BBT - question about accuracy?

[jodee]

Hi, am on the Clomid thread and have been charting my BBT since last June. I see the shift in temp. (since being on clomid), but does anyone know why my temp varies so much when I take two temps back to back?

eg, today I am on CD13 and have missed a clomid cycle, so I need to know if I have ov'd - first temp on waking was 36.35, it bleeped quite quickly,which I have noticed happens sometimes. Second temp immediately after was 36.53, which to me indicates I have ov'd, looking at my charting, so how do I know which temp is the more accurate? Anyone else have this?

My thermometer has started doing this actually. I took 2 readings for exactly the same reason as you, I thought it had beeped far quicker than normal. My second reading was a lot higher. It wasn't around potential OV so it wasn't a worry for me, but if it had been I would have stressed myself out about it!!

What I have started doing is just taking it a few times and recording the highest temp. I make sure I do them all immediately one after the other and don't move or anything.

I am not saying this is necessarily the right thing to do... so if anyone has advice I would be grateful to hear it too Other than buy a new thermometer, cos I have only had this one a few months!!

Hi Ready, funnily enough, this morning I also took a third reading, which was even higher at 36.75! I'm going to go with the middle reading, but I still don't know which is the more accurate. Not sure how long a thermometer is meant to last, I know you can't change the batteries in them, maybe mine's on its last legs!

I agree with Ready on this - my philosophy (perhaps inaccurate!) is that the thermometer can only give a falsely LOW reading, rather than a falsely high one, due to not perhaps being left in long enough.

I was finding my temps so erratic that I have now started taking them vaginally and they are more steady. And yes, I always take the highest of the two readings if I do more than one.

I agree Xcharlotte - I can't see how it could give an incorrect higher reading - jus the lower one. I have been thinking it may be because I move it in my mouth and if it loses contact with the underside of my tongue it may think that is the end of the reading IYSWIM???? So this morning I firmly held it in place touching the sensor part under my tongue and the 2 readings were 0.01 apart, so I will try and do that from now on.

What a palaver!!

Jodee, how long have you had yours?? Mines only 3 months old so it shouldn't be the battery.

As a bit of a geek I have a suggested explanation: The thermometer is cold when you first put it in your mouth, so it cools down that bit of skin a bit. Then on the second reading it's already nicely near body temp, so doesn't take any of the warmth from the skin. On the basis of this argument the second temp should be more accurate.

PS, I could be talking absolute rubbish!

Hi all, your replies make sense, because when I take the first reading what I do is press the button first then put it under my tongue, so tomorrow I will try it the other way around (and try not to jiggle it around too much in my mouth also!)

Ready, I've had mine 7 months now - getting slightly weary of the whole TTC/temping thing, as well tbh. But I'm pretty sure I ov'd this month then, even though I skipped a clomid cycle, so maybe New Years Eve and a bottle of vino did more than see in 2007 !

Jodee, me too, I always press the button first. There we'll both be in the morning, getting that thermometer warm first

Hang in there with the ttc!! I read that it can take 6months to a year and be completely normal. Some people just take longer than others.

My DH reckons his "boys" are just being polite to my eggs!!