Evidence & references
Every quantity displayed anywhere on this site, with the publication it came from, plus a full account of what was merged and what was deliberately left out.
Numbers used in this tool
| Quantity | Value | Source | Evidence type |
|---|---|---|---|
| Incidence of AFE | ~2–6 per 100,000 births | SMFM 2026, citing refs 4 and 6 | Narrative review / cohort |
| Case fatality, “classic” cases | ~20–40% or more | SMFM 2026, citing refs 4 and 6 | Narrative review / cohort |
| DIC accompanying AFE | >80% of cases | SMFM 2026, citing ref 2 | Guideline |
| Onset window | During labour or within 30 min of delivery of the placenta | Ref 5 | Research case definition |
| Time to delivery if no ROSC | 4 minutes | Figure 1; refs 3, 7 | Guideline / expert review |
| Maximum acceptable OR transfer | Under 2 minutes (text: 1–2 min) | Figure 1 and text | Expert consensus |
| Initial comprehensive labs | Within 5 minutes of CPR initiation | Figure 2 | Expert consensus |
| Timekeeper interval | 1 minute | Figure 1; Figure 2 | Expert consensus |
| ECMO, pooled case reports | 72% maternal survival; 6% major neurologic sequelae; n = 79 | Ref 9 | Systematic review of case reports |
| Tranexamic acid | 1 g IV over 10 min | Figure 1; ref 11 | Expert consensus / cohort |
| Norepinephrine | 0.05–3.3 mcg/kg/min | Figure 1; ref 20 | Expert consensus |
| Dobutamine | 2.5–5.0 mcg/kg/min | Figure 1 | Expert consensus |
| Milrinone | 0.25–0.75 mcg/kg/min | Figure 1 | Expert consensus |
| Inhaled epoprostenol | 10–50 ng/kg/min | Figure 1 | Expert consensus |
| IV epoprostenol | 1–2 ng/kg/min via central line | Figure 1 | Expert consensus |
| Inhaled nitric oxide | 5–40 ppm | Figure 1 | Expert consensus |
| Sildenafil | 20 mg orally, if awake and alert | Figure 1 | Expert consensus |
| Oxygenation target | SpO2 94–98% | Figure 1 | Expert consensus |
| Fluid bolus size | 500 mL, then reassess | Figure 1 | Expert consensus |
A note on the norepinephrine unit
Figure 1 of the 2026 statement prints the vasopressor range in mg/kg/min. This tool uses mcg/kg/min, the unit in which the identical 0.05–3.30 range is published elsewhere (ref 20) and the unit used for the two inotropes in the same figure. Doses throughout this site are computed on that basis.
What this tool merged, and what it left alone
Merged. The statement publishes the same response twice, as a text checklist (Figure 1) and as a cardiac-arrest flow chart (Figure 2), and the two are not identical. Four items appear only in Figure 2: activation of the obstetrical emergency response team with its named disciplines; ensuring intravenous or intraosseous access; requesting the resuscitative cesarean delivery kit to the patient's location; and initial comprehensive laboratory assessment within 5 minutes of CPR initiation. All four are included here, each labelled with its figure. A clinician working from the printed checklist alone would not have them.
Left alone. No dose, threshold, interval or recommendation has been added, rounded, converted or inferred, with the single exception of the norepinephrine unit noted above. Where the source gives no dose — oxytocin and the other uterotonics — none is supplied. Where the source declares something out of scope, this tool says so rather than filling the gap: comprehensive cardiac arrest management in pregnancy, including defibrillation timing and drug dosing, belongs to a separate pregnancy-specific flowsheet (ref 7), and post-stabilization ICU management is outside the statement's scope.
Added as clearly labelled annotation. Two safety items appear on the live checklist that are not in the SMFM statement and are marked as LiveEvidence annotations: a warning against tocolysis for the hypertonus of a suspected AFE, and a note to stop an oxytocin infusion already running at the moment of collapse before restarting it for atony prophylaxis after delivery. The reasoning is on the hyperstimulation page.
Not attempted. No risk score, no probability estimate, no prediction. AFE is a clinical diagnosis of exclusion; the statement offers no scoring system and this tool invents none.
