What is beta hCG, the pregnancy hormone, and how to interpret it

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What are Beta hCGs

Beta hCG, commonly known as the “pregnancy hormone“, is a chemical substance produced by the trophoblast, that is, the first cellular stage at which the embryo is found following the fertilization process, and which will eventually give rise to the placenta.
During pregnancy, this hormone aims to stimulate the corpus luteum to produce progesterone, another hormone that will prepare the woman to face the 9 months of gestation and which, as we have already seen, explains a large part of the typical symptoms associated with pregnancy itself.

In addition, together with estrogens, it will induce the synthesis of new proteins necessary to reinforce the uterine wall in preparation for pregnancy.

As one might imagine, the dosage and study of beta hCG is useful not only in a physiological pregnancy but also in those artificially induced and even in pathological ones or in spontaneous abortions.

More specifically, the main reasons that drive doctors to search for this hormone in the woman’s blood or urine are:

  • To also approximately establish the age of the embryo;
  • Diagnose an ectopic pregnancy, that is, in an abnormal location;
  • Monitor and possibly prevent a threat of abortion;
  • Perform screening for Down syndrome, as in the case of the first trimester combined test.

In some cases, it may be required to search for beta hCG before surgical procedures or exposure to radiation that could in some way cause harm to a potential fetus of which the woman is not yet aware.

A particular situation that may require its dosage is also the suspicion of a tumoral lesion. In fact, beta hCG levels can be particularly high in conjunction with forms of ovarian cancer and even in men with testicular cancer.

In the specific case of pregnancy, however, there are specific phases in which it is better to search for the presence of beta hCG.

Beta hCG levels can thus be detected in two ways:

  • Beta hCG blood test starting from about 6-7 days after conception;
  • Beta hCG urine test starting from about 12-14 days after conception.

Usually, the first test carried out by women who suspect a pregnancy is the urine test because it is minimally invasive, quick, and easy to perform even at home, however, it is crucial to consider the timing and methods of the test execution and remember that there is the possibility of false negatives and positives.

It is also important to accompany the Beta hCG tests with a evaluation by a midwife or a gynecologist who, based on the clinical situation of the patient and the outcome of the examination, will evaluate the subsequent checks to be made and the eventual execution of a Beta hCG blood test, as well as planning the first ultrasound check.


Reference values for beta hCG

Beta hCG values can vary significantly from woman to woman even in the course of perfectly normal pregnancies.

Indeed, its levels only start to rise from the first week after conception, i.e., when the fertilized egg begins its nesting in the uterine wall. For this reason, carrying out pregnancy tests in the immediate vicinity of unprotected intercourse could result in false negatives.

Once the woman’s body begins its production, its levels double about every two days, peaking about 60-70 days after conception. From then on, it decreases slightly, settling at a value that will then remain roughly the same until the end of pregnancy.

This reduction in the blood values of the hormone could explain the reduction or even disappearance of many of the symptoms associated with pregnancy or positive symptoms after transfer, starting from the second trimester (see, for example, nausea and tiredness).

The values considered normal for men and non-pregnant women are generally less than 5 international units per liter (5IU/L or 5mIU/mL). This range indicates a negative test, above which it will then be appropriate to investigate the correct cause.

As mentioned a few lines above, values during pregnancy change significantly from week to week, as this brief schema shows:

  • Negative: < 5 mIU/ml
  • 1-2 weeks: 5-500 mIU/ml
  • 2-3 weeks: 100-5,000 mIU/ml
  • 3-4 weeks: 500-10,000 mIU/ml
  • 4-5 weeks: 1,000-50,000 mIU/ml
  • 5-6 weeks: 10,000-100,000
  • 6-8 weeks: 15,000-200,000 mIU/ml
  • 8-12 weeks: 10,000-100,000 mIU/ml


Studying how beta hCG values evolve throughout the pregnancy is also crucial to have an indirect idea of how it is proceeding. Lower than normal values in a confirmed pregnancy state can be a sign of distress, such as:

  • Problems in the evolution of pregnancy;
  • Error in the calculation between the beginning of pregnancy and the last menstrual cycle;
  • Ectopic pregnancy;
  • Spontaneous abortion.

Higher than normal values may instead mean:

  • Recent spontaneous abortion;
  • Error in the calculation between the beginning of pregnancy and the last menstrual cycle;
  • Molar pregnancy: that is a condition in which the embryo implants but fails to grow correctly, turning into a cellular mass inside the uterus;
  • Twin pregnancy.


The less common, but still to be evaluated, causes of high Beta hCG values include situations outside of pregnancy:

  • cancer, including tumors that secrete hCG, such as germ cell tumors, affecting ovaries, testicles, bladder, pancreas, stomach, lung, and liver;
  • endocrine disorders, particularly problems with the pituitary gland;
  • presence of abnormal antibodies in the blood;
  • use of certain fertility drugs.

Interpreting the results of a beta hCG test on your own is therefore extremely complex, for this reason, Fertilab clinic makes its professionals completely available to guide you along the entire pregnancy journey to the fulfillment of a dream, such as becoming parents.


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