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著者: 金山尚裕 静岡医療科学専門大学校

監修: 金山尚裕 静岡医療科学専門大学校

著者校正/監修レビュー済:2024/03/21
参考ガイドライン:
  1. 日本産科婦人科学会日本産婦人科医会:産婦人科診療ガイドライン産科編2023
  1. 日本産婦人科医会:母体安全への提言2020
患者向け説明資料

改訂のポイント:
  1. 『産婦人科診療ガイドライン産科編2023』の発行に伴いレビューを行った(同ガイドラインに基づく変更はなし)。
  1. その他、軽微な変更、追記を行った。

概要・推奨   

病態・疫学・診察 

疾患情報(疫学・病態)  
  1. 羊水塞栓症とは、羊水が母体血中へ流入することにより生じる病態で、流入した羊水によりアナフィラクトイド反応が発生し補体、凝固、線溶系、キニン系が活性化し播種性血管内凝固症候群(DIC)、子宮弛緩症となる状態である。また、羊水が母体血中に流入すると子宮・血管の平滑筋攣縮により子宮胎盤循環不全が発生し急激な胎児機能不全となる。
  1. 症状は、分娩周辺期の特に破水後の呼吸困難、胸痛、意識消失、ショック症状などの心肺虚脱、分娩後のサラサラした出血および弛緩出血、原因不明の胎児機能不全、原因不明の強度の下腹痛などがある。
  1. 羊水塞栓症の発症頻度は以前、約2万から8万分娩に対し1例程度と考えられていが、播種性血管内凝固症候群(DIC)・弛緩出血を主体とする疾患に羊水塞栓症が含まれる例があることより、実際の頻度はもっと高いと考えられている。
 
羊水塞栓症に合併しやすい病態

DICと弛緩出血が7割程度の羊水塞栓症に合併する。

出典

W M Gilbert, B Danielsen
Amniotic fluid embolism: decreased mortality in a population-based study.
Obstet Gynecol. 1999 Jun;93(6):973-7.
Abstract/Text OBJECTIVE: To examine the risk factors and pregnancy outcomes associated with 53 cases of amniotic fluid embolism that occurred in California during the 2-year period January 1, 1994 to December 31, 1995.
METHODS: Data were obtained from a computerized database that contains linked records from the vital statistics birth certificate and hospital discharge summaries of both mother and newborn. This database covered all singleton deliveries that occurred in 328 civilian acute-care hospitals in California, which represented 98% of all deliveries in California. All cases of amniotic fluid embolism were examined for other pregnancy complications.
RESULTS: There were 1,094,248 deliveries during that 2-year period. Fifty-three singleton gestations had the diagnosis of amniotic fluid embolism, for a population frequency of one per 20,646 deliveries. Fourteen women with amniotic fluid embolism died, for a maternal mortality rate of 26.4%. There were 35 (66%) diagnoses of disseminated intravascular coagulation (DIC), 38 (72%) diagnoses of hemorrhage, and 25 (47%) diagnoses of obstetric shock. Among the 14 women who died, the frequency of DIC (79%) and hemorrhage (71%) was not different compared with that of the survivors (62% and 72%, respectively), but obstetric shock was higher (86%, P = .02) than in survivors (33%). The average maternal length of stay for survivors was 6.5 days (range 3-27 days, median 5 days). The cesarean rate was 60% and the frequency of fetal distress was 49%.
CONCLUSION: In this population-based study of reported cases of amniotic fluid embolism, the maternal mortality rate (26.4%) was significantly less than previously reported and might reflect a more accurate population frequency. In addition, patients who survived and patients who died had similar pregnancy complications, suggesting that amniotic fluid embolism was present in all cases and not limited to those who died.

PMID 10362165
 
  1. わが国で平成元年から16年までの間に193例が妊産婦死亡で剖検されたが、その中で羊水塞栓症が24.3%と第1位であった[1]
  1. 最新の英国の報告では10万分娩中2例とされている。死亡率は以前60~80%と非常に高率であったが、最近の報告では20~40%との報告がある[2]
  1. 帝王切開や吸引・鉗子分娩は羊水塞栓症のリスクが高い[3]
 
