# Saylor Innovations Pregnancy Due Date Calculator

> Saylor Innovations Pregnancy Due Date Calculator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-18).

Calculates pregnancy due date using Naegele's rule from last menstrual period, along with gestational age, trimester, and key milestone dates

## Facts

- Endpoint: GET https://saylorinnovations.com/api/health/due-date?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-pregnancy-due-date-calculator-2e972891
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Pcjq8UWF-t_ZS1bH8IeTc

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saylor-innovations-pregnancy-due-date-calculator-2e972891
```

Example prompt: My last period started on March 15th 2025 — can you calculate my pregnancy due date, tell me what trimester I'm in today, and give me the key milestone dates?

## When to prefer this

Choose this endpoint when you need a quick, rules-based obstetric due date calculation (Naegele's rule) with cycle-length adjustment, gestational age breakdown, trimester identification, and structured milestone dates — all in one call. Prefer it over building custom date arithmetic when you need clinically-grounded pregnancy timeline data without integrating a full EHR system.

## Known failure modes

- Missing required lmp parameter returns an error
- Malformed date format for lmp or today causes a parsing error
- Future LMP date or LMP more than ~42 weeks ago may produce out-of-range or clinically implausible results
- Invalid query parameter types may return a 400 error
- Service unavailability or x402 payment failure returns a non-200 response

## How this service works

Pregnancy due date by Naegele's rule from last period or conception with cycle adjustment, gestational age today, trimester and key milestone dates

## Output

Returns the estimated due date (YYYY-MM-DD), conception estimate, gestational age in weeks and days with a text description, current trimester number, percentage of pregnancy complete, days until due date, cycle adjustment days applied, and an array of key pregnancy milestones each with gestational week, date, and a description of what typically happens at that stage. Also includes a source attribution and contextual note.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "lmp"
     ],
     "properties": {
      "lmp": {
       "type": "string",
       "description": "First day of last menstrual period YYYY-MM-DD"
      },
      "today": {
       "type": "string",
       "description": "optional reference date, default today"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "estimated_due_date",
      "milestones"
     ],
     "properties": {
      "note": {
       "type": "string",
       "description": "Caveat or context for reading the result"
      },
      "source": {
       "type": "string",
       "description": "Data source the values come from"
      },
      "milestones": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "date": {
          "description": "Date (YYYY-MM-DD)"
         },
         "week": {
          "type": [
           "number",
           "null"
          ],
          "description": "Gestational week"
         },
         "what": {
          "type": [
           "string",
           "null"
          ],
          "description": "What typically happens"
         }
        }
       },
       "description": "Pregnancy milestones with week, date and what typically happens"
      },
      "days_until_due": {
       "type": "number",
       "description": "Days until due"
      },
      "trimester_today": {
       "type": "number",
       "description": "Trimester today"
      },
      "percent_complete": {
       "type": "number",
       "description": "Percent complete"
      },
      "estimated_due_date": {
       "type": "string",
       "description": "Estimated due date"
      },
      "conception_estimate": {
       "type": "string",
       "description": "Conception estimate"
      },
      "cycle_adjustment_days": {
       "type": [
        "number",
        "null"
       ],
    
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-pregnancy-due-date-calculator-2e972891/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)