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Low hCG levels in pregnancy: Causes, Treatments, and Symptoms

Low hCG levels in pregnancy: Causes, Treatments, and Symptoms

If you know about home pregnancy tests, then you are familiar with the hormone known as human chorionic gonadotropin. Also known as beta hCG or hCG levels, it is the hormone released during pregnancy and used by home pregnancy tests to determine if you’re pregnant (a positive pregnancy test result).

HCG levels usually increase in a predictable pattern with some notable changes and innovations as early pregnancy progresses. This article will discuss what slow rising hCG means and what it means for your pregnancy.


The role of hCG in pregnancy

The pregnancy hormone hCG is produced by cells surrounding a growing embryo that later forms the placenta. hCG production begins after implantation, and the levels increase rapidly during the first weeks of pregnancy.

After successful implantation and hCG begins to be produced, the corpus luteum produces progesterone throughout the first trimester of pregnancy.

Progesterone is essential because the womb lining will not shed without it, preventing the embryo from being implanted on the uterus lining. hCG prevents this from happening by ensuring that the corpus luteum continuously produces progesterone until the placenta is formed, which takes overproduction.

Besides aiding fetal growth and triggering progesterone production, hCG also supports other bodily functions during pregnancy. In addition, it smoothens the muscle cells found in the uterine walls and promotes the development of new blood vessels in the uterus. Both are important developments for maintaining a healthy pregnancy.

Normal hCG Levels in Early Pregnancy

The pituitary gland naturally produces human chorionic gonadotropin, which occurs in both females and males throughout their lives. However, because its primary role in pregnancy is hCG production, it is usually at its highest during the first weeks (first trimester) of pregnancy and then rises exponentially.

HCG continues to rise in early pregnancy until around the 9-12 week mark (last weeks of the first trimester). Standard levels vary from one woman to another and depend on different factors, including the number of embryos you are carrying and how your body reacts to the pregnancy. A woman carrying two or more embryos will have a higher hCG level than a woman with one embryo because of the hormone’s role in early pregnancy and fetal development.

Human chorionic gonadotropin: first four weeks of pregnancy

Typically during the first four weeks of pregnancy, slow-rising hCG levels double every 48 to 72 hours, then by week 6, slow every 96 hours, and around ten weeks peaks again before levelling off and remaining constant throughout the pregnancy.

Standard hCG levels act as a guide during weeks that follow implantation to determine the normal range of pregnancy in each week. However, these levels vary from one woman to another. They will entirely depend on how your body reacts to pregnancy, whether or not you’re carrying multiples, and what’s normal for you.

A single measurement of your hCG levels will not provide information to determine how many weeks pregnant you are. You have to do multiple hCG tests to confirm if your levels are increasing at the recommended rate. Low, slow-rising hCG levels and numbers can occur due to different reasons and doubling times are not the only signs of concern or trouble.

Checking hCG doubling time is not usually necessary in low-risk pregnancy and is generally recommended for cases where there are underlying problems such as previous miscarriages.

HCG levels vary from one woman to another, but there should be little concern if they are within the normal range and increasing steadily. Even though home pregnancy tests are designed to test or detect hCG presence in the urine, only a blood test can determine the exact levels.


Human Chorionic Gonadotropin Levels Chart Week by Week

The table below provides the range of normal levels measured in milli-international units of hCG hormone per millilitre of blood (mIU/mL).

Pregnancy Week (weeks since last menstrual period)
Standard hCG Range
Non-pregnant0 – 5 mIU/mL
3 weeks5 – 50 mIU/mL
4 weeks5 – 426 mIU/mL
5 weeks18 – 7,340 mIU/mL
6 weeks1,080 – 56,500 mIU/mL
7-8 weeks7,650 – 229,000 mIU/mL
9-12 weeks25,700 – 288,000 mIU/mL
13-16 weeks13,300 – 254,000 mIU/mL
17-24 weeks4,060 – 165,400 mIU/mL
25-40 weeks3,640 – 117,000mIU/mL

Low hCG Levels

Low slow hCG levels, in most cases, should not be a cause for concern. Even though the doubling guidelines apply to 85% of normal pregnancies, all pregnancies don’t follow this pattern. In approximately 15% of viable pregnancies, hCG appeared to rise slower. Your doctor will check these levels keenly throughout the first trimester, but remember that it is not the only tool to monitor your pregnancy.

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What do low slow hCG levels mean?

