Behind the scenes on the "Dice" post

I had a bit of fun with my last post, trying to fit the story of the odds of each stage of conception into a Dungeons-and-Dragons type dice game, but I wanted to write out the thinking and the figures behind it too. It's not hugely scientific, of course. I've used as accurate figures as I could find to squeeze into the format, but the idea behind the whole exercise was just to say, basically, most of this is down to chance. You can get everything "right" and still get crappy rolls. You can do everything "wrong" and get perfect 20s every time. And hopefully it helps you see - if you keep running the scenario enough times, most people will eventually get through it successfully even if it takes a while.

Chapter 1: Timing

I picked a title for this which I hope hinted that I feel like it's really the biggest myth in TTC going. This is all you hear - it's all about the timing, it's all about hitting those right days. Pinpointing ovulation is essential! Pee on ALL OF THE STICKS.

Yeah, no. Calm down. It's okay. The average woman's cycle is anywhere from 24 - 32 days long. The fertile period is 5 days regardless of cycle length, which means you're fertile for anywhere between 15-20% of your cycle, or 17-25% if you discount your period days. That means that even if you have sex totally at random, you still have around a 1-in-5 chance of hitting the fertile period totally by accident. In fact, if you're counting "at random" as being "When we feel like it" you probably have a higher chance than 1 in 5, because women produce hormones around ovulation time which not only make them more easily aroused, they also produce extra pheromones which make them more attractive to men. So you're both more likely to get horny around ovulation time anyway.

I added some bonuses for various methods of tracking, I didn't weight them, because they stack. I decided on a max of 15 rolls because some research shows that sperm is stronger when there are 48 hours between ejaculations.

The takeaway: Most couples don't need to time sex or obsess over when they are ovulating. It can be useful to track if your opportunities for having sex are really slim or (obviously) if you're inseminating manually. And of course, it can be fun/interesting to track and it can help to date a pregnancy more accurately, but it's definitely not as essential as people make it out to be. If it's stressing you out, it's okay to stop worrying about it.

Chapter 2: Conception

The second stage is pretty easy to pass. If you reach the right timing, sperm have a fairly unhindered journey to the fallopian tubes. If you have a lot of EWCM/fertile mucous then this is helped. If you don't, you might want to try using sperm-friendly lube. Hence the bonus cancels this penalty.

Chapter 3: Implantation

Arguably the most important stage. It's definitely the hardest to pass. There's not a huge amount you can do to help this, but taking vitamins IS proven to have an effect, so go for it. This is probably the main cause of that overall statistic that only 20-25% of couples actively trying for a baby will get pregnant each cycle they try. If you fail at this one - bad luck! Try again from the start and see how many imaginary cycles it takes.

Chapter 4: Chemical Pregnancy

I deliberated over whether to include this, because there's some question over how often it happens or whether it even really exists or where the line falls between chemical and early miscarriage. But it's so often talked about that I decided it was worth including. I made it totally random because I couldn't find any research or statistics over correlated factors, but the figure is as accurate as I could find.

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So, that's everything. I hope you had fun running the simulation. Let me know if there's anything else you'd include in the calculations!

The Dice of Conception

Are you ready for the adventure of a lifetime?

Are you a little bit (or a lot, we don't mind) geeky or nerdy?

Do you love stats? Do you have a collection of dice?

Then our story into the odds of conception can begin.

Ensure you are sitting comfortably. This campaign should be played as a couple. (Convenient dice rollers can be found online). The game can be repeated for each cycle until success is gained or participants become weary.

If you don't know what this post is, or you want to see the behind-the-scenes first, see this post.

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Chapter 1: The Great Myths of Time

Be afeared, for the timing of conception is fragile and mysterious. Many days must the deed be done to ensure correct positioning of the spermatozoa for successful conception. Missing even one day is a mistake with harsh consequences. You have been warned.

Participants may consult the Oracle of the Female Body or the sacred Texts of Knowing in order to increase their odds.

Roll a d10 for every day you have sex/inseminate this cycle. You may roll up to 15 times.

+1 boost for each type of knowledge of determining fertile time:
BBT monitoring
Cervical fluid monitoring
Cervical position monitoring
Ovulation Tests
Counting days (in any form including charting other signs)
- 1 penalty for the female partner being under severe stress or ill
- 5 penalty, overriding all other bonuses/penalties if anovulatory cycle is confirmed.

To pass: At least one roll with a score of 9 or higher. Multiple passes do not confer extra bonuses.

Chapter 2: A Hostile Journey

Congratulations, faithful child-seekers, for you have passed the first boundary to success. The spermatozoan tribes must now make their way through a hostile environment to the Tunnels of Fallopia, where they may rest a spell. Second, you must achieve conception; the miraculous fusing of sperm and egg. Healthy troops are important, and a clear path can be set with fluids of fertility.

Roll 1 d10 to determine whether the sperm successfully meet with the egg.

-3 penalty for known low sperm count or motility
-1 penalty for low/no egg white cervical mucous
+1 bonus for using sperm-friendly lube

To pass: A score of 3 or higher.

Chapter 3: To Burrow into a Womb

The egg has successfully been fertilised, like the bountiful ground - but the couple may not yet rejoice, for an arable pasture in the womb must now be sought. The health of spermatozoa and ovum are crucial to this stage, so participants with a known sickness in their ancestors must accept a penalty; whereas participants who partake of the sacred herbs will find a clear benefit.

Roll 1 d20 to determine whether implantation is successful.

-3 penalty for each partner being a known carrier of miscarriage or infertility causing genetic disorder
+1 bonus to each partner taking fertility vitamins proven to affect the quality of sperm/eggs.

To pass: A score of 14 or higher.

Chapter 4: The Chemical Boss

The positive omen on the rod of passing water has been received and there is much rejoicing in the couple's household. However, the conception journey is sadly not at a safe end. Mercifully, the monster of chemical origins is weak, and can often be passed without incident.

Roll 1 d6 to determine whether you avoid a chemical pregnancy.

To pass: A score of 2 or higher.



Photo credit: pathlost on Flickr