Reclaiming Reproductive Control: A Feminist Approach to Fertility Consciousness

This essay is reproduced here as it appeared in the print edition of the original Science for the People magazine. These web-formatted archives are preserved complete with typographical errors and available for reference and educational and activist use. Scanned PDFs of the back issues can be browsed by headline at the website for the 2014 SftP conference held at UMass-Amherst. For more information or to support the project, email

Reclaiming Reproductive Control: A Feminist Approach to Fertility Consciousness

by Susan Bell, Paula Garbarino, Jeanne Hubbich, Adrienne Ingrum, Lyn Koehnline, & Jill Wolhandler

‘Science for the People’ Vol. 12, No. 1, January/February 1980, p. 6–9 & 30–35

Fertility Consciousness, the recognition of times in a woman’s menstrual cycle when she is potentially fertile, is something that all women can learn and is every woman’s right. “Common knowledge” about fertility has been lost through the isolation of women from each other and the medicalization of women’s reproductive functions. We are a group of feminists working in a program sponsored by the Women’s Community Health Center in Cambridge, Massachusetts, attempting to make this information available through self-help groups. 

We began three years ago as a small research group on natural birth control, observing our own bodies and searching out and studying both scientific and practical (lay) literature. By September 1977 we were ready to share with others what we had learned about menstrual cycles, body changes, indicators of fertility, and effective natural birth control. Since then we have facilitated Fertility Consciousness/Woman Controlled Natural Birth Control self-help groups — teaching, learning from, and sharing experiences with women. In our own self-help group of facilitators and through work with others we have become increasingly aware of the political implications of this information. 

In this article we will critically assess the different methods of natural birth control, clarify what we mean by Fertility Consciousness and Woman Controlled Natural Birth Control, and discuss some of the political issues we have raised in our group. We will outline ways in which women might go about assessing Natural Birth Control classes. (See box.) 

There are a number of techniques which can be applied to prevent or to facilitate conception; in this article we will consider only contraceptive aspects. Techniques range from the rhythm method and methods based on observation of basal body temperature and changes in the cervix and other parts of the body (including cervical mucus), to the use of machines to measure physical and chemical properties of the mucus. The rhythm method is based on calendar calculations of a woman’s menstrual cycle lengths over a period of time and an assumption that future cycles will be similar to past. It has been shown that for birth control purposes the past is not an accurate predictor of the future, which explains why the rhythm method is not effective. 

There are three effective methods of natural birth control in common use: basal body temperature, ovulation method, and sympto-thermal methods. A sustained rise in basal body temperature can indicate that ovulation has occurred but gives no information about fertility before ovulation. Basal body temperature is often altered by the time of day, amount of sleep, alcohol consumption, illness or other factors; and basal thermometers are impractical in many situations. Many women have temperature patterns that are difficult or impossible to interpret1: for example, very slow or “stair step” rise or temperatures too erratic to demonstrate a sustained rise after ovulation. Therefore, the basal body temperature method has limited usefulness. 

Sympto-thermal methods combine basal body temperature with observation of mucus, cervical changes associated with ovulation, and sometimes even calendar rhythm. These indicators are used to confirm each other in defining times of potential fertility. However, they do not always coincide exactly, and a woman does not consider herself infertile until all signs are in agreement. In most cases sympto-thermal methods are unnecessarily complicated and are not as widely applicable as the Ovulation Method. 

The Ovulation Method is based entirely on observations of cervical mucus that flows to a woman’s vulva and the sensation of wetness that accompanies this. This mucus is the only sign that is used to assess a woman’s potential fertility each day. Mucus is affected by very few factors other than hormonal events, and mucus changes accurately signal ovulation. Unlike any other sign, cervical mucus also indicates infertile days in the absence of ovulation. For example, cycles without ovulation are common in women who are breastfeeding, approaching menopause, or who have recently stopped taking birth control pills. Since accurate observation and assessment of mucus depend only on interpretation by the woman herself, she can completely demedicalize the birth control process, keeping it entirely in her own hands and out of the control of the medical profession. 

We have chosen to provide detailed information on mucus observation and the ovulation method as a primary tool for Woman Controlled Natural Birth Control. We use the term “Fertility Consciousness” to indicate the broader applications for increasing our understanding of our bodies and cycles. 