Full reference list
1
PRIMARY SOURCE
Society for Maternal-Fetal Medicine (SMFM), Martinez-King LC, Combs CA, Montgomery DM, Toner LE, Dildy GA; SMFM Patient Safety and Quality Committee. Society for Maternal-Fetal Medicine Special Statement: Checklist for initial management of amniotic fluid embolism—Updated 2026. Pregnancy. 2026;2(5):e70364.
doi:10.1002/pmf2.70364
Every checklist item, time threshold, dose and target on this site comes from Figure 1 (checklist, version July 27, 2026) and Figure 2 (cardiac arrest flow chart) of this statement.
2
GUIDELINE
Pacheco LD, Saade G, Hankins GD, Clark SL; Society for Maternal-Fetal Medicine. Amniotic fluid embolism: diagnosis and management. Am J Obstet Gynecol. 2016;215(2):B16-B24.
doi:10.1016/j.ajog.2016.03.012
SMFM Clinical Guideline No. 9. Diagnostic framing, the >80% DIC figure, and the statement that uterine tone abnormalities may be a consequence of shock rather than the cause.
3
EXPERT REVIEW
Pacheco LD, Clark SL, Klassen M, Hankins GDV. Amniotic fluid embolism: principles of early clinical management. Am J Obstet Gynecol. 2020;222(1):48-52.
doi:10.1016/j.ajog.2019.07.036
Cryoprecipitate in preference to plasma, the vasopressor-inotrope-pulmonary vasodilator strategy, early echocardiography, and ECMO despite coagulopathy.
4
NARRATIVE REVIEW
Clark SL. Amniotic fluid embolism. Obstet Gynecol. 2014;123(2 Pt 1):337-348.
doi:10.1097/AOG.0000000000000107
Clinical Expert Series. Incidence of 2-6 per 100,000, case fatality range, DIC as the confirming finding, and the immune rather than embolic model of the syndrome.
5
CASE DEFINITION
Clark SL, Romero R, Dildy GA, Callaghan WM, Smiley RM, Bracey AW, et al. Proposed diagnostic criteria for the case definition of amniotic fluid embolism in research studies. Am J Obstet Gynecol. 2016;215(4):408-412.
doi:10.1016/j.ajog.2016.06.037
Onset during labour or within 30 minutes of delivery of the placenta; the research case definition underlying the clinical diagnosis.
6
COHORT
Mazza GR, Youssefzadeh AC, Klar M, Kunze M, Matsuzaki S, Mandelbaum RS, et al. Association of pregnancy characteristics and maternal mortality with amniotic fluid embolism. JAMA Netw Open. 2022;5(11):e2242842.
doi:10.1001/jamanetworkopen.2022.42842
Population-level epidemiology and case fatality, cited by the 2026 statement alongside ref 4.
7
GUIDELINE
Jeejeebhoy FM, Zelop CM, Lipman S, Carvalho B, Joglar J, Mhyre JM, et al. Cardiac arrest in pregnancy: a scientific statement from the American Heart Association. Circulation. 2015;132(18):1747-1773.
doi:10.1161/CIR.0000000000000300
The 4-minute rule for initiating delivery during CPR, and the pregnancy-specific cardiac arrest management this checklist deliberately leaves to a separate flowsheet.
8
TERMINOLOGY
Rose CH, Faksh A, Traynor KD, Cabrera D, Arendt KW, Brost BC. Challenging the 4- to 5-minute rule: from perimortem cesarean to resuscitative hysterotomy. Am J Obstet Gynecol. 2015;213(5):653.e1.
doi:10.1016/j.ajog.2015.07.019
Basis for the 2026 terminology change from perimortem cesarean delivery to resuscitative hysterotomy. Page range as printed in the source reference list.
9
SYSTEMATIC REVIEW
Trieu NHK, Nguyen NN, Pham HM, Huynh DQ, Mai AT. Extracorporeal membrane oxygenation in amniotic fluid embolism: a systematic review of case reports. ASAIO J. 2025;71(2):143-148.
doi:10.1097/MAT.0000000000002269
79 pooled cases: 72% maternal survival and 6% major neurologic sequelae. Case reports only, so subject to publication bias toward survivors.
