Helping You Monitor Your Fertility

Recommended Pages for Further Reading


"These techniques are natural, inexpensive, and highly effective when applied correctly."


Ovulation Calendar


Fertility awareness methods can be highly effective. By tracking personal symptoms, fertility and ovulation can be detected. This makes it possible to increase your odds of achieving or avoiding conception both inexpensively and naturally.

The techniques are not foolproof and do require some expertise. The material on this site will help teach you how to get started. When used correctly, fertility awareness has a very high success rate.

Effectiveness of Achieving Pregnancy

Healthy couples who use fertility awareness techniques described on this site can conceive up to 5-7 times faster than Child those that do not. This statistic is based on published research. Fertility charting is particularly helpful for couples experiencing fertility problems, since they may otherwise require a year or more to conceive without assistance. Monitoring fertility levels helps ensure that couples can capitalize on every available opportunity for conception.

There is a wealth of research to support these significant benefits. Two examples are cited below.

The University of Pavia, Italy teamed up with the U.S. National Institutes of Health to consider how best to time intercourse to get pregnant [1]. The published article confirmed findings of earlier studies. In particular, the studies by M. Hull et al. [2] are compared against that of Hilgers et al [3]. In the study not using fertility awareness, it took 6 months for 75% of the participants to achieve pregnancy. The other study featured a group that was taught to use fertility awareness techniques. This second group was able to achieve the same level of success in only 1 month (76% achieved pregnancy). This shows that couples were able to conceive up to 6 times faster by understanding the female interval for fertility.

In the New England Journal of Medicine, Allen J. Wilcox et al. published research findings on the probability of conception and other related metrics [4]. The research characterized the likelihood of conceiving on a given date relative to a known ovulation date. If the reported probabilities are assumed, the overall probability of conception can be derived statistically. Assuming a 28-day cycle, a couple only has a 4.7% chance of conceiving when having intercourse on one arbitrarily selected date. Using fertility awareness techniques to identify ovulation, couples can greatly improve their chances. The probability of success increases to 33% if fertility awareness techniques are used to accurately identify ovulation and time intercourse with it. This theoretical example suggests that couples would be roughly 7 times more likely to conceive under these circumstances. The actual benefit fluctuates as the frequency of intercourse varies, but is still significant.

Effectiveness as Contraception

The effectiveness as a means of avoiding pregnancy depends upon the individual symptoms being tracked. The highest success rate is achieved when symptothermal techniques are used to analyze both basal body temperatures and cervical mucus. When used properly, the success rate can exceed 99%. Charting cervical mucus or temperatures alone is less effective, but can still yield success rates well into the upper 90s. Tracking multiple symptoms is helpful in case one symptom is obscured by an outside force (e.g. if an illness skewed your temperature readings).

Overall effectiveness relies on the quality of the recorded data. If temperatures are taken inconsistently or influenced by environmental conditions, the data and interpretation can suffer. It may also take time to become proficient at monitoring your symptoms. If it is absolutely critical that pregnancy is avoided, you should take additional precautions since no single technique can promise 100% effectiveness.

Some sources classify the rhythm or calendar method as a means of fertility awareness. This technique does not consider daily observations and instead only defines rules based upon cycle length and menstruation dates. The effectiveness of this technique varies widely. To be effective, the female cycle must be extremely regular in length from month to month. If this and other assumptions are not upheld, the success rate falls dramatically (below 60%). This technique is therefore not recommended by itself.

To cite just one example of scientific data, consider Allen Wilcox's article in the New England Journal of Medicine [4]. The research identifies only 6 days around ovulation that can result in pregnancy. If left up to chance, having intercourse on an arbitrary day in a 28-day cycle can lead to a 4.7% chance of getting pregnant. The likelihood of conception can theoretically be reduced to zero if these 6 fertile days are known and avoided.

In reality, the exact date of ovulation may not be known precisely in advance. Clinical studies have the benefit of hindsight. When these practical limitations are considered, the fertile window grows slightly to account for possible variation in the identified date of ovulation. In practice, the likelihood of conception immediately outside of this range remains low, but is not actually zero.

Like most forms of birth control, fertility awareness is not 100% effective. If it is essential that you do not become pregnant, please consider taking additional precautions.


  • [1] "Bayesian Methods for Searching for Optimal Rules for Timing Intercourse to Achieve Pregnancy." Scarpa, Bruno and Dunson, David. August 28, 2005.

  • [2] "Population study of causes, treatment, and outcome of infertility." Hull, M., Glazener, C., Kelly, N., Conway, D., Foster, P., Hinton, R., Coulson, C., Lambert, P., Watt, E., and Desai, K. December 14, 1985. British Medical Journal.

  • [3] "Cumulative pregnancy rates in patients with apparently normal fertility and fertility-focused intercourse." Hilgers, T., Daly, K., Prebil, M., and Hilgers, S. Journal of Reproductive Medicine.

  • [4] "Timing of Sexual Intercourse in Relation to Ovulation - Effects on the Probability of Conception, Survival of Pregnancy, and Sex of the Baby." Allen J Wilcox, M.D., Ph.D., Clarice R. Weinberg, Ph.D., and Donna D. Baird, Ph.D. December 7, 1995. New England Journal of Medicine.