NFP 101: Glossary of Frequently Used Terms

Have you ever heard someone toss around a term when talking about NFP and thought “Huh, wonder what that is?” Yep – us, too! That is why we made this glossary to help. We hope to make NFP accessible to all. Please reach out if you have any questions. The Office of NFP is here for you!


Basal body temperature (BBT): The temperature of the body when completely at rest (the body’s lowest temperature), taken orally immediately after waking up. BBT rises after ovulation.

Billings (BOM): The Billings Ovulation Method. Learn more here.

Cervical mucus (CM): Cervical fluid produced by the cervix – under hormonal influence.

Cervical mucus methods (CMMs): NFP methods based on daily charting of cervical mucus observations.

Charting: Making daily notes of the body’s fertility signs.

Couple to Couple (CCL): Couple to Couple League. Learn more here.

Creighton (CrMS): CREIGHTON MODEL FertilityCare System. Learn more here.

Cycle: The woman’s menstrual cycle.

Enkindle: The Office of Natural Family Planning’s infertility support ministry. Learn more here.

Instructor: An individual who teaches a method of NFP.

Intro session: The introductory course into a natural family planning method. The session typically provides an explanation of a woman’s cycle, human fertility, and the basics of the method. Learn more here.

Loss: Refers to pregnancy or infant loss, including miscarriage.

Luteinizing hormone (LH): A hormone that stimulates ovulation.

Marquette (MM): The Marquette Method. Learn more here.

NaPro: NaProTECHNOLOGY (Natural Procreative Technology). Learn more here or find a list of NaPro Physicians in St. Louis here.

Natural Family Planning (NFP): The general title for the scientific, natural, and moral methods of family planning that can help married couples either achieve or postpone pregnancy.

Ovulation prediction kit (OPK): An at-home urine test kit that measures hormone levels. Utilized with the Marquette Method.

Peak Day (Peak): The last day of a women’s most fertile sign during her cycle.

Primary infertility: When a couple who has never been pregnant has difficulty conceiving after 6 months of fertility focused intercourse or 12 months of random intercourse.

Provider: a teacher trained to provide instruction for a particular method of NFP

Secondary infertility: Difficulty conceiving after at least one prior pregnancy.

Sympto-thermal methods (STM): NFP methods based on observing and charting several signs of fertility, such as basal body temperature, cervical changes, and cervical mucus. Couple to Couple is a STM.

TTA: Trying to avoid pregnancy.

TTC: Trying to conceive.