NFP: 1st Randomized Clinical Trial in 20 Years

Natural Family Planning

First Randomized Clinical Trial of Natural Family Planning in More Than 20 Years

Reviewed by Thomas Bouchard, MD

Fehring et al. (2012) have published the first randomized comparison of two Natural Family Planning (NFP) methods for avoiding pregnancy, identified 3 randomized controlled trials that have been published: Medina et al. (1980), comparing the Ovulation Method to the Sympto-Thermal Method in Colombia; Wade et al. (1981), comparing the Ovulation Method to the Sympto-Thermal Method in Los Angeles; and Kass-Annesse (1989), comparing use of a vaginal sponge with and without a calendar plus Basal Body Temperature Method. There have been many observational cohort studies since that time, but Fehring et al.’s study would be the first randomized trial registered with

This 12-month prospective trial, published in the journal Contraception, recruited 667 couples randomized to use either a ClearBlue Fertility Monitor (CBFM) with an algorithm or a mucus-based method with an algorithm. The CBFM is a handheld monitor that detects both estrogen and LH in the urine, and displays the following readings – Low (no hormone change), High (estrogen change above baseline detected) or Peak (LH above threshold detected). The Cervical Mucus Monitoring (CMM) group monitored changes in their mucus using a three point scale (Low, High, Peak, similar to the readings on the CBFM). Both groups received online instructions in the use of an algorithm in addition to the monitor or mucus observations to establish the fertile window. Both groups charted online and pregnancies were evaluated based on the couple’s intention at the beginning of each cycle; motivation to avoid pregnancy on a scale of 1-10 was also evaluated in each cycle. Pregnancies were classified as “perfect-use failure” when the instructions were followed, and “user failure” when instructions were not followed. Acceptability of the method was evaluated with a survey and continuation rates were measured.

Total unintended pregnancy rates (including perfect use and user failure) were 7 per 100 women at 1 year for the monitor group and 18.5 per 100 women at 1 year for the mucus group, which was significantly different based on a hazards regression model. Perfect-use unintended pregnancy rates were 0 per 100 women at 1 year for the monitor group and 2.7 for the mucus group, with no significant difference between these rates. Acceptability survey scores for both methods increased over time, and there was no difference in acceptability between the two groups. Continuation rates went from 82.2% at 3 months to 40.6% at 12 months for the monitor group and from 66.4% at 3 months to 36.6% at 12 months for the mucus group; there was no difference in continuation rates between the groups. The most common reasons were “lost to follow-up,” “no longer interested” and “wishing to achieve pregnancy.”

The authors concluded that both monitor and mucus based methods had low perfect-use unintended pregnancy rates, and showed that the monitor group had fewer total unintended pregnancies than the mucus group. These rates are better than those reported by Trussell et al. (2011) in his evaluation of fertility awareness based methods. They comment that the high discontinuation rates were related to initial non-participation, as well as being “lost to follow-up,” “no longer interested” and “wishing to achieve pregnancy.”

Fehring and colleagues need to be congratulated for their rigorous randomized comparison of two methods of NFP. Their comparison of a “high tech” (using a urine fertility monitor) and a “low tech” (using mucus) method with the combination of an ovulation-based algorithm highlights the success of the newer method of NFP versus the traditional “gold standard” method of observing mucus. Those with experience in mucus based methods may be interested by the higher total unintended pregnancy rate in the mucus group, even with the use of an algorithm as a “double check” in this group. The difference between perfect use and total (perfect use as well as incorrect use) unintended pregnancy rates highlights the fact that when presenting NFP methods to users, it is important to quote “real world” pregnancy rates that include both correct and incorrect use of the method (rather than the “ideal” numbers of perfect use). Trussell should be happy to see these results so that he can update his oft quoted contraceptive failure rates for fertility awareness methods.

There were no differences in method acceptability between the groups, which suggests that both high tech and low tech methods represent viable options for different couples, depending on their needs. The initial and ongoing expense of the monitor may represent an obstacle to some which the authors do not discuss; however, because the study was funded this would not have been an issue for the study participants. As a personal reflection, the monitor may be a more acceptable method for NFP-naive users and medical professionals, who often place more credence in a test result than a physiologic sign; on the other hand, the mucus based method may be more acceptable to NFP-experienced users who have seen many decades of successful use of mucus based methods and may be skeptical of the use of new technologies in NFP.

