# Flamm VBAC admission score

Flamm VBAC score

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/flamm_vbac`
HTML: https://magentlab.com/docs/flamm-vbac
Markdown: https://magentlab.com/docs/flamm-vbac.md

Not a medical device. Not a diagnosis, dose, or listing recommendation.

## What it computes

Sum the Flamm 1997 admission VBAC points (max 10) from caller-assigned age, vaginal-birth history, first-cesarean indication, and admission cervical factors, and return the published 49% or 95% success rates only for scores 0–2 and 8–10.

## When to use

When an agent already has Flamm 1997 admission factors and needs the published point total, not a trial-of-labor order, cervical exam, Grobman nomogram, or invented intermediate percents.

## When not to use

- Not a medical device and not a trial-of-labor or cesarean order. magent does not examine the cervix.
- Flamm 1997 published VBAC success of 49% for scores 0–2 and 95% for scores 8–10. Scores 3–7 return the point total without a success percent.
- Does not implement the Grobman VBAC nomogram. This tool has no race input.

## Formula

```
Flamm VBAC = age_lt_40 2 + vaginal_birth (none 0, before_first_cesarean 1, after_first_cesarean 2, before_and_after 4) + non_ftp_indication 1 + effacement (gt_75 2, from_25_to_75 1, lt_25 0) + dilation_ge_4 1; Flamm 1997; max 10; published VBAC success 49% scores 0-2 and 95% scores 8-10
```

## Citation

[Vaginal birth after cesarean delivery: an admission scoring system](https://doi.org/10.1016/S0029-7844(97)00531-0)
Flamm BL, Geiger AM
Obstet Gynecol. 1997;90(6):907-910
DOI: [10.1016/S0029-7844(97)00531-0](https://doi.org/10.1016/S0029-7844(97)00531-0)

## Worked example

### Age under 40 only (score 2, published 49%)

Given: `age_lt_40=true, dilation_ge_4=false, effacement=lt_25, non_ftp_indication=false, vaginal_birth=none`

1. age_lt_40 true → 2; vaginal_birth none → 0; non_ftp_indication false → 0; effacement lt_25 → 0; dilation_ge_4 false → 0
2. score = 2 (max 10); scores 0-2 publish 49% VBAC success


### All lowest (score 0, published 49%)

Given: `age_lt_40=false, dilation_ge_4=false, effacement=lt_25, non_ftp_indication=false, vaginal_birth=none`

1. All Flamm 1997 factors at the 0-point value
2. score = 0 (max 10); scores 0-2 publish 49% VBAC success


### Maximum published score (score 10, published 95%)

Given: `age_lt_40=true, dilation_ge_4=true, effacement=gt_75, non_ftp_indication=true, vaginal_birth=before_and_after`

1. age_lt_40 2 + before_and_after 4 + non_ftp_indication 1 + gt_75 2 + dilation_ge_4 1
2. score = 10 (max 10); scores 8-10 publish 95% VBAC success


## Also searched as

- Flamm VBAC score
- Flamm Geiger score
- VBAC admission score
- Flamm 1997
- trial of labor after cesarean score
- successful VBAC score
- TOLAC admission scoring system
- vaginal birth after cesarean admission score

## Parameters

- `age_lt_40` (boolean, required): Maternal age under 40 years as assigned by the caller (Flamm 1997). true scores 2. true or false. magent does not date the patient.
- `vaginal_birth` (string, required): Prior vaginal birth history as assigned by the caller (Flamm 1997). Choose one: none scores 0; before_first_cesarean scores 1; after_first_cesarean scores 2; before_and_after scores 4. magent does not read the obstetric history.
- `non_ftp_indication` (boolean, required): First cesarean was for a reason other than failure to progress (Flamm 1997). true scores 1. true or false. magent does not read the operative indication.
- `effacement` (string, required): Cervical effacement at admission as assigned by the caller (Flamm 1997). gt_75 scores 2; from_25_to_75 scores 1; lt_25 scores 0. magent does not examine the cervix.
- `dilation_ge_4` (boolean, required): Cervical dilation at or above 4 cm at admission as assigned by the caller (Flamm 1997). true scores 1. true or false. magent does not examine the cervix.

## Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

Method: `POST /api/calc/flamm_vbac`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: PREVIEW

