Charting your temperature: a beginner's first three cycles, week by week
Basal body temperature charting can confirm when you ovulated. Here is a week-by-week beginner's guide to taking, recording and reading your temperature calmly.
By PreggieLover 3 min read
The thermometer sits on your bedside table. The alarm goes off at 6.30, and before you have even opened your eyes properly, you reach for it. That small morning habit is basal body temperature (BBT) charting, and over a few cycles it can tell you a great deal about your body. Here is how to begin, without turning your mornings into an exam.
What BBT shows, and what it does not
Your resting temperature rises slightly after ovulation because of progesterone, usually by a few tenths of a degree Celsius, and stays higher until your next period. If you become pregnant, it usually stays raised. So BBT confirms ovulation after it has happened. It is wonderful for learning your pattern, but on its own it cannot tell you in advance when to try. That is why many women combine it with cervical mucus or ovulation tests.
What you need
- A basal thermometer, which reads to two decimal places.
- A paper chart or a tracking app.
- A consistent morning routine.
Cycle one, week one: just practise
Start on day one of your period. Each morning, take your temperature as soon as you wake, before you sit up, talk, drink or check your phone. Try to take it at roughly the same time each day, after at least three hours of unbroken sleep. Record it. Do not try to interpret anything yet. You are simply building a habit.
Cycle one, weeks two and three: notice the noise
Your temperatures will bounce around a little. That is normal. Make a note of anything that might affect a reading: a late night, alcohol the evening before, illness, a broken night's sleep, a different wake-up time, travel. These notes help you ignore odd readings later.
Cycle one, week four: look for the shift
Somewhere in the middle of your cycle, you may notice that your temperatures move to a higher level and stay there. A common rule is to look for three days in a row that are higher than the previous six days. Ovulation most likely happened the day before the rise. Draw a line across your chart under the higher temperatures; the gap between the two levels is your shift.
Cycle two: add one more sign
Now that the morning habit is easy, start noticing cervical mucus each day too. Watch how the wettest, most slippery mucus usually appears just before your temperature rises. Seeing the two signs agree is often the moment charting “clicks”.
Cycle three: read your pattern
By now you may be able to answer some useful questions:
- Roughly which cycle day do I tend to ovulate?
- How long is the time from ovulation to my period (my luteal phase)?
- Is my pattern fairly steady, or does it vary?
Take these charts to your doctor if you have concerns. A pattern with no clear temperature shift over several cycles, or a very short time between ovulation and your period, is worth discussing. Your doctor may suggest a blood test to check ovulation.
When BBT is not for you
Shift work, a baby or toddler who wakes at night, broken sleep or illness can make BBT unreliable. Some women also find it makes them anxious first thing in the morning. If that is you, it is fine to stop. There are other ways to understand your cycle, and regular intimacy every two to three days works without any charting at all.
A morning practice for your soul too
Every morning, as you reach for that thermometer, you can reach for God as well. “It is of the LORD'S mercies that we are not consumed, because his compassions fail not. They are new every morning: great is thy faithfulness” (Lamentations 3:22-23). Whatever yesterday's temperature said, today's mercy is fresh. Try saying a one-line prayer while the thermometer beeps: “Thank You for new mercies today.”
A morning prayer
Lord, as I wake and take this small reading, I also take hold of Your new mercies. Help me to learn my body with patience, and to remember that You are faithful in the high days and the low ones. Amen.
Frequently asked questions
Can basal body temperature predict ovulation?
Not in advance. BBT rises after ovulation, so it confirms that ovulation has probably happened. Combine it with cervical mucus or ovulation tests to predict your fertile days.
When should I take my basal body temperature?
As soon as you wake, before getting up, talking or drinking, at roughly the same time each day and after at least three hours of unbroken sleep.
This article is for general information and encouragement, not medical advice. Please talk to your doctor or midwife about your own health and your baby's.
