Accuracy of BBT confirmed ovulation

[mugster]

So, awhile ago, somebody mentioned that they had a clear BBT shift and then an ultrasound that showed they had NOT yet ovulated. I was curious as to why that might be, since we use the temp shift as a gold standard (for confirming ovulation) around these parts. I went digging and found this paper, which surveys relevant studies:

link

Of particular interest to me, was the finding that “BBT-determined ovulation days were scattered from day –1 to day +3 of actual ovulation,”

If I parse that correctly, that means if you actually ovulate on cd 14, you could see a shift anytime from cd 13 - cd 17. Obviously if you combine with secondary signs sometimes things become more clear. But my takeaway is: 1. What seems like a short lp or an early turning of a test might not actually be ... 2. Perhaps be more expansive with your fertile window. 

I just thought I'd share, because people frequently worry about conflicting signs and treat their O date like it is a sure thing.

Also, according to the same article, in an earlier study "Only 22.1% of the 77 cycles that were determined by endocrine profiles to be
ovulatory and to have adequate luteal phases demonstrated an interpretable shift," suggesting many more cycles may be ovulatory than appear to be.

Anyway, obviously BBT give us some idea what is going on, but the researcher in me just wanted to complicate things a bit and share what I found.

[treble]

Can I see your chart? I'd like to see if maybe there was another way of reading it and it didn't show confirmed ovulation.

[heatherj9603]

The temp spike could have been her getting sick, had bad sleeping patterns, etc. I'm sure it happens, but bbt is a pretty sure Fire way of confirming ovulation. Sounds like she was the exception and not the rule.

[mugster]

Feb 26, 2015 12:13:19 GMT -5 treble said:

Can I see your chart? I'd like to see if maybe there was another way of reading it and it didn't show confirmed ovulation.

Oh, I don't have a question about my chart. I wasn't even doing the research because of my chart. I was just curious if there were studies about how well bbt confirmed ovulation days matched up with ultrasound confirmed ovulation days, and thought it interesting that the research suggests that the thermal shift could happen before or several days after ovulation. I guess, I meant this more as a PSA, since some people seem to drive themselves nuts over pinning down their ovulation dates precisely when it is clear that they have ovulated, but not clear when...

ETA: Here is my utterly non-wonky chart: My Ovulation Chart

[mugster]

Feb 26, 2015 12:19:16 GMT -5 heatherj9603 said:

The temp spike could have been her getting sick, had bad sleeping patterns, etc. I'm sure it happens, but bbt is a pretty sure Fire way of confirming ovulation. Sounds like she was the exception and not the rule.

Sure, but the most positive study that is mentioned suggested "that BBT agreed with ultrasonography in 74% of the cases." Which means, it doesn't in 26% of cases, which is still a large number.

[morwen]

Yeah I think i saw that article before, maybe someone who's volunteered for writing can do up an article on this. Assuming the study is scientifically sound my take away is always start having sex a week before expected O and keep going until your CHs confirm ( if FF says your 3 dpo you should at least be 2 DPO)

I'd be curious how much OPKs would help since they still give you a window, not an exact timeframe. Not that I personally use them but if O is predicted more accurately with both and what the differential is

[becwheat]

BBT has a lot of room for user error. It is very hard for any clinical trial to control all the variables that go with a woman charting her BBT.

Even the most experienced charter makes mistakes. I would have to see how the study was designed and what the protocol looked like.

[mugster]

Feb 26, 2015 12:30:21 GMT -5 morwen said:

Yeah I think i saw that article before, maybe someone who's volunteered for writing can do up an article on this. Assuming the study is scientifically sound my take away is always start having sex a week before expected O and keep going until your CHs confirm ( if FF says your 3 dpo you should at least be 2 DPO)

I'd be curious how much OPKs would help since they still give you a window, not an exact timeframe. Not that I personally use them but if O is predicted more accurately with both and what the differential is

This was basically my takeaway.

[longhornwino0907]

I know I mentioned this with my first IUI last month. I had a +OPK and a temp shift that had FF saying I ovulated on CD11. I went in on CD12 for an ultrasound to see if I had ovulated because it was so early, and I hadn't I had a follie measuring at 24, so we went ahead with the IUI, but yeah, FF was wrong and I had to override it. Also, this time, my temp shift has FF thinking I ovulated on CD12. I called my RE to report a + OPK on CD12 and asked about the temp shift, and they said they don't rely so much on temps when it comes to medicated (Femara only, in my case) IF treatment cycles. So I'm really torn on what I think about temps these days. I still do it, but I'm not sure how much stock I should put in them because of my experiences the last two months.

