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You may be eligible.if you qualify.
See how it works
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You may be eligible.if you qualify.
See how it works
The Science Behind Conceivable
Fertility is a connected system.
Conceivable studies the subclinical signals that can stack together to make conception and pregnancy more or less likely, and separates what is established, associated, emerging, and still being tested.
Is Conceivable evidence based?
In part, and we say which part. Conceivable’s component signals, such as cycle length, training load and energy availability, draw on published reproductive-health research, linked beside each claim on this page. The five-domain framework and current Conceivable Score are our own organizing system, and they have not yet been independently validated as a pregnancy predictor.
Our 2014–2016 pilot was retrospective, single-arm and self-reported, so it cannot show that the program improves pregnancy rates.
Read the pilot methods, results and limitations →
01The bigger picture
One signal rarely tells the whole story.
People often arrive with “unexplained infertility,” the label used when standard testing finds no clear cause1. Yet their physiology may not look unexplained at all.
Small disadvantages can stack. Systems can reinforce one another. Patterns can emerge before disease.
That is a hypothesis we are testing, not an established finding.
robustness
Each signal nudges the others.
02Reinforcing loops
Small signals can reinforce each other.
These are common patterns and Conceivable hypotheses, not a validated model.
Common pattern · Sleep
Experimental sleep loss lowers insulin sensitivity and raises hunger2. The caffeine step is a hypothesis.
Common pattern · Training
High training load without enough fuel can disturb ovulation and the luteal phase3,5. The loop itself is a hypothesis.
Common pattern · Stress
Hypothesis: stress touches several of these at once.
Short or light bleeding, fatigue and a weak post-ovulatory temperature pattern together are a constellation worth investigating. No one of them is a diagnosis.
03Understanding the evidence
Normal, associated, or predictive?
Is it abnormal?
Outside a clinical range, may warrant evaluation.
Is it associated with outcomes?
Linked to outcomes in research, but not necessarily abnormal.
Does it predict outcomes?
Helps estimate future outcomes, requires stronger validation.
A normal workup can rule out important pathology. It cannot tell you how every part of the system is functioning together.
04The five domains
An organizing framework. Not five diagnoses.
Energy
Fuel · recovery · metabolism · fatigue
Blood
Bleeding · iron · clotting · circulation
Hormones
Cycle · ovulation · PMS · endocrine
Temperatures
Thermal shift · luteal pattern
Stress
Sleep · autonomic load · recovery
These are organizing lenses, not five diagnoses.
See how the Conceivable Score uses the five domains →05How we grade evidence
How does Conceivable grade evidence?
Every claim is also labeled by role: medical, contextual, optimization, prognostic, or intervention.
06What we know and what we are testing
What does research support, and what are we still testing?
What research supports
What we are still testing
- Absolute luteal temperature patterns.
- PMS phenotypes.
- Whether constellations predict more than single variables.
07Key examples
What does the research say about periods, exercise, food and more?
What does your period tell you?
In 2,653 Danish women planning pregnancy, cycles under 25 days were associated with lower fecundability than 27–29 day cycles7.
Does hard exercise affect fertility?
Five or more hours a week of vigorous activity was associated with lower fecundability, but not among overweight or obese women8.
Is there a fertility diet?
No single fertility diet has been shown to work for everyone.
What can basal temperature tell you?
Physicians reading charts placed ovulation within a day of the hormonal peak in only about 22% of ovulatory cycles with adequate luteal phases6.
Symptoms are not all the same
PMS is not one thing.
Acne, anxiety, cravings, headaches, insomnia and cramping may reflect different underlying patterns. We’re studying the combinations.
08Research
What we’re actively studying.
None of these questions is settled.
Thermal phenotype
How temperature level, shift and stability relate to conception and pregnancy outcomes.
High training load and low energy availability
How training load, recovery and energy availability influence cycles and fertility.
Menstrual and clotting phenotype
Whether bleeding and clotting patterns add information inside a larger constellation.
Cumulative constellation burden
Do patterns of modest signals predict time to pregnancy better than the single signals alone?
09Our own data · Conceivable internal
Our 2014–2016 pilot, in brief.
22 of 105 sub-fertile participants (21%) reported a pregnancy during the program. The pilot had no control group, and pregnancies were self-reported. It was retrospective and single-arm.
In 2026 we re-audited the raw data and retired several older claims.
Common questions
Frequently asked questions about Conceivable’s science.
Author and review. Written by Kirsten Karchmer, founder of Conceivable. Evidence checked against primary sources (AI-assisted review). Last reviewed: October 2026.
Revision history. October 2026: historical pilot re-audited; older pregnancy-uplift and Score-change claims retired.
Is Conceivable scientifically validated?
Does Conceivable diagnose infertility?
Can someone have normal fertility tests and still have subclinical reproductive-health issues?
Is the five-domain model medically established?
Did Conceivable's pilot prove the program improves pregnancy rates?
Go deeper
Where to read next.
How the Score works
What it measures, what it cannot tell you, and how missing data are handled.
Read the methods →How we evaluate evidence
Our source hierarchy, evidence labels and review process.
Read the methodology →What we’re studying
The open questions behind the research program.
See the questions →References
Every link opens the record on PubMed.
- 1American Society for Reproductive Medicine Practice Committee. Evidence-based treatments for couples with unexplained infertility: a guideline. Fertil Steril. 2020;113(2):305–322. PubMed 32106976
- 2Morselli L, Leproult R, Balbo M, Spiegel K. Role of sleep duration in the regulation of glucose metabolism and appetite. Best Pract Res Clin Endocrinol Metab. 2010;24(5):687–702. PubMed 21112019
- 3De Souza MJ, Toombs RJ, Scheid JL, et al. High prevalence of subtle and severe menstrual disturbances in exercising women: confirmation using daily hormone measures. Hum Reprod. 2010;25(2):491–503. PubMed 19945961
- 4Loucks AB, Thuma JR. Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J Clin Endocrinol Metab. 2003;88(1):297–311. PubMed 12519869
- 5Williams NI, Leidy HJ, Hill BR, et al. Magnitude of daily energy deficit predicts frequency but not severity of menstrual disturbances associated with exercise and caloric restriction. Am J Physiol Endocrinol Metab. 2015;308(1):E29–E39. PubMed 25352438
- 6Bauman JE. Basal body temperature: unreliable method of ovulation detection. Fertil Steril. 1981;36(6):729–733. PubMed 7308516
- 7Wise LA, Mikkelsen EM, Rothman KJ, et al. A prospective cohort study of menstrual characteristics and time to pregnancy. Am J Epidemiol. 2011;174(6):701–709. PubMed 21719742
- 8Wise LA, Rothman KJ, Mikkelsen EM, et al. A prospective cohort study of physical activity and time to pregnancy. Fertil Steril. 2012;97(5):1136–1142. PubMed 22425198
- 9Fei C, McLaughlin JK, Lipworth L, Olsen J. Maternal levels of perfluorinated chemicals and subfecundity. Hum Reprod. 2009;24(5):1200–1205. PubMed 19176540
- 10Conforti A, Mascia M, Cioffi G, et al. Air pollution and female fertility: a systematic review of literature. Reprod Biol Endocrinol. 2018;16(1):117. PubMed 30594197
Conceivable is an educational, prioritization and tracking tool. It does not diagnose, treat or replace medical care.