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میزان hCG در بارداری/دانشجویان مامایی بخوانند.



 

The human chorionic gonadotropin (hCG) test is done to measure the amount of the hormone hCG in blood or urine to determine whether a woman is pregnant. HCG is produced by the placenta during pregnancy.

HCG may also be produced abnormally by certain tumors, especially those that develop from an egg or sperm (germ cell tumors). Therefore, hCG levels are usually tested in a woman who may have cancer of the ovaries or abnormal tissue growing in her uterus (molar pregnancy) instead of a normal fetus. In a man, hCG levels may be measured to help determine whether he has cancer of the testicles.

HCG in pregnancy
An egg is normally fertilized by a sperm cell in a fallopian tube. Within nine days after fertilization, the fertilized egg moves down the fallopian tube into the uterus and attaches (implants) to the uterine wall. Once the fertilized egg implants, the developing placenta begins releasing hCG into your blood. Some hCG also gets passed in your urine. HCG can be detected in the blood before the first missed menstrual period, as early as six days after implantation.

HCG helps to maintain your pregnancy and affects the development of your baby (fetus). Levels of hCG increase steadily in the first 14 to 16 weeks following your last menstrual period (LMP), peak around the 14th week following your LMP, and then decrease gradually. The amount that hCG increases early in pregnancy can provide information about your pregnancy and the health of your baby. Shortly after delivery, hCG can no longer be detected in your blood.

More hCG is released in a multiple pregnancy, such as twins or triplets, than in a single pregnancy. Less hCG is released if the fertilized egg implants in a place other than the uterus, such as in a fallopian tube. This is called an ectopic pregnancy.

The level of hCG in the blood is often used in a maternal serum triple or quadruple screening test. Usually done between 16 and 18 weeks, these tests measure the amounts of three or four substances in a pregnant woman's blood. The triple screen measures alpha-fetoprotein (AFP), beta human chorionic gonadotropin (beta-HCG), and a type of estrogen (unconjugated estriol, or uE3). The quad screen measures these substances and the hormone inhibin-A. The levels of these substances—along with a woman's age and other factors—help estimate the risk that her child may have certain problems or birth defects.

In some cases a combination of screening tests is done in the first trimester to look for Down syndrome. The screening combines ultrasound measurement of the thickness of the fetus's neck (nuchal fold) and measurements of beta-HCG and a protein called pregnancy-associated plasma protein A. The accuracy of this screening is about the same as that of the second trimester maternal serum quad screening.1

 Should I have the maternal serum screening test (triple or quad screen)?
Routine pregnancy testing is usually done on a urine sample. The test does not measure the exact amount of hCG, but it indicates if hCG is above the normal, nonpregnant level. Home pregnancy tests that detect hCG in urine are also widely available.

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  Should I have the maternal serum triple or quadruple test (triple or quad screen)? 
Why It Is Done

A test for human chorionic gonadotropin (hCG) is done to:

Determine whether you are pregnant.
Detect an ectopic pregnancy.
Detect and monitor the treatment of a molar pregnancy.
Determine whether chromosome abnormalities, such as Down syndrome, are present.
Detect and monitor the treatment of a cancer that develops from an egg or sperm (germ cell cancer), such as cancer of the ovaries or testicles. In such cases, a test for alpha-fetoprotein may be done along with a test for hCG.
How To Prepare

If a blood sample is collected, no special preparation is needed before having this test.

If urine testing is done, the first urine of the day is generally the best to use because it contains the highest concentration of hCG. A urine sample collected at least four hours after the previous urination will also contain high amounts of hCG.

How It Is Done

Human chorionic gonadotropin (hCG) may be measured in a sample of blood or urine.

Blood sample collection
The health professional will:

Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
Clean the needle site with alcohol.
Put the needle into the vein. If the needle is not placed correctly or if the vein collapses, more than one needle stick may be needed.
Attach a tube to the needle to fill it with blood.
Remove the band from your arm when enough blood is collected.
Apply a gauze pad or cotton ball over the needle site as the needle is removed.
Apply pressure to the site and then a bandage.
Urine collection
If possible, collect a sample from the first urine of the day (this urine generally contains the highest level of hCG). A urine sample collected at least four hours after the previous urination will also contain high amounts of hCG.

Place the collection container into the stream of urine and collect approximately 4 Tbsp(59.15 mL) of urine.
Avoid touching the rim of the container to your genital area, and avoid getting toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.
Finish urinating into the toilet or urinal.
Carefully replace the lid on the container and return it to the lab. If you are collecting the urine at home and cannot get it to the lab within an hour, refrigerate it.
How It Feels

Blood test
You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. However, many people do not feel any pain (or have only minor discomfort) once the needle is positioned in the vein. The amount of pain you feel depends on the skill of the person drawing the blood, the condition of your veins, and your sensitivity to pain.

You may feel anxious while awaiting results of an hCG test done to determine the health of your baby.

