Lead Follicle 29 mm, am I at risk of ovulating?


#1

I went in for my u/s today on day 8 of stims. The biggest follicle in my left ovary is measuring at 29 mm, there are about 4 others over 15 mm, and the rest are a bunch of 12s, 13s, and 14s. I have been told to continue Follistim and come back tomorrow for an u/s.

I am worried that I might ovulate on my own tonight, even though I am on Lupron (5 units). Am I right to worry? What is the usual scenario with a 29 mm follicle? Has something like this happened to anyone?

Any thoughts would be much appreciated!


#2

I had this same scenario last cycle and actually had two or three at this size. I went on to stim another two days after that point and had 15 eggs retrieved. I wasn’t on Lupron though I was on Ganirelex for the antagonist cycle.


#3

I read somewhere today that Ganirelix is a much more powerful suppressor than Lupron, and is given in my kind of situation. Too late now, but I wonder why I wasn’t given Ganirelix earlier? :frowning: Something very similar happened in my IVF #1 too, only it was 23 mm not 29 mm…


#4

They just work differently.

Preventing ovulation requires preventing GnRH from the hypothalamus from activating the receptors on the pituitary and thus releasing an LH surge.

Ganirelix is an antagonist of GnRH. That means it blocks the action of GnRH. It competitively binds to the same receptor, but does not activate it (no LH surge). With the receptors bound, the GnRH cannot get to it to cause an LH surge.

Lupron is one of the GnRH agonists. That means it acts similarly to GnRH. When Lupron is first taken, it activates the GnRH receptors and causes an immediate LH surge. With daily use, it depletes the pituitary and desensitizes the GnRH receptors. After two weeks on daily Lupron, it’s very unlikely to have an LH surge.

Another GnRH antagonist is Cetrotide.

Other GnRH agonists are Buserelin, Triptorelin, and Synarel.


#5

Ghost, thanks, this is the best explanation I have read anywhere!

I can sleep easy tonight then! :slight_smile:

I have one more question - my RE has asked me to stop Menopur immediately, while continuing Follistim.
Do you think this is because the LH in Menopur could possibly induce ovulation? Can the body be tricked into thinking there is an LH surge?


#6

[quote=icanhazbabies]Ghost, thanks, this is the best explanation I have read anywhere!

I can sleep easy tonight then! :slight_smile:

I have one more question - my RE has asked me to stop Menopur immediately, while continuing Follistim.
Do you think this is because the LH in Menopur could possibly induce ovulation? Can the body be tricked into thinking there is an LH surge?[/quote]
The “LH activity” in menopur is actually a tiny amount of hCG. I think it’s around 20 IU, but I don’t recall for sure. Whatever it is, it’s way too small to mature the oocytes.

hCG and LH activate the same receptors in the ovaries. This has two main effects. One is to mature the oocytes. The other is after ovulation, to keep the follicle (now called a corpus luteum) making hormones, most importantly progesterone and estradiol to prepare the endometrium and sustain the pregnancy. However, there is some debate as to whether a little “LH activity” is needed, beneficial, or harmful in the follicular phase.

In the natural cycle, GnRH from the hypothalamus causes the release of both LH and FSH simultaneously from the pituitary, all through the stimulatory (follicular) phase and during the LH surge, so in the natural case, LH is always present while the follicles develop.

hCG and LH are almost identical molecules with the same biological effect, but the small differences cause LH to have a much shorter half-life than hCG. LH disappears quickly, while hCG lasts and lasts. Biologically, that makes sense.


#7

Interesting. Your post makes me wonder as to how Menopur helps in an IVF cycle. I always thought it was because the LH helped the eggs mature a little every day.

Your post brings up one more point. As you point out, some LH is always present in nature during the follicular phase. Clearly, during stims the natural FSH to LH ratio becomes wildly skewed. Does using Menopur also help because it corrects a little towards normal?

In other news, my 29 mm follicle seems to have shrunk overnight to about 24 mm or so, and I will trigger tonight. So my initial fears have turned out to be unfounded.