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Postgraduate Training Course in Reproductive Health/Chronic Disease

Natural Contraceptive Methods

Kirsten M Vogelsong, PhD
ScientistUNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and
Research Training in Human Reproduction, (HRP)
Department of Reproductive Health and Research
World Health Organization
CH-1211 Geneva, Switzerland

See also presentation


The goal of the lecture is to provide each student with knowledge, understanding and appreciation of:

  • The rationale for increasing contraceptive choice by making available natural methods.
  • The various natural methods of family planning.
  • Current research designed to simplify and mainstream natural methods.
  • New technologies under development designed to aid women in determining and managing their own fertility.


Natural Family Planning (NFP) refers to a variety of methods used to prevent or plan pregnancy, based on identifying a woman’s fertile days. For all natural methods, abstinence or avoiding unprotected intercourse during the fertile days is what prevents pregnancy. The effectiveness and advantages of NFP address the needs of diverse populations with varied religious and ethical beliefs. They also provide an alternative to women who wish to use natural methods for medical or personal reasons. For reproductive health service providers, NFP expands options and improves the quality of family planning services. Statistics indicate that in many countries around the world, periodic abstinence and NFP methods play a major role in people’s efforts to manage their fertility. A variety of natural methods have been established and are used globally; however there is a need for better tools, training, and instruction in NFP in order to maximize the potential benefits of these methods. Ongoing efforts seek to improve the quality of NFP services and to develop new methods and technologies that can allow simpler, more effective natural methods to be delivered to a broader range of couples.

NEED FOR NATURAL FAMILY PLANNING (NFP) – Advantages and disadvantages

For individual couples, the goal of practising contraception varies from postponing childbearing, spacing births and limiting family size to absolute freedom from childbearing. Contraceptive needs of couples vary according to their type of relationship, purpose of contraception and age. Methods of fertility regulation need to adequately meet the varied and changing personal needs of couples in their reproductive lives and in the widely different geographical, cultural, religious and service delivery settings around the world.

Globally, about 15 % of married women report using methods based on periodic abstinence to achieve family planning objectives. Side effects, or fear of side effects, account for the vast majority of non-use and discontinuation from use of “modern” methods of family planning. The demand for natural methods, therefore, is very high.

Natural family planning is the only contraceptive method that empowers couples to control their fertility irrespective of economic status and independent of logistics supplies and distribution systems.

Women and couples using NFP frequently cite advantages including:

  • Increased self-awareness and knowledge of their fertility
  •  Increased reliance on their own resources rather than a family planning program or other sources of contraception
  •  Increased independence from costly or distant medical services
  • Freedom from artificial substances and the side effects or potential medical risks of other methods
  • Reduced re-supply costs associated with commodity-based methods
  • Enhanced partner communication and intimacy
  • For some, the ability to adhere to religious and cultural norms.

On the other hand, disadvantages of NFP include:

  • No protection from sexually transmitted infections
  • Requires training by qualified instructor
  • Very unforgiving of incorrect use
  • Requires partner consent and cooperation
  • Less appropriate for women with irregular on unpredictable menstrual cycles
  • Requires daily or regular monitoring and recording


Fertility awareness is an extension of the client empowerment approach to natural family planning. Fertility awareness helps people – men and women – learn about their bodies so that they can:

  • Identify what is healthy and normal for each individual throughout the life cycle;
  • Identify signs and symptoms that may indicate a need to seek health care;
  • Practice behaviors that have positive effects on their reproductive health;
  • Develop communication and self-advocacy skills to help them deal effectively with partners and health care providers about their reproductive health;
  • Skills developed through a fertility awareness approach can be tailored and targeted to children and adolescents to help young people understand their changing bodies and learn to protect their own reproductive health.

These skills encourage the development and maintenance of healthy behaviors as well as active participation in one’s own reproductive health care. Since women are potentially fertile on only 6 to 8 days of every menstrual cycle, knowledge of how to recognize or identify these days is empowering. Many women accept a calendar based approach to family planning, yet few are practicing the correct methodology. Similarly, many subfertile women who are trying to achieve conception would benefit from such knowledge as well. Based on ecological, feminist, economic, family and common-sense viewpoints, all women are entitled to this simple and fundamental information1.


Natural methods of family planning use one or more indicators to identify the beginning and end of the fertile time during the menstrual cycle. To identify the start of the fertile time, women can use a calendar calculation, observe cervical secretions, or monitor the changes in the position and feel of the cervix. To mark the end of the fertile window, women can use those same indicators as well as monitor the change in their basal body (resting) temperature (BBT).

