Our beta-hCG doubling time calculator can be found on our main Calculators page. Any extra information you need to help you interpret your betas can be found below.
Everything you're about to read about betas will make the subject as clear as mud. Beta hCG measurements should be viewed only as guidelines and estimates, and cannot be compared between one woman and another. Low numbers can be normal, high numbers can be normal, and perfectly normal numbers can fool everyone. Betas are like gremlins. You'd rather not have to deal with them and they totally wreck your life while they're around ... yet you want to know as much about them as possible.
Our strongest advice is this: once you have had two or three quantitative hCG tests and your doctor says everything is progressing well, then take that as a positive sign and put your mental energy elsewhere. Betas are a special form of torture that only assisted reproductive technology patients get to endure -- most women who get pregnant without help never even get a quantitative hCG test done - their doctors just test to see if there is any measurable pregnancy hormone in the bloodstream and then move on. For those women special enough to live in a world where quantitative hCG tests are important and nerve-wracking (you, we presume), here's everything-you-need-to-know-that-probably-won't-tell-you-want-you-want-to-know.
What is a beta test?
A beta test, also known as beta hCG (human chorionic gonadotropin), is a blood test that confirms pregnancy. A qualitative hCG simply reports whether or not there is hCG present in the bloodstream, while a quantitative hCG reports the level of hormone that is present.
What is hCG?
hCG is human chorionic gonadotropin, better known as "the pregnancy hormone." The body begins to produce hCG when an embryo begins to implant in a uterus, which is typically 8 to 10 days after conception.
My doctor told me I'm pregnant, but didn't give me a beta number. What does that mean?
It may mean that your doctor ran a qualitative hCG test rather than a quantitative hCG test. Call your doctor's office, ask to speak to his/her nurse, and ask them if you have a quantitative hCG value. If you did not get this test done, request that they perform this test ASAP, and then again two days later. Then you'll have as much information as you can.
What should my quantitative hCG be?
There can be a tremendous variation in "normal" hCG levels. The following chart is what most textbooks consider to be normal; however, you must remember that this is only one measure of your pregnancy's progress!
|Time from LMP||hCG (mIU/mL)|
|3 weeks||5 - 50|
|4 weeks||5 - 426|
|5 weeks||19 - 7340|
|6 weeks||1080 - 56,500|
|7 - 8 weeks||7650 - 229,000|
How do I know whether my betas are rising normally?
Typically, betas will double in value every 48-72 hours. This means that if your beta is 150 on Monday, it should be around 300 between Wednesday and Thursday. Confusing? You bet. Just enough to make us all nutty.
Beta hCG Blood Levels Over Time
My first beta is only 25. What does that mean?
There's no real way to tell, yet. The most important thing you need in order to answer this question is another test in 48 hours. Your doubling time will give you a much better indication of whether your pregnancy is progressing.
What are the reasons my beta may be low?
There are so many reasons that betas can start out "low" or "high."
- Depending on your procedure (if you had an IUI done, a cancelled cycle during which you had intercourse, or if you're pregnant using natural 'rhythm' timing), you may not know your ovulation date. Without knowing your ovulation date or your date of transfer, you may not have your pregnancy test done at the right time.
- Another reason for a low beta is that some embryos are "late" implanters. Typically, an embryo begins to implant and your body begins to produce hCG between 8-10 days past conception. But it's possible your embryo had a slower start.
- Some research shows that frozen embryos are slower/later to implant than fresh embryos. So if you did a frozen embryo transfer (FET), this may be the case.
- Your number may be low because you had a chemical pregnancy. Sadly, this is a very early miscarriage. It is estimated that up to 25% of pregnancies end in early miscarriages - but researchers aren't sure. Most women who go through IVF know everything about their lab values, practically to the minute. But in the rest of the population, women can experience a chemical pregnancy without ever knowing it.
- Your number may just be low, and there's no way to know why. Remember the range in that table, above? There's a big range of acceptable values, and that means someone has to be at the low end. It could be you, and there is nothing unusual with your pregnancy. (I know of one woman whose first beta was 4. She has a three year old boy.)
My beta is not doubling every 48-72 hours. What does this mean?
For what it's worth, I hate the beta roller-coaster. This period of time in an IVF cycle is just the worst. I'm sorry you even have to read this!
Your embryo may be a slow starter. The doubling time is a guide -- an estimate that doctors use to help gauge a pregnancy's early progress. But not everyone follows the rules. Sometimes a low doubling time in the beginning means nothing. Sometimes, it's bad news.
- A slow doubling time can mean your embryo is not viable. You've done everything you can do, and there is nothing you can do now but wait.
- Your embryo may just not make it, for whatever reason we won't know. Your embryo may have chromosomal abnormalities which keep it from being viable.
- Your pregnancy may be ectopic -- outside of the uterus. An embryo can travel out of the uterus and up a fallopian tube, or even out into the abdominal cavity. Ectopics are rare, but they happen.
- You may have a blighted ovum. This is another type of miscarriage, in which the embryo attaches to the uterine wall but then ceases to develop. However, the cells continue to form the pregnancy sac, which is what is causing a slow rise in the hCG numbers.
My beta dropped from one of my first measurements, but then started going up normally again. What's going on?
If your beta is continuing to double every 48-72 hours again, there is a great chance that everything is fine.
- One of the lab readings may have been an error.
- You may have had a vanishing twin. This happens when two embryos implant and start producing hCG, but then one of them dies. You start with "twice" the hCG, and then the number drops - but as the remaining embryo grows, your doubling time is back to normal again. Congrats on your singleton!
My beta dropped really quickly, and my doctor wants me to test again in two days. Tell me there's hope.
There is absolutely always hope. If you hang out on some of the IVF community sites for long enough, I promise you'll hear every success story in the book. But a sharp drop in your beta hCG usually means that you are miscarrying. Keep hoping until your doctor tells you otherwise, because it is not always the case.
My beta is through the roof! It's higher than any of my friends' betas have been - what does that mean?
The beginning to each of these answers seems to be the same: you might just have an unusual number. But there are other reasons for a high beta.
- Multiples. Did you transfer 2 or more embryos?
- Spontaneous twins. Sometimes, the embryo splits and you get identical twins. Identical twins (one embryo, split) are not as typical in IVF as fraternal twins (two embryos), but it can happen.
- A molar pregnancy. (This is really unusual - don't even worry about this unless your doctor tells you to.)
When am I in the clear? When does the beta hell end?
Once a beta is somewhere between 1,000-2,000 mIU/mL, a gestational sac can usually be seen via transvaginal ultrasound. Once your doctor sees that sac, you're off of the beta roller-coaster.