The Ovulation Method — Historical and Political Background 

The fact that cervical mucus is related to fertility was known well before modern times. The Bantu people in East Africa passed this information from grandmother to granddaughter at puberty. Each woman used a smooth stone to wipe the outer lips of her vagina to collect the mucus. We also know that the Native American Cherokee people passed similar information from mother to daughter. Disruption of these and other cultures has broken down traditional communication networks and values. Countries like the United States have further encouraged the breakdown of traditional communication by exporting profitable and sometimes dangerous medical birth control devices to control reproduction throughout the world. 


Modern research into cervical mucus began in the 1950s in Australia. Drs. Lyn and John Billings were looking for a method of child spacing that was both acceptable to the Catholic Church and effective in preventing pregnancy.2 The Billings measured women’s hormone levels by blood and urine tests while at the same time asking the women to observe their vaginal discharge and note their sensations of wetness or dryness at the vaginal lips. They found that women were able to identify the time of ovulation as accurately as the laboratory measurements of hormone levels! Women did not need to follow their basal body temperature in order to do this.3 The Billings continued their work, devising “rules” for preventing or facilitating pregnancy based solely on mucus observations and gave it the name “Ovulation Method” or “Billings Ovulation Method”. 

The development of the Billings Ovulation Method was initiated by a priest, Maurice Catarinich, whose duties included marriage counseling. He selected John Billings to pursue medical research to find a solution to the weaknesses of the calendar rhythm method, the only “fertility regulation” method approved by the Roman Catholic Church at that time. Many Catholics around the world — leaders as well as rank and file — were rebelling against the prohibition of more effective methods. The goal of the research was to find a natural method that was effective in preventing pregnancy while also serving to reinforce Catholic teachings on sexuality, marriage, and women. 

The Billings Ovulation Method is aimed at promoting and strengthening traditional marriage rather than increasing the range of choices open to women. Concepts of “family planning” and “child spacing” are emphasized, with motherhood within the nuclear family held up as the ultimate fulfillment of woman’s “natural” role. A woman’s right to control her body is denied: 

Fundamental to the philosophy that inspires teachers of the method, and hopefully, those that learn it, is a rejection of all forms of artificial contraception, sterilization and abortion, leaving the marriage act always open to the transmission of life.4

EIRTAW Workshop

The EIRTAW Workshop (Ethical Issues in Human Reproductive Technology: Analysis by Women) held at Hampshire College in June 1979 analyzed issues in the areas of contraception, sterilization abuse, prenatal diagnosis, neonatal care, sex preselection and in vitro fertilization. Adapted papers, edited discussion and commentary from the EIRTAW Workshop will be published by Humana Press, Clifton Park, NJ, in the fall of 1980. Tentatively titled Women Analyze Reproductive Technologies (eds., Helen B. Holmes, Betty B. Hoskins and Michael Gross), the proceedings will appear in two volumes. To be put on the list for prepublication notification write: EIRTAW, P.O. Box 1022, Amherst, MA 01002.

Transmitting these values is fundamental to the way the Billings Ovulation Method is usually taught. Often teachers are more concerned with propagating this value system than with knowing and teaching the method accurately: 

The teacher will inevitably communicate her own hierarchy of values to the clients. Her attitudes towards married love, towards the place of the physical sexual act in married life. . . . will be sensed by the client, and will hopefully influence them [sic] to their advantage.5

In order to ensure that women learn this value system, the teaching is usually done on an individual (or married couple) basis or in classes including men, so that women remain isolated from freely sharing experiences with one another. The stated goal is to give each woman only the bare minimum of information necessary for her to use the method. This oversimplification, also found in books, is summarized by the term “KISS” (keep it simple, stupid!), a shorthand way to remind teachers that they should share as little factual information as possible. 

Formation and Role of WOOMB 

The leading promoters of the Billings Ovulation Method define their work as both religious and political. Since they are extremely concerned about retaining control of the Billings Ovulation Method as well as propagating it, they have formed the World Organization/Ovulation Method/Billings (WOOMB) and registered a trademark in its name. To obtain WOOMB approval for an event or for written materials, applicants must prove that their philosophy conforms with that of WOOMB. WOOMB is trying to gain a monopoly over selection and training of teachers by requiring and controlling a teacher certification process. Criteria include acceptance of and adherence to the moral philosophy of WOOMB. 

