Natural Family Planning

Issues of Concern

The physiology of the menstrual cycle and the periodicity of fertility are the basis for natural family planning. The hormonal changes before and after ovulation lead to detectable, identifiable physical changes. After ovulation, the ovum is only viable for about 12 to 24 hours, whereas sperm can only survive in the genital tract for approximately 3 to 5 days after ejaculation. Together, these factors allow a couple to identify the so-called fertile period. Generally, a woman is fertile from 5 days before ovulation to 24 hours after.[9] Couples using natural family planning to prevent pregnancy should avoid intercourse or use alternative contraceptives, such as condoms, during the fertile time.

Progesterone is released from the corpus luteum after ovulation. An effect of progesterone on the hypothalamus is an increase in body temperature. If a patient tracks her basal body temperature with an oral thermometer, she can identify when a sustained rise of approximately 0.5 °F occurs. This increase roughly correlates with ovulation. Identifying this day of the cycle (approximately day 14 of a 28-day cycle, where day 1 of the cycle is day 1 of menses) allows a patient to avoid or target ovulation in future cycles. For accuracy, patients should measure their temperature before rising in the morning, including getting up to use the restroom, eating, drinking, and brushing their teeth.

Cervical secretions are also affected by the hormonal changes of the menstrual cycle. Before ovulation, the developing follicle produces estradiol, which in turn produces cervical mucus that is hospitable to sperm capacitation (maturation) and sperm passage through the cervix. This mucus is clear, wet, abundant, and stretchy, often called egg-white. This type of mucus appears about 3 to 4 days before ovulation and remains present until immediately after ovulation. After ovulation, progesterone produced by the corpus luteum leads to changes in cervical secretions, inhibiting sperm migration and capacitation.

The increase in estrogen before ovulation causes an increase in sodium chloride in mucus. This release occurs in both cervical secretions and saliva. This increase in sodium chloride is observable under microscopy, where crystallization leads to arborization or ferning.[10] Estrogen also changes the character of the cervix itself. Under the influence of estrogen during the period of fertility, the cervix is more open, soft, high, and straight.[11]

Methods of Natural Family Planning

Standard days method: This calendar method determines fertility using the probability of pregnancy relative to ovulation and relies on ovulation occurring near mid-cycle. The method involves avoiding unprotected intercourse during cycle days 8 to 19. The standard days method is the easiest to teach, and it requires the fewest days of alternative contraception or abstinence. This method is suitable only for women with menstrual cycles 26 to 32 days long.[12] In a clinical trial, the typical user pregnancy rate of the standard days method was approximately 12 per 100 women per year.[13] The pregnancy rate was <5 per 100 women per year with correct use.

Billings and Creighton methods: These 2 methods rely on observing cervical secretions. The Billings Ovulation Method is the older of these methods. The Creighton Model requires women to score their secretions based on a multi-characteristic scale. Secretions should be observed multiple times a day, such as before each urination. Fingers or toilet tissue may be used to collect cervical secretions. To prevent pregnancy, intercourse should be avoided during menses, on preovulatory days after days with intercourse (to avoid confusion with semen), on all days secretions are consistent with ovulation, and until 4 days after the last day of wet or ovulatory secretions. Multiple classes or instruction sessions are recommended if these methods ensure adequate ability to recognize, record, and interpret secretions. Further study is required to better capture the effectiveness of these methods.[6]

TwoDay method: This method is also based on cervical secretions and is similar to the above. The main difference is that the presence or absence of secretions alone is sufficient to identify the fertile period. Patients are recommended to avoid unprotected intercourse on any day when secretions are present and on the first day after. In a prospective study of the TwoDay method, the pregnancy rates were 3.5 per 100 women per year for correct use and <14 per 100 women per year for typical use.[14]

Symptothermal method: This method is multimodal and combines awareness of cervical secretion changes with basal body temperature monitoring. The presence of transparent, slippery, stretchy mucus is the main indicator of the start of the fertile period of the menstrual cycle, and the elevation in basal body temperature is considered the end of the fertile period. Patients should monitor their secretions several times daily, take their temperature each morning, and check how the cervix is positioned and feels. Patients should avoid unprotected intercourse on any day when secretions are present, all preovulatory days following intercourse, and until 3 days of higher temperatures are observed following 6 days of lower temperatures or 4 days after the last day of wet secretions—whichever of these two conditions occurs later. Similar to the Billings or Creighton methods, users of the symptothermal method may require several instructional sessions. Typical use failure rates for the symptothermal method in some studies were 13 to 20 per 100 women per year, and correct use rates were 2 per 100 women per year.[15][16]

Marquette model: This method combines the monitoring of cervical secretions with the additional option of using an electronic device to assess fertility further. The device measures estrogen and luteinizing hormone levels in the urine. Given that estrogen levels rise before ovulation and a surge of luteinizing hormone triggers ovulation itself, the device may assist users in determining their fertile windows.