10
EXPERT PANEL
Pacheco LD, Clark SM, Fox K, Bauer ME, Clark SL. Use of atropine, ondansetron, and ketorolac in suspected amniotic fluid embolism. Obstet Gynecol. 2026;147(6):780-784.
doi:10.1097/AOG.0000000000006095
Recommends against routine use of the atropine-ondansetron-ketorolac regimen; evidence limited to case reports, with defined potential harms.
11
COHORT
Fitzpatrick KE, van den Akker T, Bloemenkamp KWM, Deneux-Tharaux C, Kristufkova A, Li Z, et al. Risk factors, management, and outcomes of amniotic fluid embolism: a multicountry, population-based cohort and nested case-control study. PLoS Med. 2019;16(11):e1002962.
doi:10.1371/journal.pmed.1002962
INOSS pooled surveillance from five countries. Cited by the 2026 statement for tranexamic acid; also the source of the finding that oxytocin in labour is not significantly associated with AFE while prostaglandin induction is.
12
SYSTEMATIC REVIEW
Wiseman D, Simard C, Yang SS, Koolian M, Abenhaim HA, Lipes J. Echocardiography findings in amniotic fluid embolism: a systematic review of the literature. Can J Anaesth. 2023;70(1):151-160.
doi:10.1007/s12630-022-02343-9
The right ventricular dysfunction and pulmonary hypertension that justify early echocardiography and targeted right-heart therapy.
13
CONSENSUS BUNDLE
Morton CH, Hall MF, Shaefer SJM, Karsnitz D, Pratt SD, Klassen M, et al. National Partnership for Maternal Safety: consensus bundle on support after a severe maternal event. J Obstet Gynecol Neonatal Nurs. 2021;50(1):88-101.
doi:10.1016/j.jogn.2020.09.160
Patient and family support resources referenced in the debrief section.
14
SYSTEMATIC REVIEW
Seys D, Wu AW, Van Gerven E, Vleugels A, Euwema M, Panella M, et al. Health care professionals as second victims after adverse events: a systematic review. Eval Health Prof. 2013;36(2):135-162.
doi:10.1177/0163278712458918
The basis for addressing staff needs, not only patient and family needs, in the post-event debrief.
15
REGISTRY
Stafford IA, Moaddab A, Dildy GA, Klassen M, Berra A, Watters C, et al. Amniotic fluid embolism syndrome: analysis of the United States International Registry. Am J Obstet Gynecol MFM. 2020;2(2):100083.
doi:10.1016/j.ajogmf.2019.100083
What registry reporting yields, and why the statement asks that every suspected case be submitted, including those with poor outcomes.
16
METHODS
Society for Maternal-Fetal Medicine, Bernstein PS, Combs CA, Shields LE, Clark SL, Eppes CS. The development and implementation of checklists in obstetrics. Am J Obstet Gynecol. 2017;217(2):B2-B6.
doi:10.1016/j.ajog.2017.05.032
Implementation methodology underlying the unit readiness steps.
17
GUIDELINE
American College of Obstetricians and Gynecologists. Committee Opinion No. 680: the use and development of checklists in obstetrics and gynecology. Obstet Gynecol. 2016;128(5):e237-e240.
doi:10.1097/AOG.0000000000001772
Checklist design and development principles cited by the statement.
18
SUPERSEDED
SMFM Patient Safety and Quality Committee; Combs CA, Montgomery DM, Toner LE, Dildy GA. Society for Maternal-Fetal Medicine Special Statement: checklist for initial management of amniotic fluid embolism. Am J Obstet Gynecol. 2021;224(4):B29-B32.
doi:10.1016/j.ajog.2021.01.001
The 2021 version, replaced by ref 1. Retained so units still circulating the old page can identify what changed.
19
GUIDELINE
American Heart Association. 2025 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care: recommendations for peripartum patients with life-threatening suspected amniotic fluid embolism. 2025.