In order to broaden legitimacy, achieve more credibility, and gain access to government funding, attempts are often made to camouflage the Catholic control of natural family planning programs. For example, non-Catholic supporters are often prominently used; also programs which appear to be sponsored by independent groups “just happen” to use space provided by a Catholic hospital.  

Exploitation and Cooptation of Feminist Issues 

WOOMB and other natural family planning organizations also capitalize on and coopt some of the issues promoted by feminists. They claim to be speaking out strongly against the sexual exploitation of women which they say is facilitated by the use of the other birth control methods that enable women to be available for men’s pleasure every day, without substantial risk of pregnancy. (According to the “rules” of the Billings Ovulation Method, women should “abstain” from intercourse during times when they are fertile.) When examined further, however, their statements reveal concern about protecting the dignity of “natural” womanhood (and reinforcing the nuclear family). They do not address the differences in power between men and women within heterosexual relationships. 

A striking example is a story presented at an international conference on the Billings Ovulation Method, International Institute V, about how the Billings Ovulation Method solved a “marriage problem.” In this case the “drunk and inconsiderate husband” regularly raped his wife. The wife was instructed to be seductive and demand intercourse every night she was infertile. A decrease in the husband’s drunkenness and rape was presented as evidence that previous sexual rejection by his wife had been the cause of his “inconsiderate” behavior. 

WOOMB and other natural family planning movement groups also know that women are concerned about the health risks and possible complications of non-natural birth control methods. Proponents of the Billings Ovulation Method have prepared and circulated well-researched papers on harmful effects of hormonal contraceptives, IUDs, and sterilization. However, these presentations sometimes contain incomplete information and overstatement to the point of misrepresentation. There is a glaring absence of discussion of barrier methods (diaphragm and jelly, foam and condom, cervical cap), which have no serious health risks. When barrier methods are mentioned, they are dismissed with a brief allusion to “unaesthetic” aspects of their use. Encouraging facts about high effectiveness and physical safety are omitted. Reading this literature, one would conclude that when women wish to use birth control, they have only two alternatives: to risk serious injury by using dangerous contraceptives or to follow the WOOMB philosophy. 

WOOMB and the natural family planning movement also claim to be fighting population control. At International Institute V we were told that American economic greed motivated funding for population control programs in Third World countries and linked population control programs to foreign aid. The real solution to poverty in these countries, according to Lyn Billings, is child spacing through use of the Billings Ovulation Method. In fact, the Catholic natural family planning movement is exploiting the reactions of Third World people, who oppose coercive population control programs, by offering an effective alternative. Unlike other natural methods, which require thermometers and calculations, the Billings Ovulation Method is a technique that can be easily exported throughout the Third World by means of the Church’s missionary structure. Also, the missionaries gain political influence and spread their moral teachings among the people. 

Although the natural family planning hierarchy supports population control for the Third World, it exhorts white higher class populations to increase their birth rates. A recent publication directs natural birth control users as follows: 

Among the contraceptive populations of the West, I believe that the message ought to be “get having babies! — you are going to ruin your country and often your personal future, by regarding, say, two as quite enough, when you have no great excuse.”6

Alternatives to Catholic-controlled Programs 

A variety of non-Catholic groups offer natural birth control programs. Some have New Age religious or spiritual perspectives which reinforce stereotyped roles for women and oppose other types of birth control and abortion. Other programs present natural methods simply as birth control that is free of physical side effects and can enhance communication between partners. Recently, some corporations are developing programs to cash in on newly available federal funding. 

Other groups teaching natural birth control have adopted the terminology used by Catholics, often without examining the assumptions inherent in the use of these terms. Since the Ovulation Method was developed to promote Catholic values, it is steeped in restrictive assumptions about sexuality, morality and women. For example, Roman Catholic morals consider penile/vaginal intercourse with ejaculation directly into the vagina as the only approved form of sexual activity. “Abstinence” therefore means not having intercourse and also not having sexual contact of any kind. For people whose sexual expression includes activities other than penile/vaginal intercourse, the meaning of the word abstinence may be unclear. Further, the word abstinence perpetuates sexist assumptions that penile/vaginal penetration is the most desirable sexual activity and anything else must be inferior. As women talk more about sexual experiences and feelings, they more clearly understand the oppressive nature of these assumptions. In an analysis of women’s descriptions of ways they do and do not experience sexual satisfaction, Shere Hite reports: 

