When you become pregnant, your body releases human chorionic gonadotropin. For this reason, fertility specialists may use HCG along with other hormones and medications to help you become pregnant if you normally cannot. MayoClinic.com states that specialists often use HCG with such drugs as clomiphene and hormones such as follicle-stimulating hormone and human menopausal gonadotropin to help your ovaries release their eggs. Some people also use HCG as part of a weight reduction plan, although according to MayoClinic.com, little evidence exists that HCG actually helps you lose weight.
Fertility
If you take the HCG injections as part of a weight loss plan, it can produce the side effect of making you more susceptible to becoming pregnant. Because this hormone helps you produce an egg for fertilization, you may become pregnant unexpectedly. Check with your doctor before taking the HCG injections for weight loss if you are of childbearing age. She may recommend extra precautions against unwanted pregnancy if you take HCG for weight loss.
Early Puberty
A physician may recommend using HCG in boys if they have a problem with their testicles. In some boys, the testicles do not drop into place as they should. HCG may help the testicles move into their correct location, but it also may induce early puberty, Drugs.com reports. This can cause a boy to become capable of impregnating a female earlier than normal. The boy may experience indications of puberty such as excessive sweating, acne increases, growth of pubic hair and vocal changes. Talk with the boy's doctor as soon as possible if any of these changes begin to occur too early.
High Sperm Count
Men may take HCG to increase their sperm count. This may enable them to help their partners conceive. Although this is an intended effect of HCG in men, it may become a problem. It may fertilize a woman's egg despite contraceptive measures.
OHSS
If you as a woman take HCG injections to become pregnant, the infusion of the hormone into your body may cause you to experience ovarian hyperstimulation syndrome, Drugs.com reports. This very serious medical condition can be fatal. If you recognize any of its symptoms, report it to your doctor immediately. Symptoms may include decreased urination, diarrhea, gaining weight, severe pain in your pelvis, shortness of breath and bodily swelling.