[anonymouseliza]

Well, charts are a tool and can be mistaken. But they give strong indicators and guidelines and remain the cheapest, easiest way to track/confirm ovulation that we really have (particularly bbt combined with cm and cp tracking).

It's interesting though.

[becwheat]

To clarify I have had too much experience with "simple" protocols being a nightmare in regards to compliance for many of my patients. So, I can totally see women in a trial who may be new to charting not recording accurate data.

eta wrong word

[joy]

Feb 26, 2015 12:31:55 GMT -5 becwheat said:

BBT has a lot of room for user error. It is very hard for any clinical trial to control all the variables that go with a woman charting her BBT.

Even the most experienced charter makes mistakes. I would have to see how the study was designed and what the protocol looked like.

This is 100% where I am.

[pismoduo]

Feb 26, 2015 12:34:06 GMT -5 longhornwino0907 said:

I know I mentioned this with my first IUI last month. I had a +OPK and a temp shift that had FF saying I ovulated on CD11. I went in on CD12 for an ultrasound to see if I had ovulated because it was so early, and I hadn't I had a follie measuring at 24, so we went ahead with the IUI, but yeah, FF was wrong and I had to override it. Also, this time, my temp shift has FF thinking I ovulated on CD12. I called my RE to report a + OPK on CD12 and asked about the temp shift, and they said they don't rely so much on temps when it comes to medicated (Femara only, in my case) IF treatment cycles. So I'm really torn on what I think about temps these days. I still do it, but I'm not sure how much stock I should put in them because of my experiences the last two months.

This is an interesting point, and I think it lends itself very well to what becwheat was saying. It seems likely to me that many women who are having ovulation confirmed by ultrasound would be doing so because they are doing a medicated IVF treatment, where BBT might not be so reliable. So the question really becomes how the study was done and what factors the researchers were controlling for.

[mugster]

Feb 26, 2015 12:37:15 GMT -5 joy said:

Feb 26, 2015 12:31:55 GMT -5 becwheat said:

BBT has a lot of room for user error. It is very hard for any clinical trial to control all the variables that go with a woman charting her BBT.

Even the most experienced charter makes mistakes. I would have to see how the study was designed and what the protocol looked like.

This is 100% where I am.

Good point. The article linked is a survey of studies, some as old as 1980 and none more recent than 2005. I'm sure that each study had different protocols and all might be a disaster.

[joy]

Feb 26, 2015 12:40:47 GMT -5 mugster said:

Feb 26, 2015 12:37:15 GMT -5 joy said:

This is 100% where I am.

Good point. The article linked is a survey of studies, some as old as 1980 and none more recent than 2005. I'm sure that each study had different protocols and all might be a disaster.

I think the general message is good: basal body charts can be wrong.  But, I also don't think you should throw the baby out with the bathwater.  It still has so many pluses even with its minuses.  And it's good to be aware that basal body temping isn't 100% right 100% of the time.

[ghostmonkey]

I don't think anyone would claim they are 100%. It gives you a narrowed down window and a day that is likely. And it's part of why you 1) shouldn't use temping with medicated cyclees (IIRC they rarely line up perfectly) and 2) shouldn't freak out about your LP shifting a couple days in either direction.

It's more of a "you ovulated on this day-ish". Also why FF counts O+1 in your fertile window. There's a lot of room for user error.

[mugster]

Lost in all the text in my original post may have been my takeaways:

"But my takeaway is: 1. What seems like a short lp or an early turning of a test might not actually be ... 2. Perhaps be more expansive with your fertile window."

I'm certainly not advocating giving up on BBT...

[cateyes]

Feb 26, 2015 12:44:14 GMT -5 joy said:

Feb 26, 2015 12:40:47 GMT -5 mugster said:

Good point. The article linked is a survey of studies, some as old as 1980 and none more recent than 2005. I'm sure that each study had different protocols and all might be a disaster.

I think the general message is good: basal body charts can be wrong.  But, I also don't think you should throw the baby out with the bathwater.  It still has so many pluses even with its minuses.  And it's good to be aware that basal body temping isn't 100% right 100% of the time.

I think another thing is that people place to much faith in what a program like FF tells them. It is a computer and can be wrong too. As you learn about your body, your cycles, and your other signs-you can do FF's job better then it can. So it may say CD 14 but you can look at all your signs and history and know that maybe CD 15 or 16 is the better bet. It is a computer, not the end all be all. 