Insisting that women should have orgasms during intercourse, from intercourse, is to force women to adapt their bodies to inadequate stimulation and the difficulty of doing this and the frequent failure that is built into the attempt breeds (sic) recurring feelings of insecurity and anger…. Sex is defined as a certain pattern — foreplay, penetration, intercourse, and ejaculation — …. indeed, intercourse is the pattern…. This pattern is what oppresses women.7

The Ovulation Method Teachers Association (OMTA) is an organization formed by non-Catholic teachers of the Ovulation Method to coordinate and distribute information about this Method. OMTA is a positive alternative to the natural family planning programs. The organization publishes a newsletter which provides a forum for sharing information, concerns and experiences, reviews published books and articles, and updates information and statistics about the Ovulation Method. In addition, OMTA is developing a rigorous, responsible, nonmoralistic set of criteria for teacher training and certification, and offers referrals for Ovulation Method instruction and followup in the U.S.A.8

The Ovulation Method — A Practical Explanation 

To use the Ovulation Method for birth control a woman keeps a daily record of any sensation of wetness or lubrication at her vulva and notes the characteristics of any vaginal discharge present on the external vaginal lips. She learns how to interpret the significance of different kinds of discharge, according to the “rules” of the method. With this information and an understanding of the menstrual cycle, a woman can determine each day whether she is potentially fertile or infertile. To avoid pregnancy, a heterosexual woman who is using this information for contraception simply avoids penile/vaginal contact on all days of potential fertility. 

The rules for determining potential fertility are based on biological information about the survival time of an egg cell after ovulation and the survival time of sperm cells in a woman’s reproductive tract. There is only one time in each cycle when an egg is released (or two eggs in the case of non-identical twins). Egg survival is no longer than 12-24 hours. Without favorable cervical mucus, sperm cannot travel through the cervix, and die within a matter of hours. With favorable cervical mucus sperm have been known to survive in a woman’s reproductive tract and fertilize an egg up to five days after intercourse. 

The Ovulation Method provides a way to recognize the approach of ovulation. The cells lining the cervix respond to ovarian hormone changes by secreting different types of mucus. As an egg is maturing, the ovary produces increasing amounts of estrogen and the consistency of the cervical mucus changes, producing a wetter and more lubricative vaginal discharge. This is a sign that activity is occurring which could lead to ovulation. Estrogen levels drop just before ovulation and progesterone starts to rise at about the time of ovulation, resulting in a noticeable change in the mucus. This change, which is characteristic for each individual woman, signals the approximate day of ovulation. 

Very simplistically, estrogen dominates the preovulatory part of the menstrual cycle and progesterone the postovulatory phase. Although there is always some mixture of mucus types, estrogen dominant mucus is necessary for fertility. Among other functions, this type of mucus nourishes and transports sperm and protects them from vaginal acidity, which is lethal to sperm. Mucus that is fluid enough to flow from the cervix to the external vaginal lips may contain enough estrogen dominant mucus to support sperm life. Thus, checking for the presence of mucus that has flowed out of the vaginal opening is an accurate gauge of hormonal activity. All days of external mucus before ovulation plus an interval following it are presumed to be potentially fertile. 

A woman learns to recognize her mucus pattern over the course of one or more cycles. She describes her mucus in her own words, records the description each day, and applies the rules to determine whether she might be fertile on that day. Mucus characteristics vary quite a bit from woman to woman, so that it is difficult or impossible for many women to learn adequately from the profusion of books attempting to teach natural birth control techniques. The most effective teachers are women who themselves practice mucus observation and have learned how to share their knowledge responsibly.9

Studies have shown that the efficacy of the Ovulation Method compares favorably to other highly effective birth control methods (condom and foam, diaphragm and cream or jelly, IUD, pills, sterilization, and abortion).10 When assessing efficacy of any birth control method, the fact that different measures of efficacy are used makes it difficult to compare some studies. 

