Tuesday, September 28, 2010

Is BBT charting of any use for infertile couples

Ovulation type medical thermometer

During the luteal phase of the cycle, the corpus luteum produces the hormone progestrone, which elevates the basal body temperature ( BBT) . When the basal body temperature has gone up for several days, one can assume that ovulation has occurred. However, it is important to remember that the BBT chart cannot predict ovulation - it cannot tell you when it is going to occur !

In the past, doctors felt the basal temperature chart was a useful tool. It allowed the patient to determine for herself if she is ovulating as well as the approximate date of ovulation, but only in retrospect. Basal body temperature charts are easy to obtain and the only equipment required is a special BBT thermometer.

General instructions for keeping a basal body temperature chart include the following :

  1. The chart starts on the first day of menstrual flow. Enter the date here.
  2. Each morning immediately after awakening, and before getting out of bed or doing anything else, the thermometer is placed under the tongue for at least two minutes. This must be done every morning, except during the period.
  3. Accurately record the temperature reading on the graph by placing a dot in the proper location. Indicate days of intercourse with a cross.
  4. Note any obvious reason for temperature variation such as colds, or fever on the graph above the reading for that day.

However, the major limitation of the BBT is that it does not tell you in advance when you are going to ovulate - therefore its utility in timing sex during the fertile period is small. Interpreting the BBT chart can be tricky for many patients - rarely do the charts look like those you see in textbooks!

Also, keeping a BBT chart can be very stressful - taking your temperature as the first thing you do when you get up in the morning is not much fun. What is worse is that you start to let the BBT chart dictate your sex life. This is why though the BBT chart used to be a useful method in the past, it's utility is limited today - and newer methods are available which are more accurate are available. We advise our patients never to chart their BBTs - we feel they are just a waste of time.

Want to find out what your fertile time is ? You can use our free online fertility calculator to determine when you ovulate !

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  1. Anonymous9:39 PM

    I couldn't disagree more. Charting can be a great way to develop an understanding of your cycle and predict when ovulation is most likely to occur. For my first baby this worked great and we conceived the first month of trying (I had been charting for a few months prior). If I hadn't charted I would not have been aware that I ovulated on day 10 of my cycle and so would likely have missed ovulation regularly.

    For my second child I wasn't charting and when my period was late it caused stress because I had no idea if I had ovulated and was likely pregnant or if I was having an anovulatory cycle or if I had just ovulated late etc. Since then I have gone back to ovulating again.

    Taking my temp in the morning isn't hard and I set my alarm for earlier than my usual wake up time, take my temp then turn over and go back to sleep.

    In addition charting has allowed me to recognise a hypothyroid condition due to low temps. It was a final piece of a puzzle of health symptoms that seemed hormone related and so prompted me to go to the doctors to have my thyroid checked.

    I have found on fertility boards where users don't chart their BBT they often rely on OPKs and when they see the LH surge they expect ovulation to follow. This is unfortunate as an LH surge does not guarantee ovulation yet couples stop doing their baby-making a couple of days later and potentially miss their real window of opportunity. If they were charting their BBT they would be able to see if ovulation has occurred and know to keep trying.

    Charting your BBT is certainly not a waste of time in itself. Whether it adds to stress for infertile couples would be down to the individual couple but for most at least charting a month or two (particular with some support) can give a wealth of information about their fertility which they can put to good use even if they decide not to continue charting month after month.

  2. I agree charting is a useful way to learn about your cycle - but there are easier and kinder ways !

    As long as you are sensible enough not to let it become your obsession, it's fine to do it. However, if you look at some of the online discussions which women have about their BBT charts, you will agree with me that charting seems to become a full time occupation for some women.

    An LH surge does not guarantee ovulation - but neither dose a rise in BBT !

    Dr Aniruddha Malpani, MD
    Malpani Infertility Clinic, Jamuna Sagar, SBS Road, Colaba
    Bombay 400 005. India
    Tel: 91-22-22151065, 22151066, 2218 3270, 65527073

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  3. Really? BBT can tell you: If you are ovulating, during which days you tend to ovulate, and how long your luteal phase is.

    That's not important? It sure is! And BBT can be done in your own home, costs less than repeated blood tests, and is less invasive.

    No, it can't tell you when you'll ovulate. And it's not an instant, one month, cure. But it can give you a whole lot of information that you'd otherwise have to do bloodwork to get.

    Don't you think that's better than dumping extra hormones into your body, even if it might take a few months? And IUI/IVF/Clomid aren't one-month miracles, either. Each one of them takes time. Rarely do they work the first time. And even when they do, they cost a LOT of money and you put a LOT of hormones into your body. Sounds great, huh?

    So, why not tell people to chart their BBT before getting worked up that they're infertile?


    P.S. - I know someone who smoked through two pregnancies because "it was too stressful to quit". Is that what you tell your patients, too?

  4. BBT charting was developed over 50 years ago when doctors did not have anything better to offer to their infertile couples! To continue using it mindlessly when there are better options available ( such as OPKs which can be done at home and are cheap and much more reliable) makes no sense to me !


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