[frankenboom]

Feb 26, 2015 12:45:45 GMT -5 ghostmonkey said:

I don't think anyone would claim they are 100%. It gives you a narrowed down window and a day that is likely. And it's part of why you 1) shouldn't use temping with medicated cyclees (IIRC they rarely line up perfectly) and 2) shouldn't freak out about your LP shifting a couple days in either direction.

It's more of a "you ovulated on this day-ish". Also why FF counts O+1 in your fertile window. There's a lot of room for user error.

Question - and I'm only quoting you because your explanation is further down...do docs not recommend temping with medicated cycles because the medicine may affect BBT? Or is there another reason? Just asking cause I'm curious.

[moutonrouge]

This was an interesting read - thanks mugster ! I can see the compliance error being an issue, but it seems like that would replicate in the rest of the population as well to some extent. I'd also love to know how they designed the study, selection, etc.

[joy]

Feb 26, 2015 12:46:12 GMT -5 mugster said:

Lost in all the text in my original post may have been my takeaways:

"But my takeaway is: 1. What seems like a short lp or an early turning of a test might not actually be ... 2. Perhaps be more expansive with your fertile window."

I'm certainly not advocating giving up on BBT...

Ha - no, I'm sorry.  I didn't mean to suggest you did.

I was just worried that someone might read this and think "Ah, so basal body temping has no purpose and I'll just stop!"  That was my concern.  So, I put it out there that no, no, that shouldn't be the take away here.  I didn't mean you said that.

I'm failing with words today.

[ghostmonkey]

Feb 26, 2015 13:10:21 GMT -5 frankenboom said:

Feb 26, 2015 12:45:45 GMT -5 ghostmonkey said:

I don't think anyone would claim they are 100%. It gives you a narrowed down window and a day that is likely. And it's part of why you 1) shouldn't use temping with medicated cyclees (IIRC they rarely line up perfectly) and 2) shouldn't freak out about your LP shifting a couple days in either direction.

It's more of a "you ovulated on this day-ish". Also why FF counts O+1 in your fertile window. There's a lot of room for user error.

Question - and I'm only quoting you because your explanation is further down...do docs not recommend temping with medicated cycles because the medicine may affect BBT? Or is there another reason? Just asking cause I'm curious.

That is part of it as well. There's already room for error and add in meds that can affect temps, and it cal lead to unnecessary frustration. The u/s trumps the chart anyway, so it's not necessary.

[frankenboom]

Feb 26, 2015 13:14:41 GMT -5 ghostmonkey said:

Feb 26, 2015 13:10:21 GMT -5 frankenboom said:

Question - and I'm only quoting you because your explanation is further down...do docs not recommend temping with medicated cycles because the medicine may affect BBT? Or is there another reason? Just asking cause I'm curious.

That is part of it as well. There's already room for error and add in meds that can affect temps, and it cal lead to unnecessary frustration. The u/s trumps the chart anyway, so it's not necessary.

Gotcha - just trying to understand how it all works. It's very interesting to me.

[anonymouseliza]

One of the things that hits me is how often I see discussion about non-ideal temping (not temping at the same time everyday, not getting three hours of sleep, etc.) and we always say you'll have to check and see. I know people do things to leave their charts looking neat that really could affect temp (not changing temp time when temping earlier or later is one example I saw very recently). That all affects the accuracy. Even in a controlled study there is margin for human error because maximizing the controls so that only effect on temperature is the body is nearly impossible. Even where in your mouth you put the thermometer can affect the reading by tenths of a degree, which could result in crosshairs (or not) when you are talking about charting.

Still, as has been noted, pluses definitely outweigh the minuses for quick, easy info about the likelihood of ovulation and timing of sex and related things like lp length, spotting at odd times and such-like.

[Unknown]

Feb 26, 2015 13:10:21 GMT -5 frankenboom said:

Feb 26, 2015 12:45:45 GMT -5 ghostmonkey said:

I don't think anyone would claim they are 100%. It gives you a narrowed down window and a day that is likely. And it's part of why you 1) shouldn't use temping with medicated cyclees (IIRC they rarely line up perfectly) and 2) shouldn't freak out about your LP shifting a couple days in either direction.

It's more of a "you ovulated on this day-ish". Also why FF counts O+1 in your fertile window. There's a lot of room for user error.

Question - and I'm only quoting you because your explanation is further down...do docs not recommend temping with medicated cycles because the medicine may affect BBT? Or is there another reason? Just asking cause I'm curious.

Another reason is because you are being monitored by bloodwork and u/s, and those are better indicators of ovulation.

ETA: I see GM already answered this, so sorry for repeating.