Urine test
There is normally no discomfort involved with collecting a urine sample.

Risks

Risks of a blood test
There is very little risk of complications from having blood drawn from a vein.

You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
Rarely, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.
Continued bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medications can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medication, tell the person before your blood is drawn.
Urine test
There are no risks associated with collecting a urine sample.

Results Human Chorionic Gonadotropin (hCG)

Test Overview

The human chorionic gonadotropin (hCG) test is done to measure the amount of the hormone hCG in blood or urine to determine whether a woman is pregnant. HCG may also be measured to determine whether cancer of the ovaries or testicles is present.

Normal
Normal values may vary widely from lab to lab.

Human chorionic gonadotropin (hCG) levels in blood  Men and nonpregnant women:
 Less than 5 international units per liter (IU/L)
 
Pregnant women:
 About 24 to 28 days after the last menstrual period (LMP):
 5–100 IU/L
 
4 to 5 weeks after the LMP:
 50–500 IU/L
 
5 to 6 weeks after the LMP:
 100–10,000 IU/L
 
Peak, 14 to 16 weeks after the LMP:
 12,000–270,000 IU/L
 

 

hCG levels in urine  Men:
 None (negative test)
 
Nonpregnant women:
 None (negative test)
 
Pregnant women:
 Detectable (positive test)
 

 

High values
If you are pregnant, levels of human chorionic gonadotropin (hCG) that are higher than expected can indicate a multiple pregnancy (such as twins or triplets), a molar pregnancy, Down syndrome, or may suggest that you are further along in an early pregnancy than estimated by your last menstrual period (LMP).
In a man or a nonpregnant woman, a high hCG level can indicate a tumor (cancerous or noncancerous) that develops from a sperm or egg cell (germ cell tumor), such as a tumor of the testicles or ovaries. It may also indicate some types of cancer, such as cancer of the stomach, pancreas, large intestine, liver, or lung.
Low values
If you are pregnant, levels of hCG that are lower than expected can indicate an ectopic pregnancy, death of your baby, or may suggest that you are not as far along in an early pregnancy than estimated by your last menstrual period (LMP).
If you are pregnant, levels of hCG that are decreasing abnormally can signal an impending miscarriage (spontaneous abortion).
What Affects the Test

Factors that can interfere with your test and the accuracy of the results include the following:

A urine test for human chorionic gonadotropin (hCG) done very early in pregnancy (during the first week after implantation) or done on a urine sample taken in the middle of the day may not always detect early pregnancy.
HCG results may remain high (positive) for up to four weeks after a completed miscarriage (spontaneous abortion) or therapeutic abortion.
An injection of hCG to treat infertility may cause test results to appear high for several days after the injection.
Blood in the urine sample or soap residue in the collecting container
Diuretics and promethazine (such as Phenergan, Prorex, or Anergan) can cause inaccurate low hCG levels in urine test results.
Heparin, a medication used to prevent blood from clotting (anticoagulant)
Medications. These include hypnotics (such as Ambien), antipsychotics (such as Mellaril, Stelazine, and Serentil), antinausea medications (such as Compazine and Phenergan). Be sure to tell your health professional what medications you take.
What To Think About

Home pregnancy tests that detect hCG in urine are widely available. For more information, see the medical test Home Pregnancy Tests.
A blood test for human chorionic gonadotropin (hCG) is usually more accurate than a urine test. If pregnancy is suspected even after urine test results do not indicate pregnancy (negative results), a blood test can be done, or another urine test should be repeated in a week.
HCG results may remain high (positive) for up to four weeks after a completed miscarriage (spontaneous abortion) or therapeutic abortion.
The level of hCG in the blood is often used in maternal serum triple or quadruple screening test. Usually done between 16 and 18 weeks, these tests measure the amounts of three or four substances in a pregnant woman's blood. The triple screen measures alpha-fetoprotein (AFP), beta human chorionic gonadotropin (beta-HCG), and a type of estrogen (unconjugated estriol, or uE3). The quad screen measures these substances and the hormone inhibin-A. The levels of these substances—along with a woman's age and other factors—help estimate the risk that her child may have certain problems or birth defects. For more information about estriol and hCG, see the medical tests Alpha-Fetoprotein (AFP) in Blood and Estrogens.
In the past, pregnancy testing involved injecting a sample of a woman's urine into an animal (such as a rabbit). Shortly afterward, the animal was sacrificed and its organs were examined for signs that hCG was present. However, pregnancy testing no longer requires the use of an animal to detect hCG.
A normal hCG value does not rule out the possibility of a tumor in the uterus, ovaries, or testicles. HCG is only one part of an overall evaluation when a tumor is suspected.
References

Citations
American College of Obstetricians and Gynecologists (2004). ACOG issues position on first-trimester screening methods. Available online: http://www.acog.org/from_home/publications/press_releases/nr06-30-04.cfm.

 

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