Fetal Head Station Calculator
Format an independently clinically reported signed fetal-head station relative to the stated ischial-spine plane, negative above/positive below. Not identify anatomy or infer delivery readiness from displacement.
Description
Fetal-head station describes the assessed level relative to the ischial-spine reference plane.
Fetal-head station describes the assessed level relative to the ischial-spine reference plane.1
A station coordinate differs from presentation, position or a prediction of labor progress.
When to use Fetal Head Station Calculator
Use this tool to calculate or review the supplied observations under the stated rules. Establish the observation date, units, measurement context and independently applicable clinical reference or calibrated model.
How to use Fetal Head Station Calculator and understand its results
- Establish the observation date, units, measurement context and independently applicable clinical reference or calibrated model.
- Enter independentlyReportedSignedStationCm, using the field meanings and rules below, then run the tool.
- Read result.recordedSignedStationCm, result.referencePlaneRelationship. Use the units and sign conventions below.
- Correct any reported input issue and run again. Before using a successful result, check the stated units, signs, reference scope and observation coverage.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| independentlyReportedSignedStationCm | Independently reported signed station cm | number | Required |
Require a finite station coordinate between −5 and 5 inclusive; fractional coordinates are accepted. Return that value and its relationship to the caller-established ischial reference plane: below for positive, above for negative and at the plane for zero.
station=callerAssessedStation; relation=sign(station) relative to ischial plane Use the matching field units and the exact boundary, ordering and reference rules above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Structured result; its nested fields below contain the actual calculation or selected reference | object |
| result.recordedSignedStationCm | Recorded Signed Station Cm; preserve the subtraction order and sign defined in the mechanics | number |
| result.referencePlaneRelationship | Recorded station below, at or above the caller-established ischial-spine plane | string |
{
"input": {
"independentlyReportedSignedStationCm": -2
},
"output": {
"result": {
"recordedSignedStationCm": -2,
"referencePlaneRelationship": "above-stated-ischial-spine-plane"
}
}
}Limitations and assumptions
Dating evidence, acquisition conditions and applicable clinical references remain independently established. The output describes supplied observations or a conditional model without diagnosing an outcome, choosing a dose or verifying clinical applicability.
Missing required fields, unknown fields, wrong types and violated rules return input issues. Numeric values and outputs must be finite. Extremely large composite outputs are rejected.
Alternative or Complementary methods
For a related step, use Fetal Presentation Lookup: Fetal presentation names the part presented toward the birth canal. For a complementary comparison, use Fetal Position Lookup: Fetal position uses a reference landmark to describe orientation within a presentation.
References
-
Fetal Head Station Calculator — tool.io
Similar or alternative tools
- Fetal Presentation Lookup
Fetal presentation names the part presented toward the birth canal.
- Fetal Position Lookup
Fetal position uses a reference landmark to describe orientation within a presentation.