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, 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 what 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.
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 percent 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 now.)
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 two 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.