Ok, so I did a bad thing during my first 2WW. I opened the Brill book. Even though I’d read the thing cover to cover already. I flipped back to the section on charting and BBT. And what I found has FREAKED ME OUT.
“We rarely see conception occur in people who have a BBT lower than 97.3.” p 236
I have always had a lower than average body temperature. I almost never pass 99 when I’m sick. In the months that I have been charting my BBT, prior to O is usually in the 96’s After O it has never gone above 98.3. Coverline is typically 97.1. Brill seems to suggest that this indicates a thyroid problem. The paper charts at the back of the Weschler book don’t even go below 97. I actually had a PCP mention a concern about my thyroid about 7 years ago and at that time I had all the blood tests done and everything checked out normal. But still, it’s FREAKING ME OUT.
So, a question for all of you that track your BBT. What is usually your lowest, highest, and coverline temp? If you do not temp orally, please indicate that as well.
Oh, and for those following along at home, I am 5DPO and could not feel more normal.

I had the same panic — my temperature is also always below normal, and when temping orally, rarely went above 97. (between 96 and 96.5 in first half, between 96.5 and 97 in second half.)
Obviously, I haven’t gotten pregnant yet, but here’s what I’ve been told:
-It’s not actually the temperature that counts, but that it raises and sustains the raise after ovulation.
-If you have low body temp, yeah, it could mean a thyroid problem (which I think really is what Brill WAS getting at, from my reads) and as long as you get that checked out, don’t worry about it. The Doc had them check my thyroid levels in the blood draw, and they came back normal.
-This is why I started temping Down There. Well, that, and my oral temps were all sorts of rocky. Up and down and up and down (I’m a mouth breather at night). The benefit to temping Down There? You see that your core temperature is NOT necessarily the same as your oral temperature, and it relieved me to see that I was not “too cold to sustain life,” as was my irrational fear for quite some time.
By: N on June 19, 2008
at 8:08 am
I was just going to comment that N had had a similar situation and starting doing vaginal temps, but I see she commented first (above) so there you go. As long as you’ve ruled out thyroid issues, I wouldn’t worry …. !
By: Lizzie on June 19, 2008
at 8:27 am
Fern has low temps too and we also freaked out over that sentence. She got her thyroid checked and it’s fine so we don’t worry. Also, when we first started, we bought a second thermometer and that raised the temps too
I think N is right, as long as you’re temps are in a good pattern, don’t worry about the actual numbers (since you know you don’t have a thyroid problem).
By: Olive on June 19, 2008
at 9:46 am
Before I started the meds, my temps were low too. I had my thyroid checked twice – both times the results were fine. I really wouldn’t worry about it if you’ve had your thyroid checked. If you haven’t, it’s a simple blood test your insurance should cover.
Sometimes Brill needs to give it a break.
By: mrsbluemont on June 19, 2008
at 10:02 am
mrsbluemont- Amen to that! I’m seriously not a fan of that book.
By: strawberry on June 19, 2008
at 10:06 am
i think if you have already been checked for thyroid issues and been cleared, you are good to go! i wouldn’t stress about it! the brill book can be the devil.
By: giggleblue on June 19, 2008
at 10:40 am
There were two easy ways to give Ms. Mel a heart attack while she was pregnant: (a) reminding her that pregnancies produce babies, (b) allowing her to take virtually anything from What to Expect seriously. I didn’t fully realize this until I’d already had Ash, but sometimes it’s a mother’s (or potential mother’s) responsibility to determine that a medical professional is full of crap.
Being the wife of someone who’s been tested extensively for thyroid problems — if you test negative, put it out of your mind. And I wouldn’t worry about feeling normal. Plenty of women who get pregnant “the old fashioned way” never realize they’re pregnant till they start getting a bump.
By: Mel on June 19, 2008
at 7:50 pm
Thanks everyone, for your advice and your reassurance. Lesson learned, no more reading. I shall remain ignorant and blissful.
By: nutella on June 20, 2008
at 8:41 am
I’m not sure what the temps should or should not be, BUT I think the Brill book is alarmist throughout. We do not own it because it scares us. (we have read it, thank god it was years before ttc, but it almost made us afraid to try)
By: j. k-c. on June 20, 2008
at 3:15 pm
IMO that’s bullshit. I’m pretty sure my pre-O temps were around 97.3 and my post-O temps were around 98.1-98.3 at the highest. How does your temp differ “down there?” Higher or lower? Just curious.
By: Jeannette on June 21, 2008
at 6:52 am
Again, thanks for your calming words everyone. I have relegated the Brill book to a shelf far far away. And Jeannette, I have never temped any way but orally. My “biphasic shift” is pretty clear, it’s just that my overall temps seem to be lower than the average.
By: nutella on June 21, 2008
at 9:17 am