Gonadotropin plus hCG versus hCG alone for egg retrieval

This study looked at the outcomes of a new egg retrieval strategy in women undergoing in-vitro fertilization (IVF). Researchers compared a 2-drug combination ("dual-trigger") to the standard hCG trigger injection.

IVF requires eggs retrieved from the ovaries to be fertilized by sperm in a laboratory dish. To stimulate the final maturation and release of eggs from the ovaries doctors typically give what is called a "trigger" injection about 35 hours before egg retrieval.

Triggering can be achieved using two types of drugs: hCG (human chorionic gonadotropin) or gonadotropin-releasing hormone (GnRH) analogs, such as triptorelin (Trelstar). Typically, a single hCG injection is given, as this drug was found to improve subsequent pregnancy outcomes compared to other gonadotropin drugs. However, hCG administration alone can increase the risk of ovarian hyperstimulation syndrome (OHSS) – a serious medical complication which may require hospitalization. GnRH analog triggering virtually eliminates the risk of OHSS but is not as effective as hCG.

The present study enrolled 376 women undergoing 378 IVF cycles with intracytoplasmatic sperm injection (ICSI: a technique involving the direct injection of sperm into the egg). All participants received the same ovulation stimulating protocol using a drug of the gonadotropin-releasing hormone (GnRH) antagonist class (e.g. Ganirelix, Cetrorelix). Researchers tested the hypothesis that by combining hCG with triptorelin in a "dual trigger" injection, the risk of OHSS could be reduced while maintaining or improving the pregnancy rate achieved with the standard hCG (alone) trigger. Half of the participants received the standard hCG trigger, while the other half received the dual trigger.

Pregnancy rates were found to be higher with the "dual trigger" treatment: 50.7% versus 40.1% with hCG alone. Birth rates were also higher: 41.3% with the "dual trigger" versus 30.4% with the hCG trigger. There was only one case of OHSS which occurred in the group receiving hCG alone.

The "dual trigger" approach, using hCG in combination with a GnRH analog, yielded better pregnancy outcomes and may help reduce the risk of OHSS.

This was a rather small trial – the above results need to be confirmed by larger studies involving more participants and longer follow up.

If you are considering IVF treatments (with or without ICSI) consult with your doctor about the egg retrieval protocols available in your case.