# Natural Cycles

**Canonical:** https://apis.io/providers/natural-cycles/  
**Website:** https://www.naturalcycles.com/  
**APIs profiled:** 0

Natural Cycles is a Swedish women's-health company behind the first birth-control application cleared by the US FDA (2018) and CE-marked in Europe as a Class IIb medical device. Its subscription app uses a proprietary temperature-based algorithm to identify fertile and non-fertile days from a user's daily basal body temperature, supporting both preventing and planning pregnancy as well as cycle, ovulation, and perimenopause tracking. Temperature is captured with a paired Bluetooth basal thermometer or through consumer wearables the app integrates with — Apple Watch, Oura Ring, and the NC B1 band. Natural Cycles publishes clinical research, an educational content library (CycleMatters), an e-commerce shop for thermometers and tests, and a public bug-bounty / responsible-disclosure program, but it does not expose a public developer API, developer portal, or OpenAPI. Backed by EQT Ventures.

## Kin Score — 13.6 / 100 (emerging)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+1.1 from 12.5).

| Facet | Score |
|---|---|
| Discoverability | 61.1 |
| Contract Quality | 0.0 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 10.5 |
| Developer Ergonomics | 4.8 |
| Commercial Clarity | 21.1 |
| Access Clarity | 21.1 |

Regulatory layer — **Health**: 25.0 (matched via tags).

## Agent readiness — 2.6 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | yes |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## Security (2)

- **Natural Cycles Domain Security** — TLSv1.3 · HSTS · DMARC
- **Natural Cycles Vulnerability Disclosure** — security.txt · contact published

## Tags

Company, Health Tech, Femtech, Women's Health, Fertility, Birth Control, Cycle Tracking, Wearables, Digital Health, Medical Device

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/natural-cycles/). Scores are computed from the provider's own public artifacts under a published rubric.