羊水塞栓症によるNRFS発生機序

羊水が母体血中に流入すると子宮・血管の平滑筋攣縮により子宮胎盤循環不全が発生し急激な胎児機能不全となる。一方流入した羊水によりアナフィラクトイド反応が発生し補体、凝固、線溶系、キニン系が活性化しDIC、子宮弛緩症となる。
羊水が母体血中に流入し、子宮血管および子宮平滑筋の過剰な収縮により子宮胎盤循環が阻害され、NRFSとなる。

出典

著者提供
問診・診察のポイント  
  1. 分娩周辺期:特に破水後の呼吸困難、胸痛、意識消失、ショック症状などの心肺虚脱

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文献 

Naohiro Kanayama, Junko Inori, Hatsue Ishibashi-Ueda, Makoto Takeuchi, Masahiro Nakayama, Satoshi Kimura, Yoshio Matsuda, Jun Yoshimatsu, Tomoaki Ikeda
Maternal death analysis from the Japanese autopsy registry for recent 16 years: significance of amniotic fluid embolism.
J Obstet Gynaecol Res. 2011 Jan;37(1):58-63. doi: 10.1111/j.1447-0756.2010.01319.x. Epub 2010 Nov 18.
Abstract/Text AIM: To clarify the cause of maternal deaths, an autopsy is essential. However, there has been no systemic analysis of maternal death in Japan based on autopsy cases.
MATERIAL & METHODS: Maternal death reports were retrieved from a large amount of registered autopsy data on maternal death in the series of 'Annual of pathological autopsy cases in Japan'. These files contain 468,015 autopsy records from 1989 to 2004. We collected 193 cases of maternal death due to direct obstetric causes. We recorded all the data into Excel files. Then we analyzed the causes of death and classified them into 11 categories.
RESULTS: The causes of maternal death were as follows: amniotic fluid embolism (AFE), 24.3%; disseminated intravascular coagulation (DIC) related to pregnancy-induced hypertension, 21.2%; pulmonary thromboembolism, 13.0%; injury to the birth canal, 11.4%; medical and surgical complications, 9.8%; and atonic bleeding or DIC of unknown cause, 8.3%. A discrepancy between the clinical diagnosis and pathological diagnosis was frequently observed in cases of AFE, septic DIC and injury to the birth canal. AFE diagnosed by autopsy was often clinically diagnosed as atonic bleeding or DIC of unknown cause before death. Half of the cases of AFE diagnosed by autopsy were associated with DIC.
CONCLUSION: We found that AFE, DIC related to pregnancy-induced hypertension, pulmonary thromboembolism and injury to the birth canal were the major causes of maternal death in Japan. AFE had various clinical features such as uterine atony and DIC in addition to pulmonary cardiac collapse.

© 2010 The Authors. Journal of Obstetrics and Gynaecology Research © 2010 Japan Society of Obstetrics and Gynecology.
PMID 21083840
S L Clark, G D Hankins, D A Dudley, G A Dildy, T F Porter
Amniotic fluid embolism: analysis of the national registry.
Am J Obstet Gynecol. 1995 Apr;172(4 Pt 1):1158-67; discussion 1167-9.
Abstract/Text OBJECTIVE: We analyzed the clinical course and investigated possible pathophysiologic mechanisms of amniotic fluid embolism.
STUDY DESIGN: We carried out a retrospective review of medical records. Forty-six charts were analyzed for 121 separate clinical variables.
RESULTS: Amniotic fluid embolism occurred during labor in 70% of the women, after vaginal delivery in 11%, and during cesarean section after delivery of the infant in 19%. No correlation was seen with prolonged labor or oxytocin use. A significant relation was seen between amniotic fluid embolism and male fetal sex. Forty-one percent of patients gave a history of allergy or atopy. Maternal mortality was 61%, with neurologically intact survival seen in 15% of women. Of fetuses in utero at the time of the event, only 39% survived. Clinical and hemodynamic manifestations were similar to those manifest in anaphylaxis and septic shock.
CONCLUSIONS: Intact maternal or fetal survival with amniotic fluid embolism is rare. The striking similarities between clinical and hemodynamic findings in amniotic fluid embolism and both anaphylaxis and septic shock suggest a common pathophysiologic mechanism for all these conditions. Thus the term amniotic fluid embolism appears to be a misnomer.

