MoM in pregnancy

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

International MoM standards in pregnancy

The letters MoM, which are not very clear to patients, mean Multiple of Median. The median in this situation is an average indicator corresponding to a certain period of pregnancy. When speaking about MoM, gynecologists mean a coefficient that helps 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 tests is divided by the average accepted value corresponding to the given gestational age.

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 woman's test results are as close as possible to the average statistical ones. For example, if we evaluate the standard pregnancy indicator - hCG - then the MoM indicators 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 (presence of bad habits, excess weight, etc.). Since such programs are different and there are many of them, the 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 future baby and the pregnant patient.

HCG in MoM by weeks of pregnancy

During pregnancy, a special role is played by human chorionic gonadotropin, known to all as the hormonal substance hCG. It is this that stimulates the mechanisms that are necessary for normal gestation, 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 diagnostics. β units appear in the bloodstream immediately after the egg is implanted into the endometrium, which occurs approximately on the ninth day after ovulation. During a normal pregnancy, the hCG level tends to double every couple of days, with its peak increase occurring in the tenth week. From this period onwards, its values begin to decrease over the course of two months, and then stabilize. Some women also experience a new growth spurt in the later stages of pregnancy: high MoM hCG in this case can indicate the development of placental insufficiency.

In what cases can a doctor prescribe a MoM hCG test to a pregnant patient?

• As part of general diagnostics at the initial stage of pregnancy.
• During ongoing diagnostics throughout pregnancy.
• If there is a suspicion of ectopic pregnancy, fetal fading.
• In case of existing threat of spontaneous termination of pregnancy.
• When conducting the so-called “triple analysis” (estriol, ACE) in order to identify developmental defects in the unborn child.

HCG MoM norm during pregnancy by week

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

The hCG level can be determined in IU/ml or mIU/ml. Its normal levels in IU/ml are:

Gestation period from the day of the last menstruation	Approximate hCG level
Second week	50-300
From the third to the fourth week	1500-5000
From the fourth to the fifth week	10000-30000
From the fifth to the sixth week	20000-100000
From the sixth to the seventh week	50000-200000
From the seventh to the eighth week	40000-200000
From the eighth to the ninth week	35000-140000
From the ninth to the tenth week	32500-130000
From the tenth to the eleventh week	30000-120000
From the eleventh to the twelfth week	27500-110000
From the thirteenth to the fourteenth week	25000-100000
From the fifteenth to the sixteenth week	20000-80000
From the seventeenth to the twenty-first week	15000-60000

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

AFP in MoM during pregnancy

AFP stands for alpha-fetoprotein. It is a protein substance produced in the liver and digestive system of the embryo. AFP testing is performed on pregnant patients to determine developmental defects in the future baby.

AFP values depend on many factors, such as the diagnostic methods used. To avoid misunderstandings, the deviation of the AFP level from normal values is usually calculated using the same MoM – the degree of multiplicity of the median.

The normal MoM value when taking the APF test is considered to be in the range of 0.5-2.

These numbers are found to be elevated in the following situations:

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

A decrease in MoM AFP levels is observed:

• with trisomy 18, 21 (associated with Down syndrome);
• in case of developmental delay;
• in case of intrauterine death, spontaneous abortion;
• with hydatidiform mole.

In addition, a low level may only be a consequence of an error in calculating the gestational age (meaning that the actual conception occurred later than previously assumed).

AFP MoM norm during pregnancy by week

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

The norm is calculated using 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 is not informative enough during pregnancy. The test results should be compared with the ultrasound conclusion, the study of the level of placental hormones, the values of hCG and free estriol. Only a comprehensive assessment of the results will allow us to determine the risk of fetal malformations.