Timing and TTGP

LadyMillil · March 2016

I've noticed a lot of discussion on WTO/TWW recently about how often you need to have sex during FW. I did a medical journal search and found 2 articles that gave numbers for how many times couples had sex during FW and how many of those cycles resulted in pregnancy. Each women provided a daily FMU sample for the researchers to determine O and sex was self reported. Pregnancies resulted only when sex was between -5 and O, so 6 fertile days each cycle.

Sex on -2, -1 or O had the best chance of getting pregnant
Sex ED had a slightly better chance of pregnancy then EOD

Here's the breakdown/summary of the two papers. They give number of cycles recorded and number of pregnancies that occurred and I used that to get the %

1 time - 26% or 27% cycles resulted in pregnancy
2 times - 28% (both studies) cycles resulted in pregnancy
3 times - 35% or 38% cycles resulted in pregnancy
4 times - 36% or 49% cycles resulted in pregnancy
5 times - 26% of 30% cycles resulted in pregnancy
6 times - 10% or 11% cycles resulted in pregnancy

I couldn't find any reason to explain why there was such a huge discrepancy between the studies with 4 times.

khbear · March 2016

Thanks for posting this! This is really interesting. Can you link the studies or cite them? I want to look at them.

I have to wonder about outside factors having an effect on these rates. Three to four times in the FW seems like the magic window, and that's probably less stressful for most couples to achieve, so that's good news. But how does that jive with ED being slightly more effective than EOD?

eta - affect/effect typo, doh!

mrsdee15 · March 2016

Thank you for this!! I'd love to see the studies also.

princesslockness · March 2016

*lurker siggy warning* It seems to me, that depending on the man's ability to replenish his sperm would play a factor in ED vs EOD.

mrsdee15 · March 2016

Kate08Young said:

*lurker siggy warning* It seems to me, that depending on the man's ability to replenish his sperm would play a factor in ED vs EOD.

Yes, thank you, I was thinking something like this but couldn't articulate it.

LadyMillil · March 2016

This one is open access and not super technical

https://www.nejm.org/doi/full/10.1056/NEJM199512073332301#t=articleTop

This one I had to use my institutional subscription to access so I'm not sure if it's available for free anywhere

https://www.ncbi.nlm.nih.gov/pubmed/8068836

LadyMillil · March 2016

Kate08Young said:

*lurker siggy warning* It seems to me, that depending on the man's ability to replenish his sperm would play a factor in ED vs EOD.

I didn't have a chance to look into it, but it seems like there is a generally a lower count on the second day of ejaculating, but if a man has a normal count to begin with this shouldn't have an impact on fertility. They did hypothesize that there may be other biological factors that could impact semen quality and subsequent fertility when ejaculation happens too frequently but didn't detail exact what that was.

LadyMillil · March 2016

khbear said:

Thanks for posting this! This is really interesting. Can you link the studies or cite them? I want to look at them.

I have to wonder about outside factors having an effect on these rates. Three to four times in the FW seems like the magic window, and that's probably less stressful for most couples to achieve, so that's good news. But how does that jive with ED being slightly more effective than EOD?

eta - affect/effect typo, doh!

I'm not great with probability but this is what they said:
ED probability 0.37 (0.25 live birth)
EOD probability 0.33 (0.22 live birth)
No ranges provided

babymish · March 2016

This is really interesting. Crazy how 6 days is so much lower than the others. SO and I would never be able to manage 6 days but this makes me feel better about that!

BigBadWolf12 · March 2016

This just helped me make my decision for aiming for EOD next cycle instead of ED....though I still don't understand how ED is better than EOD but 4 times is better than 6....and I have a math degree.....granted, Stats was my nemesis and I claim it's not real math

haha

pretzel2plus1 · March 2016

Thanks for posting, @ladymillil! Our goal for this cycle was to work on our timing, so this makes me feel more confident in it.

Also, I just love stats! It was my major and my graduate degree, so papers like these get me really excited.

picklesplease · March 2016

Thank you for posting! This will be a big help to DH and I as we gear up for BDing EOD this month.

HurricaneAmelia · March 2016

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

KarliQ88 · March 2016

I'm new so i need to ask... What does ED and EOD stand for?

LadyMillil · March 2016

KarliQ88 said:

I'm new so i need to ask... What does ED and EOD stand for?

Every day and every other day

FloridaStanley · March 2016

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

I have often wondered where this 20% comes from.

LadyMillil · March 2016

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

4 times during one FW had the best odds of pregnancy.
I'm not sure about the research that leads to the 20% comes from, but I've read some things that suggest if you aren't tracking O and just have unprotected sex whenever that your odds are 20%-ish but if you're tracking O and time sex your odds increase because you've got sperm there when the egg appears.