The continuation rates are problematic, but are not out of keeping with other NFP studies with high discontinuation rates. The initial non-participation rates are unfortunate since 19% of the recruits did not provide any charts at all although they received a free fertility monitor, and one has to question their motivation to participate. Those “lost to follow-up” are particularly difficult to track since their recruitment was online and there is no face-to-face time with most participants; this is one of the flaws with an internet-based approach to recruitment. Those who discontinued for “wishing to achieve pregnancy” are inevitable in a population inclined to use NFP.

Fehring et al. mention in their methods recording couples’ motivation for avoiding pregnancy. This is an important variable in the evaluation of pregnancy intention. They do not mention this anywhere else in their results or discussion, and it is of interest. I would be very interested in seeing the results of the motivation analysis in these two groups of participants. The inclusion of motivation in this randomized study is another example of the thoroughness with which Fehring and his colleagues have developed this, the first randomized trial of NFP methods in over 20 years, and will be a model for NFP studies in the years to come.

1. Fehring, R. J., M. Schneider, K. Raviele, D. Rodriguez, and J. Pruszynski. 2012. Randomized comparison of two Internet-supported fertility-awareness-based methods of family planning. Contraception 88 (1):24-30.
2. Grimes, D. A., M. F. Gallo, V. Grigorieva, K. Nanda, and K. F. Schulz. 2010. Fertility awareness-based methods for contraception. Cochrane Database of Systematic Reviews (Online), (4), CD004860. Digital object identifier number: 10.1002/14651858.CD004860.pub2.
3. Kass-Annese, B., K. I. Kennedy, K. Forrest, H. Danzer, A. Reading, and H. Hughes. 1989. A study of the vaginal contraceptive sponge used with and without the fertility awareness method. Contraception 40 (6): 701-714.
4. Medina, J. E., A. Cifuentes, J. R. Abernathy, J. M. Spieler, and M. E. Wade. 1980. Comparative evaluation of two methods of natural family planning in Columbia. American Journal of Obstetrics and Gynecology 138 (8): 1142-1147.
5. Trussell, J. 2011. Contraceptive failure in the United States. Contraception 83 (5): 397-404.
6. Wade, M. E., P. McCarthy, G. D. Braunstein, J. R. Abernathy, C. M. Suchindran, G. S. Harris, et al. 1981. A randomized prospective study of the use-effectiveness of two methods of natural family planning. American Journal of Obstetrics and Gynecology 141 (4): 368-376.

Obstetrics-Gynecology Residents Report Limited Experience with Natural Family Planning
One of the essential components of good obstetrics and gynecological care is the provision of correct information on family planning methods. Therefore, having knowledge (and experience*) with all methods of family planning would be important for an obstetrics-gynecology (OBGYN) residency program. Researchers involved with (OBGYN) residency therefore sought out to determine the knowledge and training that OBGYN residents obtain with specific reference to barriers and over-the-counter (OTC) family planning options.

The researchers first developed and validated an 18 item questionnaire on knowledge and exposure to OTC family planning methods using Virginia Commonwealth University OBGYN residents. The 18 items included five questions on condom use, three on use of the diaphragm, and three on the use and counseling of spermicides. Other questions were on demographics, year in residency, and whether they wanted to learn about these methods. Included among the items was whether they ever counseled about Natural Family Planning and if they ever advised the use of Cycle Beads. They then randomly selected 50 of the 253 OBGYN residency programs in the United States and contacted the directors of the programs to help distribute the questionnaires and to help with compliance in taking the survey. They mailed out 959 surveys and received 202 (21%) of which 4 were excluded due to false responses.