The calendar calculations used to identify the fertile time were developed in the 1930s to estimate the days the woman is fertile in the current cycle based on her past cycle lengths. If a woman uses a calendar calculation, the interval of time identified as potentially fertile is longer than the actual time she is fertile. This is because most calendar calculations take into account the lifespan of the gametes and fluctuations in past cycle length. The more a woman’s cycle length varies, the longer the interval identified as potentially fertile.

The fertility signs and symptoms observed during women’s menstrual cycles are caused by changes in circulating estrogen and progesterone levels. The estrogen produced in increasing amounts by the growing follicle changes cervical secretions. After menstruation, the cervical secretions are negligible or absent. As more estrogen is produced by the follicle, more fluids are secreted. Initially, these secretions are sticky, thick, and cloudy. As estrogen levels peak at midcycle, the secretions become clear, stretchy, and slippery. The last day on which clear, stretchy, slippery secretions are observed is known as the peak day. These cervical secretions facilitate sperm transport through the cervix into the upper female genital tract where fertilization takes place. The presence of cervical secretions on a given day indicates that the woman is fertile.

Near midcycle, the pituitary releases a surge of luteinizing hormone (LH). LH triggers ovulation and the ruptured follicle is then transformed into the corpus luteum (CL). The progesterone produced by the CL counteracts the actions of estrogen and causes secretions in the cervix to dry up and form a mucus plug that prevents sperm from traveling through the cervix. Progesterone also increases BBT around the time of ovulation.

Estrogen and progesterone also cause changes in the position and feel of the cervix itself. As ovulation approaches, the opening of the cervix becomes softer and wider, and the cervix pulls up higher in the vagina. After ovulation, the cervix returns to a lower position, and its opening closes and feels more firm. Because fluctuating levels of hormones make fertility signs imprecise markers of the beginning and end of the fertile time, women must abstain or use a barrier method for several days longer than the actual fertile time.

Recent research shows that the actual fertile time is only about 6 days each cycle. The length of the fertile time is related to the lifespan of the gametes: sperm can live up to 5 days inside the female genital tract, and the egg lives less than one day.

NATURAL CONTRACEPTIVE OPTIONS – Methods and related research


Refraining from penetrative sex provides 100% protection from pregnancy, and offers effective prevention of transmission of sexually transmitted infections as well. While this may be an impractical long-term family planning method for married couples, there are examples of periods of prolonged abstinence in certain cultural settings. Programs aimed at unmarried adults and adolescents to delay first sex can have a positive impact in pregnancy prevention and can have other health, education and economic benefits too.

Withdrawal or Coitus interruptus

The withdrawal method of family planning is unlike other natural methods in that it is male-controlled. Withdrawal has been used for centuries, following the discovery that ejaculation into the vagina leads to pregnancy; this method prevents pregnancy by preventing contact between the sperm and the egg. This method is practiced by significant percentages of contracepting couples in Rumania, Turkey, the Czech Republic, and Mauritius. Most couples in those countries cite concerns about health and side effects of modern methods as a major reason for using withdrawal, along with partner preference, lack of knowledge of and access to modern methods, and the cost of modern methods.

An analysis of the literature on withdrawal revealed a lack of rigorous data on current prevalence, acceptability, use-effectiveness, service delivery issues and safety of this method3. Although it has been criticized as an ineffective method, withdrawal probably offers a level of contraceptive protection similar to that of barrier methods. Effectiveness depends largely on the man’s ability to withdraw prior to ejaculation. The best estimates of effectiveness indicate that about 4% of couples who use the method perfectly would experience a pregnancy in the first year; among typical users, the probability of pregnancy would be about 19% in the first year of use4. While this probably is not an ideal method of family planning, it should remain an option for those who are using it effectively.

Calendar methods - based on calculations of cycle length

In calendar rhythm methods, a woman makes an estimate of the days she is fertile based on past menstrual cycle length. She does this with the expectation that the length of her current cycle, and thus the time of her fertile phase, will not vary greatly from previous menstrual cycles.