Accessed via cpr.heart.org, as cited in ref 1
Recommends against atropine in the absence of bradycardia. Web-published guidance, no DOI; cited as it appears in the source reference list.
20
CORROBORATING
Feng Y, Yang HX. Interpretation of Chinese expert consensus on diagnosis and management of amniotic fluid embolism. Chin Med J (Engl). 2020;133(14):1719-1721.
doi:10.1097/CM9.0000000000000886
Publishes the identical 0.05-3.30 range for norepinephrine in mcg/kg per min. Publishes the norepinephrine range in mcg/kg per min; the basis for the unit used throughout this site.
21
REGISTRY
Clark SL, Hankins GD, Dudley DA, Dildy GA, Porter TF. Amniotic fluid embolism: analysis of the national registry. Am J Obstet Gynecol. 1995;172(4 Pt 1):1158-1169.
doi:10.1016/0002-9378(95)91474-9
The original US registry. Reported no correlation between AFE and either prolonged labour or oxytocin use, and proposed the anaphylactoid rather than embolic model.
22
COHORT
Kramer MS, Rouleau J, Baskett TF, Joseph KS. Amniotic-fluid embolism and medical induction of labour: a retrospective, population-based cohort study. Lancet. 2006;368(9545):1444-1448.
doi:10.1016/S0140-6736(06)69607-4
Three million Canadian deliveries. Medical induction aOR 1.8 (1.3-2.7); dystocia protective. The paper that put induction on the AFE risk-factor list.
23
COHORT
Abenhaim HA, Azoulay L, Kramer MS, Leduc L. Incidence and risk factors of amniotic fluid embolisms: a population-based study on 3 million births in the United States. Am J Obstet Gynecol. 2008;199(1):49.e1-49.e8.
doi:10.1016/j.ajog.2007.11.061
Three million US births. Induction aOR 1.5 (0.9-2.3), not significant; dystocia again protective (aOR 0.4).
24
REVIEW
Conde-Agudelo A, Romero R. Amniotic fluid embolism: an evidence-based review. Am J Obstet Gynecol. 2009;201(5):445.e1-445.e13.
doi:10.1016/j.ajog.2009.04.052
Side-by-side tabulation of the two large cohorts. Its risk-factor list contains no entry for tumultuous labour, uterine hypertonus or tachysystole.
25
COHORT
Fitzpatrick KE, Tuffnell D, Kurinczuk JJ, Knight M. Incidence, risk factors, management and outcomes of amniotic-fluid embolism: a population-based cohort and nested case-control study. BJOG. 2016;123(1):100-109.
doi:10.1111/1471-0528.13300
UKOSS. Prostaglandin without oxytocin aOR 6.46; oxytocin without prostaglandin aOR 2.80; both together aOR 2.43 — a gradient that runs the wrong way for a contraction-force mechanism.
26
LETTER
Funk M, Damron A, Bandi V, Aagaard K, Szigeti R, Clark S. Pulmonary vascular obstruction by squamous cells is not involved in amniotic fluid embolism. Am J Obstet Gynecol. 2018;218(4):460-461.
doi:10.1016/j.ajog.2017.12.225
Cited by the 2026 statement for the pathophysiology update. Removes mechanical obstruction from the causal account.
27
COMMENTARY
Lisonkova S, Kramer MS. Amniotic fluid embolism: a puzzling and dangerous obstetric problem. PLoS Med. 2019;16(11):e1002976.
doi:10.1371/journal.pmed.1002976
Perspective accompanying ref 11, by the author of the 2006 induction cohort.
28
METHODOLOGICAL
Wagner M. From caution to certainty: hazards in the formation of evidence-based practice — a case study on evidence for an association between the use of uterine stimulant drugs and amniotic fluid embolism. Paediatr Perinat Epidemiol. 2005;19(2):173-176.
doi:10.1111/j.1365-3016.2005.00630.x
A documented case study of how the uterine-stimulant/AFE association was constructed. Listed as a pointer only — the full text has not been read for this site and the direction of its argument is not characterised here.
References transcribed from source records and publisher pages; individual fields have not each been verified against PubMed. Refs 21–28 support the hyperstimulation analysis and are not cited by the SMFM statement.