# Due Date

The dating wheel, with the assumptions it hides made explicit.

**Why delegate it:** Gestational age counts from the last menstrual period, not conception — the most misunderstood fact in the subject, and one models restate wrongly. Naegele's rule also assumes a 28-day cycle, and ACOG publishes a five-row table for when an ultrasound should replace period-based dating that nobody recalls correctly.

Site: https://due-date-zeta.vercel.app

## Tools

### `due_date` — Due date and gestational age, with ACOG redating applied

Estimate a due date from a last menstrual period, a known conception date, an IVF transfer, or an ultrasound measurement. Gestational age is counted from the LAST PERIOD, not conception: at "6 weeks pregnant" conception was about 4 weeks ago. Applies the cycle-length adjustment most calculators skip, and the ACOG Committee Opinion 700 thresholds for when a scan should replace the period-based date. Dates must be YYYY-MM-DD; free-form dates are refused. A due date is a reference point, not a prediction. Not medical advice, and the response says so in its payload.

Direct endpoint: `https://due-date-zeta.vercel.app/api/v1/estimate`

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Via the aggregator: `https://gumballtools.com/api/mcp`
Direct: `https://due-date-zeta.vercel.app/api/mcp`