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You’ve tracked your menstrual cycle, planned intercourse around ovulation, and now you are in the two-week wait wondering when you can take a pregnancy test.
You know pregnancy tests measure the amount of hCG in your system. But how long after implantation does hCG rise?
Would you be surprised to learn hCG starts rising before implantation?
That’s right!
The embryo starts to secrete hCG a few short days after fertilization as part of preparing the uterus for implantation.
Read on to learn how this happens and the symptoms you may experience as your hCG levels climb.
Let’s begin by quickly reviewing what hCG is and how to test your levels.
What is hCG and how is it measured?
hCG, human chorionic gonadotropin, is known as the “pregnancy hormone”. It has a major role in maintaining a healthy pregnancy. One of its main functions is to stimulate the corpus luteum to produce progesterone.
You can measure your hCG levels via a blood or urine test.
Here is a table that highlights the difference between blood and urine tests:
When does hCG get secreted?
To begin, let’s examine the timeline surrounding fertilization and implantation.
Around halfway through your menstrual cycle, ovulation occurs. This is when an egg is released from your ovary.
The egg gets swept into the fallopian tube where it can be fertilized for up to 24 hours. If sperm meets an egg during this time, then fertilization can occur.
Once fertilization is complete, the embryo begins its travel to the uterus. The embryo rapidly divides during this time.
When the embryo reaches its 8-cell stage, which is around 3-4 days after fertilization, it begins to secrete hCG. This means that hCG is actually secreted before implantation!
hCG binds to receptor sites located on the outer layer of the uterus. This causes the uterus to undergo a process called decidualization.
You can think of this process as the uterus preparing itself to be a healthy foundation for the embryo to implant and then grow and develop.
So you can see that not only is hCG important in maintaining a pregnancy, but it also plays a crucial role in getting pregnant.
(Note: The amount of hCG secreted at this time is not enough to get a positive pregnancy test.)
Now that we understand how hCG aids in the implantation process, let’s look at how quickly hCG rises once implantation is complete.
How long after implantation does hCG rise?
As mentioned in the previous section, hCG starts getting secreted before implantation. But hCG levels only start to double around every 48 hours after implantation. This rate of increase continues during the first 6-7 weeks of pregnancy.
hCG plays a critical role in early pregnancy because it stimulates the corpus luteum to secrete progesterone. And progesterone is essential for a healthy pregnancy.
Read more: Progesterone Levels by Week: What’s Normal During Pregnancy?
Your hCG levels increase exponentially the first days after implantation, but you won’t get a positive pregnancy test just yet.
It’s best to wait until the day after your missed period to begin testing. On 9-10 DPO the average level of hCG is 0.93 mIU/mL. But the threshold for at-home pregnancy tests is around 20 mIU/mL! You’ll get a false negative result if you test too early or with a test that is not sensitive enough.
hCG levels peak around the 10-11th week mark. From here they remain steady. You can see in the chart below the normal range for hCG per week.
The chart shows there is a wide range of what is considered normal. In the 10th week, your hCG level could be as low as around 44,000 mIU/mL or as high as 170,000 mIU/mL. That’s a pretty big difference!
Note: The value of hCG is not the most important factor. What matters most is the rate at which your hCG levels increase. You could have hCG on the lower end, but as long as it increases at least 66% every 48 hours, you’re good to go!
Read more: hCG Doubling in Pregnancy: Why it Matters
So what happens when hCG levels increase in the body?
Symptoms associated with rising hCG levels
You can’t have a pregnancy without hCG, but that doesn’t mean hCG doesn’t cause some unpleasant side effects. And remember, progesterone levels rise alongside hCG levels. So this double whammy can cause a variety of early pregnancy symptoms!
You may experience some of the following symptoms of rising hCG levels:
- Nausea and vomiting (“morning sickness”)
- Fatigue
- Moodiness
- Darkening of areola
- Food cravings
- Dizziness/light-headedness
Key Takeaways:
- Contrary to popular belief, hCG is secreted before implantation. It is an important step in preparing the uterus for implantation.
- The embryo secretes hCG to help prepare the uterus to be a healthy foundation for the embryo to implant and then grow and develop.
- hCG levels typically double every 48 hours after implantation.
- “Normal” hCG levels vary from woman to woman. Try not to worry if your levels are on the lower end. The most important factor is that your hCG levels rise by at least 66% every 48 hours.
- Don’t give in to temptation! Wait for the first day after your missed period to take a pregnancy test. Testing too soon could give you a false negative.
- You may experience symptoms like nausea and vomiting, fatigue, moodiness, darkening of the areola, food cravings, and dizziness/light-headedness as your hCG levels rise.
FAQs
There is not one hCG level that indicates successful implantation. The important thing is that hCG levels rise at the standard rate of at least 66% every 48 hours.
hCG levels typically double every two days after implantation. The standard rate is that hCG levels should increase by at least 66% every 48 hours.
Some pregnancy tests on the market say they are “early detection tests”. They claim they can detect hCG as early as 10 DPO. However, this will depend on your hCG levels. The anticipation of taking a test can be unbearable, but it’s still best to wait until the day after your missed period. This will prevent you from the emotional rollercoaster of getting a false negative.
There are a few reasons your hCG levels are higher than expected. You could be farther along than you thought. Or you could be pregnant with twins or triplets! Rarely, it could be a sign of a molar pregnancy.
Causes of low hCG levels include an ectopic pregnancy, impending miscarriage, or an anembryonic pregnancy. Please consult your healthcare provider if you’re concerned about your hCG levels. But remember- a low hCG level does not reflect the health of your pregnancy. There may be nothing to worry about as long as your hCG levels are doubling every 48 hours.
Read more: Pregnant But hCG Rising Slowly: What to Know
Higher hCG levels could cause more symptoms like nausea and vomiting or no symptoms at all! One study showed that while only 50% of women experienced symptoms on 20 DPO, 89% of women reported symptoms by week 8. Rising hCG levels in pregnancy can lead to symptoms like fatigue, dizziness, moodiness, and breast tenderness.
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