Terms Explained: what is Natural Family Planning?

If you want to know more about the hormonal balance of the female body; if you want to avoid pregnancy without the use of artificial hormones, side effects, or prescriptions; or if you are curious about ways to maximize your chances of conceiving a baby; this is the week for you!

July 25 – 31, 2021, is Natural Family Planning Week.

Natural Family Planning (or, NFP) is an umbrella term referring to several different methods by which people can try to achieve or avoid pregnancy and/or can monitor their hormonal health. Because some female bodies (those in a certain age range and in good reproductive health) are naturally fertile for some days every cycle and infertile for most days,  people can track periods of potential fertility and likely infertility to maximize or minimize the chances of pregnancy. Different ways to do this tracking are all part of NFP. And, because the natural times of fertility and infertility reflect the presence or absence of key hormones, NFP allows people to determine whether those hormones are appropriately produced within their bodies.

People determine their likelihood of being fertile by taking their temperatures, observing cervical mucus, observing vaginal sensations, testing hormone levels in their urine, and more. Different methods that fall under the NFP umbrella use different indicators to track fertility. Let’s look at some examples.

The Rhythm, Calendar, or Standard Days Method is what a lot of people unfamiliar with NFP think of when they hear “NFP”. This method involves counting the number of days from when a period starts to when – historically for that person – ovulation is first and last likely to occur. For someone with very regular cycles, this method can work great. But because cycles change so much based on everything from diet to stress, science and our understandings of female bodies quickly provided methods that can more precisely narrow down the fertile window.

The Billings Ovulation Method was one of the first NFP methods to incorporate or rely on signs from the female body other than the timing of a period. It uses cervical sensations, mucus presence, and mucus characteristics to determine likely fertility.

The Creighton Model is a version of the Billings Ovulation Method that is standardized such that Creighton-trained doctors and OBGYNs can provide care across locations. This method relies primarily on cervical mucus and sensation observations and can be very helpful for those struggling with PCOS or other difficult-to-diagnose reproductive disorders.

FEMM also uses cervical mucus and focuses on holistic health (including reproductive health) rather than only on reproductive health. There are FEMM-trained medical providers who can support people through hormonal issues from infertility to depression to acne. Because of these resources, this method can be very helpful for those who are interested in how hormones impact multiple aspects of their life experience even beyond fertility.

The symptothermal method (also called Couple to Couple League or SymptoPro in reference to two of the biggest organizations that teach it) uses data from cervical mucus and body temperatures. This method is often recommended for people who want to supplement their cervical mucus observations with another fertility indicator.

The Marquette Method typically involves the use of a monitor to determine comparative levels of urinary hormones over the course of a cycle. It is often recommended during periods where cervical mucus can be trickier to read (such as postpartum or menopause).

Boston Cross-Check uses all of these tools – cervical mucus observations, hormonal tracking with a monitor, and body temperatures. Lots of NFP users like to have data and information on different aspects of their fertility, and this method incorporates all of those.


Keep in mind that often people will use multiple tools even if they aren’t required by one method. Someone might be a symptothermal method user who uses at-home urinary tests for luteinizing hormone to supplement their cervical mucus observations. Or, someone might be a Creighton user who also temps (= takes their body temperature daily as a sign of fertility).

If you’re curious about NFP, feel free to reach out to me so we can chat! Different resources will be more helpful to you depending on what kind of method you’re interested in, so with a quick conversation, I can help you find the instructor, book, or websites that would be most helpful to you.

Happy NFP Week!

Photo by JESHOOTS.COM on Unsplash

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s