Various versions of the calendar method exist, with each using a specific rule to determine when the fertile phase is most likely to occur. All of the variations involve setting the days of avoidance of unprotected intercourse by subtracting the upper limit of the rule from the number of days in the shortest of the previous 6 menstrual cycles and subtracting the lower limit of the rule from the number of days of the longest of the previous 6 menstrual cycles. For example, a woman’s last 6 menstrual cycles range from 26 to 31 days in length. She has been taught the 11-18 rule, which means that she will abstain from sex or use a barrier method from day 8 (26 subtract 18) until day 20 (31 subtract 11) on month 7. This interval may be modified each month, according to the length of previous cycles. Other rules include 9-19, 7-12, and 12-17; one meta analysis of eight studies of calendar rhythm estimated that, in typical use, the failure rate of this method falls between 15 and 18 pregnancies per 100 woman-years5. An analysis of perfect use of the calendar methods in the United States indicates that 9% of women using this method correctly will experience a pregnancy in the first year of use6.

The calendar method is reportedly the most common of the natural methods; however, the great majority of couples who report relying on this method do not follow such a methodological approach (see below). In addition, women with irregular or unpredictable cycles are not good candidates for this method.

Methods based on symptoms and signs

Ovulation Method, Billings Method, Cervical Mucus Method

These methods are based on the changes in cervical secretions due to the effects of circulating levels of estrogen and progesterone, as described above. Introduced in the 1960s, these methods rely on daily self-examination for the detection of the quantity and evaluation of the quality of cervical secretions. Women are taught to feel for secretions throughout their cycles. Couples either abstain from sex or use a barrier method during menstruation and on alternate days prior to the appearance of cervical mucus. They abstain from unprotected intercourse from the time that the first sticky mucus appears until four days after the last clear, stretchy, slippery mucus is observed.

Data collected during a World Health Organization (WHO) study in five countries – New Zealand, India, Ireland, the Philippines and El Salvador – showed that, when this method was used correctly, the first year probability of pregnancy was 3.4%, but that the method was unforgiving of incorrect use; imperfect, or typical, use resulted in a 22.5% failure rate in the first year7.

Basal Body Temperature (BBT) Method

Due to the actions of progesterone on the hypothalamus, a woman’s body temperature rises slightly after she ovulates (0.2 to 0.5 degrees C) and remains elevated until the end of the cycle, until menstruation. Women who use this method must chart their temperature every day, immediately after waking up and before getting out of bed or drinking any liquids. Couples relying on this method must abstain from unprotected intercourse between the first day of menstruation until after the third consecutive day of elevated body temperature, so unprotected sex is limited to the postovulatory infertile time. This method is quite demanding for the couple as it imposes the longest duration of abstinence from unprotected sex, typically between 14 and 21 days. The effectiveness is high, if couples can adhere to this schedule. Among perfect users, the first year probability of pregnancy is only about 2%; during typical use, the probability of pregnancy is closer to 20%6.

Sympto-Thermal Method

This method combines several techniques to predict ovulation. It typically includes monitoring and charting cervical mucus and position and temperature changes on a daily basis and may include other signs of ovulation, such as breast tenderness, back pain, abdominal pain or “heaviness,” or light intermenstrual bleeding. To use this method correctly, couples must abstain from unprotected sex from the first sign or sensation of wet cervical mucus until the woman’s body temperature has remained elevated for three days after peak day is observed. Effectively, the method uses the guidelines of the ovulation method to determine the onset of the fertile period and the guidelines of the BBT method to determine its end. This method reduces the number of days of abstinence required by the BBT method alone. However, the daily measurement and charting is more demanding than any of the above methods. As with other natural methods, the pregnancy rate for perfect users is about 2-3% in the first year; users who do not consistently follow the rules of the method can expect a 13-20% chance of pregnancy in the first year.

Lactational Amenorrhea Method (LAM)

Research has confirmed that a form of breastfeeding to achieve contraception, called the lactational amenorrhea method, or LAM, is more than 98% effective during the first 6 months following delivery. Based on years of data from thousands of women in more than a dozen countries, the research also suggests that LAM may be dependable for longer – perhaps up to a year after giving birth.

During breastfeeding, ovulation is inhibited by a series of physiological responses to nipple stimulation. More frequent or intense suckling sends nerve impulses to the mother’s hypothalamus that disrupt normal signals to the pituitary controlling hormone secretion; the resulting abnormal pattern of LH secretion is inhibitory to ovarian activity. When breastfeeding diminishes with less frequent breastfeeding and/or more frequent supplemental feeding, the chance of ovulation and subsequent pregnancy rises.

To use LAM correctly, a woman must remain amenorrheic (no menstrual bleeding) since delivery, fully or nearly fully breastfeed, and be within six months of delivery. When any of these criteria changes, the woman should immediately begin to use another form of contraception if she wishes to prevent another pregnancy.

Some study results suggest that lengthening the six-month criterion to nine or even 12 months after delivery might be possible under certain conditions, although more research is necessary before changing this criterion.


