February 21, 2022
Factors Impacting Natural Conception Cycles: A Review of Research
By Thomas Pacheco
Editor’s Note: This is a review of research published by Gnoth et al in 2020 in Archives of Gynecology and Obstetrics titled, “The impact of disturbances in natural conception cycles.” Thomas Pacheco summarized the study while on the FACTS elective, which introduces the various fertility awareness-based methods (FABMs) that can be used effectively for family planning as well as the clinical applications of FABMs and charting the female cycle. Future physicians like Pacheco finish their training with more evidence-based information to communicate with their patients about fertility and women’s health in ways that expand their choices. This summary offers reassuring news regarding the effect of ubiquitous stressors on rates of conception.
Successfully conceiving can be a tenuous and stressful time filled with uncertainty. When outcomes do not go according to plan or match our personal timelines, it can be easy for self-doubt to creep in. For couples practicing FABMs, these feelings may be even more intense due to the depth of knowledge of one’s body and planning that goes into this process. Pairing this precarious time with an age in which every answer, however qualified or unqualified, is at our fingertips, the challenge turns to deciding which information to trust. Getting to the bottom of what actually makes a scientific difference regarding conception rates can be difficult.
In the 2020 study [i] reviewed below, the authors examined the often speculated question of whether minor stresses such as head colds, aches, pains, and subjective psychological stress affect conception rates, and whether attempts at relaxation make a positive difference. The researchers also found answers to the longstanding question of whether sexual intercourse during the time of implantation negatively affects pregnancy rates (spoiler – it does not, and may actually increase rates!).
The authors based this study off a large, ongoing, prospective natural fertility dataset from Germany that includes 43,999 recorded menstrual cycles from 1985 to the end of 2016. This data is organized primarily around the symptothermal method and double-check approach to fertility tracking which uses basal body temperature, mucus recordings, and calculations to predict ovulation and the fertile window. Within this database is also a semi-detailed record of subjective stressors/relaxers that occurred in the women’s lives during these cycles.
Using strict criteria for selection (see figure 1 in the reference paper [i]), the authors whittled the pool down to 237 subjects who had sufficient fully documented pre-conception and conception cycles. They then split the group into a study group (145 with some form of stress during their conception cycle) and a control group (92 with no recorded stress) to compare outcomes. A scientific panel determined what qualified as a stress (often reflected in the temperature recordings of the subjects) and included things like diseases/physical symptoms (colds, headache, throat and limb pain, among others), psychological stressors (being on call at work, building a house, death of a pet, and insomnia, among others), as well as sexual intercourse during the implantation phase (determined through the charts) to see how these elements affected pregnancy rates. They did the same with the effects of relaxers like vacation and holidays that occurred around the time of ovulation.
Using an array of statistical tools and models, the authors found that within the study group and compared to the control group, stressors were significantly higher during cycles that led to conception than pre-conception cycles.
Similarly, the study found that sexual intercourse during the range of time of embryonic implantation (5-9 days post-ovulation) had no negative effects and was actually statistically associated with higher rates of conception cycles.
Finally, the effects of relaxation on conception rates showed no positive association and conferred no advantage. Across the board, disturbances (as defined by the authors) were significantly associated with higher rates of pregnancy.
Severe disease and extreme physiologic conditions (e.g., intense exercise) are well known to negatively affect fertility and disrupt the hypothalamic-pituitary-ovarian axis. Similarly, it is generally accepted that extreme psychological stress is independently associated with negative impacts on fertility.
This study, however, demonstrates that the usual minor illnesses and stresses of life like minor colds, fevers, or increased mental stress from a busy work schedule have no negative effects on conception rates. In fact, these factors were associated with an increase in the rates of conception in a statistically significant manner.
The authors speculate that this increase in conception during times of minor stress may be due to a change in the immunological environment of the body and uterus (‘immunological distraction’) which allows for improved chances of conception and implantation. Along these same lines, sexual intercourse during the phase of embryonic implantation post-ovulation has no negative effects on pregnancy rates, and seems to actually increase the rates of pregnancy.
This study clearly has some limitations such as the subjective interpretations of the reported stressors and the lack of objective qualifiers for these stressors. Furthermore, the analysis was performed purely through chart review without interviews with the study subjects or qualitative data beyond what is reflected in the database. However, this research does begin to tackle these notoriously hard-to-study questions and adds some legitimate scientific evidence to help make informed decisions. The study findings should help relieve some of the tiresome burdens and guilt we place on ourselves to live stress-free lives while trying to get pregnant. The miracle of life remains a mystery in many ways, and it can be scary to think that much of it may be beyond our control. Fortunately, through studies like this one and using FABMs, we continue to grow in our understanding of our bodies and those factors we do have the ability to influence and change.
 Gnoth C, Keil AK, Schiffner J, et al. The impact of disturbances in natural conception cycles. Arch Gynecol Obstet. 2020;301(4):1069-1080. doi:10.1007/s00404-020-05464-y.
 Klein DA, Poth MA. Amenorrhea: an approach to diagnosis and management. Am Fam Physician. 2013;87(11):781-788.
 Ferin M. Clinical review 105: Stress and the reproductive cycle. J Clin Endocrinol Metab. 1999;84(6):1768-1774. doi:10.1210/jcem.84.6.5367.
About the Author
Thomas Pacheco is a fourth-year medical student at Georgetown University School of Medicine in Washington, DC. He plans to pursue a residency in psychiatry and is excited to apply what he has learned in the FACTS elective course to his future specialty. The observable mind-body connection is beautifully apparent with fertility awareness alongside the tremendous distress it can sometimes cause. He hopes to use these tools and information to help empower and treat his future patients.