Threat to Birth Control Establishment 

As the health risks, pregnancy rates, and political implications of chemicals and mechanical birth control devices become more widely known and understood, many women are becoming interested in methods that do not involve drugs or devices. Widespread practice of effective birth control through knowledge of our own bodies threatens some of the profits reaped by drug companies, doctors, and medical facilities. In addition, it challenges the belief that doctors must “take care of’ women’s reproductive capacity. 

In response to these threats, many doctors and family planning programs refuse to inform themselves about the Ovulation Method. They actively discourage women from learning about this or other natural methods. They try to intimidate women who already use natural birth control, by maintaining that unwanted pregnancy may occur if they do not switch to a different kind of birth control. 

Issues to Consider in Choosing a Group 

  1. Who is doing the teaching? (a woman with experience herself? a male-female couple? a medical person? a nun or priest?) Where did the teacher learn how to teach the method? 
  2. What is the format? (individual sessions, lecture classes, or more participatory classes or groups? Is there more than one meeting?) 
  3. Is there an option to learn in an all-women group? If all classes are open to men, is the orientation toward monogamous heterosexual couples? If not, what efforts are made to insure support for other sexual lifestyles? 
  4. Which natural method is offered? (Ovulation Method or sympto-thermal?) If sympto-thermal, does it include any calendar rhythm calculations? (calendar rhythm does not work) 
  5. What support is available during the learning process, especially for the first few cycles? What follow-up arrangements are there after that time? 
  6. Where does the registration fee go? (are you unwittingly supporting a cause you would find offensive?) Is the teacher self-employed? Is there a sponsoring organization? Is the program receiving any government or other funding? 
  7. What is the teacher’s position on other methods of birth control? Will she refer to a facility that provides a full range of birth control options? Is she knowledgeable about positive as well as negative aspects of other birth control methods? Does she feel that natural methods are “the best” or “the only acceptable” options? 
  8. What is the teacher’s position on abortion? Does she support women’s right to choose abortion? Would she refer you to an appropriate facility if you became pregnant and wanted information about getting an abortion? 
  9. What is the sponsoring organization’s position on birth control and abortion (repeat questions 7 and 8)? Some teachers try to disguise or downplay their connection with anti-abortion, anti-contraception organizations, especially when talking to feminists. If you do not get straightforward answers to questions 6-9, be suspicious. If you hear the term ‘pro-life’ used, remember that this indicates an anti-woman, anti-abortion ideology. 

Mechanization of Ovulation Method: Unnecessary and Likely Ineffective 

Projects are also underway to coopt the Ovulation Method by developing machines and devices which measure changes in cervical mucus at times of potential fertility. Some of these products are designed to require frequent visits to a doctor’s office, while others are being developed for purchase and use in the home. Newspapers and magazines have reported that these new technologies, when available, will revolutionize the birth control field by providing effective birth control without side effects. This ignores the fact that the Ovulation Method, scientifically based, highly effective, used successfully around the world, is available now, without the development, rental, or sale of any devices. In fact, many misinformed articles continue to appear, portraying natural birth control as difficult to learn, not very effective, and not suitable for responsible women. 

It is unlikely that any device to measure mucus changes will increase the effectiveness of the Ovulation Method in preventing pregnancy. In fact, there are reasons to predict the opposite. No machine can take into account the wide range or variation from woman to woman; in contrast, each woman making her own mucus observations can concentrate on her own individual cycle. The rules of the Ovulation Method allow for special circumstances and unpredictability from one cycle to the next.11 In addition, a mechanical device is subject to errors in manufacture as well as operational failure during use. But mechanical devices can be used to generate profits and discourage women from becoming autonomous in controlling our reproduction. 

We cannot emphasize enough that the use mechanical devices to take quantitative measurements is unnecessary for birth control. It is neither mysterious nor difficult for the vast majority of women to become aware of their own mucus changes and to recognize ovulation with the same accuracy as sophisticated laboratory measurements of hormone levels. 

Fertility Consciousness/Woman Controlled Natural Birth Control 

Birth control methods have the potential for allowing women to control our reproductive lives. These methods can also be used as a tool of political and social repression. Many experimental and potentially dangerous birth control methods have been widely spread throughout the world in a coercive manner for the purposes of population control. Women of color are among the special targets. Many poor and Third World women are injected with Depo-provera or sterilized without their understanding or consent. Birth control methods are promoted without giving full explanations of risks, without giving adequate information about and access to the full range of methods to choose from, and without increasing a woman’s knowledge of her own body. 

