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Basal Body Temperature – The Rule of Thumb

If you’ve been trying for a while now to get pregnant, you no doubt know all about your BBT (basal body temperature) and how it can be used to determine just when you might be ovulating. But do you really understand the basics of charting so that you can be sure that you’re doing it right?

The following information is all about charting basics so that you know if you’re making the most of this fertility tool or not. In order for you to be able to analyze your chart correctly, it’s important that you have the most accurate data as possible recorded.

This means recording your basal body temperature in the most reliable you can.

YourBabyLibrary -basal body temperature
YourBabyLibrary-Charting Basics The Rule-of-Thumb

When to Take Your Temperature

You need to take your temperature first thing when you wake up in the morning. This means taking it before you do anything else, even getting up to go to the bathroom. Even reaching over to check your cell phone for messages can mess up your temperature.

Keep the thermometer right beside your bed along with a pen and a pad of paper. Get in the habit of reaching for that thermometer before you do anything. Take your temperature and then record it on the pad of paper.

Then remember to shake down the thermometer so that you don’t have to do it the next morning!

Taking Your Temperature at the Same Time

It’s important that you take your temperature at the same time every morning. So if you normally get up at 6 am during the week, you’ll have to do the same on weekends and even on holidays! If you like, you can go back to sleep after you’ve taken and recorded that temperature.

The reason for this is that once you wake up, your resting body temperature will rise every 30 minutes by about 0.1 of a degree. This is going to ruin the accuracy of your chart so while you’re trying to get pregnant get used to waking up at 6 am in order to maintain the accurateness of your chart!

You should also try to get at least five hours of sleep before you take your temperature. Any less than five consecutive hours of sleep and your basal body temperature isn’t going to be accurate.

This might mean saying goodbye to those late nights for a while, but it will be well worth it when it comes to accurately predict when you’re ovulating.

The BBT Thermometer

By now you know that an ordinary thermometer isn’t going to cut it. You’ll need to use a special BBT thermometer that is able to measure your temperature in the right degrees. You can either take your temperature orally or vaginally if you like.

The majority of women just prefer to stick that thermometer in their mouth every morning. Try not to break it! You want to use the same thermometer that you started out using to ensure accuracy.

If you have to start with a new one then start using it on the first day of your new cycle. Make sure that you make a small note on your chart so that you remember what happened with your temperature at that time.

Keeping Notes on Your BBT Chart

There are going to be times when you sleep in or when you just forget to take your temperature and write it down. Even though missing an accurate temperature or two now and then isn’t going to make it impossible for you to predict your ovulation date, you’ll still want to make a note of it on your BBT chart.

You’ll also want to make notes about when you’re sick or if you’ve had a few drinks at a party the night before. Both illness and alcohol can result in a temperature that is a bit inaccurate.

Keeping notes will help you from one month of your cycle to the next when it comes to reading your chart.

When to Start Charting

While it doesn’t really matter when you start charting your basal body temperature, ideally you’ll want to start on the first day of your menstrual cycle.

Keep taking your temperature through your entire period even though you’re probably wondering what the point is.

The point is that you want to get in the habit of taking your BBT. Once you’ve been charting for a few months you can skip taking your temperature on the first few days of your period and then just take it on the last couple of days.

Of course, if you have a short period then you might not want to stop charting at all.

The Accuracy of Basal Body Temperature (BBT)

After a few months of taking your BBT, you’ll start to see a pattern. When your temperature rises enough that you can notice it and then stays elevated, you can with some accuracy confirm that you’ve ovulated.

This means that when the next month comes along you’ll quite reliably know when you’re going to be ovulating so that you time intercourse with your partner about three days before.

While not 100 percent accurate, many women who chart their BBT find that they have an easier time conceiving.

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