Article at a Glance
- hCG levels tell you if you're pregnant. Pregnancy tests measure how much hCG — the pregnancy hormone — is in your blood or urine. hCG begins producing 10 days after conception, doubling every 48 to 72 hours in the first trimester.
- Normal hCG levels in pregnancy vary, but when women test above 25 mIU/mL, they're pregnant. hCG levels can reach a height of nearly 300,000 mIU/mL by 9-12 weeks. Low levels do not necessarily mean an unhealthy pregnancy, but hCG levels can be rechecked every 48 to 72 hours.
- Low hCG levels could indicate a miscalculated conception date, ectopic pregnancy, or miscarriage. hCG levels that are very high could also indicate an incorrect pregnancy date, multiples, or a molar pregnancy. Abnormal hCG levels have been associated with pre-term delivery, preeclampsia, and other pregnancy conditions, so it's best to discuss any concerns with your OB/GYN.
Last updated April 21, 2018.
When you become pregnant, the world throws a lot at you. Not only do you need to start thinking about the life growing inside of you and what it means for the future of your family, but you need to start taking action on a few things. From knowing what foods and medicines to avoid, to skipping happy hour after work, to learning all about baby’s development — it can all be pretty overwhelming. On top of that, there are those lovely hormones to contend with!
So, what are pregnancy hormones, exactly? This post will discuss Human Chorionic Gonadotropin (hCG), commonly known as the pregnancy hormone, and what the varying levels mean for both you and baby.
What is hCG and what does it do?
First off, it’s important to understand how pregnancy tests work and what they measure. When you take a pregnancy test, either by blood or urine, it either measures how much hCG is present or whether hCG is present at all. False positives are pretty rare, so elevated hCG levels are a good bet for pregnancy, with some exception.
As soon as 10 days after conception, a woman will start to produce hCG via the placenta. hCG helps with the secretion of progesterone during the first trimester, which strengthens the uterus with a lining of blood vessels and capillaries able to support a fetus.
hCG levels typically double every 48 to 72 hours, reaching their peak within the first 8-11 weeks of pregnancy and declining after.
What is the beta-hCG test for pregnancy?
Depending on what type of pregnancy test you take, it’ll have a different name. The beta-hCG test is one name for a quantitative blood test — how much hCG is in your blood — and is done to confirm pregnancy, determine the age of the fetus, and screen for Down syndrome. It also can diagnose an ectopic pregnancy or early miscarriage.
This hCG test also may be called one of the following in your doctor’s office:
- quantitative serial beta-hCG test
- repeat quantitative beta-hCG test
- quantitative blood pregnancy test
If one of these tests comes back negative, it usually means you’re not pregnant — unless it was performed too early in the pregnancy. The test can be repeated every 48 to 72 hours, as often as hCG levels fluctuate.
What are normal hCG levels?
According to the American Pregnancy Association, it can be difficult to attach a number to “normal.” When women are not pregnant, however, their hCG levels will be under 5 mIU/mL — anything above 25 mIU/mL is considered positive for pregnancy.
hCG numbers can vary pretty widely, otherwise, with some increasing much faster and others tapering off more quickly. However, here are some general hCG readings based on gestation, with how many weeks have passed since your last missed period (LMP).
hCG Levels by Week
- 3 weeks LMP: 5-50 mIU/mL
- 4 weeks LMP: 5-426 mIU/mL
- 5 weeks LMP: 18-7,340 mIU/mL
- 6 weeks LMP: 1,080- 56,500 mIU/mL
- 7-8 weeks LMP: 7,650-229,000 mIU/mL
- 9-12 weeks LMP: 25,700-288,000 mIU/mL
- 13-16 weeks LMP: 13,300-254,000 mIU/mL
- 17-24 weeks LMP: 4,060-165,400 mIU/mL
- 25-40 weeks LMP: 3,640-117,000 mIU/mL
As mentioned above, elevated hCG levels are a pretty good sign you’re pregnant, but if you are on certain antibiotics or have cancer, your hCG also can be out of whack.
See also: Pregnancy Problems: Early Warning Signs
Can your hCG levels fluctuate in early pregnancy?
Yes, absolutely. While hCG levels can be an indicator of a healthy pregnancy, low levels do not necessarily indicate an unhealthy pregnancy, and should be rechecked every 48-72 hours. An ultrasound is going to be your best test for determining the development of baby after 5-6 weeks gestation.
However, low hCG levels could mean a couple of things: a miscalculated pregnancy date, an ectopic pregnancy, or a miscarriage. High levels, on the other hand, also can indicate a miscalculated pregnancy date, multiples, or a molar pregnancy. Molar pregnancies are the result of a genetic error during fertilization, are rare, and will rarely develop into an embryo. Abnormal hCG levels also have been associated with preeclampsia, a dangerous pregnancy condition, and pre-term delivery.
If you are bleeding or have a history of miscarriage, your doctor may recheck your hCG levels often. However, some bleeding during the first trimester is common, and you shouldn’t assume the worst based on hCG levels alone. You should, however, contact your doctor right away, as spotting can indicate an ectopic pregnancy. Ectopic pregnancies are life-threatening to the mother if not treated immediately.
If you unfortunately do experience a pregnancy loss, your hCG levels will return to non-pregnant levels in about 4-6 weeks.
All that said, hCG levels should never be the sole determinant of the viability of a pregnancy, otherwise your doctor may tell you the wrong news.
What is the hCG diet?
A bit of a fad — and dangerous one, at that — the hCG diet has nothing to do with pregnancy or what you should do during pregnancy, but you’ve probably heard of it. That’s why we thought it was worth mentioning here.
The hCG diet an extreme weight-loss regimen that’s been around since the 1950s that involves injections of the hCG hormone and a very low-calorie diet of about 500 calories per day. Proponents claim that it helps boost metabolism without leaving you feeling hungry, but it is neither safe nor approved by the U.S. Food and Drug Administration, and studies even have found hCG ineffective at curbing hunger.
The average woman gains 25-35 pounds during pregnancy, consuming up to 2,400 calories per day in the third trimester of rich, wholesome foods. If you’re looking to lose a little weight before pregnancy, make sure you do it the healthy way, and always be sure to consult with your doctor about any weight or diet concerns. You should never start a new diet or make any significant lifestyle changes, like increasing the intensity of your exercises, while pregnant without talking to your doctor first to determine what’s right for you and your baby.
Should I worry about my hCG levels?
Given how much hCG levels can fluctuate early on in pregnancy, it’s better to stress less and wait for an ultrasound to determine the health of your baby. However, we do know that seeing “good” hCG levels is encouraging. Whatever you can do to remain positive will help both you and your developing baby throughout the wonderful journey of pregnancy.
If you do have any concerns, make sure to reach out to your doctor. He or she will best be able to put your mind at ease or at the least, give you more information to help you throughout the course of your pregnancy.