Information on the HCG Injection

By Diane Ursu

Infertility is the inability to get pregnant after frequently trying for 12 months. Without medical assistance, however, some women may take as long as 36 months to get pregnant. One option is to seek medical treatment by seeing a gynecologist or an infertility specialist who will test hormone levels to determine which treatments are necessary, including the HCG injection.


The pituitary gland releases the follicle-stimulating hormone (FSH), which stimulates a follicle on one of the ovaries to mature and release an egg. The release of the egg is called ovulation, which is the time when a woman is fertile. The egg is swept into the fallopian tube, where fertilization takes place. The fertilized egg travels to the uterus and implants within the inner uterine lining, called the endometrium, producing a pregnancy.


Women seeking fertility treatment will undergo hormonal testing. The menstrual cycle is complex and requires the right amount of hormone production at the right time. Hormones control the maturation and release of the egg, and the ability of the body to sustain a pregnancy. Many women experiencing infertility need treatment that will promote proper egg maturation and ovulation. HCG injections are used to stimulate ovulation after other hormone treatments are used to grow follicles.


HCG, or human chorionic gonadotropin, is one of the hormones responsible for triggering the release of an egg, or ovulation. FSH stimulates a follicle to grow and mature in preparation for ovulation, while human menopausal gonadotropin (hMG) is a medication that is used to stimulate ovulation, like HCG. Women undergoing fertility treatment many use HCG, FSH and hMG together.


The timing of HCG administration is critical in fertility treatment. Clomiphene (Clomid) is often used to stimulate follicular growth in the ovaries. Ultrasound imaging is then used to determine whether the follicles are large enough -- the goal is 18 to 20 mm -- and whether there are too many follicles of the desired size. When the desired number of follicles, usually two to four, reaches the desired size, the HCG injection is used to stimulate the follicles to release their eggs.

Side Effects

HCG injections are associated with an increased occurrence of multiple pregnancies (twins or triplets). Women using the HCG injection may also experience symptoms such as abdominal and pelvic discomfort, bloating, fatigue, headache, irritability, sore breasts, and water retention.

About the Author

Diane Ursu has an associate's degree in diagnostic medical sonography and worked as a sonographer for five years. She is also a mountain biking advocate and has sat on the board of directors for multiple non-profit organizations.