Can a dual trigger shot improve IVF birth rates?

This study looked at whether using two hormone injections to trigger ovulation can improve birth rates from assisted reproductive technology (ART) when all embryos are frozen. It found that cycles with trigger injections of both human chorionic gonadotropin (hCG; Pregnyl) and GnRH agonist (Decapeptyl) had higher birth rates.

ART infertility treatments include in vitro fertilization (IVF) and related procedures. The first step of ART is to stimulate the ovaries to grow multiple follicles, which contain the oocytes (eggs). Once the follicles reach the right size, a hormone trigger injection is given. This trigger causes the DNA (genetic material) in each oocyte to divide so it is ready to be fertilized, and also prepares the follicle to release the oocyte.

In a natural menstrual cycle, luteinizing hormone (LH) serves as the trigger. The LH surge lasts 24 to 48 hours. However, an injection of synthetic LH does not last long enough to cause ovulation (release of mature eggs). Instead, ART typically uses an injection of synthetic hCG, which is similar to LH but lasts longer. However, hCG also increases the risk of ovarian hyperstimulation syndrome (OHSS), or the ovaries responding too strongly to stimulation. OHSS carries a risk of serious complications.

Gonadotropin-releasing hormone agonist (GnRH-ag) causes the body to release its own LH. Combining both GnRH-ag and low-dose hGC is known as a dual trigger. This method acts more like the LH surge in a natural menstrual cycle. In a fresh ART cycle, the dual trigger can increase the number of oocytes retrieved. It is not known if a dual trigger improves the outcomes of ART.

This study used records from 4438 cycles of ART. After stimulation of the ovaries, 1445 of the ART cycles used hCG to trigger ovulation. The other 2993 cycles used a dual trigger of both hCG and GnRH agonist. All of the embryos were frozen. The records followed patients until either they gave birth, or all of the embryos were transferred.

There were significantly more oocytes collected in cycles using dual trigger (6.4 vs. 6.0). However, significantly more of the embryos were good-quality in the hCG group (50.1% vs. 47.8%).

After a single frozen embryo transfer (FET), significantly more patients in the dual trigger group became pregnant as confirmed by ultrasound (58.2% vs. 48.2%). There were also more live births per FET in the dual trigger group (31.7% vs. 26.6%).

The researchers also looked at the total birth rate across multiple FETs, using all embryos from a cycle of ART. There was a higher cumulative birth rate in the dual trigger group (50.5% vs. 44.3%).

This study found that patients using a dual trigger of both hCG and GnRH agonist had higher pregnancy and birth rates from ART cycles.

The patients in the two groups had significant differences, including hormone levels and length of infertility. Additional studies are needed where the type of trigger shot is assigned by the researchers.