By Natalie Corrilo, MD
July 31, 2019

Editor’s Note: This is a review of research[i] published by Fehring et al in 2017 in The American Journal of Maternal Child Nursing titled, “Effectiveness of a Natural Family Planning Service Program.” The article was reviewed and summarized by Dr. Natalie Corrilo as part of a two-week online elective taught by FACTS executive director and co-founder, Dr. Marguerite Duane, at Georgetown University College of Medicine. The study sought to determine and compare extended use-effectiveness of the Marquette Method online system among women seeking to avoid pregnancy.

The Marquette Method (MM) online system of natural family planning (NFP) was developed by nurses and is managed by nurses, a bioethicist, and an obstetrician gynecologist with expertise in natural family planning. Women who register are able to participate in forum discussions and consultations with the experts. The system also offers free information about fertility health as well as teaching about charting, indicators of fertility, and instructions for achieving and avoiding pregnancy. Multiple studies have provided evidence for effectiveness of the Marquette Method online system. However, there have only been a few studies of extended use-effectiveness with natural family planning. Given that methods of family planning require behaviors to be effective, it is important to analyze whether extended use results in an increase in unintended pregnancies.


This 24-month prospective study conducted between April 2008 and April 2015 examined effectiveness rates for 663 non-breastfeeding women who were over the age of 18, had at least one menstrual cycle of charting, and wished to use the online system to avoid pregnancy. Most women were Euro-American/Catholic, had a mean age of 30.4 years, and were married, with a mean of 1.77 children. The participants were able to use the online charting system with either electronic hormonal fertility monitoring or cervical mucus monitoring, or they could use both fertility indicators together. The online system then calculated the women’s fertile windows.

The study recorded unintended pregnancies as correct use when there was no charting of intercourse during the fertile window. It recorded unintended pregnancies as incorrect use when there was intercourse during the fertile window.

Among the 663 participants, there were 2 unintended pregnancies per 100 at 24 cycles of correct use and 15 unintended pregnancies at 24 cycles of typical use. Women using the electronic fertility monitor alone had a lower rate of unintended pregnancies (6 at 24 cycles) compared to women using cervical mucus monitoring alone (19 per 100 women at 24 cycles) or both fertility indicators (18 unintended pregnancies at 24 cycles). In this study, the use of an electronic hormonal fertility monitor and online menstrual charting was the most effective method to avoid pregnancy, but the monetary costs may be a consideration for some couples.

A strength of this study was its inclusion of women with irregular cycles, broadening its applications to a larger population of women. It is vital to note that in this study, 70% of the unintended pregnancies were due to a conscious decision to not follow the instructions to avoid intercourse during the fertile window. Therefore, this study highlights that “motivation of the couple” is key to successfully avoiding or achieving pregnancy using the MM online system.

The fertility monitor proved to be the most effective tool for tracking signs of fertility in this study, presumably at least partly because it was easier to use. Providing easy-to-use NFP tools and resources is critical for successful extended use of the Marquette Method online system. Given that the online system was designed in 2008, updating the website may improve accessibility and create an even more user-friendly method of NFP. In this study, most women were of Euro-American descent; it will be important to reach out to underserved populations who may benefit greatly from NFP.

[i] Fehring, Richard J, and Mary Schneider. “Effectiveness of a Natural Family Planning Service Program.” MCN. The American Journal of Maternal Child Nursing, U.S. National Library of Medicine, 2017,


Author Bio: Natalie Corrilo, MD was born and raised in Los Angeles, California. She attended Dartmouth College and majored in literature and chemistry. Before starting medical school, she volunteered as a health education teacher at a high school that had eliminated its health education funds due to budget cuts. Since then, she became passionate about adolescent health and medicine in general. Dr. Corrilo was a 4th year medical student at Georgetown University School of Medicine when she wrote this article. She recently started pediatric residency at Children’s Hospital of Los Angeles. Her goal is to become a community pediatrician and work with underserved populations.


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