A Brief Introduction to Fertility Awareness Based Methods

Fertility Awareness Based Methods (FABMs) can be used for family planning and gynecologic health monitoring. FABMs rely on an understanding of the woman’s cycle to determine when a couple is most likely to conceive. Beginning at puberty, healthy men are generally always fertile, whereas healthy women are only fertile a few days each menstrual cycle. This fertile window is about six days long—the five days before ovulation and the day of ovulation.

The hormones that regulate a woman’s cycle and result in ovulation also produce observable external signs that indicate when she may be fertile. These external signs or biological markers include the appearance and sensation of cervical fluid, the basal body temperature, the position of the cervix, and the presence of estrogen metabolites or luteinizing hormone measured using urinary test strips.   The cervical mucus and cross check methods teach women or couples to track one or more of these signs to discover the pattern of each individual woman’s cycle and to identify when she may be fertile.  The calendar-based methods use empirical women’s cycle data to determine a fertile window.

These modern methods are well researched and can be utilized effectively to achieve or avoid pregnancy. A woman typically ovulates only once a month, and the ovum or egg is only viable for 12-24 hours. In the presence of healthy, fertile cervical fluid, the man’s sperm are only able to survive in the reproductive tract for 3-5 days. By tracking a woman’s fertile and infertile days, couples  can identify the ideal time of the month to engage in sexual relations to achieve pregnancy.  Or, to prevent pregnancy, couples would abstain from intercourse and avoid genital contact, including fluid secretions, during the fertile phase of her cycle.

Some couples may also choose to use a barrier method during the fertile window, which is referred to as a “Fertility Awareness Combined” approach.  If couples rely on a contraceptive barrier (e.g., condoms, etc.), the lower typical use effectiveness rates of the barrier method would apply (e.g. condoms are 82% effective with typical use).  Since the natural methods do not involve hormone-altering chemicals or substances, couples have the freedom to switch from avoiding pregnancy to achieving pregnancy without any delay.

Here is a list of the most studied methods. Please click on the links below for a description of each method.

Cervical Mucus Methods

  • Billings Ovulation Method™ (BOM)
  • Creighton Model™ (CrM)
  • Two Day Method

Cross Check Methods

  • Sympto-thermal
  • Sympto-hormonal (Marquette)

Standard Days Method

Lactational Methods

  • Lactational Amenorrhea Method
  • *Billings, Creighton, Marquette and Symptothermal methods all have protocols for breastfeeding women