In this post I will discuss the differences between agonist and antagonist IVF protocols. If you would just like information about dual trigger shots, skip down to the bottom.
Because I had mild OHSS (ovarian hyper stimulation syndrome) with my last egg retrieval (agonist protocol), my IVF clinic wants me to do an antagonist cycle this time. The antagonist cycle should decrease the chance of having OHSS again.
Antagonist vs. Agonist Protocols
What’s the difference between an antagonist and an agonist cycle? From what I understand, it’s all about what drugs are used to prevent ovulation during stimulation and what drug is used for your trigger shot. It has nothing to do with which drugs are used for stimulation.
Typically, agonist protocols are used initially for most patients. Agonist protocols usually use Lupron to prevent ovulation during stimulation and hCG (10,000 IU) to trigger ovulation. Usually this works just fine, but OHSS is prolonged and exacerbated by hCG. So, if you had mild OHSS before the transfer and then get pregnant after your embryo transfer, your hCG will increase even more and your OHSS will get worse. Many clinics will not do the embryo transfer if you have signs of OHSS. They will freeze your embryos and then transfer them after your next period.
As I mentioned, the stimulation drugs are the same during either protocol. For me, I’m doing 300 Gonal F, 75 mg Repronex, and 2.5 mg Saizen. During an antagonist protocol, a drug like Cetrotide is used to prevent ovulation and then Lupron is used for the trigger shot.
I bet your next question is, “Wait a second. I thought you said Lupron is used to prevent ovulation in an agonist cycle. How can it also be used to trigger ovulation?” Great question. Over the long term, Lupron prevents the surge of LH that triggers ovulation. In the short term, Lupron causes that big surge of LH. So, during a typical agonist protocol where Lupron is used daily, there is an LH surge after the first dose, but it doesn’t cause ovulation because the follicles haven’t been stimulated yet. In other words, there aren’t any eggs to release so even though the Lupron causes an LH surge, nothing happens. Of course, during the antagonist protocol, you don’t use Lupron at all until the trigger shot. There are lots of eggs to release so when you do the trigger shot, the LH surge causes the eggs to mature.
When I was first told I would be doing an antagonist cycle this time to prevent OHSS, I was disappointed. Many studies show that antagonist cycles yield fewer eggs and/or fewer mature, high quality eggs. But one or two recent studies show that the yield and quality are similar. Some people think that the reason antagonist cycles don’t always perform as well is because doctors use it less frequently and they aren’t as good at dosing it correctly.
Dual Trigger Shot
As I was doing my research about antagonist protocols, I came across 2 studies that looked at using dual trigger shots for the antagonist cycle. Each one used hCG as the second trigger shot, but at a much lower dose than is typically used. This one used 6,500 IU of hCG and this one used just 1,000 IU and was studying patients who had OHSS on a previous cycle. In both studies the results show a dramatic improvement when a dual trigger was used. There were far more pregnancies when hCG was used in combination with another trigger.
After seeing these two studies, I immediately emailed the links to my Reproductive Endocrinologist and asked about adding hCG to my Lupron trigger. After consulting with his colleagues he agreed that the research looked promising. So, now I will use Lupron and 4,000 IU of hCG for my trigger.
If you had OHSS or your doctor is putting you on an antagonist cycle, be sure to print out these 2 studies and bring them to your next appointment.
For this antagonist cycle, for stimulation I’m using:
And, of course, a dual trigger using:
Can’t get enough? Read about my IVF #3 protocol 🙂