HCG monitoring is essential to determine the status and health of early pregnancy. HCG levels usually fall in a wide range, and typically your doctor will check how the levels change (whether they are rising or not). They are more concerned about the rate of change than the actual number.

Low slow rising hCG levels have different meanings and could indicate different possible scenarios. A Low beta hCG result could signify that you miscalculated the date of your pregnancy and you’re not far along as you thought. It’s possible to miscalculate your pregnancy date if you’re not tracking your cycles, have irregular periods, or are unsure about the dates. Your doctor should perform further tests to determine gestational age.

Slow rising hCG levels could also indicate other problems in the pregnancy that may eventually lead to pregnancy loss. If a pregnancy does not progress, the initial hCG levels may appear normal but fail to rise after subsequent tests if a pregnancy does not progress. If you get this type of result, it could signify that you may have a miscarriage or one has already occurred without your knowledge. Falling hCG levels are usually a sign of miscarriage, but in most cases will be accompanied by other symptoms such as passing tissue or clots, bleeding, and cramping.

low slow rising hCG levels causes

Apart from miscarriage, low, slow-rising hCG levels could also signify an ectopic pregnancy or a blighted ovum. Even though they are different conditions hCG hormone plays a role because they both involve the development of a fertilized egg.

A blighted ovum occurs when an egg that has been fertilized attaches itself to the womb but fails to develop. It occurs early in pregnancy and may go unnoticed by many women. The symptoms occur as normal menstruation, and most women think that it’s their period.

An ectopic pregnancy is a dangerous and life-threatening condition where the fertilized egg, instead of attaching itself to the uterine lining, remains in the fallopian tube and develops. As an ectopic pregnancy continues to develop or progress, it is accompanied by other physical symptoms such as dizziness, shock, heavy bleeding, or severe abdominal pain that indicate a problem. Low or slow rising hCG levels can indicate an ectopic pregnancy, but your health care provider or doctor will have to do more than hCG tests alone before giving you a diagnosis.

It is crucial to note that low, slow-rising hCG does not necessarily indicate pregnancy problems. A small but significant percentage of pregnancies with low hCG levels go on without complications.

Can you get pregnant with low hCG?

Even when hCG levels are slow or low rising, it’s still possible to have a successful pregnancy. The levels vary from one woman to another and even between pregnancies. So, if you have had a complication previously, human chorionic gonadotropin levels should not be taken as a sign that you will not get pregnant again.

Can home pregnancy test detect low hCG levels?
Can home pregnancy tests detect low hCG levels?

What can cause high hCG levels?

Because of the wide range, HCG levels are driven by pregnancy development, and It can be hard to determine a high hCG level. High human chorionic gonadotropin levels in normal cases mean that you’re carrying multiples, you may have miscalculated your pregnancy date, or it may be the result of using fertility drugs.

In most cases, doctors are usually not concerned about high levels due to the above reasons. Still, in rare cases, hCG levels could indicate a serious complication known as a molar pregnancy (chromosomal abnormalities of an embryo). Molar pregnancies are a rare form of abnormality where implantation of a non-viable egg occurs in the uterus and develops into a non-cancerous mass instead of a fetus.

Is it possible to increase hCG levels?

It may be tempting to look for ways of increasing your hCG levels, but it cannot be done. It is impossible to make your levels go up even if you want to. The changes in your hCG levels are valuable information to determine the health of your pregnancy. Attempting to change those numbers to artificially increase human chorionic gonadotropin levels will only mask the problems instead of indicating them.

Low hCG and miscarriage

Unfortunately, the most common reason for slow rising hCG is usually a miscarriage. Your doctor will be more concerned about the viability of your pregnancy if your hCG levels go down and fail to rise. They will most likely do a transvaginal ultrasound and blood tests to check for other problems.

If your hCG levels decrease from previous measurements or are not close to doubling, it is most likely a sign that the pregnancy is not viable because the embryo is no longer developing. This is because the body stops the production of hCG to support fetal growth after the embryo stops developing, and the tests done by your doctor will reflect that.

Low levels of hCG don’t always indicate a miscarriage, and they are also used as a baseline to track the changes throughout the pregnancy. However, it is not a good sign if the levels start dropping. Declining hCG levels after getting a positive pregnancy result means high chances of the pregnancy being non-viable.

Tracking hCG levels

A blood test is the most accurate way to track and detect slow rising hCG levels. Home pregnancy tests only detect the hormone but not the amount of hCG in your urine. Even though some pregnancy tests in the market are designed to tell you if your hormone levels have risen over the baseline, they cannot monitor healthy pregnancies.