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Wondering if your high hCG levels could mean twins are on the way?
It’s definitely a possibility.
One study found that hCG levels were doubled for twins and nearly quadrupled for triplets.
But that doesn’t mean all pregnancies with high hCG mean twins. Keep reading, and we’ll uncover all you need to know about twin hCG levels and signs of a twin pregnancy.
Normal hCG levels during pregnancy
Twins or not, most healthy pregnancies follow standard hCG patterns. This starts with your hCG levels doubling about every two days after successful implantation.
After about week 6 or 7, this rate begins to slow down. And by around 10 weeks gestation, hCG values will usually peak. From there, the levels will stay the same or begin to decrease. (Either of these routes is normal.)
During the remainder of the pregnancy, the normal range of hCG is anywhere from 20,000 to 200,000 IU/L. This is clearly a very wide range of hCG levels. So there will be some overlap between singleton and multiple pregnancies. That’s why not every pregnancy with high hCG levels is a twin pregnancy.
Though this trend is seen across all pregnancies, the specific values of hCG vary from woman to woman. In the next section, we’ll first see the general ranges for hCG by week.
hCG Levels: Singletons
First, it’s helpful to understand the normal hCG progression for singletons.
hCG levels chart by week for a singleton pregnancy
In the chart below, you’ll see normal hCG ranges for a singleton pregnancy. Hopefully, these values will give you a better idea of how your rising levels of hCG compare.
Now that you’ve seen the normal trend for hCG, it’s important to keep this in mind:
- The values listed here are just for reference. Normal hCG levels vary from woman to woman and pregnancy to pregnancy.
- The rate of hCG increase is more important than your initial hCG levels.
Now that you understand singleton hCG levels, let’s get into what hCG levels look like for multiples.
hCG Levels: Singletons vs. Twins vs. Triplets
One study examined over 400 IVF pregnancies and came up with a method for calculating predicted hCG levels. In the chart below, you’ll see predicted hCG levels for twins, singletons, and triplets.
As you can see, the hCG levels for twins at 3 weeks are much higher than the singleton levels. And for triplets, the levels are 3-4 times higher.
But the general pattern of rising hCG stays the same. (About every two days, the levels double.)
Do twin pregnancies always have higher hCG?
In most cases, yes. Research shows that higher hCG levels come with the territory of having twins. But remember, the range of normal hCG levels varies greatly. So there will be a lot of overlap in levels between twin pregnancies and singleton pregnancies. That means high hCG doesn’t always indicate a twin gestation.
But let’s take a closer look at what the latest studies suggest about twin pregnancy and hCG. Check out this table below for some recent findings.
In sum, these studies show that twin pregnancies reach higher levels of hCG. And compared to singleton pregnancies, hCG levels for twins remain higher for longer.
But when will you know for sure if your higher hCG is caused by a twin gestation? How early can twins be detected?
To know if your high hCG levels are due to twins, you’ll need to wait until your first ultrasound. This is because higher hCG levels are possible in non-twin-pregnancies too. Typically your first ultrasound scan will be around 6 to 7 weeks. But if you’re undergoing ART, it could be even earlier.
In the next section, you’ll learn other factors (besides twins) that can cause higher hCG levels.
Other causes of high hCG levels
As mentioned, not all instances of high hCG are caused by twins. Below are some other reasons you could experience higher hCG levels.
1. Singleton pregnancy with higher hCG
In some singleton pregnancies, higher hCG levels are completely normal. This is because the range for normal hCG levels is very wide. This means one healthy pregnancy could have hCG levels of 20,000 mIU/mL. And another normal pregnancy could have hCG levels of 200,000 mIU/mL.
To better determine the health of a pregnancy, it’s better to consider the doubling rate of hCG. And try your best to avoid comparing levels with other women. Every pregnancy is unique.
2. Miscalculated date of conception
You could have higher levels of hCG if you are further along in the pregnancy than you thought. This may happen if you mixed up the exact date of your last menstrual period (LMP). It can also occur if you ovulated earlier in your cycle than you thought.
