Natural Family Planning (NFP) using the Sensiplan Method
Sensiplan is a modern, evidence-based method of Natural Family Planning (NFP) that combines the observation and charting of two primary fertility signs: cervical mucus and basal body temperature (BBT). It is part of the broader Symptothermal Method (STM) of fertility awareness.
Core Components:
1. Basal Body Temperature (BBT):
After ovulation, progesterone causes a measurable rise (typically ~0.2–0.5°C) in resting body temperature. This thermal shift confirms that ovulation has occurred.
After ovulation, pregnancy is no longer possible in that cycle because the ovum (egg) can only be fertilized within a narrow window of approximately 12 to 24 hours. Once this time has passed, the egg degenerates, and the endometrium transitions under the influence of progesterone (luteal phase), making both fertilization and implantation physiologically impossible until the next ovulatory cycle begins.
2. Cervical Mucus:
Changes in cervical mucus reflect estrogen levels. Fertile mucus is clear, stretchy, and resembles raw egg white. Its presence indicates a high chance of ovulation.
3. Optional Cervical Changes:
Some users observe cervical position and texture as an additional fertility sign.
Explanation:
Fertilization window: The egg survives only 12–24 hours post-ovulation.
Sperm lifespan: Up to 5 days, but only relevant before ovulation.
Luteal phase: Progesterone dominates, cervical mucus becomes impenetrable, and the endometrium prepares for either implantation or menstruation — no new fertilization is possible till the next cycle.
No new ovulation: A second ovulation within one cycle is hormonally suppressed once the first has occurred.
Scientific Foundation:
Sensiplan is based on over 30 years of clinical research conducted primarily in Germany by the Arbeitsgruppe NFP at the University of Düsseldorf and other institutions.
It follows strict, standardized observation rules and evaluation protocols that are documented in the official Sensiplan manual, which has been updated regularly to reflect new data.
Efficacy:
Perfect-use efficacy (used correctly every cycle):
Pearl Index: 0.4 = comparable to the pill.
Typical-use efficacy (real-life usage):
Pearl Index varies between 1–2, depending on user discipline and correct application = better than the pill.
Evidence & Publications:
1. Frank-Herrmann, P., et al. (2007). “The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behavior during the fertile time: a prospective longitudinal study.” Human Reproduction, 22(5), 1310–1319. https://doi.org/10.1093/humrep/dem003
2. Gnoth, C., Frank-Herrmann, P., et al. (2002). “Cycle characteristics after discontinuation of oral contraceptives.” Gynecological Endocrinology, 16(4), 307–317.
3. Sensiplan Manual "Natürlich und sicher Das Praxisbuch. Familienplanung mit Sensiplan" by Stiftung NFP (latest edition). Based on data from over 40,000 cycles.
Conclusion:
Sensiplan is not a vague “natural” method. It's a rigorously developed scientific method, rooted in endocrinology, female physiology, and statistical analysis. It is peer-reviewed, reproducible, and used in medical and educational settings in Europe.
This method can also be used to increase the chances of getting pregnant!
Fun fact: it gets support from an order of the Catholic Church here in Germany (Malteser)
(one of my own temperature graphs)
