If you have been tested positive for pregnancy, it is because of the rise in the circulating hCG levels in your blood and urine. hCG or Human Chorionic Gonadotropin is one such pregnancy hormone that starts its production immediately after the sperm, and the egg fertilizes, i.e., immediately after conception.
If opting for fertility treatment, this hormone is injected into the reproductive tract to trigger pregnancy and activate the functions of other pregnancy hormones- estrogen and progesterone.
Produced by the syncytiotrophoblastic cells of the placenta during pregnancy, hCG helps identify normal pregnancy. The hCG levels constantly step up after conception and after the first semester stabilizes itself for the rest of the pregnancy period.
This article gives you an insight into the week-by-week levels of the required hCG levels during pregnancy.
In this Article
hCG during pregnancy
hCG hormone is a member of the glycoprotein hormone (GPH) family, having two subunits-
- hCGα or alpha hCG and
- hCGβ or beta hCG
- Along with partially degraded nicked forms.
Among the two subunits, hCGβ is produced by the placental cells, gradually increasing after conception, during early pregnancy, and slowly disappearing post-pregnancy.
The other functions of the hCG hormone during pregnancy are:
- Stimulating progesterone production in the corpus luteum, especially during early pregnancy
- Exerts physiological functions of the uterus for an upcoming pregnancy
- It also stimulates the production of prolactin required during pregnancy.
- hCG injections are used to induce ovulation and post-ovulation changes of the placenta in an Assisted Reproductive Technology (ART) cycle.
Everything you need to know about beta hCG levels
hCG tests are of two types:
- A qualitative test- to check the presence of hCG in the blood
- A quantitative test- also known as the beta hCG test, notes the amount of hCG present in the blood.
The hCG hormone is usually measured in milli-international units per milliliter (mIU/mL). And as mentioned earlier, with advancing pregnancy, the hCGβ levels get higher, and by 96 hours, its levels can double.
Some of the important facts you need to know about hCGβ are discussed below.
- The hCG levels provide information about the pregnancy health and the health of the uterus.
- A simple at-home pregnancy test kit confirms pregnancy by checking the presence of hCG in the urine sample of the testee. A consecutive retest or a blood hCG test (beta hCG test) gives an accurate pregnancy confirmation.
- When it comes to checking pregnancy health, through beta hCG test, multiple hCG tests instead of a single hCG confirmation with a gap of a few days can give an accurate assessment of the health during pregnancy. A 5-6 week ultrasound can give you more accurate results of a healthy pregnancy.
- While checking for pregnancy, the beta hCG level of less than 5 mIU/mL shows you are less likely to be pregnant. And beta hCG levels above 25 mIU/mL are positive for pregnancy.
- If the beta hCG levels during pregnancy are between 6 to 24 mIU/mL, you will need a retesting done to check the rise of hCG levels and confirm pregnancy.
- Transvaginal or transabdominal ultrasound can show a predominant gestational sac when the beta hCG levels reach 1,000-2,000 mIU/mL. An ultrasound at these levels of hCGβ can confirm an appropriate conception date.
- Note of caution: If your body is making too much hCGβ. A higher than the usual rise in hCG can indicate a miscalculation of pregnancy dating, the possibility of multiple pregnancies (twins or triplets), or the formation of an abnormal mass within the uterine walls and not the embryo implantation.
- However, if the hCG levels are in their lower normal range, normal and healthy pregnancy is possible.
- And sometimes, if hCG levels rise slower than expected, there can be a likelihood of having an ectopic pregnancy- a pregnancy where the embryo gets implanted outside the uterus.
- Consecutive and multiple blood hCG tests and ultrasound is necessary to confirm any condition of the uterus and pregnancy.
- The beta hCG test levels should not be used to calculate the pregnancy due date. The hCGβ levels vary between pregnancies and situationally.
Beta hCG levels in the blood- week by week chart during pregnancy
While the pregnancy test kit can confirm the presence of hCG in urine a day after you have missed your period, you can opt to check with your doctor with a conclusive beta hCG blood test.
Now, what is a positive beta hCG test? A positive beta hCG test indicates that you are pregnant. From 2 weeks pregnant, the hCG levels increase as,
- During the second week from the last menstrual period (LMP), the ovulation would have occurred.
- Within 24 hrs of ovulation, fertilization of gametes or conception takes place.
The low hCG levels can be measured as early as 8-10 days post-conception or by week 3. Slowly the hCG levels increase during the first trimester of pregnancy. However, during the second and third trimesters, the hCG levels stabilize and gradually lower or diminish post-pregnancy or delivery.
Here is the week-by-week normal hCG range observed during a normal pregnancy.
|Pregnancy in weeks||Normal hCG range|
|Week 3 of pregnancy||6 – 70 IU/L|
|Week 4 of pregnancy||10 – 750 IU/L|
|Week 5 of pregnancy||200 – 7,100 IU/L|
|Week 6 of pregnancy||160 – 32,000 IU/L|
|Week 7 of pregnancy||3,700 – 160,000 IU/L|
|Week 8 of Pregnancy||32,000 – 150,000 IU/L|
|Week 9 of pregnancy||64,000 – 150,000 IU/L|
|Week 10 of pregnancy||47,000 – 190,000 IU/L|
|Week 12 of pregnancy||28,000 – 210,000 IU/L|
|Week 14 of pregnancy||14,000 – 63,000 IU/L|
|Week 15 of pregnancy||12,000 – 71,000 IU/L|
|Week 16 of pregnancy||9,000 – 56,000 IU/L
|Week 16- week 29 of pregnancy
|1,400 – 53,000 IUL|
|Week 29 to week 41 or 42 of pregnancy (Third trimester)|| 940 – 60,000 IU/L
Beta hCG is an essential hormone to detect pregnancy and the levels of beta hCG during pregnancy indicate various health conditions of the uterus and pregnancy. The above article covers everything you need to know about beta HCG levels during pregnancy, with the normal range of hCG to be present for a normal pregnancy to occur. If you are pregnant and want to get tested for your hCG levels or understand the required hCG count, check with your doctor.