Where the method comes from
Medical informationThe Billings Ovulation Method was developed in Melbourne, Australia, by Drs John and Evelyn Billings, who began their research in the 1950s with the goal of helping couples who could not rely on the calendar rhythm method. Working with scientists who studied the hormones of the cycle, they showed that the mucus produced by the cervix changes in a predictable way as ovulation approaches, and that a woman can recognize this change herself.
The method spread widely because it is simple and needs no equipment. It is taught in many countries and languages, and its basic idea has shaped other mucus based methods, including the Creighton Model.
What a woman observes
Medical informationThe central sign in Billings is sensation. Through the day, as she goes about ordinary activity, the woman notices whether she feels dry, moist, wet or slippery at the vulva, and she also notices what she sees, if anything. She does not need internal examination. Each evening she records the most fertile sign of the day in simple words or symbols.
Over a cycle a pattern appears. After menstruation many women notice a basic pattern that does not change from day to day, which signals infertility. As estrogen rises, the sensation changes and mucus becomes more fertile, ending in a slippery sensation. The last day of that most fertile sign is called the peak. Fertility is considered to continue until the end of the third day after the peak, after which the rest of the cycle is infertile.
| Phase | What is often noticed | Meaning in the method |
|---|---|---|
| Menstruation | Bleeding | Recorded; possible fertility in short cycles |
| Basic infertile pattern | Dry or an unchanging sensation | Infertile, within the Early Day Rules |
| Change of pattern | Moist or wet, mucus appearing | Fertility has begun |
| Peak | Last day of slippery sensation | Ovulation is near |
| After the peak | Return to dryness or stickiness | Infertile from the fourth day after the peak |
The basic rules in general terms
Medical informationBillings teaching includes a small set of rules. The Early Day Rules guide couples before the peak, for example by advising intercourse only in the evening on alternate dry days, so that the next day's observation is not confused. The Peak Rule marks the start of the infertile time after the third full day past the peak. Couples who hope to conceive use the slippery days as their most fertile time.
These rules are described here only to show how the method thinks. Learning them correctly needs an accredited teacher who reviews your charts, especially in the first months, after stopping hormonal contraception, while breastfeeding and as menopause approaches. In studies, well taught methods like Billings show perfect use effectiveness above 98 percent; typical use depends on teaching and on how clearly spouses agree on their plan.
Why Billings fits Church teaching
Church teachingThe Catechism teaches that periodic continence and methods based on self observation and the use of infertile periods conform to the objective criteria of morality. They respect the bodies of the spouses, encourage tenderness and foster freedom. Humanae Vitae 16 says that when spouses have well grounded reasons to space births, they may use the natural cycles and come together only in the infertile times, which is essentially different from contraception.
Billings is one faithful way to live this. The Church does not prefer one method over another, and the reasons for postponing a pregnancy are for the couple to discern generously before God. Our page on NFP vs contraception explains why the timing makes a moral difference.
Periodic continence, that is, the methods of birth regulation based on self-observation and the use of infertile periods, is in conformity with the objective criteria of morality. These methods respect the bodies of the spouses, encourage tenderness between them, and favor the education of an authentic freedom.
Learning Billings as a couple
Pastoral guidanceBillings is often taught in a short introductory session followed by follow up chart reviews with an accredited teacher, in person or online. Ask your parish or diocese which teachers are available, and whether marriage preparation in your diocese includes a particular method.
Make it shared work. The wife observes, but both spouses read the chart and make decisions together. Couples who talk about their plan at the start of each cycle find abstinent days easier to carry with patience and affection. If you are still choosing, compare methods in our guide to natural family planning, and remember that charting serves a larger goal, a marriage where Catholic intimacy is honest, generous and joyful.
A woman need not have "regular" cycles. NFP education helps couples to fully understand and interpret their combined fertility, so that they can discern when to postpone or attempt pregnancy.
Sources
Every source below is linked to the full text on vatican.va or usccb.org. Quotations are short and given word for word.
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USCCB NFP Pastoral guidance
USCCB, What is Natural Family Planning?
Natural Family Planning is the general name for scientific, natural and moral methods that help married couples either achieve or postpone pregnancy. The methods rely on observing the natural signs of the fertile and infertile phases of a woman's cycle, with no drugs, devices or surgery, and they respect the unitive and procreative meaning of the conjugal act.
Read the source -
Is NFP based on guesswork? Pastoral guidance
USCCB, Is NFP based on guesswork?
NFP is based on scientific facts about fertility, not guesswork. Research on cyclic changes in cervical mucus and the temperature rise after ovulation led to programs that teach couples to observe and interpret these signs, and research continues to refine the methods.
Read the source -
Who can use NFP? Pastoral guidance
USCCB, Who can use NFP?
Any married couple can use NFP; a woman need not have regular cycles. The methods can be adapted to different reproductive situations, including irregular cycles, breastfeeding and the years approaching menopause, ideally with help from a trained NFP instructor.
Read the source -
CCC 2370 Doctrine
Catechism of the Catholic Church 2370 (The Sixth Commandment)
Periodic continence, the methods of birth regulation based on self-observation and the use of infertile periods, conforms to the objective criteria of morality: these methods respect the spouses' bodies, encourage tenderness and foster freedom. By contrast, every action intended to render procreation impossible, before, during or after intercourse, is intrinsically evil.
Read the source -
HV 16 Magisterium
Pope Paul VI, Humanae Vitae 16 (1968)
If there are well-grounded reasons for spacing births, arising from the physical or psychological condition of the spouses or from external circumstances, married couples may take advantage of the natural cycles and have intercourse only during infertile times. This differs essentially from contraception, which impedes the natural process.
Read the source -
USCCB Married Love Pastoral guidance
USCCB, Married Love and the Gift of Life (what NFP is)
NFP is based on a woman's cycle: a man is fertile throughout life, a woman only a few days each cycle. NFP today is not calendar guessing but learning to read clear signs of fertility; it can be very effective for postponing pregnancy and also helps couples who want a child identify ovulation.
Read the source