KarliQ88 · March 2016

Thank you @LadyMillil

TheJerilu · March 2016

LadyMillil said:

KarliQ88 said:

I'm new so i need to ask... What does ED and EOD stand for?

Every day and every other day

This was driving me bonkers - in my office, EOD is end of day, so I was trying to fit something morning-related into ED. Early day? My brain was still set in work mode vs baby mode.

Thanks for clarifying! Also, thanks for the super interesting breakdown in the original post.

mrsdee15 · March 2016

LadyMillil said:

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

4 times during one FW had the best odds of pregnancy.
I'm not sure about the research that leads to the 20% comes from, but I've read some things that suggest if you aren't tracking O and just have unprotected sex whenever that your odds are 20%-ish but if you're tracking O and time sex your odds increase because you've got sperm there when the egg appears.

I have such a science boner right now. This makes me weirdly excited for the next cycle.

LadyMillil · March 2016

babymish said:

This is really interesting. Crazy how 6 days is so much lower than the others. SO and I would never be able to manage 6 days but this makes me feel better about that!

In both studies 6 days was a small number of cycles so it could just be low because the sample size is too low.
We could do 6 days in a row on vacation, but in our day to day lives it's difficult, so I was glad to see that missing a day or 2 (or 3) during FW didn't have a huge impact on odds of getting pregnant.

whiska · March 2016

@LadyMillil Whoooo! Thanks for this!

My gripes (not directed at you, of course!!):
1) This data is from the 80s (and the modeling study uses the data from the first). With all the cheaper lab tech now it seems like this would be easy to replicate today. I want moar data!
2) I wish they would run a new study with just nulliparous (only n/3 here) or tease it out from the larger data set because secondary infertility is less common than primary. This would jack up conception rates and skew the appearance of probability for those who are TTC#1 because they've been lumped in with people who are already fertile, if that makes sense?
3) This all but confirms the fact that I'm going to need ART because it seems like we definitely should have conceived on our own by now. Damn. Calling the RE today to make an appointment.

Aurora1973 · March 2016

mrsdee15 said:

*trim*
I have such a science boner right now. This makes me weirdly excited for the next cycle.

Every bit of this is pure awesome.

vintageandrea90 · March 2016

mrsdee15 said:

Kate08Young said:

*lurker siggy warning* It seems to me, that depending on the man's ability to replenish his sperm would play a factor in ED vs EOD.

Yes, thank you, I was thinking something like this but couldn't articulate it.

This pic just made me die laughing. I can't stop looking at it

EML2011 · March 2016

LadyMillil said:

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

4 times during one FW had the best odds of pregnancy.
I'm not sure about the research that leads to the 20% comes from, but I've read some things that suggest if you aren't tracking O and just have unprotected sex whenever that your odds are 20%-ish but if you're tracking O and time sex your odds increase because you've got sperm there when the egg appears.

I don't think this is accurate. When I first started with my current RE, he gave me a sheet that cites the success rates with IUI is 15-20% (or roughly the same as a "normal" couple without any fertility issues) and the success rate for IVF was roughly 40-50% per cycle. I couldn't imagine having sex ED/or sex 4 days of your fertile window is really more successful/as successful as IVF (or even IUI for that matter). I don't know the sources, but I will see if I can dig up the paper when I get home tonight to see if it cites anything.

Kay6519 · March 2016

EML2011 said:

LadyMillil said:

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

4 times during one FW had the best odds of pregnancy.
I'm not sure about the research that leads to the 20% comes from, but I've read some things that suggest if you aren't tracking O and just have unprotected sex whenever that your odds are 20%-ish but if you're tracking O and time sex your odds increase because you've got sperm there when the egg appears.

I don't think this is accurate. When I first started with my current RE, he gave me a sheet that cites the success rates with IUI is 15-20% (or roughly the same as a "normal" couple without any fertility issues) and the success rate for IVF was roughly 40-50% per cycle. I couldn't imagine having sex ED/or sex 4 days of your fertile window is really more successful/as successful as IVF (or even IUI for that matter). I don't know the sources, but I will see if I can dig up the paper when I get home tonight to see if it cites anything.

The normal couple percentage is based on the likelihood of the sperm actually successfully fertilizing the egg as many sperm die in the process. The more sperm there to attempt to fertilize the egg, the better the odds of success. Hence the better chance of success with multiple ejaculations during the fertile period.

The sperm have to burrow through to get to fertilize the egg, and many of them will die off in the process. Basically think of it like tearing down the Berlin Wall. Can one team of men accomplish it? Probably, but it will take them alot longer than several teams of men working to tear down the wall.