Keeping women ignorant about our bodies is another way to control women, decreasing our ability to make choices, creating dependence on the medical establishment, and medicalizing our reproductive function. This can be countered by learning to examine and understand our own bodies; learning that there is a range of variation rather than one standard norm; validating our experiences by sharing them; exploring what we all have in common as women; and formulating new questions to address. We call this process self-help. Self-help challenges the existing power of the medical establishment over women’s lives. As we know more, we can make stronger demands for changes in the medical system and reclaim control of women’s health care. Learning about mucus observation and the Ovulation Method in a self-help group is an empowering experience that goes beyond providing tools for fertility consciousness and for woman controlled birth control. 

In fertility consciousness self-help groups we share information about female sexual and reproductive organs, including cervical self-examination, as well as detailed information about the Ovulation Method. Groups of 10-12 women meet with two experienced and trained facilitators for five weekly, 3-hour sessions. Most women will have the opportunity to observe a full cycle of mucus changes during that time. We also hold follow-up sessions once a month which are open to all women who have completed a group. 

Everyone is encouraged to be an active participant, sharing her experiences and reporting on her mucus observations from week to week. Rather than a teacher-to-class dynamic, women support each other in developing confidence in mucus observations and taking responsibility for our reproductive lives. The group process creates a setting in which women can explore issues uncovered by learning this information. For example, many woman have been taught that their vaginal discharges are abnormal or unclean; it can be both liberating and politicizing to discover that these discharges are a universal and informative sign of healthy body functioning and to think about why this kind of information has been withheld from us.


Beyond Birth Control 

Our goal is to provide both information and a process that women can choose to use in a variety of ways. Relying on a natural birth control method raises issues about responsibility for contraception, conflicting feelings about becoming pregnant, communication with male sexual partners, applying “rules” to sexual behavior, and who it is that defines sexual expression in relationships. Lesbian and celibate women, as well as heterosexually active women who use non-natural birth control. have found it relevant and empowering to understand the changes they experience throughout their menstrual cycles. Women in menopause self-help groups have also been excited to gain access to this way of monitoring estrogen levels in their bodies. 

Many women are interested in combining fertility consciousness with the use of barrier methods —  condoms, foam, diaphragm, cervical cap — and we discuss this as an option. Since the Billings and other Ovulation Method researchers condemn barrier methods as immoral, they have not studied these combinations of methods. As facilitators we make it clear that there is a possibility of higher pregnancy rates for women using barrier methods during fertile times. Women share experiences in learning whether they can distinguish mucus in the presence of spermicides. We talk about the significance of losing a day’s observations after the use of jellies or spermicides at various times in the cycle. Women can then take responsibility for making informed decisions, knowing the scientific basis of the Ovulation Method and the philosophy that motivated and determined the research process. 

In summary, when natural birth control information is presented along with a restrictive set of values about women’s biological functions and roles in society and the family, natural birth control reinforces women’s oppression. When this information is presented as a wholesome form of birth control without challenging the oppressive assumptions which shaped the development of these methods, women gain an important birth control option but the Catholic assumptions continue to be perpetuated. When this information is used as a self-help tool, it expands not only the birth control choices available to women but also our abilities to demedicalize and control our own bodies and our reproductive lives.


This is not a complete list of references. Rather, it concentrates on some basic studies in the development and testing of the Ovulation Method, some sources of scientific information, and good sources of Ovulation Method information (see especially Nos. 10 and 11). There are many books available on “natural birth control” methods and programs of different sorts; we do not recommend any of these books not listed below. Please contact Fertility Consciousness Group, Women’s Community Health Center, 639 Massachusetts Ave. #210, Cambridge, MA 02139, for more information. 

