HCG may also be produced unusually by certain tumors, particularly those that originate from an egg or sperm cell (germ cell tumors). Normally, HCG levels are tested in a woman who may have irregular tissue developing in her uterus, a molar pregnancy, or a cancer in the uterus rather than a normal pregnancy. Various HCG examinations may be made after a spontaneous abortion to be sure a molar pregnancy is not present. In a man, HCG levels may be valuated to help observe whether he has cancer of the testes.

Once the fertilized egg embeds, the growing placenta starts discharging HCG into blood. Some HCG also gets into the urine. HCG can be detected in the blood before the first missed menstrual period, as early as six days after implantation.

HCG helps to preserve pregnancy and have an effect on the growth of the fetus. HCG levels increase gradually in the first 14 to 16 weeks following the last menstrual period (LMP), and peak around the 14th week accompanying LMP, and then decline slowly. The quantity that HCG augments early in pregnancy can give information about pregnancy and the health of the baby. HCG can no longer be detected in the blood soon after delivery.

More HCG amount gets discharged in a multiple gestation, for example twins or triplets than in single pregnancy. Less HCG is released, if the fertilized egg implants in a place except the uterus, such as in an oviduct. This is known as an ectopic pregnancy.

On the other hand, HCG injections are used to energize the leydig cells in males to synthesize testosterone. The intratesticular testosterone is needed for spermatogenesis from the sertoli cells. Characteristic denotations for HCG in men comprise hypogonadism and fertility treatment.

HCG is widely used as a parenteral fertility medication instead of luteinizing endocrine. In the company of one or more mature ovarian vesicles, ovulation can be activated by the administration of HCG. As ovulation will happen about 40-45 hours after the injection of HCG, procedures can be scheduled to make the most of this time sequence. Therefore, patients who go through IVF normally get HCG to activate the organic process, but have their eggs repossessed at about 36 hours after inoculation, a few hours before the eggs actually would be discharged from the female internal reproductive organ (ovary).

Routine pregnancy examination is frequently made on a urine sample. The examination does not compute the precise amount of HCG, but it indicates if HCG is above the normal level (nonpregnant level). Home pregnancy examinations that prove HCG in urine are also commonly available.