PMID 7726251
Michael S Kramer, Jocelyn Rouleau, Thomas F Baskett, K S Joseph, Maternal Health Study Group of the Canadian Perinatal Surveillance System
Amniotic-fluid embolism and medical induction of labour: a retrospective, population-based cohort study.
Lancet. 2006 Oct 21;368(9545):1444-8. doi: 10.1016/S0140-6736(06)69607-4.
Abstract/Text BACKGROUND: Amniotic-fluid embolism is a rare, but serious and often fatal maternal complication of delivery, of which the cause is unknown. We undertook an epidemiological study to investigate the association between amniotic-fluid embolism and medical induction of labour.
METHODS: We used a population-based cohort of 3 million hospital deliveries in Canada between 1991 and 2002 to assess the associations between overall and fatal rates of amniotic-fluid embolism and medical and surgical induction, maternal age, fetal presentation, mode of delivery, and pregnancy and labour complications.
FINDINGS: Total rate of amniotic-fluid embolism was 14.8 per 100,000 multiple-birth deliveries and 6.0 per 100,000 singleton deliveries (odds ratio 2.5 [95% CI 0.9-6.2]). Of the 180 cases of amniotic-fluid embolism in women with singleton deliveries during the study period, 24 (13%) were fatal. We saw no significant temporal increase in occurrence of amniotic-fluid embolism for total or fatal cases. Medical induction of labour nearly doubled the risk of overall cases of amniotic-fluid embolism (adjusted odds ratio 1.8 [1.3-2.7]), and the association was stronger for fatal cases (crude odds ratio 3.5 [1.5-8.4]). Maternal age of 35 years or older, caesarean or instrumental vaginal delivery, polyhydramnios, cervical laceration or uterine rupture, placenta previa or abruption, eclampsia, and fetal distress were also associated with an increased risk.
INTERPRETATION: Medical induction of labour seems to increase the risk of amniotic-fluid embolism. Although the absolute excess risk is low, women and physicians should be aware of this risk when making decisions about elective labour induction.

PMID 17055946
Tomoaki Oda, Naoaki Tamura, Rui Ide, Toshiya Itoh, Yoshimasa Horikoshi, Masako Matsumoto, Megumi Narumi, Yukiko Kohmura-Kobayashi, Naomi Furuta-Isomura, Chizuko Yaguchi, Toshiyuki Uchida, Kazunao Suzuki, Hiroaki Itoh, Naohiro Kanayama
Consumptive Coagulopathy Involving Amniotic Fluid Embolism: The Importance of Earlier Assessments for Interventions in Critical Care.
Crit Care Med. 2020 Dec;48(12):e1251-e1259. doi: 10.1097/CCM.0000000000004665.
Abstract/Text OBJECTIVES: Amniotic fluid embolism is a rare disease that induces fatal coagulopathy; however, due to its rarity, it has not yet been examined in detail. The strict diagnostic criteria by Clark for amniotic fluid embolism include severe coagulopathy complicated by cardiopulmonary insufficiency, whereas the Japanese criteria also include postpartum hemorrhage or Disseminated Intravascular Coagulation in clinical practice. Amniotic fluid embolism cases with preceding consumptive coagulopathy may exist and are potential clinical targets for earlier assessments and interventions among amniotic fluid embolism cases fulfilling the Japanese, but not Clark criteria. The present study was performed to compare coagulopathy in the earlier stage between the amniotic fluid embolism patients diagnosed by Clark criteria (Clark group, n = 6), those by the Japanese criteria (Non-Clark group, n = 10), and peripartum controls and identify optimal clinical markers for earlier assessments of amniotic fluid embolism-related consumptive coagulopathy.
DESIGN: Retrospective case-control study.
SETTING: A single university-based center. Our amniotic fluid embolism registry program has accumulated clinical information and blood samples since 2003.
PATIENTS: Amniotic fluid embolism patients in the Clark and Non-Clark groups between 2009 and 2017 and peripartum controls.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: Clinical information was collected on hemoglobin levels, platelet counts, and coagulation- and fibrinolysis-related variables. Fibrinolytic parameters were also measured and compared among the three groups before blood transfusion. Fibrinogen levels in all patients in the Clark group and most in the Non-Clark group decreased earlier than hemoglobin levels, which was consistent with the high hemoglobin/fibrinogen ratio and, thus, is a promising clinical marker for the earlier assessment of amniotic fluid embolism-related consumptive coagulopathy.
CONCLUSIONS: Earlier evaluations of consumptive coagulopathy and hyperfibrinolysis using the hemoglobin/fibrinogen ratio following preemptive treatment may reduce the occurrence or prevent the aggravation of severe coagulopathy in amniotic fluid embolism patients.