EML2011 · March 2016

So you're saying that there's an equal or better chance of getting pregnant from having sex 4 times and IVF? Ok...

whiska · March 2016

This study showed that for couples who had intercourse 4 times during the fertile window (and only 4 times), 36-49% of them conceived. The data is the data; the only way it can be inaccurate is if the original researchers incorrectly transcribed the numbers. Perfect frequency analysis should give us probabilities (so saying you have a 36-49% chance of conceiving if you too bd 4 times during the fw) but this is not a perfect sample. It mixes nulligravida and primi/multigravida, small sample, and we don't know what other methods these women were using to conceive.

And IVF rates given by REs usually come attached to a very specific demographic. Eg age, infertility factor, number of embryos transferred, etc.

Also of note is this is for conception (not live births), as the data is from a study on early pregnancy loss.

sldp123 · March 2016

EML2011 said:

So you're saying that there's an equal or better chance of getting pregnant from having sex 4 times and IVF? Ok...

I could be totally wrong in my thinking, but I find this believable. The study was of couples with no known fertility issues. And I would imagine most/all couples who are doing IUI and IVF have fertility issues that are impacting the success rates.

LadyMillil · March 2016

EML2011 said:

LadyMillil said:

HurricaneAmelia said:

Am I reading this correctly, that people that have sex 4 times in one ovulatory cycle have a 36-49% of getting pregnant in any give cycle? That seems high....I mean, I love it if thats true, but I thought the "norm" was 20% per cycle? Or maybe I am misreading?

4 times during one FW had the best odds of pregnancy.
I'm not sure about the research that leads to the 20% comes from, but I've read some things that suggest if you aren't tracking O and just have unprotected sex whenever that your odds are 20%-ish but if you're tracking O and time sex your odds increase because you've got sperm there when the egg appears.

I don't think this is accurate. When I first started with my current RE, he gave me a sheet that cites the success rates with IUI is 15-20% (or roughly the same as a "normal" couple without any fertility issues) and the success rate for IVF was roughly 40-50% per cycle. I couldn't imagine having sex ED/or sex 4 days of your fertile window is really more successful/as successful as IVF (or even IUI for that matter). I don't know the sources, but I will see if I can dig up the paper when I get home tonight to see if it cites anything.

My RE said that in a healthy couple regular sex with no O tracking has about a 20% success rate, and that tracking O increases your chances but she didn't give us stats on how much
When dealing with IF, IUI can bring your chances up to 15-17% each cycle and IVF has a 40% success rate, whereas IVF with ICSI and PGD brings it to 65%

IUI and IVF are almost always used in couples that have a low chance of getting pregnant naturally. If a healthy couple did IUI their success rate would likely be higher than the typical IUI success rate of 15-20%. DH and I have a 3-5 average each FW on 13 cycles and have no pregnancies. Our odds of getting pregnant naturally are slim because of male and female factor IF. The studies weren't looking at the success rates for pregnancy when IF was involved, they were looking at generally healthy couples, and for generally healthy couples having sex 4 times during FW gave them the best shot at conceiving.

I also want to point out that one study had the 36% success rate for 4x, which seems in line with the 1, 2, 3 times success rates and another study had the 49% success rate, which seemed really high to me.

EML2011 · March 2016

@whiska and @ladymillil I simply meant that I don't believe that this study portrays an accurate picture of the population. No study is perfect and I don't want women using this site to think "wow, I've had sex 4 times in my fertile window for the last x many months and I'm not pregnant so there's obviously something wrong with me." There's a reason why drs (and many women on this site) are constantly reiterating that there is a 15-20% chance of conceiving every month and it can take a healthy couple up to a year to conceive.

While temping is widely accepted on this site as the best way to determine O, it can be misinterpreted. Couples that are getting IUI's are being monitored by ultrasounds and blood work to determine when they will O (and are likely getting drugs administered to make sure they O at the most optimal time for the sperm to meet the egg). I can understand how a couple with infertility undergoing an IUI and a healthy couple temping to hit O have roughly the same changes to get pregnant on any given cycle, but I'm having a hard time understanding that a couple BDing 4 times during FW have the same or better chances as a couple going through IVF. First off, the two leading causes of infertility in couples are male factor and PCOS/anovulatory which are greatly reduced (if not nullified) by IVF. Even when couples don't go forward with additional testing, only the best embryos are chosen for IVF. This minimizes the possibility that egg and sperm quality are the issue. On any given month even a healthy couple can have egg/sperm quality issues. To say that the healthy couple STILL has the same if not a better chance of the embryo implanting is a hard concept for me (especially since the women going through IVF is likely taking meds for implantation). My inability to understand a concept has little baring on it, and since this wasn't the basis of the study it's hard to say for sure. This could also be my attempt to make myself feel better about the looming probability that IVF is in my and DHs very near future, but either way.

@whiska to your comment on demographic, my clinics sheet was broken out by age, diagnosis, # of embryos, single, twin, 2+, live births, etc. I can't find my sheet, but there are similar summaries on the CDCs and RESOLVE websites.

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