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Effectiveness / Studies

"There is no doubt about it: some physicians are well informed about Natural Family Planning and they strongly encourage its use. Some are so convinced about the medical and moral hazards of unnatural forms of birth control that Natural Family Planning (NFP) is the only form of conception control they will offer to their patients.

Natural Family Planning Research Database

"However, the fact that some methods of NFP can be 99% effective in the avoidance of pregnancy seems unknown to most of the general public — including many health professionals. The fact that the fertility awareness which is a key element of modern NFP is also very helpful to couples of marginal fertility in seeking pregnancy is also unknown

"There are three basic reasons for widespread ignorance and prejudice regarding natural family planning.

"First of all, many health care prefessionals are uninformed about the modern methods of natural family planning. Therefore, they group various natural methods that are entirely different together under the title of 'rhythm'…

"Secondly, many people, including health care providers, are skeptical of anything natural. Their orientation is so much towards drugs, surgery, and devices that they find it difficult to believe that common, ordinary married couples can understand their mutual fertility well enough to achieve the same effectiveness associated with powerful drugs.

"Thirdly, some organizations that specialize in or are oriented towards unnatural forms of birth control have been unfair in their treatment of NFP. Old rhythm studies from Latin America with low effectiveness rates are quoted and requoted, but a recent and well designed study by the U.S. federal government showing a 100% method effectiveness is ignored or misquoted…

"The Sympto-Thermal Method taught by the Couple to Couple League and most other teaching organizations uses the two natural signs of cervical mucus and the waking temperature plus certain information from the woman's own previous cycle history, and these three factors are used together in a crosschecking way. Users are generally taught about physical changes in the cervix for further corroboration

Method Effectiveness

The Los Angeles Study: 100% Method Effectiveness

"Between 1976 and 1978, the U.S. Department of Health, Education, and Welfare conducted a prospective study to determine the relative user effectiveness of two different systems of natural family planning.1 Participants were randomly assigned to either the Sympto-Thermal Method (STM) or Ovulation Method (OM) sides of the study…The resulting group of 1257 couples had an average age of 28 and had only one child per family… The couples who followed these simple rules achieved a 100% effectiveness rate in avoiding pregnancy, i.e. zero unplanned pregnancies. (The couples who used the OM rules had 5.67 unplanned pregnancies per 100 woman years of exposure, i.e. about a 94% method effectiveness rate. Better OM results were achieved in a five nation World Health Organization study: a standard pearl rate of 2.6; i.e., a 97.4% method effectiveness rate.)2

"A 100% effectiveness rate cannot be sustained in a large population and thus claims made for the STM state '99% method effectiveness'."

The Fairfield Study: 99% Method Effectiveness

"Between 1970 and 1973, 1022 couples participated in a five nation (Canada, Colombia, France, Mauritius, U.S.A.) study called the Fairfield Study after the university of the principal investigator.3…The couples who followed these more liberal rules achieved a method effectiveness rate of 99% according to the Pearl formula (9 unplanned pregnancies in 14,416 months of exposure).

The Roetzer Studies: 99% and 100% Method Effectiveness

"Dr. Joseph Roetzer has distinguished between the method effectiveness of Phase I and Phase III according to his rules.4 In his 1978 study, he reported that coitus during the first six days of the fertility/menstrual cycle yielded one pregnancy in 8,532 cycles, a Pearl rate of less than ).2 per 100 woman years of exposure, i.e. well within a 99% method effectiveness. Using a combination of three days of well elevated temperatures crosschecked by three days of the disappearance of the more fertile mucus to determine the start of Phase III, couples experienced zero unplanned pregnancies in 17,000 cycles, i.e. a 100% method effectiveness rate.

The Creighton Model is a method of fertility awareness developed by Dr. Thomas Hilgers, director of the Institute for the Study of Human Reproduction at Creighton University in Omaha.

Studies have found it to be highly effective for both avoiding (99% effective) and achieving pregnancy. A 14-year five-state study [Journal of Reproductive Medicine, June 1998] showed the method to have a 99.5% rate for method effectiveness, and a 96.8% use effectiveness rate ("real-life" rate that includes use errors).  Research shows oral contraceptives ("The Pill") to have a 97.0% user effectiveness rate.

NFP frees the body of chemical pollutants (e.g., the Pill and injectable hormonal birth control methods).

