A “trigger shot” is a medication used in fertility treatments to precisely time ovulation. Accurate timing is crucial for increasing the chances of conception in assisted reproductive technologies. This article explains the trigger shot’s role, its typical ovulation timeline, and its significance in various fertility procedures.
Understanding the Trigger Shot
A trigger shot is an injectable medication that induces the final maturation and release of eggs from the ovaries. The most common type contains human chorionic gonadotropin (hCG), a hormone mimicking the natural luteinizing hormone (LH) surge that occurs just before ovulation. This surge signals mature follicles to rupture and release their eggs.
Some trigger shots use a GnRH agonist, such as Lupron, which stimulates the body’s own natural LH surge. The trigger shot’s primary function in fertility treatments is to provide a controlled and predictable signal for eggs to complete development and prepare for release. This signal is important for coordinating subsequent fertility procedures.
The Ovulation Timeline
Ovulation generally occurs about 36 hours after a trigger shot. While 36 hours is the most common timeframe, variability exists, with ovulation sometimes happening between 34 and 42 hours post-injection. This predictable timing makes trigger shots widely used in fertility treatments.
Individual response to the medication and the specific treatment protocol influence exact timing. For instance, in an IVF cycle, egg retrieval is scheduled 36 to 40 hours after the trigger shot to collect eggs before natural ovulation. The trigger shot ensures a synchronized event, allowing specialists to plan procedures precisely.
Precision for Conception
Precise ovulation timing after a trigger shot is important for various fertility treatments. For timed intercourse, individuals are advised to have sexual intercourse around the predicted ovulation window, often the night of the injection and again 24 to 36 hours later. This ensures sperm are available when the egg is released for fertilization.
For intrauterine insemination (IUI), the procedure is typically scheduled 24 to 36 hours after the trigger shot to coincide with ovulation. This direct placement of sperm into the uterus during the optimal window increases conception likelihood. In in vitro fertilization (IVF), the trigger shot prepares eggs for retrieval, timed precisely before natural ovulation to collect mature eggs. This coordination is key to successful assisted reproductive procedures.
After the Shot: What to Expect
After a trigger shot, individuals may experience mild side effects. Common symptoms include localized pain or tenderness at the injection site, bloating, abdominal or pelvic discomfort, headaches, cramping, or breast tenderness. These sensations relate to hormonal changes and ovarian activity induced by the shot.
Healthcare providers provide specific instructions for next steps, such as timed intercourse or IUI timing. For IVF cycles, egg retrieval is planned within the precise 36-hour window. Medical professionals monitor for ovulation confirmation using blood tests for progesterone levels or ultrasound scans.
When Ovulation Deviates
While the trigger shot is designed to reliably induce ovulation within a specific timeframe, there are rare instances when ovulation might not occur as expected. Deviations can include individual biological variations, improper administration of the shot, or a lack of adequate response to the medication. If the trigger shot is taken too early, it could lead to premature ovulation, which can affect the timing of subsequent fertility procedures.
If an individual suspects that ovulation did not occur as anticipated, it is important to contact their fertility clinic immediately. Medical professionals can assess the situation through blood tests to check hormone levels or ultrasound monitoring to confirm follicular rupture. While a missed or delayed trigger shot can complicate a cycle, medical oversight can often help manage the situation, potentially by adjusting the treatment plan or rescheduling procedures.