hCG Levels by Week: What You Need to Know

What is hCG, and how does it affect your pregnancy?

We’re breaking down hCG levels by week so you can get a handle on the pregnancy hormone and one step closer to mamahood.

You’ve learned about lots of hormones while trying to conceive — estrogen, progesterone, luteinizing hormone… the list goes on!

Now that you’re pregnant (yay!), maybe you thought your hormone class was over, right?

Not so fast.

Once you conceive, a new hormone comes into play: human chorionic gonadotropin, or hCG.

How does hCG affect your pregnancy and what information can it tell you?

Let’s dig into normal hCG levels week by week to find out.

In this article: 📝

What Is hCG?

hCG is Human chorionic gonadotropin, often referred to as “the pregnancy hormone” because it’s at its highest levels during pregnancy.

It’s produced by the placenta after the fertilized egg implants in your uterus.

Fun fact: a pregnancy test works (like this highly-rated one on Amazon) by detecting hCG in your urine.

The catch? It requires high levels for a BFP (big fat positive), so an at-home pregnancy test taken too early might not pick up your rising hCG.

To avoid a false negative (and that pinch of disappointment), it’s recommended to wait until around the time of your expected period.

Even better is opting for a blood test, since there’s more hCG in your blood than in your urine.

It all depends on your excitability babe.

You could always do both.

Why is hCG important?

When you get pregnant, hCG helps to build up the lining of your uterus (making a cozy home for your fertilized egg) and tells your ovaries to stop ovulating.

The ability to measure hCG can also provide vital information for identifying a normal pregnancy and a pathologic pregnancy.

Far from the small stuff!

All you need to grasp right now is that a rapidly increasing hCG level, especially in the first trimester, is a good sign of a developing embryo.

Likewise, low hcg levels in pregnancy could indicate some potential pregnancy-related complications, including possible pregnancy loss.

hCG Levels Week by Week

You might be thinking that measuring your hCG levels throughout your pregnancy is a must for ensuring all is progressing as it should be.

But, according to Dr. Kiarra King, this isn’t actually true.

“Most of the time we don’t check HCG levels routinely. It’s typically in the case of determining the viability of a pregnancy, and assessing for conditions such as ectopic pregnancy.”

But typically, after conception, it’s perfectly normal for your hCG levels to rise as your body prepares for the months ahead.

Once the placenta is formed, your hCG levels will begin to fall.

It’s all good, it just means that with progesterone picking up the slack, hCG can take a back seat.

So lets look at these early variations in closer detail:

What are normal hCG levels at 4 weeks?

hCG becomes detectable in urine about 10 days after ovulation.

What could be considered “week 4” of pregnancy. (Week 1 starts the first day of your last period.)

hCG levels at 4 weeks pregnant are ideally about 5 to 426 mIU/mL (that’s units per milliliter of blood).

If at 4 weeks pregnant hcg levels are low, this could be down to a simple miscalculation and you’re not as far along as you thought.

Your doctor will be able to carry out further testing to know for sure.

What is a normal hCG level at 5 weeks?

After implantation, pregnancy hormone levels should start to rapidly increase, doubling every couple days.

hCG levels at 5 weeks should be about 19 to 7,340 mIU/mL.

That’s a big increase from week 4!

And it just keeps getting bigger.

hCG levels at 6 weeks will increase to around 1,080 to 56,500 mIU/mL.

All signs of a placenta hard at work like the rent is due tomorrow.

If you’re wondering what normal hCG levels are throughout pregnancy, you can look at an hCG levels chart by week, like this one from the americanpregnancy.org.

You can see that the hormone level goes up and up and up until about week 12, then it starts to decline.

The decline might be one reason that morning sickness tends to ease up at the end of the first trimester.

What else can hCG tell us?

The range of normal hCG levels varies greatly during each stage of pregnancy.

Generally, high or low numbers aren’t always a cause for concern but sometimes, yes, they could indicate an issue:

Low hCG levels

Some women have lower levels or their levels don’t increase as quickly as they “should,” but their pregnancy is still perfectly healthy.

Sometimes a low hCG level just means that you’re earlier in pregnancy than you thought.

But sometimes a low hCG level or especially a decreasing level can be a sign of pregnancy loss.

If you’re having bleeding or other miscarriage symptoms, your doctor might test your hCG levels to see what is going on.

If you’re wondering, At what hCG level will I miscarry?, there’s unfortunately no clear-cut answer to that question.

Your doctor will look at the trend in your levels to make a diagnosis.

High hCG levels

High hCG levels could mean that you’re farther along in pregnancy than you thought.

It could also mean – surprise! – you’re having twins!

If you get a positive on a pregnancy test very early, like 8 days after ovulation, that might mean your hCG levels are very high due to a twin pregnancy.

But the only way to be sure you’re having twins is to get an ultrasound.

And if you are having twins, you might want to look at an hCG levels chart by week, like this one.

High hCG levels could also indicate other extremely rare issues, like a tumor or a molar pregnancy.

In any case, it’s best not to hazard a guess on your own (or put your mind into a spin).

A healthcare professional will be able to guide you no matter your concerns.

And when it comes to your health, no worry is too small to bring up.

You know your body better than anyone.

Well, now you can add hCG to your vastly expanding knowledge of all things pregnancy.

There are so many changes going on in your body, inside and out.

Wherever you are in your pregnancy journey, the Peanut community has your back.

Day or night.