Incidence, risk factors, and consequences of amniotic fluid embolism

Fatal amniotic fluid embolism: incidence, risk factors and influence on perinatal outcome

PURPOSE

This study aimed to estimate the incidence of fatal amniotic fluid embolism, describe its risk factors, and analyze perinatal outcomes.

METHODS

Maternity cases and newborn records of amniotic fluid embolism were collected from the Zhejiang Maternal Surveillance System from October 2006 to October 2019. This study strictly limited the diagnostic criteria for AFE and excluded suspicious cases in order to minimize false-positive AFE cases. The risk factors of fatal amniotic fluid embolism and the relationship between perinatal prognosis and AFE were investigated using logistic regression analysis, estimating the adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

149 cases of amniotic fluid embolism were registered, of which 80 cases were fatal. The estimated fatal AFE incidence was 0.99 per 100,000. The occurrence of fatal AFE was significantly correlated with spontaneous vaginal delivery (aOR 12.3, 95% CI 3.3-39.2) and cardiac arrest (aOR 64.8, 95% CI 14.6-287.8). The average diagnosis time of fatal AFE is 85.51 min, and the peak period of female death is 1-12 h after the onset of the disease, accounting for 60% (48/80) of cases. Fatal amniotic embolism is a cause of intrauterine fetal death and fetal death during delivery (aOR 11.957, 95% CI 1.457-96.919; aOR 13.152, 95% CI 1.636-105.723). Of the 149 confirmed AFE cases, 11 cases of stillbirth occurred, 12 cases were stillborn, and 7 cases of neonatal death were reported. The perinatal mortality rate was 202 per 1000.

CONCLUSIONS

Early detection, diagnosis, and treatment of amniotic fluid embolism are essential to avoiding fatal AFE. Clinicians should fully evaluate the pros and cons of choosing the delivery method for pregnant women. When cardiac arrest occurs in women with amniotic fluid embolism, obstetricians should be particularly careful and provide timely and effective treatment to minimize the fatality rate. The outcome of AFE is not only related to maternal survival but also plays a decisive role in the prognosis of the infant over the perinatal period.

The Impact of Severe Maternal Morbidity on Perinatal Outcomes in High Income Countries: Systematic Review and Meta-Analysis

While there is clear evidence that severe maternal morbidity (SMM) contributes significantly to poor maternal health outcomes, limited data exist on its impact on perinatal outcomes. We undertook a systematic review and meta-analysis to ascertain the association between SMM and adverse perinatal outcomes in high-income countries (HICs). We searched for full-text publications in PubMed, Embase, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Scopus databases. Studies that reported data on the association of SMM and adverse perinatal outcomes, either as a composite or individual outcome, were included. Two authors independently assessed study eligibility, extracted data, and performed quality assessment using the Newcastle-Ottawa Scale. We used random-effects modelling to calculate odds ratios (ORs) with 95% confidence intervals. We also assessed the risk of publication bias and statistical heterogeneity using funnel plots and Higgins I2, respectively. We defined sub-groups of SMM as hemorrhagic disorders, hypertensive disorders, cardiovascular disorders, hepatic disorders, renal disorders, and thromboembolic disorders. Adverse perinatal outcome was defined as preterm birth (before 37 weeks gestation), small for gestational age (SGA) (birth weight (BW) < 10th centile for gestation), low birthweight (LBW) (BW < 2.5 kg), Apgar score < 7 at 5 min, neonatal intensive care unit (NICU) admission, stillbirth and perinatal death (stillbirth and neonatal deaths up to 28 days). A total of 35 studies consisting of 38,909,426 women were included in the final analysis. SMMs associated with obstetric hemorrhage (OR 3.42, 95% CI: 2.55-4.58), severe hypertensive disorders (OR 6.79, 95% CI: 6.06-7.60), hepatic (OR 3.19, 95% CI: 2.46-4.13) and thromboembolic disorders (OR 2.40, 95% CI: 1.67-3.46) were significantly associated with preterm birth. SMMs from hypertensive disorders (OR 2.86, 95% CI: 2.51-3.25) or thromboembolic disorders (OR 1.48, 95% CI: 1.09-1.99) were associated with greater odds of having SGA infant. Women with severe hemorrhage had increased odds of LBW infant (OR 2.31, 95% CI: 1.57-3.40). SMMs from obstetric hemorrhage (OR 4.16, 95% CI: 2.54-6.81) or hypertensive disorders (OR 4.61, 95% CI: 1.17-18.20) were associated with an increased odds of low 5-min Apgar score and NICU admission (Severe obstetric hemorrhage: OR 3.34, 95% CI: 2.26-4.94 and hypertensive disorders: OR 3.63, 95% CI: 2.63-5.02, respectively). Overall, women with SMM were 4 times more likely to experience stillbirth (OR 3.98, 95%C 3.12-7.60) compared to those without SMM with cardiovascular disease (OR 15.2, 95% CI: 1.29-180.60) and thromboembolic disorders (OR 9.43, 95% CI: 4.38-20.29) conferring greatest risk of this complication. The odds of neonatal death were significantly higher in women with SMM (OR 3.98, 95% CI: 2.44-6.47), with those experiencing hemorrhagic (OR 7.33, 95% CI: 3.06-17.53) and hypertensive complications (OR 3.0, 95% CI: 1.78-5.07) at highest risk. Overall, SMM was also associated with higher odds of perinatal death (OR 4.74, 95% CI: 2.47-9.12) mainly driven by the increased risk in women experiencing severe obstetric hemorrhage (OR 6.18, 95% CI: 2.55-14.96). Our results highlight the importance of mitigating the impact of SMM not only to improve maternal health but also to ameliorate its consequences on perinatal outcomes.