Other devices can be used to identify whether a patient is fertile. Some devices use miniature microscopes to observe the saliva or cervical mucus to determine whether ferning is present. Some handheld devices assist in measuring cycle length and correlating the cycle day with basal body temperatures.

Lactation amenorrhea method: Unlike other forms of natural family planning, the lactation amenorrhea method of pregnancy prevention relies on a lack of ovulation in the postpartum period when meeting specific criteria. Women must be exclusively breastfeeding, and they must be feeding at least every 4 hours in the day and every 6 hours in the night. This method only applies for the first 6 months after delivery, and the patient must not have restarted menstruation. If the patient meets all of these requirements, the effectiveness of this contraceptive method is up to 92% to 100%.[17]

Given the complexity of natural family planning methods, some patients should consider alternative forms of family planning. For example, women who cannot reliably identify their ovulation based on menstrual cycle or cervical mucus may not be candidates for natural family planning. These exclusions include women with irregular periods, such as in polycystic ovarian syndrome, younger girls whose hypothalamic-pituitary-ovarian axis is not yet mature, and women who are perimenopausal or postpartum and breastfeeding. 

Additional candidates who are not ideal for natural family planning are women with abnormal uterine bleeding, such as a history of polyps, fibroids, adenomyosis, hyperplasia, or malignancy; or abnormal cervical bleeding, such as cervical infections and cervical cancer. A patient presenting with undiagnosed abnormal bleeding for family planning counseling should undergo an evaluation for the bleeding, and she can consider options besides natural family planning until her evaluation is satisfactory. Women with cervical or vaginal infections may also face difficulties in assessing their cervical mucus. Women who have other reasons for temperature fluctuations, such as systemic illness leading to fever, cannot accurately track ovulation based on basal body temperature.

Some patients or couples may not be able to afford fertility tracking devices. The cost or time off work required to attend classes or instructional sessions may be prohibitive to some. Failure rates can differ based on socioeconomic status, with the poorest and youngest women facing the highest risk of unintended pregnancy.[7] Some individuals may find the tasks of monitoring temperatures or secretions to be onerous or off-putting. Lastly, some couples may find it difficult, or undesirous, to adhere to avoidance of unprotected intercourse during fertile times. The success of natural family planning requires highly motivated patients and couples.

Clinical Significance

There are several reasons why patients may choose natural family planning. For some patients, religious beliefs play a significant role in the decision to utilize this method.[18] Others may have concerns about the potential adverse effects or complications associated with other contraceptive methods. Some may have already experienced adverse effects or complications and desire to try what they perceive as more natural methods.[5] Regarding achieving pregnancy, both fertile and infertile couples can benefit from a knowledge of the menstrual cycle and how the hormonal changes affect their bodies. In general, women who know their fertility can have more agency over their bodies and life choices or options compared to those who lack this understanding.

Lack of awareness and education may impact the use of natural family planning. In a survey of clinicians in the United States, one-third did not mention natural family planning to their patients, and 40% only discussed it with selected women.[19] Facilitating autonomy requires clinicians to equip patients with adequate knowledge for decision-making. Without a comprehensive discussion of options, proper informed consent is not possible.

Many cellphone applications claim to support patients who desire to use natural family planning. Care must be taken when recommending or using these applications. Applications should be meticulously evaluated before a patient relies upon them for contraception, as some applications may contain false or inaccurate information.[8] 

Nursing, Allied Health, and Interprofessional Team Interventions

Because natural family planning often requires time-intensive patient education or multiple instructional sessions, patients interested in this method greatly benefit from a coordinated team approach. The pharmacist dispensing contraceptive pills or a clinician performing a routine wellness visit may identify patients interested in pursuing natural family planning.

Subsequently, a trained educator—a clinician, nurse practitioner, or dedicated interprofessional team member—can be called upon to perform the detailed teaching necessary to effectively use natural family planning methods. These educators are essential in ensuring patients receive accurate, comprehensive instructions on fertility awareness and related methods. Awareness of all family planning methods, including natural family planning, allows clinicians to provide patient-centered and individualized options. 

Nursing, Allied Health, and Interprofessional Team Monitoring

Nurse monitoring is 2-fold in the context of natural family planning. First, nurses should identify patients who may be motivated to pursue natural family planning or may be good candidates for natural family planning and facilitate the education of those patients. Patients may confide in the nurse any current or prior discontent with a contraceptive method. Nurses may be the ones to elicit the patient's history.

Secondly, nurses, especially in the outpatient setting, play an essential role in monitoring signs that patients may not be ideal candidates for natural family planning. A good menstrual history may identify patients with irregular periods or abnormal uterine bleeding. Monitoring patients who cannot accurately describe the length or frequency of their periods is crucial, as these patients may be poor candidates for natural family planning. Given that these methods require motivation from both partners, nurses should also consider the dynamics of the relationship. If the patient shows interest in natural family planning but the partner exhibits hesitancy or concern, this may impact the overall success of the method. Monitoring the involvement and support of both partners is essential in ensuring that natural family planning is a viable option.