Natural family planning (NFP) is a term which includes all methods of fertility control that center on a couple’s awareness of the woman’s fertile period.
NFP has many advantages which commend it to many couples who do not wish to rely on external methods:
- NFP can be quite effective in reducing the odds of pregnancy, to less than one per cent per year. However, since many couples do not use the method perfectly, the typical-use pregnancy rate is closer to 25 percent.
- These methods are almost cost-free except for a basal body thermometer and perhaps a menstrual calendar.
- They do not involve the use of any medication so no side-effects occur.
- They help women become more aware of their cycles and related physiological changes.
- Couples can either plan for achieving or avoiding a pregnancy using their awareness of the woman’s fertility pattern.
- Women are able to better recognize abnormalities in their menstrual cycles and reproductive systems as a result of greater awareness of their bodies.
- It promotes communication and responsibility-sharing within couples.
- It is acceptable within all cultures and religious groups.
- There are no medical contraindications as such.
- It does not require the input of a healthcare provider but leaves fertility within the couple’s control.
NFP is a process which has its own negatives, if the couple considers them to be such:
- It is a couple-centered process so both partners need to agree to use these methods.
- They do not protect the couple against sexually transmitted infections (STIs). Where appropriate, couples must use condoms or other barrier methods as well.
- Couples require careful observation and training for accurate recording, for a few months, before they can be used reliably to predict fertile days. This is more difficult but still quite possible with irregular cycles.
- Time and effort must be invested to observe and accurately record fertility indicators, which may not be possible for busy women.
- The coitus interruptus method has a high failure rate and puts great stress upon the male partner to remember to remove the penis just before ejaculation. Viable sperm may be present in the fluid that escapes before ejaculation, and sperms may also swim up from just outside the vagina to cause fertilization.
Some factors may make this method difficult, such as:
- Low-grade viral infections which may change the basal body temperature (BBT).
- Doing anything before taking the BBT may change the readings.
- The use of some medications, or the presence of some infections, may lead to cervical mucus alterations.
- Stress, or travel, may change fertility indicators.
- Recent hormonal contraceptive use may alter signs of fertility.
- Altered signs in the post-partum or post-abortal period.
Women for whom pregnancy is strictly contraindicated should not use NFP. Such women include:
- Those with poorly controlled high blood pressure, or cardiac disease.
- Those with high risk of fetal abnormalities, such as alcoholic or drug-abusing women, or if they are on teratogenic medications.
- Those with irregular periods which make it difficult to predict the fertile period may want to choose another method of contraception.
- Those with medical conditions that alter fertility indicators:
- Pelvic inflammatory disease or bacterial vaginosis, which cause increased vaginal discharge, until the condition is resolved.
- Thyroid or liver disease which can cause absence of the normal signs of ovulation.
- Medications such as lithium which alter cervical mucus production.
- Women with multiple sexual partners which increases their risk of contracting a STI.
- For at least two cycles, women who have used emergency contraception should not use NFP.