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What Actually Is That “Trigger Shot”?

You’ve heard it before—the trigger shot. You know that it’s necessary for ovulation during your fertility treatments, but what exactly is it?

The “trigger shot” is a simple name for Human Chorionic Gonadotropin (hCG), which is a pregnancy hormone produced by the placenta that encourages the production of progesterone. It is usually given after gonadotropins are used to spark ovulation during fertility treatments like intrauterine insemination (IUI) or in vitro fertilization (IVF).

So how does it work? It can be helpful to think of hCG as similar to the luteinizing hormone (LH)—in fact, the two are quite similar chemically. Similar to a natural LH surge, a shot of hCG causes the follicle to release its egg. As a result, ovulation usually occurs about 36 hours after the trigger shot is given. So, in order to give procedures like IUI the greatest possibility of success, they are usually scheduled 36 hours following the shot.

For more information on hCG—and other similar options—check out this video where Dr. Elena Yanushpolsky of the Center for Infertility and Reproductive Services at Brigham and Women’s Hospital discusses the pros and cons.

Click image to play.

For more information on hCG and Fertility Drugs, visit!

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