  1. E.l. Billings, J.J. Billings. “Symptoms & Hormonal Changes Accompanying Ovulation.” The Lancet, Feb. 5, 1972.
    The initial publication on the correlation of cervical mucus observations by 22 lay women (“housewives”) and hormonal changes. The study demonstrates that “normal” women can predict and identify ovulation by noting the pattern of vaginal mucus symptoms, without recourse to temperature measurement or more specialized tests.
  2. Hanna Klaus M.D. et al. “Use Effectiveness and Analysis of Satisfaction levels with the Billings Ovulation Method: Two Year Pilot Study.” Fertility and Sterility, Vol. 28, No. 10, Oct. 1977.
    Joan Goebel M.D., Ralph E. Woods M.D., Mary Castles PhD, George Zimny PhD. A 2 yr. study of 135 women using Billings Ovulation Method. There were 1381 exposure cycles during 1st year and 580 during 2nd year. Total conception rates were 1.303 per 100 woman months for 1st year and 1.8961 per 100 woman months for 2nd year. Biologic failure (method failure) are 0.072 per 100 woman months, the first year and 0.517 per 100 months for 2nd year. Continuation rate 51.8%. Compares use effectiveness of other contraceptives to Ovulation Method: 
  3. M.C. Weissmann, L. Foliaki, E.l. Billings, J.J. Billings. “A Trial of the Ovulation Method of Family Planning in Tonga.” The Lancet Oct. 14, 1972.
    282 women using Billings Ovulation Method for 250.3 mo. total (average approx. 8.8 mo. each woman). Of the 81 pregnancies occuring, 28 were due to couples not using the method because they wanted more children. 50 women ignored indications of possible fertility (user failure) and 2 pregnancies were from teaching failures and 1 from method failure.
  4. Billings & Billings. “Teaching the Safe Period Based on the Mucus Symptom.” Linacre Quarterly, Vol. 41, No. 1, Feb. 1974.
    Another review of the Billings Ovulation Method, including teaching experiences and philosophy of the Billings.
  5. Don P. Wolf PhD, Luis Blasco M.D., Mohammad A. Khan PhD, Mitchell Litt D. Eng. Sc. “Human Cervical Mucus II. Changes in Viscoelasticity During the Ovulatory Menstrual Cycle.” Fertility and Sterility, Vol. 28, #1, Jan. 1977.
    Correlates high mucus viscosity with favorable sperm penetribility and with the ovulatory phase of the menstrual cycle.
  6. J.F.P Kerin, C.D. Matthews, J.M. Svigos and M. Makin in Journal of Reproduction and Fertility #46, 1976. pp. 499-500.
    Cervical mucus is most favorable to the penetration of spermatoza on the day preceeding and the day of the LH surge, and thereafter decreases rapidly.
  7. John Marshall “Cervical Mucus and Basal Body Temperature Method of Regulating Births.” The Lancet, Aug. 7, 1976.
    84 women used the method for 1195 cycles. There were 22 unplanned pregnancies per 100 woman cycles. No distinction is made between method failure and user failure.
  8. World Health Organization, Special Programme of Research, Development and Research Training in Human Reproduction: Seventh Annual Report, Geneva Nov. 1978. Reprinted in Family Planning Perspectives, Vol. 2, No. 1, Jan./Feb. 1979.
    890 women contributed 2685 cycles resulting in 19.4 pregnancies per 100 woman years use effectiveness. 98.5% method effectiveness.
  9. Frank J. Rice, Claude Lanctot, Consuelo Garcia-Devesa, “Effectiveness of the Sympto-thermal Method of Natural Family Planning: An International Study.”
    Sympto-thermal method used Basal Body Temperature, mucus and calendar calculations. 1022 couples contributed 21,736 cycles and reported 128 unplanned pregnancies, a rate of 7.47 conceptions per 100 woman years. Only 16 pregnancies occurred when the couples were following instructions, giving a theoretical effectiveness of 0.93 pregnancies per 100 woman years using the Pearl formula. Couples trying to prevent any pregnancies had a failure rate of 4.13%; those only delaying a pregnancy had a failure rate of 14.83%. The Symptothermal method used alone had a failure rate of 6.24% while use of contraceptive devices with the Sympto-thermal method had a failure rate of 10.33%. Method failure using Pearl index was 0.75% over 24 months for couples using STM only. User failure 5.49%. STM with barrier methods during a portion of the fertile period: method failure 1.36%; user failure 8.97%.
  10. Guren, Denise, and Gillette, Nealy. The Ovulation Method: Cycles of Fertility. Self-published. June, 1977. Available in bookstores or from Denise Guren, 4760 Aldrich Road, Bellingham, Washington 98225. Cost $3.20 postpaid. Clear, concise, without religious orientation; best presentation of the Ovulation Method in print.
  11. Ovulation Method Newsletter. Available from Ovulation Method Teachers Association, P.O. Box 14511, Portland, Oregon 97214. An excellent newsletter, including new information about Ovulation Method, program reports, reviews of books and articles.

