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Basal Body Temperature: BBT Charting

Fertility Charting allows you chart and predict ovulation based on calendar patterns, cervical mucus analysis, and changes in your body temperature - or Basal Body Temperature charting. We recommend that you chart your basal body temperature fluctuations using the free online tool at OvaGraph.

Basal Body Temperature (BBT) and Ovulation Prediction

One of the many changes that take place in a woman's body during her menstrual cycle is an increase in body temperature at the onset of ovulation. During the first the first part of a woman's cycle, the body temperature is lower. With ovulation, the body temperature rises (to create a more fertile environment for the fertilized egg) and remains higher until the beginning of a woman's next cycle. The temperature increase is driven by the hormone progesterone, which increases when you ovulate.

Recording each day's body temperature - and charting the pattern of temperature changes - will help pinpoint when when ovulation has occurred and determine future patterns for predicting ovulation. Note that a sudden rise in your basal thermometer reading does not mean you are about to ovulate - it means that you have just ovulated. By charting, you can determine meaningful patterns that allow you to predict fertility in future cycles.

Because BBT charting allows a woman to confirm the onset of ovulation, it is a very useful method in helping facilitate conception - as well as understanding the general patterns and nuances of a woman's menstrual cycle.

During the first two weeks of a woman's cycle, her body temperature is lower (97.0 to 97.5 F), due to the presence of estrogen. With ovulation, a rise in body temperature takes place - caused by an increase of the hormone progesterone - in order to provide a warmer, more fertile environment. A minimum temperature rise of 0.4 to 0.6 degrees F can be measured - and this change will last through the duration of the menstrual cycle. By monitoring when this temperature change takes place, you can estimate when ovulation has taken place. You can find a digital basal thermometer designed for BBT charting here.

How to take your Basal Body Temperature    

Your Basal Body Temperature can be taken orally with a special BBT thermometer. Ideally, a larger thermometer that registers from 96 to 100 degrees (in easy-to-read one-tenth degree increments) is recommended. Digital thermometers are also available. Remember, you are attempting to discern as little as a two-tenths of a degree of difference in temperature, so selecting a quality thermometer and following directions are crucial.

Important: Your BBT temperature refers to a 'resting' or 'base' temperature. That means that your BBT must be measured prior to any physical activity, after at least three to four hours of sleep. Make sure that you read thermometer directions - and if you have any questions or unique considerations, consult your physician.

1. Taking Your BBT Temperature

Take your BBT temperature first thing each morning - as soon as you wake up. You must remain in bed (as physical activity can increase your temperature) and avoid eating or drinking or even moving. Either insert the thermometer in your mouth - or alternatively your rectum - and wait five minutes. Read the temperature to within 1/10 of a degree and record the reading.

2. Charting Your BBT Temperature

Starting on day one of your menstrual cycle - the first day of your period - begin recording your BBT temperature using a calendar or notebook and graph paper. Each morning, record your temperature. Plot each day's BBT on the graph. Your temperature rise may be sudden, gradual, or in steps. The pattern may vary from cycle to cycle.

3. Predicting Ovulation

For most women, 96 to 98 degrees is considered normal prior to ovulation and 97 to 99 degrees after ovulation. By charting the differences - in one-tenth degree increments - you can determine when ovulation has taken place. Typically a rise of at least 0.4 to 0.6 degrees will take place at ovulation, though for different women the temperature increases may be sudden or gradual. Over time, charting your BBT will help you predict ovulation.

BBT Limitations in Ovulation Prediction

BBT charting only tells you when ovulation has already occurred - and is therefore important for predicting general patterns. To predict ovulation, LH testing (ovulation predictor kits) is more effective - and examining cervical mucus is also a very valuable method.

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> Ovulation Testing


My husband and I have been trying for baby #2 for 19 months. We have a son who is 4 years old. My husband and I are in our 20's and healthy. I just don't understand why we have not gotten pregnant yet. Also I know I ovulate because I record my BBT. Is there anyone else that is having this issue with TTC #2?

my husband and i have been going on an emotional rollercoster for the past year. i found out i had endometriosis in august 2009, my doctor put me on lupron shots for 6 months, i took my last one in april 2010. i went back to my doctor in november 2010 because i still had not had my period after the lupron. he gave me provera to start my period, it worked. he also told me he wanted me to chart my bbt for 3 months to see if im ovulating. he says there is a chance im not and that i might have pcos also. so ive been charting my temperature just like he said, but my temperature is low! my temperature stays in the 96 somethings. it is usually 96.76, but then yesterday it was 97.05 and it was the same again today. what i am trying to understand is if i ovulated??? almost everything i read says your temperature rises .4 to 1.0 degrees when you ovulate and mine didnt rise that much. so i dont know what to think. on a side note i do know how everyone feels about being around pregnant women. my sister who i call fertile mertile just found out she is pregnant again and due in july. it just doesnt seem fair. i send baby dust to you all! i hope you all have a very merry christmas!!

I have not had my period for 3 months and I recently took a bunch of pregnancy tests and two came back positive and the rest negative? I went to the doctor today and he did a pee test that came back negative and he also did a pelvic exam and actually went in and checked to see if I had any cysts. He said everything looked healthy and nothing was expanded or enlarged, so he took a blood test and is getting back to me tomorrow. I have had all the symptoms of being pregnant and my husband and I have not used any birth control method. I've been feeling a lot of fatigue and have been getting headaches and a lot of cramping. Last week I got this horrible metallic taste in my mouth for two days and just found out today that, that is another symptom that you are pregnant. I really just want to figure out what is going on, plus my husband and I have been trying for awhile now. I've tried to figure out when the best time to try and conceive would be by using an ovulation kit but I can't remember the exact date of my last period. Can you please help?

