Odds by BD day?

fyziksgirl · June 2011

Alright, please don't think I'm crazy. When I first started looking online for TTC stuff, but before I started actually TTC, I came across something on some board (I wasn't a part of any yet) that was a listing of the probability of getting KU based on the day you BD relative to O. Kind of like the list here about the odds of a correct HPT depending on DPO tested, but for chances of getting pregnant based on timing of BD. It was early in my journey and I wasn't obsessive yet, so I didn't write it down.

Since then I have become obsessive but I cannot find anything like it! I remember it had something like the day before O was the highest at about 22%, two days before O was around 20%, day of O was around 12%, and everything else was lower.

Now that I'm obsessive, I really want to know! Especially since my CH just moved and screwed up my perfect BD timing, now I want to know how screwed up it is (because that will really help Embarrassed ) Plus it seems odd that 2 days pre-O would have such good odds.

Anyone seen anything like this? Can you point me to it? I've searched, but maybe my search terms suck - it won't come up!

TIA!

SunTan313 · June 2011

I was looking for this a few months ago... here you go!

fyziksgirl · June 2011

Thanks!! That makes me feel better, I was upset our BD schedule was kind of off with the new CH, but this means we still hit the 28% day Big Smile

ETA: Wow, that does seem really low though with respect to odds on day of ovulation. *cocks head*

staycee · June 2011

based on my chart for #2, we had sex 2 days before O.

However, based on all my u/s's (and I had them every 2 weeks), she dated one day off... meaning then that I actually O'd one day later. Making our sex 3 days before O.

SunTan313 · June 2011

fyziksgirl:

Thanks!! That makes me feel better, I was upset our BD schedule was kind of off with the new CH, but this means we still hit the 28% day

ETA: Wow, that does seem really low though with respect to odds on day of ovulation. *cocks head*

I know! It's kinda odd.. and this is just one website, so it could be off a little. But, it is definitely interesting! Hitting the 28% day is great

SunTan313 · June 2011

fyziksgirl:
Thanks!! That makes me feel better, I was upset our BD schedule was kind of off with the new CH, but this means we still hit the 28% day
ETA: Wow, that does seem really low though with respect to odds on day of ovulation. *cocks head*

HydeBride · June 2011

This is the one I'm familiar with:

Chances of Pregnancy by Day of Intercourse

-5 days before ov = 0%

-4 days before ov = 11%

-3 days before ov =15%

-2 days before ov = 20%

-1 day before ov = 26%

day of ov = 15%

1 day after ov = 9 %

2 days after ov = 5%

3 days after ov = 0%

Squishy622 · June 2011

Someone please correct me if I'm wrong, but I believe these odds only apply if you have EWCM (and possibly watery cm) around the time that you're fertile. Some women don't, and that makes it much harder for the sperm to survive in the days before ovulation.

fyziksgirl · June 2011

Using the wording from the chart above, I also found these numbers:

Chances of Pregnancy by Day of Intercourse

-5 days before ov = 0%

-4 days before ov = 11%

-3 days before ov =15%

-2 days before ov = 20%

-1 day before ov = 26%

day of ov = 15%

1 day after ov = 9 %

2 days after ov = 5%

3 days after ov = 0%

In this one I find it odd how high the odds are 2 days after ov! I guess it just depends on the study. The only thing consistent seems to be that the two days before are your best bets!

fyziksgirl · June 2011

fyziksgirl:
Using the wording from the chart above, I also found these numbers:
Chances of Pregnancy by Day of Intercourse

-5 days before ov = 0%

-4 days before ov = 11%

-3 days before ov =15%

-2 days before ov = 20%

-1 day before ov = 26%

day of ov = 15%

1 day after ov = 9 %

2 days after ov = 5%

3 days after ov = 0%
In this one I find it odd how high the odds are 2 days after ov! I guess it just depends on the study. The only thing consistent seems to be that the two days before are your best bets!

Oops, sorry, someone else just posted that one.

As for needing EWCM, that makes sense, it seems anything that could hurt fertility is going to bring the odds down. I'd love to know more about how these studies were carried out, but that seems truly impossible to find!

TrendyTina · June 2011

SunTan313:
I was looking for this a few months ago... here you go!

Thank you for posting this! This is very helpful.

MrsDizzyku · June 2011

Squishy622:
Someone please correct me if I'm wrong, but I believe these odds only apply if you have EWCM (and possibly watery cm) around the time that you're fertile. Some women don't, and that makes it much harder for the sperm to survive in the days before ovulation.

Sounds right to me Squish

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