- 1 to 25 items. Each item uses the same keys as the GET query parameters.
- POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
- The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
- HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
- Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
- x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request:

```json
{
  "items": [
    {
      "age_lt_40": "true",
      "dilation_ge_4": "false",
      "effacement": "lt_25",
      "non_ftp_indication": "false",
      "vaginal_birth": "none"
    },
    {
      "age_lt_40": "true",
      "dilation_ge_4": "false",
      "effacement": "lt_25",
      "non_ftp_indication": "false",
      "vaginal_birth": "none"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/flamm-vbac

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/flamm_vbac",
  "items": [
    {
      "components": [
        {
          "factor": "age_lt_40",
          "points": 2,
          "present": true
        },
        {
          "value": "none",
          "factor": "vaginal_birth",
          "points": 0,
          "present": false
        },
        {
          "factor": "non_ftp_indication",
          "points": 0,
          "present": false
        },
        {
          "value": "lt_25",
          "factor": "effacement",
          "points": 0,
          "present": false
        },
        {
          "factor": "dilation_ge_4",
          "points": 0,
          "present": false
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Flamm BL, Geiger AM",
        "doi": "10.1016/S0029-7844(97)00531-0",
        "id": "flamm-1997",
        "pmid": "9397335",
        "source": "Obstet Gynecol. 1997;90(6):907-910",
        "title": "Vaginal birth after cesarean delivery: an admission scoring system"
      },
      "formula": "flamm_vbac",
      "formula_expression": "Flamm VBAC = age_lt_40 2 + vaginal_birth (none 0, before_first_cesarean 1, after_first_cesarean 2, before_and_after 4) + non_ftp_indication 1 + effacement (gt_75 2, from_25_to_75 1, lt_25 0) + dilation_ge_4 1; Flamm 1997; max 10; published VBAC success 49% scores 0-2 and 95% scores 8-10",
      "max_score": 10,
      "score": 2,
      "vbac_success_percent": 49
    },
    {
      "components": [
        {
          "factor": "age_lt_40",
          "points": 2,
          "present": true
        },
        {
          "value": "none",
          "factor": "vaginal_birth",
          "points": 0,
          "present": false
        },
        {
          "factor": "non_ftp_indication",
          "points": 0,
          "present": false
        },
        {
          "value": "lt_25",
          "factor": "effacement",
          "points": 0,
          "present": false
        },
        {
          "factor": "dilation_ge_4",
          "points": 0,
          "present": false
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Flamm BL, Geiger AM",
        "doi": "10.1016/S0029-7844(97)00531-0",
        "id": "flamm-1997",
        "pmid": "9397335",
        "source": "Obstet Gynecol. 1997;90(6):907-910",
        "title": "Vaginal birth after cesarean delivery: an admission scoring system"
      },
      "formula": "flamm_vbac",
      "formula_expression": "Flamm VBAC = age_lt_40 2 + vaginal_birth (none 0, before_first_cesarean 1, after_first_cesarean 2, before_and_after 4) + non_ftp_indication 1 + effacement (gt_75 2, from_25_to_75 1, lt_25 0) + dilation_ge_4 1; Flamm 1997; max 10; published VBAC success 49% scores 0-2 and 95% scores 8-10",
      "max_score": 10,
      "score": 2,
      "vbac_success_percent": 49
    }
  ]
}
```

## Response fields

- `formula` (string): flamm_vbac
- `formula_expression` (string): Exact expression used
- `score` (integer): Flamm 1997 points 0-10
- `max_score` (integer): Always 10
- `vbac_success_percent` (integer): Flamm 1997 published VBAC success: 49 when score is 0-2, 95 when score is 8-10. Omitted for scores 3-7; those scores are not given invented percents.
- `components` (array): Per-factor Flamm 1997 points
- `citation` (object): Flamm and Geiger Obstet Gynecol 1997 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "factor": "age_lt_40",
      "points": 2,
      "present": true
    },
    {
      "value": "none",
      "factor": "vaginal_birth",
      "points": 0,
      "present": false
    },
    {
      "factor": "non_ftp_indication",
      "points": 0,
      "present": false
    },
    {
      "value": "lt_25",
      "factor": "effacement",
      "points": 0,
      "present": false
    },
    {
      "factor": "dilation_ge_4",
      "points": 0,
      "present": false
    }
  ],
  "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Flamm BL, Geiger AM",
    "doi": "10.1016/S0029-7844(97)00531-0",
    "id": "flamm-1997",
    "pmid": "9397335",
    "source": "Obstet Gynecol. 1997;90(6):907-910",
    "title": "Vaginal birth after cesarean delivery: an admission scoring system"
  },
  "formula": "flamm_vbac",
  "formula_expression": "Flamm VBAC = age_lt_40 2 + vaginal_birth (none 0, before_first_cesarean 1, after_first_cesarean 2, before_and_after 4) + non_ftp_indication 1 + effacement (gt_75 2, from_25_to_75 1, lt_25 0) + dilation_ge_4 1; Flamm 1997; max 10; published VBAC success 49% scores 0-2 and 95% scores 8-10",
  "max_score": 10,
  "score": 2,
  "vbac_success_percent": 49
}
```

## Errors

- HTTP 400 `invalid_flamm_vbac`: Flamm VBAC score inputs must match Flamm 1997 age, prior vaginal birth, cesarean indication, and admission cervical factors from that paper. Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [Bishop score](https://magentlab.com/docs/bishop) — Return the Bishop 1964 pelvic score as the sum of five caller-assigned integer components (dilation, effacement, station, consistency, position).

## Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/docs/mcp

## Guarantees

- HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
- exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
- HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
- Execution is timeout-bounded and concurrency-capped.
- Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.