesiculation.

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).

The norm of AFP MoM during pregnancy by week

The content of AFP in the bloodstream of a pregnant woman gradually begins to increase, starting from the 14th week. The increase continues until about 32-34 weeks, after which the level begins to decrease.

The norm is calculated by the following values:

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

It should be taken into account that the AFP or MoM indicator itself during pregnancy is not sufficiently informative. The results of the analyzes should be compared with the conclusion of the ultrasound, the study of the level of placental hormones, the values of hCG and free estriol. Only a comprehensive assessment of the results can determine the risk of malformations in the fetus.

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