Study Shows Connection of NFP and Odds of Divorce

By Jim Volpe. Originally published in Family Foundations.

One of the many important endeavors that CCL has been working on throughout its history has been to establish NFP in the scientific community as a respectable option for family planning. Mike Manhart, Ph.D. and co-author, Richard Fehring, Ph.D, RN, FAAN from Marquette University took a big step in that direction with their publication in February of this year titled “The Association of Family Planning Methods with the Odds of Divorce Among Women in the 2015–2019 National Survey of Family Growth” in the Journal of Divorce & Remarriage. While Mike has been harnessing his background in microbiology to publish papers on NFP in the past, he is most excited that this paper has been accepted by a journal with a more diverse and secular readership so that information can more readily get to those who don’t know about the best kept secret of NFP. Their analysis shows that using periodic abstinence results in a ~40% reduction in the odds of being divorced, while using the pill or hormonal contraception resulted in a ~66% increase in the odds of being divorced.

Mike has been active in the CCL community for many years, including a stint as Executive Director and Senior Scientific Consultant. In that time, he observed there was only very circumstantial evidence for Natural Planning reducing the odds of divorce, so he looked to remedy that problem by taking advantage of his experience with clinical trials.

The analysis that Mike, along with his co-author Richard Fehring, performed are based on the National Survey of Family Growth data. The NSFG, conducted by the CDC, periodically surveys a representative sample of the reproductive aged female population in the United States for many forms of statistical analysis. The survey gathered over 2000 variables through 90-minute interviews with the subjects. Richard had published papers based on the 2006-2010 NSFG which demonstrated the effect of family planning method on divorce. In 2021, Manhart and Fehring analyzed the 2015-2017 NSFG and found that those couples who had ever used NFP had half the divorce odds of those who had ever use the most common contraception.

“The consistency of these studies suggests that choice of family planning in married couples has an important influence on the likelihood of divorce and is worthy of future research.”

– Manhart and Fehring

Using the 2017-2019 publicly available information, Manhart and Fehring teamed up again to correlate the odds of divorce among “ever-married” women (that is women who are currently or previously married) with the choice of family planning method used by the couple. To get as large a sample a possible they combined the data from the 2015-2017 and the 2017-2019 surveys, adding more statistical weight due to the larger amount of data. Among the over 5,000 ever-married women in the pooled data set, all forms of contraception noticeably increased the odds of divorce whereas practicing periodic abstinence (either using calendar based or modern methods of NFP) decreased the odds of divorce. In addition, they found that variables widely recognized to be correlated with divorce such as age, education, and income had little effect on the odds of divorce in comparison to the choice of family planning method used.

As correlation and causation are difficult to separate, the paper points out that NFP users could be self-selecting from couples that already have better relationship skills. Some research from Chile indicates that this could be the case as NFP correlates with continuously improving relationship scores. Another potential reason for the findings could be that those who practice periodic abstinence have more motivation to become better communicators, developing more ways to practice nonsexual intimacy which is beneficial to a healthy marriage. Other research shows that moving from suppressing to embracing the mutual challenge of fertility drives the integration of both man and woman as equals in the relationship might be a factor in lower divorce rates. In contrast, using contraception in marriage does not encourage development of expressions of non-sexual intimacy, and facilitates suppressing (and even ignoring) the potential for new life that sexual relations have inherently integrated with them. Manhart & Fehring suggest that when an unexpected pregnancy occurs, contraceptive users may be more surprised compared to users of NFP who, even if not currently using NFP, have a better understanding of their fertility. Since an unexpected pregnancy is yet another well documented risk factor for divorce, using contraceptives in marriage may further put the relationship at risk.

“This is good, solid evidence that living the way God designed marriage is good.”

– Mike Manhart

Mike Manhart recounted some of the early efforts to gather information on NFP and divorce. Whether it was a survey of Sympto-Thermal teachers or just one person writing down everyone he could remember, the efforts were noble but not scientifically rigorous. The multiple papers Manhart & Fehring have authored, culminating in this paper, reviewed and published in a larger, secular journal, have been great steps in the direction of proving that God’s design for marriage and family is the best plan for us.