About HCG Tests and Low hCG Levels

Alex Perry

Published : Feb 05, 2024

Last Updated : Aug 08, 2024

What is an Human chorionic gonadotropin (HCG) test?

Human chorionic gonadotropin (hCG) is a pregnancy hormone that the placenta produces once an embryo implants in the uterus.

The purpose of hCG is to tell a female body to continue to produce progesterone. The hormone progesterone helps prevent instruction for the menstrual period from occurring. Thus, it protests the endometrial uterine lining and your pregnancy. 

HCG injections are often used in fertility treatments to stimulate ovulation and support early pregnancy. Also, Human chorionic gonadotropin (hCG) in men can help treat fertility-related issues. At-home pregnancy test, you can detect hCG through urine tests when the levels of hCG are high enough. It also helps to identify whether you are pregnant or not. You may need a blood test to know the exact regular reading of hCG. Read on to learn more about HCG Levels.

What are the Standard HCG levels?

The levels of standard hCG can vary significantly between women for various reasons. It depends on what is normal for them, how their body responds to the pregnancy, and how many embryos their pregnancy carries. A woman's body reacts uniquely during pregnancy, causing varying levels of standard hCG. The chart below shows HCG levels during pregnancy.

(Table) for the data of standard hCG levels

Pregnancy week (Standard hCG range)

• 3 weeks  (5–50 mIU/mL)
• 4 weeks (5–426 mIU/mL)
• 5 weeks (18–7,340 mIU/mL)
• 6 weeks (1,080–56,500 mIU/mL)
• 7–8 weeks (7,650–229,000 mIU/mL)
• 9–12 weeks (25,700–288,000 mIU/mL)
• 13–16 weeks (13,300–254,000 mIU/mL)
• 17–24 weeks (4,060–165,400 mIU/mL)
• 25–40 weeks (3,640–117,000 mIU/mL)

During the first 10-12 weeks of the pregnancy, hCG levels usually keep rising. After that, the levels may stay the same or go down after this period. It's why most women have more significant pregnancy symptoms in the first trimester. However, later, they usually get better as the levels of hCG plateau or even decrease. The Normal HCG levels you can observe during pregnancy range from 20,000 to 200,000 IU/L.

In the case of early pregnancy, the levels of hCG usually double every 2 to 3 days. When the measurements start from high, you may notice that they don't increase at the same rate. But if they create more slowly, the level increases much quicker.

If your hCG levels fall below the normal range, your doctor may ask for blood tests every two to three days to check them. This will help them determine whether the levels are rising or not. More than a single measurement of your hCG will be required and valuable to get accurate data and readings. At the beginning of pregnancy, variation with a rapid increase in number may take place. 

When it comes to detecting pregnancy, there are many over-the-counter urine pregnancy tests available. But sometimes, they may not detect hyperglycosylated hCG. And most of which accounts for the majority of hCG in early pregnancy. For most accuracy, pregnancy blood tests may help. Once you find that you are pregnant, you can estimate your due date by calculating either the date of conception or the date of the first day of your last menstrual period. 

Pregnancy blood tests-

There are two types of Pregnancy tests or pregnancy blood tests:

Qualitative hCG blood test: A qualitative test detects the production of hCG in the body. It just gives a simple yes or no answer whether you are pregnant.

Quantitative hCG test: This test helps to measure the specific levels of hCG in the blood. You can test hcg levels accurately with this quantitative test. 

What Causes low hCG levels in pregnancy?

Low levels of hCG during pregnancy can be due to several causes, such as:

• Blighted ovum
• Miscarriage
• Ectopic pregnancy
• Miscalculated gestational age
• Early pregnancy

It is not necessarily a concern if your hCG level is below the normal range. Most women with low levels of hCG may still have healthy pregnancies and babies. In most cases, even women don't find their hCG levels throughout pregnancy. 

However, there can be specific underlying causes that may affect lower levels of hCG. We have listed most of them.

Gestational age miscalculated

Doctors typically calculate your pregnancy length based on your last menstrual period. However, this calculation may be inaccurate if you have an irregular cycle or uncertainty about your dates. Low hCG levels are often detected between 6 and 12 weeks of pregnancy, but miscalculations can occur.

Ultrasounds and additional hCG tests are essential to determine the correct gestational age. These methods help identify low hCG levels and clarify discrepancies in gestational age calculations.

Miscarriage

A Miscarriage is the loss of a pregnancy before the 20th week of gestation. Sometimes, the low levels of hCG may indicate that you have had or will have a miscarriage. When your pregnancy fails to develop a placenta, then the levels of hCG may remain normal as in the initial period. The level of hCG fails to rise, and some common signs you may suspect during a miscarriage can be.

• Abdominal cramps
• Discharge of white and pink mucus
• Vaginal bleeding
• Passing tissue or clots
• Cessation of pregnancy symptoms

Blighted Ovum

A blighted ovum occurs when a fertilized egg attaches to the uterine wall but fails to develop. While the gestational sac forms, the hCG hormone does not increase because the embryo does not grow. This condition often goes unnoticed in early pregnancy, as many women may mistake it for a regular menstrual period due to typical menstruation symptoms.

If you are trying to conceive, an early pregnancy test to detect the presence of hCG is essential. This test can help confirm whether a normal pregnancy is underway.

Ectopic pregnancy

An ectopic pregnancy occurs when the fertilized egg remains in the fallopian tube and develops. It may cause the fallopian tube to rupture and lead to excessive bleeding, which can be dangerous and even life-threatening. Low levels of hCG may help indicate the chances of ectopic pregnancy. The symptoms of ectopic pregnancy are the same as normal pregnancy, but in its progression, you may suspect the following symptoms-

• Heavy vaginal bleeding
• Pain during intercourse
• You may feel pain in your belly or lower back that worsens when you strain or move. The pain might start on one side and then spread. 
• Dizziness or fainting is caused by internal bleeding.
• Internal bleeding may induce symptoms like shoulder pain. The bleeding can irritate the diaphragm and result in pain at the shoulder's tip. 
• Symptoms of shock
• Pain during a pelvic examination

How Low hCG Levels Are Treated

Low hCG levels cannot be directly treated; however, low levels alone do not always indicate a problem. If you experience a miscarriage, low hCG levels may require treatment if any pregnancy tissue remains in the uterus. You may not need treatment if the tissue passes naturally.

In cases of miscarriage, you have three treatment options:

• Wait for the tissue to pass naturally.
• Take medications to assist in passing the tissue.
• Undergo surgical treatment to remove the tissue.

For an ectopic pregnancy, the treatment options are similar to those for a miscarriage. Medications may help halt the growth of the pregnancy. If surgery is necessary, a surgical expert may need to remove the affected fallopian tube and the ectopic pregnancy.

Discuss the best treatment options with your healthcare provider if you face these conditions. Regular check-ups can help identify pregnancy risks early, allowing you to take essential steps and treatments as needed.

Final lines on the topic

Low hCG levels are not always a cause for concern. Many factors may affect hCG levels, and the reasons can be dictated. A doctor may be able to find out the hCG levels if you are concerned about it. But even if it's not, there is nothing you can do, but finding them can help you indicate other complications in the pregnancy. 

If you have a pregnancy loss, then you may have a low hCG level, but it does not mean that you will not be able to get pregnant in the future. In the case of an ectopic pregnancy, your fertility would not have any significant change as long as your other tube is functioning. But if it isn't, you may consider Reproductive technologies, such as in vitro fertilization. It can help achieve a successful pregnancy, even if it isn't possible naturally.