Charting 101: An accurate way of conceiving a baby

So you want to have a baby but you can’t figure out where to start? There’s a lot that goes into conceiving a baby — more than just having intercourse. Charting is a scientific method to help you increase your chances of becoming pregnant. Here’s what you need to know about charting to get you started.

Getting started

Picking the right thermometer

The best way to obtain an accurate temperature reading while charting is to purchase a thermometer designed specifically for fertility. The packaging on the thermometer should say Basal Body Temperature, BBT or Fertility Thermometer. These thermometers can be digital or mercury thermometers.

How to take your temperature

There are two ways to take your temperature each day — orally and vaginally. Vaginal readings are more accurate and are a better option for women who breathe with their mouths open while sleeping (this can lead to inaccurate temperature readings). No matter which method you choose, you should set your alarm to take your temperature at the same time each morning for the most accurate results.

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Charting your Basal Body Temperature (BBT)

Tip: Keep a notepad and pen by your bed to record your daily temperature, and then mark or input your information each day.

There are many options when it comes to charting. Ask your OBGYN for a chart printout, download a chart online, make one or join an online site that offers charting software and support.

No two women’s temperatures will be the same, so it’s best not to compare your chart with others. You will notice that your recorded temperatures from the beginning of your period to the day you ovulate will be lower than your temperatures from ovulation to either the start of your next cycle or a positive pregnancy test — in the case of pregnancy, your temperatures will remain elevated and you will miss your period.


Consult your doctor if you suspect that your temperatures don’t show a pattern or indicate ovulation. Some women experience non-ovulatory cycles or have fertility issues that can come to light because of charting.

Recording and discarding temperatures

It’s best to take your BBT at the same time each morning and after a three-hour continuous stretch of sleep. If you wake up early, late or multiple times during the last three hours of your sleep, you can discard the temperature and note your chart. When you use programed software — like Fertility Friend — the chart recognizes your discarded temperature and is still able to calculate your data accordingly.

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Abbreviations for charting

These common abbreviations are used on fertility sites, doctor offices and online support groups for women who are charting and trying to conceive.

  • BBT: Basal Body Temperature
  • CM: Cervical Mucus
  • CP: Cervical Position
  • LP: Luteal Phase
  • O: Ovulation
  • OPK: Ovulation Predictor Kit
  • CD: Cycle Day
  • CH: Crosshairs (the lines on your chart indicating your ovulation day)
  • AF: Aunt Flo or your period
  • BD: Baby Dance or intercourse for conception purposes
  • CL: Coverline –the line that indicates the difference between your hormones before and after ovulation.
  • DPO: Days Past Ovulation
  • HPT: Home Pregnancy Test
  • BFP: Big Fat Positive or positive pregnancy test
  • BFN: Big Fat Negative or negative pregnancy test
  • EDD: Estimated Due Date
  • LMP: Last Menstrual Period
  • TTC: Trying To Conceive

Charting your Cervical Mucus and Cervical Position

An optional part of charting is to record your Cervical Mucus (CM) and Cervical Position (CP). During a fertile woman’s regular monthly cycle, her body is preparing for a pregnancy — and does so in more ways than one. For more information about charting CM and CP, visit

More about conception and fertility

5 Things to know when you’re trying to get pregnant
Making lifestyle changes before conceiving
Planning a pregnancy? 10 steps to take


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