Risk factors, management, and outcomes of amniotic fluid embolism: A multicountry, population-based cohort and nested case-control study

BACKGROUND

Amniotic fluid embolism (AFE) remains one of the principal reported causes of direct maternal mortality in high-income countries. However, obtaining robust information about the condition is challenging because of its rarity and its difficulty to diagnose. This study aimed to pool data from multiple countries in order to describe risk factors, management, and outcomes of AFE and to explore the impact on the findings of considering United Kingdom, international, and United States AFE case definitions.

METHODS AND FINDINGS

A population-based cohort and nested case-control study was conducted using the International Network of Obstetric Survey Systems (INOSS). Secondary data on women with AFE (n = 99-218, depending on case definition) collected prospectively in population-based studies conducted in Australia, France, the Netherlands, Slovakia, and the UK were pooled along with secondary data on a sample of control women (n = 4,938) collected in Australia and the UK. Risk factors for AFE were investigated by comparing the women with AFE in Australia and the UK with the control women identified in these countries using logistic regression. Factors associated with poor maternal outcomes (fatality and composite of fatality or permanent neurological injury) amongst women with AFE from each of the countries were investigated using logistic regression or Wilcoxon rank-sum test. The estimated incidence of AFE ranged from 0.8-1.8 per 100,000 maternities, and the proportion of women with AFE who died or had permanent neurological injury ranged from 30%-41%, depending on the case definition. However, applying different case definitions did not materially alter findings regarding risk factors for AFE and factors associated with poor maternal outcomes amongst women with AFE. Using the most liberal case definition (UK) and adjusting for the severity of presentation when appropriate, women who died were more likely than those who survived to present with cardiac arrest (89% versus 40%, adjusted odds ratio [aOR] 10.58, 95% confidence interval [CI] 3.93-28.48, p < 0.001) and less likely to have a source of concentrated fibrinogen (40% versus 56%, aOR 0.44, 95% CI 0.21-0.92, p = 0.029) or platelets given (24% versus 49%, aOR 0.23, 95% CI 0.10-0.52, p < 0.001). They also had a lower dose of tranexamic acid (median dose 0.7 g versus 2 g, p = 0.035) and were less likely to have had an obstetrician and/or anaesthetist present at the time of the AFE (61% versus 75%, aOR 0.38, 95% CI 0.16-0.90, p = 0.027). Limitations of the study include limited statistical power to examine factors associated with poor maternal outcome and the potential for residual confounding or confounding by indication.

CONCLUSIONS

The findings of our study suggest that when an AFE is suspected, initial supportive obstetric care is important, but having an obstetrician and/or anaesthetist present at the time of the AFE event and use of interventions to correct coagulopathy, including the administration of an adequate dose of tranexamic acid, may be important to improve maternal outcome. Future research should focus on early detection of the coagulation deficiencies seen in AFE alongside the role of tranexamic acid and other coagulopathy management strategies.

Sudden death during hip replacement surgery: A case series

Hip arthroplasty (hip replacement) surgery is a very common procedure and is particularly common in elderly individuals, where it is typically performed following traumatic hip fracture. As with any surgical procedure, hip arthroplasties are associated with a certain degree of morbidity and mortality, with many deaths occurring in the post-operative period. As most of these cases result from trauma (fractured hips), they are typically referred for medicolegal death investigation. Occasionally, sudden cardiorespiratory collapse and death occurs during hip arthroplasty surgery. In certain medicolegal jurisdictions, all intra-operative deaths must be investigated. Although many post-operative arthroplasty-related deaths might not require autopsy, those that occur intra-operatively may require autopsy. While clinical decision-making during recent years has resulted in fewer arthroplasty-related deaths, intraoperative deaths may still occur. In this review, the authors present their experience with three intra-operative arthroplasty-related deaths, followed by a discussion related to possible mechanisms involved in the deaths.

