Coin Flip

August 20, 2008

Murgdan from Conceive This! recently posted about TTC as a game of dice. She quoted her GYN, who told her:

Remember that each cycle, even if you have perfect timing, perfect mucous, a perfect egg, you still only have a 20% chance of getting pregnant. It’s kind of like dice. One person may roll a dice and get a 6 on the first try. The next person may roll the same dice 12 times and never get a 6.

I have been thinking about my current efforts to conceive as a coin flip rather than a roll of the dice. Regular TTC odds are closer to the 1 out of 6 you get with dice, but my current odds with each IVF cycle are 50/50, just like a coin.

After IVF #1 resulted in BFP followed by BFN, DH was understandably disappointed. I told him how I was thinking about the situation, with some help from my old friend binomial probability.

With a single coin flip the odds are 50/50. But it’s possible that you can flip several times and still not get Tails. Sometimes you get Tails the first try. Usually you will get it the first few tries. But sometimes it takes a bunch of flips before you finally get Tails. Some doctors stop doing IVF after 3 or so tries because your odds are low if you’ve failed three tries, but based on probability, there’s a 1 in 8 chance that all 3 IVFs would fail. Those odds aren’t bad — those odds aren’t far off from the odds of conceiving that we had during the IUI cycles. If the odds of each IVF cycle really are 50/50, it’s likely that you’ll have success if you keep flipping a few more times. By the time you get to 7 tries, it’s less than 1% that you’ll have all 7 fail. You just have to keep flipping the coin.

It seemed to really help DH. Hooray for me, for using math to solve non-math problems. Hooray!

Not so fast. I did leave a couple of things out.

First, it’s $10,000 every time. That’s no chump change.

Second, this all assumes that the true probability is 50/50. My RE says that it is 50/50 for me, but that doesn’t mean that it’s the true probability. If a coin is loaded, the probability can change drastically. If you have a two-headed coin (yes yes, I know, like Two-Face in Batman — I can be more than one kind of geek in the same post!) you can flip a thousand times (or whatever the number of cycles would be if you did IVF every cycle for the rest of your life) and you will never ever hit Tails.

Here’s the thing. It takes a lot of flips before you start to realize that the coin may be two-headed. Harvey Dent flipped his coin many times before anyone ever figured out that it would always turn out heads, that he “made his own luck.” It took me an awful lot of unassisted cycles to finally say, this isn’t working. And then, after my first M/C and the hiatus and then subsequently letting nature take its course, it again took an awful lot of cycles before I finally said, this isn’t ever going to work without some major intervention. I’m slow to catch on sometimes, because I get so wrapped up in each coin flip (or roll of the die, or roll of the D&D 20-sided die — that’s three forms of geekiness in one post, if you’re keeping track) that I fail to see the whole picture.

For now, I’ll keep flipping the coin, assuming that it’s a fair coin. Though, if infertility has taught me anything, it’s that you can’t count on anything to be fair. But, if I keep trying, the odds are in my favor. Is Lady Luck?

24 Responses to “Coin Flip”

  1. Murgdan Says:

    Another excellent analogy! I did very well in Statistics, but it was more fun when coin-flipping and dice-rolling had nothing to do with reproduction. Or maybe this would be fun if I’d have been that girl who hit it right the first try…

  2. Danielle Says:

    But, if I keep trying, the odds are in my favor. Is Lady Luck? <—-my favorite part! I believe she is here somewhere. Why not? If we don’t believe, then what do we have to look forward to? That’s how I look at it, most of the time it works ;o)

  3. Raggedy Ann Says:

    Thank you so much for the comment you left on my blog. The one thing that I hate most about infertility is that luck plays such an important part in it. You keep rolling that die & flipping that coin…one day Lady Luck will show her face. And it’ll be when you least expect it.


  4. Ophelia Says:

    After all those years as a kid sitting in Math class wondering “Why would I need to learn this? When am I ever going to use Math equations in real life?” I finally have my answer!

    (Hailing from IComLeaveWe!)

  5. Kristin Says:

    I hated statistics but, if I had a teacher like you, it might not have been so bad. I love that someone else is showing their geekiness (cause my hubby and I are major geeks).

  6. Sassy Says:

    That was a significant part of the reason we stopped treatment, doctors would say that I’d conceive in no time but the stats said they were telling lies. Now we’re trying a different kind of gamble with adoption which means waiting up to three years to see if the coin will say approved or denied, and that’s before we wait for a match. It all does my head in sometimes.

  7. Jessica Says:

    I’m hoping that luck will be a lady for me this cycle.
    Hopefully she’s with you too 🙂


  8. Jill Says:

    Happy ICLW! I really hope this all works out for you!

  9. Adena Says:

    Thanks for visiting my blog as part of IComLeavWe! I hope you get to your goal of the “baby smiling in the back seat.”

  10. Nity Says:

    You are on fire with your stats! First in my comment and then in this post. Wow! I love the flip of a coin analogy.

  11. nh Says:

    I love that explanation – I hope that your coin is two sided and that you get that lucky flip that you really want.


  12. Deborah Says:

    Great analogy. But I tend to be the unluckiest person I know. Someone glued that damn dice to the table-LOL. I hope my luck will finally change this IVF round. Best wishes to you!


  13. Shaz Says:

    Indeed, what, when it comes to Infertility is in fact fair? Not a whole luck. All the best, I hope your next coin flip lands the way you want it to.

  14. Stephanie Says:

    The whole notion of 50/50 just seems easier for me to wrap my head around than the whole 1 in # concept.

    Good luck with your next flip of the coin.

  15. g Says:

    May luck be in your corner and all of ours!! i hate teh stats they sux! probably cause i am on the bad end of it.. hopefully that is changing!

    Best of “luck” to you!! 😉


  16. Lisa Says:

    Thanks for the thoughts! I think you, binomial probability, and my DH would get along famously (I’d get along w/the group too, but DH is pretty cozy w/all the ttc-related stats and how to work ’em.)

  17. emilythehopeless Says:

    great post.. i’m going to have my DH read it!


  18. Lisa Says:

    That’s the thing with statistics – we can always find a way to use them to our advantage! And, if only to make us feel good, that’s reason enough to do math!!

  19. Jenn Says:

    (here from ICLW) Stastics don’t mean much when you keep landing on the wrong side of them. Got everything crossed for you.

  20. InDueTime Says:

    Coming over from ICLW…

    Hoping it’s nothing but Lady Luck for you!!

  21. MamaSoon Says:

    I love this analogy. I am a logical person. And this offers me a lot of comfort. I wish you the very best in your cycle. ICLW

  22. Bonnie Says:

    Thanks for visiting my blog. I really like your dice/coin analogy. I wish I knew my probability. My RE said I had a 90% chance of getting pregnant in 3 IUIs. I am two negative IUIs down, and I can’t figure out my probability for this next cycle. Math is not my forte.

  23. Carbon Says:

    Hooray for geekiness! I’m going to roll my 2d6 and cast a spell of sticking on your next BFP.

    An ICLW Wanderer

  24. kirke Says:

    Math has never been my strong suite, but I love the analogy you presented. For some reason, it makes me feel better to hear that everyone has only a 20 percent chance of conceiving each month.

    Visiting from ICLW.

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