Of married women worldwide using some form of family planning, approximately 15% claim to use a form of periodic abstinence. Yet a very small percentage of these couples actually are using a natural method correctly. Incorrect use can be a result of lack of access to accurate or complete information or to difficulty in following or adhering to the daily monitoring required by the conventional observation-based methods. Research suggests that relatively few women have a correct understanding of their reproductive cycles and an accurate knowledge of when they are most likely to become pregnant. In a WHO study, researchers found that many women who said they were using NPF could not correctly identify the fertile days of the cycle. Many forms of calendar-based methods are used without formal training and thus are used incorrectly with a resulting high pregnancy rates. Given the demand for natural methods and their effectiveness, Georgetown University’s Institute for Reproductive Health (IRH), a long time leader in the area of NFP, with support from the United States Agency for International Development and the World Health Organization, is currently studying new simplified natural methods, retaining the principles that make natural methods a good option for some couples, while changing the characteristics that sometimes make NFP difficult for programs and users. Simplified methods should be easy to learn, teach and use. They should be effective, acceptable and feasible for programs to offer.

New Simple Calendar-Based Method

The Standard Days Method (SDM) is a new simple fertility awareness-based method. It relies on a “standard rule” or a fixed “window” of fertility that makes it easy for women to know when they are likely to become pregnant. This method involves no calculation or observation and is, therefore, easy for service providers to teach and for women to use. To avoid pregnancy, the woman should not have unprotected intercourse during the fertile window. Analysis of a large data set of women’s menstrual cycles from the WHO trial of the Ovulation Method reveal that the fertile period is between days 8 to 19 of the cycle for women whose cycle lengths range from 26 to 32 days8. About 80% of fertile women have cycles in this range. A mnemonic device can be used to teach and help couples keep track of their fertility. This can be a calendar on which women record their cycles. A device designed specifically for the SDM is a string of 32 plastic beads - a necklace - with different colors representing the fertile and infertile days of the menstrual cycle. The necklace is designed to make it very easy for women to know exactly which day of their cycles they are on, without having to write or record any information. The first day of the cycle, when bleeding begins, is represented by a red bead. Each day, the woman moves a small tight-fitting rubber ring along the necklace - from one bead to the next. Days 8 through 19 – the days on which a couple should not have unprotected intercourse – are represented by 12 specially colored beads.

Findings from a pilot study of the method showed that it is very acceptable to women and their partners and to service providers. The positive aspects of the method mentioned were that it is natural, affordable, and causes no side effects or health risks. Women appreciated the simplicity of the necklace as a means of keeping tracking of their fertile and infertile days and they used it as a tool for facilitating communication with their partners.

A recently completed trial with sites in Bolivia, Peru and the Philippines concluded that the probability of pregnancy in couples practicing this method perfectly is less than 5% in the first year of use. The “typical use” rate was closer to 12%. Despite the requirement that the couple alter their sexual behaviour when the woman is in the fertile period, the method was well accepted by couples in diverse settings. Operations research studies are ongoing to test the impact of various service delivery strategies on acceptance, correct use, and continuation of the method and to assess the introduction of the method in diverse cultural and service delivery settings.

New simpler observation-based method

The TwoDay method is a new observation-based method that relies on a simple algorithm to help women identify when they are fertile. The method is based on monitoring the signs and symptoms of fertility, namely the observation of the presence or absence of cervical secretions. The Billings Ovulation Method is based on the same principles; the TwoDay method is another approach to interpreting the changes in the characteristics of cervical secretions that is easier to teach, learn, and use. The TwoDay method requires only that a woman monitor the presence and absence of secretions to determine on each day if she is fertile. Each woman is taught to consider as “secretions” anything that she perceives coming from her vagina, except menstrual bleeding. The woman asks herself two simple questions each day: (1) Did I note secretions today? (2) Did I note secretions yesterday? If she notices any secretions (today or yesterday), she is probably fertile, and needs to abstain from unprotected intercourse to avoid pregnancy. If she notices no secretions on both days, she is not fertile. Analyses of reported secretions correlated with other indices of fertility and ovulation in the WHO data set and in an additional European data set indicate that the TwoDay method would be a highly effective approach to avoid pregnancy9.

In theoretical testing, results show that the TwoDay method would be effective in helping couples avoid pregnancy in both the pre-ovulatory and post-ovulatory phases of the cycle. Estimated probability of conception for women who abstain from unprotected intercourse according to the method rules is no more than 3%. Estimated mean length of the period for abstinence or use of a barrier method for couples practicing the TwoDay method is about 10 days.

