It is important that the corpus luteum keeps producing progesterone because loss of progesterone leads to shedding of the womb lining menstruation , which would prevent an embryo from implanting. Human chorionic gonadotrophin is the embryonic hormone that ensures the corpus luteum continues to produce progesterone throughout the first trimester of pregnancy. As well as maintaining progesterone production from the ovary, human chorionic gonadotrophin may also play a role in making sure the lining of the uterus endometrium is ready to receive the implanting embryo.
Recent studies have indicated that human chorionic gonadotrophin may help to increase the blood supply to the uterus and be involved in re-shaping the lining of the uterus in preparation for the implanting embryo. Human chorionic gonadotrophin is produced by the trophoblast cells which surround the developing embryo at approximately day five of pregnancy. The amount of human chorionic gonadotrophin in the bloodstream doubles every days as development of the embryo and placenta continue, and levels peak at around six weeks of pregnancy.
Following this peak, levels of human chorionic gonadotrophin fall although they remain detectable throughout pregnancy. Once the placenta is established, it becomes the main source of progesterone production around week 12 of pregnancy , and human chorionic gonadotrophin is no longer required to maintain ovarian function.
However, human chorionic gonadotrophin may have additional beneficial effects in the latter stages of pregnancy; such roles are currently being investigated by researchers. There is no strong evidence that high levels of human chorionic gonadotrophin cause direct negative consequences. Very high levels of human chorionic gonadotrophin are rare but can indicate hyper-proliferation of the placenta also referred to as hydatidiform moles or molar pregnancies , which can lead to cancer choriocarcinomas in some cases.
Levels of human chorionic gonadotrophin may also be elevated sometimes in association with some non-pregnancy related cancers e. Urine test Collecting a urine sample does not cause problems. Results The human chorionic gonadotropin hCG test is done to measure the amount of the hormone hCG in blood or urine to see if a woman is pregnant. Normal These numbers are just a guide. It can also mean a molar pregnancy or Down syndrome. You may also be further along in an early pregnancy than you thought, based on your last menstrual period.
In a man or a nonpregnant woman, a high hCG level can be a sign of a tumor cancerous or noncancerous.
These tumors can develop from a sperm or egg cell germ cell tumor , such as a tumor of the testicles or ovaries. It may also mean some types of cancer, such as cancer of the stomach, pancreas , large intestine, liver, or lung.
Low values If you are pregnant, a low level of hCG can mean an ectopic pregnancy or a miscarriage. It may also mean that you aren't as far along in an early pregnancy as you thought, based on your last menstrual period LMP. If you are pregnant, levels of hCG that are going down abnormally can mean a miscarriage spontaneous abortion is very likely. What Affects the Test You may not be able to have the test, or the results may not be helpful, if: You do your urine test for hCG very early in pregnancy during the first week after implantation or on a urine sample taken in the middle of the day.
The test may not always show an early pregnancy. You have had a miscarriage spontaneous abortion or therapeutic abortion. HCG results may stay high positive for up to 4 weeks after a miscarriage or therapeutic abortion. You got an injection of hCG to treat infertility. This may cause test results to appear high for several days after the injection.
There is blood in the urine sample or soap in the collecting container. These can change the hCG level. You use diuretics or promethazine. These medicines can cause false low hCG levels in urine test results. You use heparin, a medicine to prevent blood from clotting anticoagulant. You use certain medicines. These include hypnotics such as Ambien , antipsychotics, and antinausea medicines such as prochlorperazine. Be sure to tell your doctor what medicines you take.
To learn more, see the topic Home Pregnancy Tests. A blood test for hCG is generally more accurate than a urine test. If you still think you're pregnant even after your urine test results do not show a pregnancy negative results , you can try a blood test. Or you can repeat the urine test in a week. 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 a group of tests when a tumor is suspected. Screening for fetal chromosomal abnormalities. Obstetrics and Gynecology , 1 : — Manual of Laboratory and Diagnostic Tests , 8th ed. Philadelphia: Lippincott Williams and Wilkins. Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. Louis: Mosby Elsevier.
Wapner RJ, et al. Prenatal diagnosis of congenital disorders. In RK Creasy et al. Philadelphia: Saunders Elsevier. Credits Current as of: October 8, Top of the page Next Section: Health Tools. Previous Section: References Top of the page. Current as of: October 8, American College of Obstetricians and Gynecologists , reaffirmed Obstetrics and Gynecology , 1 : Testicle Female Reproductive System Pancreas.
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