Anaphylactoid Syndrome of Pregnancy

Anaphylactoid syndrome of pregnancy (ASP) is a widespread, proinflammatory, anaphylactic-like reaction that can occur when amniotic fluid enters the maternal blood circulation. ASP is characterized by four cardinal findings: respiratory distress, altered mental status, hypotension, and disseminated intravascular coagulation. ASP is commonly associated with maternal and neonatal mortality. Early recognition followed by prompt and aggressive treatment can improve survival rates and are among the most critical activities for nurses and other clinicians caring for women with ASP.

Clinical Presentation and Treatment of Amniotic Fluid Embolism

Obstetric emergencies often require intensive care intervention. Amniotic fluid embolism is a rare, unpredictable, and often catastrophic complication of pregnancy that is suspected in a woman who experiences cardiac arrest after a cesarean section. The condition occurs in approximately 1 in 40 000 births and has an average case-fatality rate of 16%. This complication may result from activation of an inflammatory response to fetal tissue in the maternal circulation. Risk factors may include maternal age over 35 years and conditions in which fluid can exchange between the maternal and fetal circulations. The presentation is abrupt, with profound cardiovascular and respiratory compromise, encephalopathy, fetal distress, and disseminated intravascular coagulopathy. Diagnosis is by exclusion and clinical presentation. Treatment is supportive, with a focus on reversal of hypoxia and hypotension, delivery of the fetus, and correction of coagulopathy. Staff debriefing and psychological support for the woman and family are vital.

Anesthetic management of amniotic fluid embolism -- a multi-center, retrospective, cohort study

INTRODUCTION

Amniotic fluid embolism (AFE) is a rare and potentially lethal obstetric complication, commonly occurring during labor, delivery, or immediately postpartum. There is a paucity of data regarding incidence, risk factors, and clinical management. Our primary objective in this study was to evaluate clinical presentation of AFE and delineate anesthesia management of these cases.

METHODS

This 10 years retrospective multi-center cohort study was performed in five tertiary university-affiliated medical centers, between the years 2005 and 2015. All documented cases of AFE identified according to the ICD guidelines were reviewed manually to determine eligibility for AFE according to Clark's criteria. All cases confirming Clark's diagnosis were included in the cohort.

RESULTS

Throughout the study period, 20 cases of AFE were identified, with an incidence of 4.1 per 100,000 births. Average age at presentation was 35 ± 5 years. Seventy percent of cases presented during vaginal delivery, 20% occurred throughout a cesarean delivery, and 10% occurred during a dilation and evacuation procedure. The most common presenting symptom was sudden loss of consciousness in 12 parturients (66.7%), fetal bradycardia in 11 parturients (55%), and shortness of breath in 10 parturients (50%). Perimortem cesarean section was performed in 55% of cases, although only one case was performed in the delivery suite, while all others were performed in the operating room. Echocardiography was performed in 60% of the cases and all were pathological. Furthermore, 20% of cases were connected to an extracorporeal membrane oxygenation machine. There was a 15% mortality rate of 15%. A further 15% suffered major neurological disability, 25% suffered minor neurological morbidity, and 45% survived without severe complications.

CONCLUSION

AFE is associated with significant maternal morbidity. This study highlights the importance of providing advanced training for the delivery suite staff for cases of maternal cardiovascular collapse secondary to AFE and increasing awareness for this rare and devastating obstetric condition.

Amniotic Fluid Embolism

Amniotic fluid embolism (AFE) is a rare but serious and potentially deadly complication of pregnancy that is unpreventable and unpredictable. Most AFE events occur during labor; however, approximately one third happen during the immediate postpartum period. Presentation is abrupt and thought to be an abnormal response to fetal materials entering maternal circulation through the placental insertion site. Care providers must recognize the signs and symptoms of AFE and react quickly to treat potential complications. This can be challenging as there are no set diagnostic criteria or specific laboratory tests. Generally, the diagnosis is based on clinical status when the classic triad of hypoxia, hypotension, and subsequent coagulopathy are noted in a laboring woman or woman who just gave birth, and no other plausible explanation can be determined. Proper treatment of AFE requires a multidisciplinary approach to decrease maternal morbidity and mortality. Knowledge, simulation, and familiarization of a Massive Obstetric Transfusion protocol can help all members of the perinatal team recognize and respond to women with AFE in a timely and effective manner. A case study is presented of a woman with a seemingly normal obstetric course that became complicated rapidly following development of an AFE.

Women's perceptions of induction of labour outcomes: Results of an online-survey in Germany

OBJECTIVE

induction of labour (IOL) is a common procedure in high income countries. It may be conducted for medical as well as non-medical reasons. Women's views on induction of labour have not extensively been evaluated as yet. Also, women's preferences for certain methods of induction including alternative and complementary methods need further exploration in order to meet their expectations and needs.

