Mercury BBT Thermometre and room temperature... HELP!

I have just wondered this lately, and will try to explain my confusion...

I have been using OPKs and BBT (mercury) thermometre since CD 12. I got a drop in temp on the first day I tested temp (I hadn't earlier as my hubbie wasn't due to fly home until CD14). The OPK I used the day before the low temp, was a negative. I got a near positive OPK on Friday (CD14)... BUT... no temperature dip and not much of a temperature rise on CD15 and 16. My OPK on CD15 and 16 were negative.. I never got a line as dark as the control (but have on all other cycles of using that brand).

I have two questions really:

1. Do you think a near-positive OPK on Friday indicates O on Saturday, even though there's been no temp drop followed by a significant temp rise??? I am REALLY hoping I didn't O on CD13. If I hadn't got that definate negative on CD12, then CD13's temperature looks a lot like my normal O temperature. I have only ovulated once on CD13 in the past 8 months... usually O on CD14-17... but with hubbie away, I had no way of BDing on CD13 just in case. And, could I have ovulated on CD13 when there was not even a faint second line on the OPK on CD12 ??

2. Is it possible that very cold room temperature has affected the quickness of responce on the BBT thermometre to reach my maximum BBT? I'm not being very clear.. but lately, Perth has been very cold, and my thermemtre was left out of it's case by the bed, in about a 5 degree C room. I put the thermemtre in my mouth for the usual time that I always do (about 3-4 minutes). But, the thermometre feels very cold on the outside of the glass... so do I need to leave it in my mouth for longer for it to "warm up" ? If this is the case, this may explain my low-ish temperatures, after my "near positive" OPK (I have recorded it as a positive as it was the darkest the line was compared with other days).

Sorry about the long post. I'm going to do another OPK tomorrow.. but would appreciate any advice ... other cycles are listed on my chart link...

thanks !!! (I am SO OVER my DH working away from home !!!!!)

Sharon I use a mercury BBT thermometer, I always leave it in for 5 mins, and it just sits on my bedside table. I haven't found it's affected by low temps (though have you thought the cold may be affecting your temp?

Re the OPK, it may be that you have (inconveniently from the sounds of it) O'd earlier. Last week I was getting fertile CM and started OPKs, got a total -ve, then very faint line, then Thursday was "near positive" which I recorded as positive - Friday was negative again, got temp rise, and FF says I O'd on Thursday. And last cycle I got my +ve OPK on O day. It just depends on when you pick up the surge - you might get it right near the end. How have your other signs been? Also in your case I guess you haven't had the temp rise to confirm O, so maybe you haven't...

Thanks for your response Sally...

I wonder if I O'd really late at night on Thursday (CD13), and just caught the tail end of the positive OPK on Friday. That might mean I'm still in with a chance if we BD'd friday night, if my eggie survived that long.... i've just checked a few charts out on FF who BD'd a day after O and got a positive HPT.

As for signs now, I had watery CM fri, creamy CM on sat but pretty well dry today. I'm going to check tomorrow's temp and OPK just in case, but yes it's looking like an early O without much OPK warning. Bugger !! Just hope I'm still in with a chance !

Will take temp over 5 mins too and see if that makes a difference.
Thanks !

Sharon, you might have - or even Od on Friday since you had watery CM then (and you have a bigger temp shift between Friday and Saturday)

Hope you caught the egg!

Deni, with so few temperatures at the start of your cycle it would be really difficult to say for sure what's gone on. In that case, I'd be much more inclined to believe the OPKs and assume that they are giving a correct indication of when you ovulated.

A dip before ovulation isn't always going to happen, and sometimes temperatures do rise fairly slowly in the first few days after ovulation. It looks to me like the temperature rise you have seen would be enough to confirm ovulation has taken place, particularly in combination with your other signs. However, FF may not be picking it due to the lack of pre-O temperatures. Give it a few more days and see how your temperature changes. BBT charting is more about identifying patterns over time than the sgnificance of one particular temperature in isolation.

Good luck!

BW

Thanks for your reply girls.. I re-took my temperature after various activities this morning including driving and a power walk, and pulled a 36.05, so I'm concluding that my thermetre is definately faulty !!! I'm disregarding all my temps the last few days. At least that solves the mystery !!!