hCG Calculator

What is hCG Human Chorionic Gonadotropin?

Human chorionic gonadotropin (hCG) is the pregnancy hormone that is produced by the placenta soon after implantation. Implantation takes place around six to twelve days after ovulation or about five days before a missed period. After the implantation, the hormone enters the bloodstream. It shows up in the blood within two to three days and in urine within three to four days of implantation. The pregnancy blood or a pregnancy serum test detects the exact amount of the hormone in the blood. The test shows positive during a missed period (1).

Increase Of hCG In Early Pregnancy:

Once the fertilized egg attaches to the uterine wall, the hCG levels rise rapidly. The levels increase throughout the first trimester and reach a peak at around 60 to 80 days after fertilization (2). Now is when you experience early pregnancy symptoms such as sore breasts, irregular spotting, vomiting, or pelvic pain, for which you should go for a pregnancy blood test for confirmation.

Normal hCG Doubling Time And How Often Does hCG Double?

hCG doubles every 48 to 72 hours in early pregnancy, and there will be no normal hCG value in the first trimester. On average, the levels double every 30.9 hours until they reach 6500 mlU/ml in the eighth week of the last menstrual period (LMP). After this, the levels increase considerably and peak between the ninth and twelfth week. The hCG levels then decrease slightly from the 12th to 16th week, after which the levels remain constant until the end of pregnancy.

More on early hCG levels

• A 48-hour increase in hCG levels by minimum 63% is considered normal.
• If the levels are above 6000 mlU/ml, it takes around four or more days for the value to double.
• When the hCG values reach up to 7200 mlU/ml, you can see a yolk sac.
• When the levels are greater than 10800 mlU/ml, you can see a visible embryo with a heartbeat.

Normal Pregnancy hCG Values

Below is the normal amount of serum hCG levels by weeks calculated from LMP(3)

• Below five mlU/ml for women who are not pregnant.
• The normal hCG levels for postmenopausal women go up to 14 mlU/ml.
• If the hCG levels are between 5 and 25 mlU/ml, it is considered “equivocal”. It means you may or may not be pregnant and you would have to repeat the test.
• If hCG levels are above 25 mlU/ml, you are pregnant.

Note: The change in hCG levels may not be consistent for all women at the same stage of pregnancy. Consult your doctor if you are uncertain about your test results.

What Is hCG Pregnancy Test?

The hCG pregnancy test helps you determine whether or not you are pregnant. If your blood shows hCG, then you are pregnant. With the progressing pregnancy, the hCG levels will fluctuate a lot and there will be several normal levels. According to the American Pregnancy Association (APA), relying solely on a single hCG level to evaluate the health of pregnant women is not advisable. Instead, multiple tests conducted a few days apart provide a comprehensive understanding of the situation (3).

Dropping and Slow Rise hCG Levels

Dropping hCG levels indicate that pregnancy is not viable. It is usually associated with failed pregnancies such as chemical pregnancies or miscarriages. A slow rise in hCG levels is linked to miscarriages or ectopic pregnancies (4). A decline in hCG levels that is slower than 21% to 35% in 48 hours is abnormal and is associated with ectopic pregnancies or the presence of trophoblastic tissue (5). Also, if the hCG levels are above 6000 mlU/ml, it is not easy to detect the possibility of pregnancy. Here, a sonogram is the best option to know the pregnancy status.

What Is An hCG Level Calculator?

hCG calculator is a tool for detecting whether or not you are pregnant and if the pregnancy is progressing normally. You can use it to calculate the hCG doubling time by using two consecutive hCG levels, the number of days past ovulation, and the time between the tests. Once you provide these values, the hCG levels calculator will automatically calculate the results.

A hCG calculator is based on how hCG levels naturally rise during pregnancy, usually doubling every 48 in the early weeks (6). Using this pattern and your test results, it estimates expected hCG levels, calculates the difference between test results, and determines the percentage increase to monitor pregnancy progress. It also creates an hCG levels chart that allows you to monitor the rise associated with low, average, and high hCG levels.

Limitations Of hCG Level Calculators

• hCG levels can vary significantly among individuals due to biological and hormonal variations. Therefore, a hCG calculator may not apply to all pregnancies.
• The calculator cannot determine pregnancy viability or detect early complications. It only provides an estimate of hCG levels.
• It is most suitable for detecting early pregnancy, as hCG levels tend to stabilize in later stages (after 20 weeks gestation), making them less reliable in specific scenarios.
• External factors, such as incorrect dates, calculation errors, and late implantation, can affect the variability of hCG measurements and the calculator’s accuracy.
• A hCG calculator should be used as a comparative tool for monitoring hCG levels. It is not a substitute for professional medical tests (7) (8) (9).

hCG Levels In Twin Pregnancy

A twin pregnancy cannot be detected from hCG values. The hCG levels rise faster in case of twins, but there isn’t much scientific data on this. However, more than one fetus could have various reasons.

Beta hCG Levels And Their Interpretation

• It is a quantitative hCG test that measures the amount of hCG hormone in the blood and can detect pregnancy at a much earlier stage, i.e., as early as two to three days following implantation, or eight to nine days following fertilization.
• Urine hCG levels are lower than blood hCG levels, and thereby blood hCG test is more sensitive and reliable. It also helps in managing pregnancy problems.
• Beta hCG levels double every two days in the first four weeks of pregnancy.
• Blood hCG tests are not helpful to understand the viability of pregnancy if the levels are over 6,000 mlU/ml, or after you are six to seven weeks into pregnancy. In such cases, an ultrasound is more helpful.
• Beta hCG doubling calculator can be used to calculate the doubling time of two beta hCG samples by entering the date of the HCG blood pregnancy test and the corresponding beta hCG value for that day.

Some Facts About HCG

• hCG test is useful in assessing pregnancy before the fetal heart rate is detected (that is before six to seven weeks into pregnancy). It helps in ruling out an early miscarriage or ectopic pregnancy.
• The hCG level increases slowly above 6,000 mlU/ml, and these levels say nothing about the progression of pregnancy. After two to three months, hCG levels slow down further, and then plateau before delivery.