DESIGN AND SETTING

we published a short online questionnaire on women'views and experiences with IOL.

MEASUREMENTS AND FINDINGS

we asked for indication and gestational age at induction; method of induction, duration of labour and mode of birth. We also asked for the extent of desired, and experienced support and participation in decision-making. Within four weeks of being online, 698 women answered the questionnaire. Most frequent reasons for induction were postmaturity (51.7%), doctor's recommendation (31.6%) and medical complications (25.6%). Most women were induced with misoprostol or dinoprostone, but nearly half of the respondents were also offered, or asked for, complementary and alternative methods (CAM). 50% or more women would have preferred more information on alternatives to IOL, methods of IOL, side effects of the drugs, information on alternatives (59.2%) and on the medication (55.3%). Many would have wished for more support (49.9%) with decision-making (55.2%), and more time (54.1%).

KEY CONCLUSION

women' expectations and needs regarding IOL are widely unmet in current clinical practice.

IMPLICATIONS FOR PRACTICE

there is a need for evidence-based information and decisional support for pregnant women who need to decide how to proceed once term is reached.

Uterine rupture after the uterine fundal pressure maneuver

OBJECTIVE

To clarify the incidence of uterine fundal pressure at delivery and its effect on uterine rupture.

STUDY DESIGN

A questionnaire was sent to 2518 institutions in Japan. We received a response from 1430.

RESULTS

Of reporting institutions, 89.4% used fundal pressure in at least some of their deliveries. Among the 347,771 women who delivered vaginally in this study, 38,973 (11.2%) were delivered with the assistance of fundal pressure. There were six cases of uterine rupture associated with uterine fundal pressure, with one case resulting in maternal death secondary to amniotic fluid embolism.

CONCLUSION

Since uterine fundal pressure may potentially cause serious injury to either the mother and/or neonates, the indications for application need to be clearly elucidated, and obstetric care providers also need comprehensive education and training.

Evaluating Midwifery Units (EMU): a prospective cohort study of freestanding midwifery units in New South Wales, Australia

OBJECTIVE

To compare maternal and neonatal birth outcomes and morbidities associated with the intention to give birth in two freestanding midwifery units and two tertiary-level maternity units in New South Wales, Australia.

DESIGN

Prospective cohort study.

PARTICIPANTS

494 women who intended to give birth at freestanding midwifery units and 3157 women who intended to give birth at tertiary-level maternity units. Participants had low risk, singleton pregnancies and were at less than 28(+0) weeks gestation at the time of booking.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes were mode of birth, Apgar score of less than 7 at 5 min and admission to the neonatal intensive care unit or special care nursery. Secondary outcomes were onset of labour, analgesia, blood loss, management of third stage of labour, perineal trauma, transfer, neonatal resuscitation, breastfeeding, gestational age at birth, birth weight, severe morbidity and mortality.

RESULTS

Women who planned to give birth at a freestanding midwifery unit were significantly more likely to have a spontaneous vaginal birth (AOR 1.57; 95% CI 1.20 to 2.06) and significantly less likely to have a caesarean section (AOR 0.65; 95% CI 0.48 to 0.88). There was no significant difference in the AOR of 5 min Apgar scores, however, babies from the freestanding midwifery unit group were significantly less likely to be admitted to neonatal intensive care or special care nursery (AOR 0.60; 95% CI 0.39 to 0.91). Analysis of secondary outcomes indicated that planning to give birth in a freestanding midwifery unit was associated with similar or reduced odds of intrapartum interventions and similar or improved odds of indicators of neonatal well-being.

CONCLUSIONS

The results of this study support the provision of care in freestanding midwifery units as an alternative to tertiary-level maternity units for women with low risk pregnancies at the time of booking.

Risk of Venous Thromboembolic Events in Pregnant Patients With Autoimmune Diseases

Objective:

The objective of this study is to evaluate the effect of autoimmune disease on the risk of venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) in pregnant women.

Methods:

Using the Health Care Cost and Utilization Project, Nationwide Inpatient Sample database from 2003 to 2011, the risk of developing DVT, PE, and VTE among pregnant patients with selected autoimmune diseases was estimated using unconditional logistic regression analysis.

Results:

Our study cohort consisted of 7 917 453 women of which 43 523 had underlying autoimmune diseases. Risk of VTE was high in pregnant women with systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, type 1 diabetes mellitus, ulcerative colitis, and Crohn’s disease.

Conclusion:

Most autoimmune diseases considerably increase the risk of VTE. Thromboprophylaxis may be considered in pregnancies with autoimmune disease, particularly those with systemic lupus erythematosus and dermatomyositis.