hCG Levels – Everything You Need To Know About hCG

hCG Levels - Everything You Need To Know About hCG

During pregnancy, your body produces a hormone called human Chorionic Gonadotropin (hCG). hCG is produced by the cells that will form the placenta. hCG starts being produced once the embryo implants in the uterine wall. Pregnancy tests work by detecting hCG levels in the blood or urine sample provided.

hCG levels can usually be detected in the blood around 11 days after conception, though it takes 12-14 days for hcg levels to be detected in a urine sample. hCG levels increase rapidly at the start of the pregnancy, but will then decline slightly until around week 16 and remain steady.

If you get a positive pregnancy test result, you are most likely pregnant. False positives are very rare. A very early miscarriage could also cause a false positive if your hCG levels haven’t yet dropped, allowing the test to pick up this hormone in your body.

What Does hCG Do?

hCG is responsible for maintaining a thick uterine lining, without this hormone the lining would begin to shred putting the pregnancy at risk. hCG is the hormone responsible for preventing periods. hCG is produced by cells that form the placenta, and this means it is not usually present in the body unless you are pregnant.

In most, but not all, healthy pregnancies, hCG levels double every two or three days at the start of the pregnancy. As the pregnancy progresses, this rate may slow to every four days, but the levels are expected to continue to rise until sometime between weeks eight and 11.

It's important to remember that all pregnancies are different. Some women may have low hCG levels throughout the pregnancy, whereas others may have very high levels, and yet both can go on to have healthy babies.

An hCG level of less than 5mlU/ml (milli-international units per millilitre) will give you a negative pregnancy test result. If your level of hCG is found to be 25mlU/ml or over, then you will get a positive pregnancy test result. Fertility drugs containing hCG can affect your hCG levels, so you should discuss this with your practitioner before having your levels checked.

Some pregnancy tests use hCG levels to date the pregnancy, but this can be wildly inaccurate due to the differing levels between women. A single hCG reading is not usually enough to give an accurate diagnoses of any potential conditions. Instead, practitioners will usually take two readings a couple of days apart to allow them to draw a comparison from the levels.

hCG Levels During Pregnancy

It's not routine for hCG levels to be checked throughout pregnancy. This will only be done if you are showing symptoms of a possible problem.

Firstly, it’s important to remember that there is no such thing as ‘normal’. What is normal for you, may not be normal to the woman sat next to you in the midwife’s waiting room. And what’s normal for your first pregnancy, may not be normal for your second. The following levels are given as a rough guide, the important bit is the change in levels each week, not the individual result itself. The following chart shows an average level range for each week dated since the first day of the last menstrual period (LMP).

Women who are not pregnant: <5.0 mIU/ml

3 weeks LMP: 5 – 50 mIU/ml

4 weeks LMP: 5 – 426 mIU/ml

5 weeks LMP: 18 – 7,340 mIU/ml

6 weeks LMP: 1,080 – 56,500 mIU/ml

7-8 weeks LMP: 7, 650 – 229,000 mIU/ml

9-12 weeks LMP: 25,700 – 288,000 mIU/ml

13-16 weeks LMP: 13,300 – 254,000 mIU/ml

17-24 weeks LMP: 4,060 – 165,400 mIU/ml

25-40 weeks LMP: 3,640 – 117,000 mIU/ml

Women after menopause: 9.5 mIU/ml

What Does It Mean If You Have Low or High hCG Levels?

If your healthcare provider checks your hCG levels and finds that they are low, they will repeat the test a couple of days later so that the numbers can be compared. Low hCG levels could be indicative of:

High hCG levels will also need to be rechecked, but could be indicative of:

  • Incorrect pregnancy dating – you may be further along than previously thought
  • Multiple pregnancy – you could be carrying twins or more. If carrying twins, your hCG levels could be as much as 30-50% higher.
  • Molar pregnancy – if a molar pregnancy occurs, there is a growing mass in the uterus but it will not develop into a baby. The mass is known as a hydatidiform mole and will produce high levels of hCG. The mole will need to be removed.

hCG Levels & Pregnancy Loss

After a pregnancy loss, hCG levels should drop down to less than 5mlU/ml within around six weeks. The time it takes to reduce will depend upon the level of the hormone at the end of the pregnancy, and how the loss occurred. If you experience a pregnancy loss, your healthcare provider will recheck your hCG levels a few weeks later to make sure they have reduced.

