Introduction
When it comes to pregnancy, the body has its own way of letting you know it's pregnant through a hormone called human chorionic gonadotropin, or hCG. When an egg become fertilized in the body, the developing blastocyst starts producing the hCG hormone. Within a few days of implantation of the embryo on the uterus walls, hCG production begins to significantly increase. This sets off the many body changes needed for a fetus to develop into a fully formed baby.
Primary Function
The primary function of hCG largely revolves around the corpus luteum. The corpus luteum is the remained of the follicle that the egg first bursts out of. The job of the corpus luteum is to produce the hormones estrogen and progesterone, which helps the uterine lining maintain the right atmosphere for the developing fetus, and also helps prevent menstruation from occurring. Once the placenta has fully developed, the corpus luteum will let the placenta take over most of the estrogen and progesterone production; However, hCG will still be present, just in smaller amounts.
Testing
The presence of human chorionic gonadotropin is the main factor in testing for pregnancy for both at-home pregnancy tests and laboratory pregnancy tests. These test come in two main forms, qualitative hCG test, and quantitative hCG tests. Qualitative tests only look for the presence of hCG to determine pregnancy. Most take home pregnancy tests are qualitative. Quantitative tests not only measure whether or not hCG is present, they also measure exactly how much hCG is in the bloodstream. This gives a more accurate result on whether or not you are pregnant, as well as an estimate of how far along you are in the pregnancy.
Levels
Monitoring your hCG levels can tell you several things. For example, when hCG levels get too high, this could signal a multiple pregnancy (such as twins), or could also be a sign of problems with the placenta, such as with a molar pregnancy. Too low of hCG levels could signal a miscarriage, or could just mean that your doctor miscalculated your pregnancy date. Unless a complication arises with the pregnancy, most women will not need regular hCG testing other than originally determining pregnancy.