I've been pregnant one time before but lost the baby after 12 weeks about 3 years ago. My husband works in another state and we only see each other maybe 2 or 3 times a week if were lucky. And usually during that time he is either doing a home project because he is not home most of the time, and when I go out to see him I see him at night time after his 12 hour shift and he's extremely exhausted. In short, We have our work cut out for us if we do time our BBT correctly and hopefully we are together at the time. Scheduling the time to be together is stres in it's self. On top of that I've been diagnosed with Poly Cystic Ovarian Syndrome (PCOS) which means I have eggs that never fall from my ovaries and I produce testosterone instead of progestrone. I'm not like Arnold or anthing, but not producing progestrone means I'm not ever going to ovulate without help. Thus, I'm taking Progestrone and Clomid as well to help me ovulate. I'm thinking of taking Yoga just to reduce the stress of all this and hopefully we can just let GO!!!. I wish the best for all on the same mission of havinging a wee little one or 2 or 3 in there arms. Many blessings to you all.

Hi all, I have been married for almost six years and we have never used protection and i haven't gotten pregnant. I have been doing the bbt for almost six months and its always so crazy. I still haven't figure it out,we want a baby so bad and feel so frustrated thinking that we might not be able to have one. How can so many women that don't want or can take care of children have so many and have no problem having them? I just don't understand. Good luck to all of you and hope that one day wecan post a msg with good news from one of us!

Hi All,
Just hopped on this site to look up info YET AGAIN as I'm sure many of you keep doing too. Although I'm not happy to hear of other women suffering from my same problem, it is comforting to find a place where we all share common ground. I have also been tracking my BBT w my husband and have seen a rise in temperature when it should and in the amount it should be. However, I still can not seem to get a positive Ovulation test that I have done for at least a month now. I just had an HSG procedure yesterday to either unblock or make sure my fallopian tubes were not blocked. Now that they are unblocked or I know they are clear, I have to make sure I'm ovulating. Obviously with the temperature it's promising, but the lack of a posistive O. Test makes it really ambiguous. Anyone else encounter this or have any input/info? Greatly appreciated if so! I wish all of you the best of luck and know exactly what you all are talking about with the difficulty of being around babies, pregnant women, and families in general. I also seem to have friends, peers, etc. that seem to get pregnant at the mere thought and already all have a couple in tow already! (I live in Utah lol) I am very lucky to have 1 son from a previous marriage, and after the way his birth went I especially treasure and feel so lucky and greatful to have him. However, I don't want to minimize how blessed I already am, but of course as my husband does not have a child of his own, and we don't have one together, we really want a baby! I have had problems with endometriosis the past couple of years, and had my menstrual cycles thrown off for over a year before we could even begin trying from the nasty depo shot. (which i would RARELY recommend to anyone!) I don't want to at all seem ungreatful or unappreciative of what I know I am already so lucky to have with already having 1 child. But even though I am very lucky and get to experience being a mom already, having 1 and wanting another you know exactly what you're missing and not getting. I don't want to minimize the grief of anyone who has not been as lucky to have any children yet, and hope you don't feel I am 'preaching to the choir'. Good luck to you all!

I too have wanted a baby for so LONG. My sisters can get pregnant at the drop of a hat -- my friends can get pregnant at the drop of a hat.

I try to be happy for them -- and I really am happy for them.... but the envy of wanting what they have is really eating me up.

I am getting frustrated, paniced and all around scared that my dream of getting pregnant is not coming true. I HATE it when ppl say to me -- OH just stop trying - and it will happen. Seriously... this is advice from the fertile mertiles of the world -- and it shoudl be BANNED or punished for being said. AHHHHHHHHHH.
Glad I found a place to vent - and have other women that are in the same spot I am!


I just starting keeping track of my BBT and I'm finding it kind of fun. Just today, I had the uptick in temperature (from 97.3 to 97.5 over the last week to 98.2 today! So that seems to mean I ovulated yesterday or the day before, which I confirmed with ovulation test strips.

Me and my husband have been trying to have a baby for over year. It hasn't worked out for us. We are going to the doctor to take some test hopeful it well give us some answer and a solution. We wish us good luck. I also started to subtract my temperature this month. good luck to you all!! my the lord answer your prays.

My husband and I have been trying to have a child for 6 months. I have always had irregular periods, and I am so confused on how to tell if I am ovulating. I took ovulation tests for 4 months and they were all negative. I went to the doctor and had my blood work done... I was told my testosterone level was a little high, my LH & FSH levels were fine, but the ratio of them was high. All of my other levels were normal. The nurse that called and gave me my results said it sounded like PCOS, but I didn't have any other signs (my insulin level was fine, I am not overweight at all and no facial hair). My doctor started me on prometrium to "jump start" my period, which worked.... but I still havent had a positive ovulation test. I am taking these tests as soon as I wake up in the morning, but sort of at different times... I might wake up at 7am, or 8:30am. Does this matter in the test result??? I am trying not to think about it, but in turn, it's all I can think about!! Has anyone else experienced trouble with ovulation, and if so, any advice?? Thanks!

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Format: 4/23/2018
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By TTC veteran and mother of two, Elizabeth Andrews.