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Fiona Peacock CONTRIBUTOR

Fiona Peacock is a writer, researcher and lover of all things to do with pregnancy, birth and motherhood (apart from the lack of sleep). She is a home birth advocate, passionate about gentle parenting and is also really tired.


11 comments

  1. I had a tubal pregnancy this past new years, they had to remove my right fallopian tube. I had a cycle the last week of january. On February 11th I went to my doctor and she did a pregnancy test that came out negative. A few days ago I realized that I’m late, I’ve taken 3 tests, they’ve all been positive. Am I really pregnant? Is it possible for my hormone levels to bounce? I plan on calling my doctor tomorrow, I’m going to be so heartbroken if I’m not pregnant.

  2. I am also worried, I had an ectopic rupture in 2000 and removal of my left tube and ovary.
    I thought it was impossible to get pg, but my last menstrual period was Feb.13th, I FEEL pregnant and have textbook symptoms, but my quant.hcg blood tests both came back at < 3 .. The nurse told me they were negative. I am afraid that it is not a healthy pregnancy and fear of another ectopic.. especially bcuz when I was pregnant in 2000 the only way they found out was through an ultrasound.. the blood tests were neg. then too. i dont think i can lose another baby and be okay with it !! 🙁
    On the other hand, if it is in fact negative, and Im not pregnant… why am I over 2 weeks late, and why do I have all of these early pregnancy symptoms?! ugh. I have to make an appt before they will do an ultrasound, so I am doing so today. Good luck to all of you going through the nerve racking waiting game, and I wish you all the best. I will try to post my end results, as I know I have been to numerous pages with comments of questions, but have a hard time findin out what really happened with the stories.
    Thanks!

  3. I took 4 tests plus the hospital. Confirm that I a
    Was pregnant went to the doctor my hcg level drop from 100 to 10 to 3 they told me I was not pregnant. But I haven’t been having no problems at all what does it means help anyone

  4. I was pregant after three days later brown blood started come out later the red blood to came out i bleed for 6 days later go to the doctor dru did hcg it was 4.3 and the doctor say am not pregant i feel sometin down and mu stomck is gettin big i feel pregant is it possible doctor say i lost the baby hrlp pls

  5. It sounds like most of you have had what are called chemical pregnancy . This is when your mind wanted it so bad, your body followed suit and made all the right pregnancy hormones rise, therefore detecting them on tests. But there was never an actual baby forming . The other alternative is a very early miscarriage, where you miscarried and your body just went on as normal because it was so early in the pregnancy. This would cause the hormones to slowly recede back to their original levels.

    1. A chemical pregnancy is actually the very early miscarriage where your body goes on as normal because the blastocyst didn’t properly implant. You can’t want it so bad that your body started producing hcg! Sorry, it just doesn’t work that way. You can however, have a phantom pregnancy where u develop symptoms, but it still doesn’t cause your body to produce hcg.

  6. I had a positive pregnancy test after missing my period, at 6 weeks of pregnancy I began to spot. I visited the ER, HCG was positive (mind you , I live in a third world country so they just say positive or negative for HCG they don’t give us the levels) and an ultra sound showed a single gestational sac of 1.74 cm and yoke sac measuring 2 mm but fetal pole was not visualized. ( I was given antibiotics for urinary tract infection and was sent home). Two days after that visit I began to bleed ( no clots) and cramp. I went back to the ER, they test and hcg came back NEGATIVE, I was sent to do another ultra sound which I did the following day. (remember third world country so, I couldn’t get one done that day) Second ultra sound showed a single irregular gestational sac measuring 0.9 cm , no fetal pole or yoke sac was seen. (which means I was miscarrying the pregnancy) BUT HCG test at this time showed a NEGATIVE again…how could HCG be negative during a miscarriage???…Positive pregnancy test, Positive hcg at first visit to ER and two ultra sounds, one showing signs of pregnancy and the other signs of miscarriage.(which is understandable) but how could HCG be negative during a miscarriage???….any answers would be appreciated…BTW could type 2 diabetes have any bearing on the hcg results.

  7. I haven’t had a period since may15th 2017 we have been trying and I had all the symptoms same as my first baby but every test is negative and blood test was negative as well, the doctors are saying stress has stopped my period but I know my body and feel like I am pregnant !?? Do I just wait?! In theory I would be 10 weeks now!

  8. My doctor said 3 to 25 is possible pregnancy. Everywhere online says under 5 is negative for a blood test. What do i believe in this next week i have to wait. I have a 4 month old.

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