World Health Organization. Cervical Mucus in Human Reproduction. Copenhagen: Scriptor, 1973. Available from Human Reproduction Unit, WHO, 1211 Geneva 27, Switzerland. Scientific and medical information on the physiology of mucus and its relation to fertility.

This article was written by Susan Bell, Paula Garbarino, Jeanne Hubbich, Adrienne Ingrum, Lyn Koehnline, and Jill Wolhandler for the Fertility Consciousness Group of the Cambridge Women’s Community Health Center. Portions of the article were presented as part of a talk at the EIRTAW (Ethical Issues in Human Reproductive Technology: Analysis by Women) Workshop at Hampshire College, Amherst, MA in June 1979. 

>> Back to Vol. 12, No. 1<<


  1. Rice, Frank J., Lanctot, Claude, and Garcia-Devesa, Consuela. “Effectiveness of the Sympto-thermal Method of Natural Family Planning: an International Study.” In press.
  2. Much of the information in this section was gathered when two members of our group attended International Institute V of the Billings Ovulation Method in Los Angeles in January 1979, as well as from reading and discussing written material.
  3. Billings, E.I. and Billings, J.J. “Symptoms and Hormonal Changes Accompanying Ovulation.” Lancet, Feb. 5, 1972.
  4. Hume, Kevin. “The Ovulation Method of Natural Family Planning.” January 1977, p. 2.
  5. Billings, John J. “Overview of the Ovulation Method — 1977.” Third Annual Institute on the Ovulation Method.
  6. Lawler, Ronald. “An Address to the Clergy.” Bulletin of the Natural Family Planning Council of Victoria. Vol. 6, No. 1, March 1979, p. 7.
  7. Hite, Shere. The Hite Report. Macmillan, New York, 1976, p. 291.
  8. For more information about OMTA, write to them at: P.O. Box 14511, Portland, Oregon 97214.
  9. For more information about the Ovulation Method, see Denise Guren and Nealy Gillette’s book, The Ovulation Method: Cycles of Fertility. June 1977. This can be ordered from Denise Guren, 4760 Aldrich Road, Bellingham, Washington 98225. Cost is $3.20 postpaid. This is the only accurate, clearly written, responsible, nonmoralistic book available.
  10. A number of factors influence effectiveness rates, including the way the method is taught or provided, the motivation of people using the method, and the way that pregnancies that occur during the study are categorized and reported. Some studies of the ovulation method use women teachers, while others use couples, men, or even correspondence courses. A study by Rice, Lanctot, and Garcia-Devesa found “a 3.5 times higher pregnancy rate for those who have not reached their desired family size over those who equal or exceed their desired family size.” (Rice, Lanctot, and Garcia-Devesa, op. cit.)
    It is also important to distinguish between different factors resulting in pregnancies. Pregnancies can result from failure of the method; that is, women who understand and apply the method correctly occasionally become pregnant. (This is true for every birth control method.) Teaching-related pregnancies result when women do not understand the method and therefore apply it incorrectly. Total pregnancy rates also include women who correctly identify a day of potential fertility and choose not to follow the rule of avoiding penile/vaginal contact. Some studies distinguish between these factors, while others do not. Recent World Health Organization studies in five countries demonstrated a 98.5% method effectiveness rate, yet concluded that the Ovulation Method was relatively ineffective because overall pregnancy rates ranged from 10.4 to 33.7 pregnancies per 100 woman years. WHO reported that 97% of women were able to interpret their mucus pattern correctly, and high pregnancy rates were due to “couples knowingly taking a chance during the fertile phase.” (World Health Organization. Special Programme of Research, Development and Research Training in Human Reproduction: Seventh Annual Report, Geneva, Nov. 1978. Reprinted in Family Planning Perspectives, Vol. 11, No. 1, Jan./Feb 1979, p. 41.) In our opinion this shows that the method is highly effective and that motivation is a critical factor.
  11. Unfortunately, space does not permit full discussion of this point. For discussion of the rules, see Guran and Gillette, op. cit.