What Is an hCG Trigger?

An hCG trigger shot is an injection of human chorionic gonadotropin administered during an IVF cycle to mimic the natural LH surge and induce final oocyte maturation approximately 36 hours before egg retrieval.

Clinical significance

The timing of the hCG trigger is critical. Administered too early, follicles may contain immature oocytes. Administered too late, spontaneous ovulation may occur before retrieval. The trigger is typically given when lead follicles measure 17 to 20 mm on ultrasound.

Common confusion

The hCG trigger is not the same as pregnancy hCG. It is an injection of the same hormone that the body produces in early pregnancy, but its purpose here is to trigger egg maturation, not to indicate pregnancy.

Related reference

/glossary/trigger-shot →/glossary/luteinizing-hormone →/glossary/egg-retrieval →/glossary/dual-trigger →/glossary/ovarian-stimulation →← Back to Glossary Index

Used in

Trigger Shot →LH →Egg Retrieval →Dual Trigger →

This content defines terminology for educational orientation. It does not constitute medical advice.

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