PMID 33031152
Naoaki Tamura, Mustari Farhana, Tomoaki Oda, Hiroaki Itoh, Naohiro Kanayama
Amniotic fluid embolism: Pathophysiology from the perspective of pathology.
J Obstet Gynaecol Res. 2017 Apr;43(4):627-632. doi: 10.1111/jog.13284. Epub 2017 Feb 11.
Abstract/Text Amniotic fluid embolism (AFE) is recognized as a type of syndrome characterized by the abrupt onset of hypoxia, hypotension, seizures, or disseminated intravascular coagulopathy (DIC), occurring during labor, delivery, or immediately postpartum, caused by the inflow of amniotic components into the maternal circulation. AFE is a rare condition but one of the most serious obstetrical complications, resulting in a high mortality rate among pregnant women. Despite earlier recognition and intensive critical management, we often encounter patients who unfortunately do not recover from the exacerbation of AFE-related conditions. A major concern is that there are no effective evidence-based therapies for AFE, because its pathophysiology is still not well understood. This article reviewed AFE, focusing on the pathology and currently proposed pathophysiology.

© 2017 Japan Society of Obstetrics and Gynecology.
PMID 28188959
妊産婦死亡症例検討評価委員会・日本産婦人科医会: 母体安全への提言2020;69-80, 2021.
Society for Maternal-Fetal Medicine (SMFM). Electronic address: pubs@smfm.org, Luis D Pacheco, George Saade, Gary D V Hankins, Steven L Clark
Amniotic fluid embolism: diagnosis and management.
Am J Obstet Gynecol. 2016 Aug;215(2):B16-24. doi: 10.1016/j.ajog.2016.03.012. Epub 2016 Mar 14.
Abstract/Text OBJECTIVE: We sought to provide evidence-based guidelines regarding the diagnosis and management of amniotic fluid embolism.
STUDY DESIGN: A systematic literature review was performed using MEDLINE, PubMed, EMBASE, and the Cochrane Library. The search was restricted to English-language articles published from 1966 through March 2015. Priority was given to articles reporting original research, in particular randomized controlled trials, although review articles and commentaries were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion. Evidence reports and published guidelines were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used for defining the strength of recommendations and rating quality of the evidence. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence.
RESULTS AND RECOMMENDATIONS: We recommend the following: (1) we recommend consideration of amniotic fluid embolism in the differential diagnosis of sudden cardiorespiratory collapse in the laboring or recently delivered woman (GRADE 1C); (2) we do not recommend the use of any specific diagnostic laboratory test to either confirm or refute the diagnosis of amniotic fluid embolism; at the present time, amniotic fluid embolism remains a clinical diagnosis (GRADE 1C); (3) we recommend the provision of immediate high-quality cardiopulmonary resuscitation with standard basic cardiac life support and advanced cardiac life support protocols in patients who develop cardiac arrest associated with amniotic fluid embolism (GRADE 1C); (4) we recommend that a multidisciplinary team including anesthesia, respiratory therapy, critical care, and maternal-fetal medicine should be involved in the ongoing care of women with AFE (Best Practice); (5) following cardiac arrest with amniotic fluid embolism, we recommend immediate delivery in the presence of a fetus ≥23 weeks of gestation (GRADE 2C); (6) we recommend the provision of adequate oxygenation and ventilation and, when indicated by hemodynamic status, the use of vasopressors and inotropic agents in the initial management of amniotic fluid embolism. Excessive fluid administration should be avoided (GRADE 1C); and (7) because coagulopathy may follow cardiovascular collapse with amniotic fluid embolism, we recommend the early assessment of clotting status and early aggressive management of clinical bleeding with standard massive transfusion protocols (GRADE 1C).

Copyright © 2016 Elsevier Inc. All rights reserved.
PMID 26987420
薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、渡邉裕次、井ノ口岳洋、梅田将光および日本医科大学多摩永山病院 副薬剤部長 林太祐による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、 著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※同効薬・小児・妊娠および授乳中の注意事項等は、海外の情報も掲載しており、日本の医療事情に適応しない場合があります。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適応の査定において保険適応及び保険適応外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適応の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
金山尚裕 : 特に申告事項無し[2025年]
監修:金山尚裕 : 特に申告事項無し[2025年]

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