MoM in pregnancy

, medical expert
Last reviewed: 07.06.2024

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A woman who is expecting a baby to be born needs to visit the doctor frequently and take laboratory tests. Of course, the results of such tests are always clear to the medical specialist, but not to the patient herself. And what to do if the cherished sheet with indicators is already in hand, and the doctor's appointment is still far away? How to understand that everything is fine with the child? What the abbreviation hCG says, many women know. But what does MoM mean in pregnancy?

International Standards for MOM in Pregnancy

The little-understood letters MoM stand for Multiple of Median, which means "multiple of median". The median in this situation is an average indicator corresponding to a certain gestational age. When speaking about the MoM, gynecologists mean the coefficient, with the help of 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 by applying the following formula: the index obtained in the tests is divided by the average accepted value corresponding to the given term of pregnancy.

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

The calculation is carried out with the help of special programs that are able not only to determine the necessary figure, but also to 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 of them, the values of MoM in pregnancy, obtained in different diagnostic institutions, may differ slightly. Strong deviations from normal parameters often indicate the presence of serious problems affecting both the future baby and the pregnant patient.

HCG in MoM by week of pregnancy

During pregnancy, a special role is played by chorionic gonadotropin, commonly known as the hormone hCG. It stimulates the mechanisms that are necessary for the normal carrying of the fetus, and also prevents the reverse development of the corpus luteum, activates the production of estrogens and progesterone at the preplacental stage.

HCG includes α and β units, the latter being the most important in diagnosis. The β-units appear in the bloodstream immediately after the oocyte has penetrated the endometrium, which occurs around the ninth day after ovulation. In normal pregnancy, the hCG indicator tends to increase twofold every couple of days, and the peak of its increase falls on the tenth week. Starting from this term, its values begin to decrease for two months, and then stabilize. In some women, a new growth spurt is also recorded in the late stages of pregnancy: a high hCG MoM in this case can indicate the development of placental insufficiency.

In what cases may a doctor prescribe a hCG MoM study for a pregnant patient?

  • As part of a general diagnosis at the beginning of pregnancy.
  • In ongoing diagnostics throughout the pregnancy.
  • In suspected ectopic pregnancy, fetal conception.
  • If there is a current threat of spontaneous abortion.
  • When performing the so-called "triple analysis" (estriol, ACE) to detect malformations in the unborn child.

The norm of hCG MoM in pregnancy by weeks

As we have already mentioned, the reference values of MoM in pregnancy may vary from one diagnostic facility to another, but they never leave the range of 0.5-2.

HCG can be measured in IU/mL or in mMe/mL. Its normal values in IU/mL are:

Period of carrying from the day of the last menstruation

Estimated hCG

Week two


Weeks three through four


Weeks four through five


Weeks five through six


Weeks six through seven


Weeks seven through eight


Weeks eight through nine


Weeks nine through ten


Weeks ten through eleven


Weeks eleven through twelve.


Thirteenth through fourteenth week.


Fifteenth through sixteenth week


Seventeenth through twenty-first week


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

AFP in MoM in pregnancy

AFP is read as alphafetoprotein. It is a protein substance produced in the liver and digestive system of the embryo. Pregnant patients are tested for AFP to determine if there are developmental defects in the unborn baby.

AFP values are dependent on many factors, such as the diagnostic methods used. To avoid confusion, the deviation of the AFP level from normal values is usually calculated using the same MoM - the degree of multiplicity to the median.

A range of 0.5-2 is considered normal MoM for ACE delivery.

These numbers are found elevated in these situations:

  • in multiple pregnancies;
  • for fetal liver tissue necrosis;
  • in disorders of fetal neural tube formation, congenital aplasia of the anterior abdominal wall;
  • for umbilical hernia or fetal kidney disease.

A decrease in AFP MoM values is observed:

  • with trisomy 18, 21 (link to Down syndrome);
  • for developmental delays;
  • for intrauterine death, spontaneous abortion;
  • for bubblegum.

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

AFP MoM norms in pregnancy by week

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

The norm is calculated by the following values:

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

It should be taken into account that AFP or MoM in pregnancy is not informative enough by itself. The results of the tests should be compared with the ultrasound findings, the study of the level of placental hormones, hCG and free estriol values. Only a comprehensive evaluation of the results can determine the risk of malformations in the fetus.

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