3. Molar pregnancy
In rare cases, higher hCG could mean a type of pregnancy complication called a molar pregnancy. This occurs in 1 in 1,000 pregnancies.
In this type of pregnancy, the fertilized egg continuously divides, creating a blastocyst. The blastocyst can implant into the uterine lining, but it will not lead to a normal pregnancy. Instead, the cells that create the placenta progress abnormally. And as a result, the fetus can’t grow normally. If the fetus does grow at all, it will end in a miscarriage, unfortunately.
At this point, we’ve seen what can cause higher levels of hCG. But if you’re wondering about other twin pregnancy signs to look out for in the meantime? Keep on skimming below.
Other Signs You’re Having Twins
As mentioned, high hCG can be one indication of a twin pregnancy. But what are some other early signs of twins that you may notice?
In general, you could experience normal pregnancy symptoms at a higher intensity. This is because twin pregnancies typically have higher levels of hCG and progesterone. And these can lead to more intense symptoms.
The following symptoms could be heightened in a multiple pregnancy:
- Nausea and vomiting
- Fatigue
- Food cravings
- Mood swings
Keep in mind that the intensity of these symptoms will vary from woman to woman in a twin or singleton pregnancy. It all depends on how your body reacts to hCG. That’s why more intense symptoms don’t definitely mean you are having twins.
Additionally, there could be a greater chance you’re pregnant with twins if your family has a history of twin pregnancies. Some people think there are other signs that could indicate twins. But many of these are anecdotal and not supported by research (at least not yet).
All this info about signs and hCG levels is helpful to know in predicting a potential twin pregnancy. But how do you actually keep tabs on your levels of hCG?
How can I check my hCG levels?
There are two major routes for hCG testing: blood tests and urine tests.
Blood hCG tests are more accurate since they can give you an exact value of hCG and hence are useful in determining if your hCG levels are higher than expected. But these types of hCG tests are not routine. Typically, you’ll only get an hCG blood test if you’re undergoing any sort of fertility treatment or if your doctor thinks something is wrong.
Urine hCG tests can be done at home and are much more common for pregnancy testing. Since these results only give you a positive or negative result, they can’t detect if your hCG levels are higher than normal.
Takeaways
- Precise levels of the pregnancy hormone hCG vary quite a bit. So if your early human chorionic gonadotropin (hCG) levels are elevated, it’s hard to tell the exact reason.
- In a twin pregnancy, hCG will be higher. But not all pregnancies with high hCG are a twin pregnancy.
- High hCG can also be seen in a normal singleton pregnancy or a pregnancy with a miscalculated due date. In rare cases, it could be due to a molar pregnancy.
- Your actual hCG levels aren’t as important as the rate at which hCG is rising. So try not to stress too much about your specific hCG levels in early pregnancy!
- Urine pregnancy tests can only tell you if your hCG level is above 20 mIU/mL to confirm pregnancy. But a blood test can give you the exact hCG level.
- Remember, every pregnancy is different. But if you think you’re pregnant with twins? Or if you’re concerned about your hCG levels? Speak to your doctor.
FAQs
hCG levels vary greatly at 5 weeks. One study shows a range of 217-8,245 mIU/mL at 5 weeks. So it’s more helpful to track the rise in hCG over time with blood tests if you’re concerned.
Around week 6 or 7, hCG rates begin slowing. This is true for both singleton and twin pregnancies. But hCG will continue to rise until peaking around 9 to 11 weeks. After this peak, hCG levels may stay elevated or they could gradually decline.
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- Chorionic Gonadotropin Beta Subunit – an overview | ScienceDirect Topics
- Doubling times of human chorionic gonadotropin increase in early viable intrauterine pregnancies
- HCG (Blood) – Health Encyclopedia – University of Rochester Medical Center
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- Role of early serum beta human chorionic gonadotropin measurement in predicting multiple pregnancy and pregnancy wastage in an in vitro ET fertilization cycle – PMC
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