Pilot studies in Guatemala, Peru and the Philippines have tested instructional protocols and materials for the TwoDay method. Results indicate that clients are able to learn and use the method effectively. Clients and providers report a high degree of satisfaction with the method. Field trials to assess the contraceptive efficacy of this method began in 2002 in Guatemala, Peru, and the Philippines, in both urban and rural settings.

Technologies to assist in the determination of the fertile window

Several instruments have been developed, or are under development, that attempt to more accurately define the fertile window for individual women. A reliable, simple, low-cost, acceptable, home-based method would allow for a shortening of the length of abstinence from unprotected intercourse. Some examples of these technologies will be discussed in the lecture.

Future for programming

Natural methods are frequently offered and promoted by organizations that provide these methods in isolation from other methods; it is the exception, rather than the rule, that these methods are offered as part of a broad method mix in any setting. Simplifying the methods to make them easier to teach and learn will make them more adaptable to integration into existing settings offering a range of methods. Testing the efficacy of these methods using rigorous methodology will allow them to be considered scientifically-based, rather than non-modern methods. In order to reach the broadest population of potential NFP clients, efforts must continue to make these methods more suitable to integration into traditional family planning service delivery settings.

Ongoing research is evaluating the potential for streamlining the training of NFP clients in Bolivia. The conventional approach in instruction is to evaluate how effective the client is at using NFP in two follow-up visits. The IRH will compare this approach to a novel procedure that determines the client’s readiness to be an independent user during her first visit. If this streamlined approach is successful, it could greatly reduce the burden on the trainers and on the clients for repeat visits.

The IRH is supporting additional work in capacity building, training, development of tools and job aids and evaluation methodologies to enhance the feasibility of “mainstreaming” natural methods; this work will allow all family planning service outlets to offer scientifically established and proven natural methods, as part of a range of options for informed choice in family planning.


  • Fertility awareness helps couples understand how to avoid pregnancy and how to become pregnant.
  • Regardless of what method of family planning they use, every woman and man will find value in learning fertility awareness.
  • Natural methods are effective when they are used correctly.
  • Natural methods are NOT effective when they are used incorrectly. With incorrect use, unprotected intercourse takes place when the woman is potentially fertile.
  • Research will lead to the development of new guidelines for simpler new regimens of NFP that can be integrated into a variety of service delivery settings.

Much of the information presented in this lecture can be found at the Georgetown University Institute for Reproductive Health web site: http://www.irh.org.

See also: The Natural Regulation of Fertility (https://www.gfmer.ch/Books/Reproductive_health/Natural_regulation_of_fertility.html).

Another useful resource is the Family Health International publication Network; the Fall, 1996 issue (volume 17, number 1) was devoted to Fertility Awareness and can be found in English, French and Spanish on the internet at: http://www.fhi.org/en/fp/fppubs/network/v17-1/index.html

  1. Ryder B, Campbell H. Natural family planning in the 1990s. The Lancet, 1995, 346:233-234.
  2. Jennings VH, Lamprecht VM, Kowal D. Fertility awareness methods. In: Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Guest F, Kowal D eds. Contraceptive Technology, seventeenth revised edition. New York; Ardent Media; 1998:309-323.
  3. Rogow D, Horowitz S. Withdrawal: a review of the literature and an agenda for research. Studies in Family Planning, 1995, 26(3):140-53.
  4. Kowal D. Coitus Interruptus (Withdrawal). In: Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Guest F, Kowal D eds. Contraceptive Technology, seventeenth revised edition. New York; Ardent Media; 1998:303-307.
  5. Kambic RT, Lamprecht V. Calendar rhythm efficacy: a review. Advances in Contraception, 1996, 12:123-128.
  6. Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Guest F, Kowal D eds. Contraceptive technology, seventeenth revised edition. New York; Ardent Media; 1998:216.
  7. Trussell J, Grummer-Strawn L. Further analysis of contraceptive failure of the ovulation method. American Journal of Obstetrics and Gynecology, 199; 165(6)Part2:2054-59.
  8. Arevalo M, Sinai I, Jennings V. A fixed formula to define the fertile window of the menstrual cycle as the basis of a simple method of natural family planning. Contraception, 1999, 60(6):357-360.
  9. Sinai I, Arevalo M, Jennings V. The TwoDay Algorithm: a new algorithm to identify the fertile time of the menstrual cycle. Contraception, 1999, 60(2):65-70.