Fertility Awareness: What Affects The Test

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What Affects the Test

For all methods

Fertility awareness methods will not work very well:

• If they are not used consistently.
• During stressful times or times when cycles are irregular, after a baby is born, after you stop taking birth control pills, or just before menopause.
• If both partners are not willing to work together to use them.

Calendar (rhythm) method

The calendar method will not work very well if:

• You have irregular, short, or long menstrual cycles.
• You breast-feed for more than 6 months.
• You supplement breast-feeding with bottle-feeding.

Basal body temperature (BBT) method

The BBT method will not work well if you:

• Have a fever.
• Take some medicines, such as aspirin.
• Are traveling, having problems sleeping, or having other stress.
• Use a different thermometer, take the thermometer out too soon, take your temperature at a different time of day, or take your temperature in a different way.

Cervical mucus method (Billings method)

The cervical mucus method will not work very well if you:

• Use vaginal lubricants or douche.
• Are breast-feeding.
• Have a vaginal infection.
• Are close to menopause.

Hormone monitoring

The results of hormone monitoring may not be correct if you do not follow the home ovulation kit instructions exactly.

Combined (symptothermal) method

Anything that changes the results of one of the methods also changes the results of the combined method.

Last updated:	March 21, 2008
Author:	Sandy Jocoy, RN
Reviewed By:	Sarah Marshall, MD - Family Medicine, Kirtly Jones, MD - Obstetrics and Gynecology
Editors:	Kathleen M. Ariss, MS, Pat Truman, MATC