The hCG Hormone & Pregnancy

When I was trying to get pregnant, I’d heard of the term “hCG” when reading blogs, articles, discussed on forums, and when listening to podcasts. I didn’t exactly know what it is. Unless you have been actively trying, undergoing fertility treatment or been initiated into the unique language of fertility specialists, you aren’t likely to know. But don’t feel weird if you’ve been a little confused. Again, I was too.

hCG is the acronym for human chorionic gonadotropin hormone. This is a pregnancy specific hormone which is incredibly important to women who are pregnant, but not of much interest to women who aren’t.

hCG is the hormone responsible for all the early pregnancy symptoms which make millions of women wonder if perhaps they are pregnant, many before they’ve done a pregnancy test. Breast tenderness, feeling emotional, nauseous and fatigued are all due to hCG surging in the body.

hCG Levels During Pregnancy

hCG levels rise consistently until around 10-12 weeks of gestation and then they tend to plateau, or even drop off. That is why in the first trimester (3 months) of pregnancy symptoms can be so much stronger and intense.


hCG levels in early pregnancy usually double every 2-3 days with an increase of at least 60% in every two days. But again, this depends on the individual woman and whether she is carrying one or more embryos. The reaction of an individual woman’s body and hormones to pregnancy is entirely unique.

Here is an hCG level chart, noted in weeks from the last menstrual period (LMP):


It is important to remember that the numbers on hCG charts are intended as guidelines only. They are not definitive and are just meant to give an indication of what can be an average hCG range. Every woman and her pregnancy is unique. What is considered normal for one may not be for another. If you have any concerns about your individual hCG readings seek a health care professional for counsel.

What I found interesting with what I read about increasing hCG is that if the measurements start off high they don’t continue to expand at the same rate. For women whose level of hCG is a little slower to get going, their increase is much quicker than others. It’s as if nature knows that the well-being and survival of the embryo is dependent on the concentration of hCG increasing and there is no time to waste.

Where Does hCG Come From?

hCG is produced by the cells which will eventually become the placenta. Long before it is fully formed, the early placental tissue sends a message to the site of the ovarian follicle where the egg was released. This area is known as the corpus luteum and it plays a really important role in influencing the production of oestrogen and progesterone. These hormones are responsible for building up a rich vascular bloody lining in the walls of the uterus which will nurture and feed the developing embryo before the placenta has had a chance to form. Without this occurring, the chances of the embryo surviving would be pretty slim. Issues relating to the function of the corpus luteum are thought to account some women experiencing fertility problems.

This upswing in hCG levels is occurring long before a woman has had her pregnancy confirmed. hCG starts being produced around a week after the egg has been released and then fertilised by the sperm. The woman may suspect she’s pregnant and be doing the date calculations, but it’s too early for there to be any definitive proof. That is why many women won’t see hCG show up on hCG strips until between 7DPO all the way through 15 DPO (Days Past Ovulation).

How Can I Tell If I’m Producing hCG?

hCG is the hormone which is detected in a pregnant mother’s urine and blood. It’s the one which is responsible for those two positive lines on the stick. If you think you’re feeling a little sensitive right now, this is nothing compared to how sensitive the hCG detectors are on even the cheapest of home pregnancy tests.


Whether the test you’ve just done says you’re pregnant or not, it won’t actually give you any idea of what your hCG levels actually are. Even a standard pregnancy test won’t detect the exact level of hCG, just whether it’s present or not. Unless of course you’ve been receiving fertility treatment and precision is the key. Finding out there’s been the slightest rise in hCG can cause hearts to flutter in couples who are getting conception support.

If you use hCG strips, be sure to purchase a pack that has the same mIU detection range/amount. When I was testing myself post IUI, for the first 8 days, I used one brand of hCG strips that detected 10 mIU. Then, I ran out of those and switched to another kind I bought, but I didn’t pay attention to the fact that it detected only 25 mIU or more.

hcg-test-stripsTest Strips with 10 mIU hCG Sensitivityaccumed-stripsTest Strips with 25 mIU hCG Sensitivity

When I saw the 2nd line on the 25 mIU brand of hCG strips be super faint, my heart plummeted and I assumed my hCG hormones were fading/dwindling and therefore, my hopes of being pregnant faltered. In reality, my hCG hormone level was probably between 10-25 mIU, but because I was using a higher-detecting hCG strip from days 9+, the 2nd line looked fainter than it had before. So, just a warning, make sure you use strips that have consistent hCG mIU detection.

What Do I Need To Know About hCG?

  • Most pregnant women don’t know what their individual hCG reading is or will be.
  • Even if you do find out your hCG level, don’t make too much of it. A low reading of hCG can still mean you are going to have a healthy pregnancy and baby.
  • A pregnancy ultrasound gives a more accurate outcome prediction than an hCG reading done in isolation.
  • An hCG reading which is measured at less than 5mlU/ml is insufficient for there to be a positive pregnancy result. A reading above 25 mlU/ml is high enough to be considered pregnancy positive.
  • A woman with an hCG reading which is between 5mlU/ml and 25mlU/ml may need further investigations to see what could be causing the elevation in her hCG levels.
  • Women can have a transvaginal ultrasound and hCG blood measurements simultaneously to work out the exact gestation of their pregnancy. A comparison of the two results can provide a very accurate assessment of the gestational age of the embryo.
  • An hCG reading in isolation is not useful. For real benefits, a series of hCG blood tests are taken a couple of days apart and the readings are compared. There is often variation with a rapid increase in numbers especially in the first few weeks of pregnancy.
  • Dating a pregnancy or gestation from hCG readings alone should not be done. This is because there is such a big variation between women, and what is considered “normal”.
  • hCG levels are not indicative of the strength, intelligence or gender of the baby. They are simply a marker for whether sufficiently high levels of hCG have been detected and then measured.

More About hCG During Pregnancy

  • When hCG levels in early pregnancy measures less than 1,200 mIU/ml, the hCG usually doubles every 2-3 days. There is normally an increase by at least 60% in the level of hCG every two days.
  • When the hCG measures between 1,200 and 6,000 mIU/ml in early pregnancy, the hCG usually takes 3-4 days to double.
  • When the hCG measures more than 6,000 mIU/ml, the hCG frequently takes more than four or even more days to double.
  • After 9-10 weeks of the pregnancy hCG levels normally decrease. This is why there can be a general improvement in a mother’s sense of well-being by this stage of her pregnancy.
  • It makes little sense to follow the hCG level in early pregnancy above 6,000 mIU/ml, as at this point the increase is normally slower and not related to how well the pregnancy is doing. After two to three months the hCG numbers in early pregnancy will slow even further and eventually hCG levels even decline before reaching a plateau for the duration of the pregnancy.


In Summary…

Don’t get too worried up about your hCG levels. I know I did though, so I have empathy. Yet, there’s little you can do to influence them and worrying and agonizing over what your level is will do nothing but stress you out.

To definitively know your hCG level it’s necessary to have blood tests. hCG levels can vary at different times of the day, from day to day and week to week. Also, how diluted your urine may be (drinking a lot of water), will change your test results on hCG strips. Remember, one off hCG reading doesn’t tell us much. It only tells you what the level is at that specific point in time. It’s the pattern of readings and levels which gives a far more accurate indication of the status of your pregnancy and how well you are doing.

Your hCG level is not under your power or control. But YOUR job is to care well for yourself and do everything you can to stay healthy. Doing this will give your baby the possible chances of growing to full term! Your body knows what to do. Listen and follow it.

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