These hormonal chemical methods are often potentially abortifacient in nature, and the long-term effects of these substances on the female body are not clearly understood at this time.

[NFP Home Study Course ($64.95), call 1-800-745-8252]

Contact Couple to Couple League for teachers and classes near you: 1-513-471-2000;


Because of her research and personal experience in her medical practice contrasting contraceptives and natural family planning [NFP], Dr. Mary Martin made the decision to join a select group of doctors who have stopped prescribing contraceptives. The vast majority of her patients have stayed with her and have learned the benefits of NFP. Dr. Martin had been receiving many calls from her patients about problems with excessive bleeding. She no longer receives such calls.

For a list of doctors who do not prescribe contraceptives, click here. 

Hormonal contraceptives (the pill, Norplant and Depo-Provera), besides being abortifacient, have side effects for the women who use them.

In addition to abnormal bleeding, serious side effects include high blood pressure, blood clots, heart attacks, migraine headaches, bone loss, and menstrual problems after ending use of the drug.

Although there are undoubtedly other factors involved, it is no coincidence that the rise in breast cancer followed 10 -15 years after hormonal contraceptives first became readily available.

The connection between abortion and breast cancer is the result of the proliferation of breast cells early in a pregnancy that remain in an unstable state when the pregnancy is ended abruptly. 

Contraceptive drugs have a similar effect on the breast. 

It is also no coincidence that women who have been on the pill for years, are finding they are infertile when they want children. The side effect is connected to the rapid aging of the cervix caused by these drugs which can lead to infertility.

Infertility is becoming a national plague, with couples spending hundreds of thousands of dollars trying desperately to conceive. Undiscriminating doctors have been, and continue to become wealthy prescribing contraceptives and then treating the side effects.

The effectiveness of contraceptives is not as high as often claimed. Contraceptive drugs are often claimed to be 99% effective (i.e. in preventing pregnancy). In fact, statistics show closer to a 7% "failure" rate (i.e. pregnancy occurs) for contraceptive drugs. 

The condom has a 15% "failure" rate.

In contrast, NFP that many critics claim is not effective has a success rate of 98%. Actually…over 20,000 women in India [were trained] to use NFP with a 0% failure rate. Statistics also show that the divorce rate for couples using NFP is 3% compared to a rate of 50% for couples who use contraception.

Contraceptive use attacks married and unmarried sexual relationships at their core.

Using contraceptives in a sexual relationships outside marriage promotes the idea that people can have sex without consequences. Reality enters the picture in the form of sexually transmitted diseases, undesired pregnancy, broken dreams, and years consumed in dead-end relationships.

Using contraceptives within marriage fosters the idea that sex is a plaything.

In fact, sex is one of the strongest tools that a couple can use to strengthen their relationship.

Treating sex like a toy leaves both partners feeling used because they are being used. After years of this, many couples divorce. These devastated relationships and marriages lead to millions of children being reared by one parent or none. Damaged families rear troubled children.  [IRLC News, vol. 32, no.1, winter 2002;]  


The FDA has approved a saliva-based ovulation prediction test (TCI Ovulation Tester) which "is an alternative to the previous urine testing, cervical mucus observation, and temperature methods". The FDA says the test is 90% reliable in predicting ovulation (Neergaard, AP/Sacramento).

According to Couple to Couple League, however, the salivary test may be used as a secondary sign for couples learning to identify the fertile time, but it is too unreliable to be used as a method of birth regulation. At best, it can help couples seeking to achieve pregnancy find out when it is time to start trying, having previously abstained to maximize sperm count. Claims of 90% are a play on words. The statistic refers to the fact that 90% of women do experience a ferning pattern concurrent with ovulation. As far as how early this sign can predict the onset of ovulation, the statistics don't bode well. Salivary testing for either beta glucorinidase or ferning are unable to forecast ovulation the necessary five days required to prevent extended sperm life from causing conception. [Keith Bower, CCL, email response, 20 Jan 03] 

For a much broader look at NFP, go to, or visit these pages:

The Effectiveness of the Creighton Model Ovulation Method in Avoiding and Achieving Pregnancy
"Use Effectiveness of the Creighton Model Ovulation Method of Natural Family Planning"; Fehring, Richard J.; Lawrence, D.; and Philpot, D., Journal of Obstetric, Gynecologic, and Neonatal Nursing Vol. 23, No. 4 . May 1994. pp. 303-309
Click here

Natural Family Planning Research Database