The best way to confirm a pregnancy is through a blood test, as it is possible to detect small amounts of the hormone HCG, which is produced during pregnancy. The blood test result indicates pregnancy when the hormone beta-HCG levels are greater than 5.0 mlU / ml.
It is recommended that the pregnancy blood test be performed after the delay in menstruation so that the results are more reliable. However it can also be performed before the delay, but there is a chance of a false negative result. No medical prescription or fasting is required to perform the exam and the result is given within a few hours after the blood collection.

What is HCG
HCG stands for chorionic gonadotrophin hormone, which is produced only when the woman is pregnant or has a severe hormonal change that is caused by any disease. Usually the beta HCG blood test is only performed when pregnancy is suspected, since the presence of this hormone in the blood is more indicative of pregnancy than the presence of this hormone in urine, which is detected through the pharmacy pregnancy test.
However, when the Beta HCG test result is undetectable or inconclusive and the woman has symptoms of pregnancy, the test should be repeated 3 days later.
If you think you are pregnant but have not yet taken the HCG beta test you can do our online test to know what your chances of actually being pregnant are:
Quantitative Beta HCG Table
The following table shows the amount of Beta HCG hormones present in each week of gestation:
Gestational age | Amount of Beta HCG in the blood test |
You are not pregnant - Negative result | Inferior to 5 mlU/ml |
3 weeks of gestation | 5 to 50 mlU/ml |
4 weeks of gestation | 5 to 426 mlU/ml |
5 weeks of gestation | 18 to 7.340 mlU/ml |
6 weeks of gestation | 1.080 to 56.500 mlU/ml |
7 to 8 weeks of gestation | 7.650 to 229.000 mlU/ml |
9 to 12 weeks of gestation | 25.700 to 288.000 mlU/ml |
13 to 16 weeks of gestation | 13.300 to 254.000 mlU/ml |
17 to 24 weeks of gestation | 4.060 to 165.500 mlU/ml |
25 to 40 weeks of gestation | 3.640 a 117.000 mlU/ml |
It is recommended that the blood test be performed after menstruation delay, because if it is performed before, it is possible that you can obtain a false negative result, that is, the woman may be pregnant but this does not come up on the results. Most likely the body failed to produce the hCG hormone at concentrations sufficient to be detectable and indicative of pregnancy.
Difference between quantitative and qualitative beta HCG
As the name implies, the quantitative beta-HCG test indicates the amount of hormone present in the blood. This examination is done from a blood sample that is sent to the laboratory for analysis. From the result of the examination it is possible to identify the concentration of the hCG hormone in the blood and, depending on the concentration, indicate the week of gestation.
The qualitative HCG beta test is the pharmacy pregnancy test that only indicates whether the woman is pregnant or not, not giving the concentration of the hormone in the blood and a gynecologist usually asks for a blood test to be performed to confirm pregnancy.
How to know if your pregnant with twins
In twin pregnancies, the hormone values are higher than those indicated for each week, but to confirm and know the number of twins, an ultrasonography should be performed from the 6th week of gestation.
The woman may suspect that she is pregnant with twins when she can know approximately which week she became pregnant, and compare with the table above to check the corresponding amount of beta HCG. If the numbers do not hit right, possibly she will be pregnant with more than 1 baby, but this can only be confirmed by an ultrasound.
Other exam results
Beta HCG results may also indicate problems such as ectopic pregnancy, abortion or anembryonic pregnancy, which is when the embryo does not develop.
These problems can usually be identified when the hormone values are lower than expected for the gestational age of pregnancy, and it is necessary to seek an obstetrician to assess the cause of the hormonal change.
What to do after you confirm pregnancy
After confirming the pregnancy with the blood test, it is important to make an appointment with a obstetrician to begin prenatal follow-up, taking the necessary tests to ensure a healthy pregnancy without complications such as pre-eclampsia or gestational diabetes, for example.