The researcher discovered that only 16.8% of the residents reported receiving formal lectures on condoms, 15.5% on diaphragms, and 12.3% on spermicides. The survey did not include a question on whether they received formal education on NFP or Cycle Beads. However, 49.5% reported counseling on NFP and 8.7% on Cycle Beads. What was meant by counseling in the use of NFP was not defined and could include that they were not effective or should only be used for helping to achieve pregnancy. The most discussed OTC family planning methods among the respondents were use of spermicide foams (93.2%) and gels (86.1%). Surprisingly, only 57% felt they had adequate knowledge to counsel about condoms. The researchers concluded that OBGYN residents receive little formal training on OTC family planning methods and need to seek more education on these methods to be adequately trained in an essential component of their practice.


The fact that they only had a 21% survey return rate limits the generalizability of these results. We also do not know if the residents only counseled use of NFP to achieve pregnancy or talked only about their faults, i.e., a 49.5% rate is fairly high. It would have been beneficial if the questionnaire also included whether they received formal education on NFP methods.

* OBGYN residents need to know about all methods of family planning, however, should only counsel use of morally acceptable methods.

Miuklavcic, A. Y., and C. R. Isaacs. 2012. Obstetrics-Gynecology resident education regarding barrier and over-the-counter contraceptives: a national study. Journal of Women’s Health 21 (11): 1196-2000.

Few Low-Income Women at Title X Clinics Receive Information on NFP
Based on the knowledge that few (i.e. less than 1%) of federally funded Title X clinic patients report using Natural Family Planning (NFP), researchers at the University of Missouri, Kansas, wished to determine the knowledge and opinions about use of NFP to prevent or plan a pregnancy among women attending such clinics. Their research purpose was also influenced by the assumption that knowledge of fertility and NFP could be better integrated into preconception planning for those couples desiring pregnancy.

In order to determine knowledge of fertility and opinions of NFP, the researchers surveyed women who attended federally funded family planning centers in 13 states. A questionnaire was distributed to administrative personnel at these centers via e-mail and the personnel were asked to provide the surveys to their patients. Through this method, they were able to obtain 465 completed questionnaires with 374 in English and 91 in the Spanish language.

The survey included questions on history of family planning methods, attitudes about contraception, the influences of contraceptives, information received about NFP, and knowledge about fertility. The NFP questions addressed whether the patients received information about NFP or fertility awareness based methods (FABM) and for what purpose. They were also asked when they thought was the most fertile time in a woman’s menstrual cycle.

The researchers found that only 20.8% (i.e., 94 of the respondents) had ever been informed about NFP at a Title X family planning clinic and only 9.1% had ever asked for or received information. Furthermore, only 37% (N=174) had correct knowledge of the fertile time of the menstrual cycle. The authors also reported that 40% of those who believed they knew the fertile time of their menstrual cycle actually had a correct response but did not report how many of the participants this represented. The researchers concluded that based on the low level of knowledge of NFP and fertility that nurse practitioners need to discuss with their clients fertility awareness and believe that this knowledge is essential for assisting women to reach their reproductive goals.

The authors also presented three cases of women who potentially could use NFP services, of which only one was provided NFP services and then, unfortunately, with back up use of condoms. These three cases were as follows. Case one was Lucinda (24 years old) and her partner who previously used condoms and now is planning pregnancy within 12-18 months. She was offered NFP with backup condoms. Case two involved (Maria) who was 25 years old with two young children and only saw her husband from Mexico 5-6 times a year. She was placed on an IUD in order to have a “forget-able” method of family planning. The third woman (Natelie) was on and off birth control pills due to irregular cycles. She was 44 years old and her partner 45 and was provided advice to seek tubal ligation. Of interest is that NFP would be a viable method for all three of these cases. The third woman, Natelie, probably has extremely low fertility (less than 2% chance of pregnancy) and since she had irregular menstrual cycles, at this stage of her life, pregnancy is most likely impossible. Furthermore, it is common for the woman to be sterilized rather than the man even though it is a more extensive procedure for her. All of these cases illustrate distrust for NFP by the health professional providing family planning services and by the couples (many in non-marital relationships) seeking family planning services.

Witt, J., K. McEvers, and P. J. Kelly. 2013. Knowledge and experiences of low-income patients with natural family planning. The Journal of Nurse Practitioners 9(2): 99-104.


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Text taken from USCCB/NFP Program website.

Used with permission.

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