The NFP files

A Marital Satisfaction Survey

"I am sending the summary of the study presented at the American Psychological Association conference [Aug. 18-21, 2005, Washington DC]. I realize it may be rather dry or evoke questions for more detail. I would be glad to answer the questions. In general, the results were not groundbreaking and need to be kept in context (such as, almost all responses came from highly satisfied couples, both NFP practitioners and users of artificial birth control, so I still don't know what would dissatisfied couples say.) I am planning to continue with a qualitative analysis of the responses to open questions (so far it was mainly statistical analysis.) 
Please let me know if you have questions.


We haven't fully digested the results of this survey, and it's not totally polished yet....but here it is. Send comments to us, vandamme (at), or directly to  marta.edgar (at)

Click here if you want to jump to the conclusion.

Marital Satisfaction and Family Planning Practices
Marta Edgar, Ph.D.
Southern Alberta Institute of Technology, Calgary, Canada


Donald Daughtry, Ph.D.
Texas A&M University, Kingsville, USA


Research indicates that the majority of sexually active heterosexual couples use some form of birth control most of the time while remaining more or less dissatisfied with their choice. Qualitative and anecdotal evidence suggests that the practitioners of Natural Family Planning enjoy particularly good marital relationships and high satisfaction with family planning practices. At the same time, stereotypes exist about the practitioners of Natural Family Planning. This study investigated whether married couples practicing Natural Family Planning (NFP) differ demographically from couples using other, artificial methods of birth control (AFP). The study also tested the idea that the modern NFP is beneficial for building better marital relationships. The following three hypotheses were tested with a MANOVA: NFP couples, as compared to AFP couples, 1) are more satisfied with their relationship as expressed by a score on the Dyadic Adjustment Scale (DAS); 2) are communicating better as expressed by a score on the Marital Communication Inventory (MCI), and 3) are more satisfied with the birth control method as expressed by the results of a Family Planning Questionnaire (FPQ). The third hypothesis was confirmed with statistically significant results. (Since the mean differences were very small, the practical significance of this finding is not clear. ) Gender effect was significant only in the communication area: women in both groups scored significantly higher than men on the MCI. The main demographic differences between the two groups pertained to higher religiosity, greater number of homemakers, greater average number of children, and greater frequency of discussing fertility-related issues among NFP practitioners than among AFP couples. The findings are discussed in terms of implications for theory, research and practice.


This topic was chosen for the following reasons:

- lack of well-developed theories about family planning;

- scant research on family planning process (as opposed to contraceptive use) and its influence on the relationship in committed heterosexual couples;

- contradictory opinions and stereotyped views about “artificial” contraception and Natural Family Planning (e.g., NFP couples seen as religious radicals who use ineffective methods and as a result have many unplanned children);

- procreative decisions are among the most important in life.

Definitions of main concepts:

Marital Satisfaction: self-reported satisfaction with relationship. Main determinants targeted in this study included communication, adjustment, intimacy and sexuality, children, jobs and income, and religious beliefs.

Artificial” Family Planning (AFP): modern methods which purpose is to prevent conception (such as hormonal, barriers, or combination), but not abortive methods.

Natural Family Planning (NFP): relying on detailed knowledge and observation of woman’s monthly fertility cycle (such as Billings Ovulation Method, Sympto-Thermal, or Creighton System).

The purpose of this study was to describe and compare NFP and AFP couples on the following dimensions:

- overall relationship satisfaction measured by the Dyadic Adjustment Scale;

- communication effectiveness measured by the Marital Communication Inventory;

- satisfaction with their chosen method of family planning measured by the Family Planning Questionnaire.

Hypothesis: NFP couples will score higher than AFP couples on the above three dimensions.


Procedure: Participants were recruited by announcing the study and distributing the questionnaires by mail, in person and by “snowballing” through organizations such as Planned Parenthood, the Couple to Couple League, churches and community centers. 601 questionnaires were sent out; 252 (42%) usable questionnaires were returned.

Participants: married couples in childbearing years (mean age: 36 years) from the USA and Canada. Those who responded were mostly White, middle class, urban-dwelling, healthy, educated, employed, married once and reporting Christian beliefs. Respondents were divided into two groups (NFP and AFP) based on their family planning practices.

Instruments (their reliability is reported as Cronbach’s alpha; the first number comes from published research, the second was obtained in this study):

- Dyadic Adjustment Scale (DAS) by Spanier (4 subscales, 32 items, α = 96/90),

- Marital Communication Inventory (MCI) by Bienvenu (46 items and open-ended questions, α = 95/92),

- Family Planning Questionnaire (FPQ) by Edgar (12 items about the use of family planning methods in general with additional 9 items addressed to NFP practitioners, α = 72; the questionnaire included also demographic part and open-ended questions for future qualitative analysis).

Statistical analysis: two data sets were created: one with (individuals) as a unit of analysis and another with (couples) as a unit of analysis (scores averaged out).


Descriptive results: the NFP and AFP groups were similar in years married (M = 10), number of contraceptives tried (M = 3), frequency of intercourse (M = 6 per month), most frequent number of children (mode = 0) and reproductive plans (46% planned to have children). The statistically significant differences included greater percentage of women homemakers among NFP couples, more frequent discussion about fertility and reproduction among NFP couples (majority reported addressing this topic at least once a month), and higher mean number of children (t = 7.73, p < .001).


Women homemakers

Discussing reproduction

Number of children

Mean Mode Range




2.5 0 0-5




1.4 0 0-3

Results of Hypothesis Testing

- NFP obtained higher means than AFP on all three measuresfile:///A:/cin_nfp.xls

- Both groups’ means were above average on all three measures

- All mean differences were small, therefore practical significance is unclear



Mean Score

Standard Deviation





























- Overall MANOVA: F (3,122) = 2.675, p = .05, with effect size η2 = .061, power = .64.

- Post-hoc analysis: the difference in family planning satisfaction was significant, with F (1,219) = 6.86, p = .01, effect size η2 = .052, power = .74

- Gender differences: statistically significant results of two-way MANOVA (the overall F = 11.55, p < .001 for the gender factor and F = 3.49, p = 016 for the method factor). The gender difference was concentrated in the MCI scores: women in both groups scored higher than men, with a significant F = 18.1, p < .001.


The descriptive demographic data demonstrated little differences between NFP and AFP groups, disagreeing with the stereotypes, particularly those that indicate NFP as either sexually deprived or lacking control over their reproduction. Both groups had similar frequency of sexual activity, similar level of overall relationship satisfaction, and both had the number of children similar to national averages. The results of hypothesis testing suggest that couples practicing NFP are more satisfied with their family planning, which supported the claims made by NFP proponents. This effect was significant even though both groups were highly satisfied with their relationship and their family planning practices. At the same time, the AFP group also exhibited relatively high satisfaction, which suggested that there may be no single perfect way to address family planning. The results did not provide support for the claim that NFP couples communicate better than AFP couples.


Theory: The study adds to the development of a theory of family planning process and to the existing body of research on couples, women’s issues, and family issues.

Research: The next step in researching family planning could be studying the causal relationship between the quality of relationship and the effectiveness of family planning. Another area important to the development of new contraceptives is acceptability studies (as opposed to effectiveness studies). It would be instructive to research the acceptability of various methods, including NFP, in various populations, since a given method must be acceptable in order to be used.

Practice: Studying the above issues can contribute to making an informed choice about the best family planning method for a particular couple. It can also add to the development of more accurate and more acceptable family planning methods and is linked to sex therapy issues.

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Updated 2/9/2007