Fetal bradycardia and disseminated coagulopathy: atypical presentation of amniotic fluid emboli

Meconium-stained amniotic fluid: a risk factor for postpartum hemorrhage

Background/aim

Clinical data with respect to the impact of meconium on the risk of maternal hemorrhage are scarce. Therefore, in this study, we aimed to determine whether meconium-stained amniotic fluid (MSAF) represents a risk factor for postpartum hemorrhage (PPH) after vaginal delivery in a large unselected population.

Patients and methods

A retrospective cohort study evaluated 78,542 consecutive women who had a vaginal delivery between 24th and 44th weeks of gestation. The women who had undergone cesarean section were excluded to avoid possible bias. Postpartum blood loss was measured with graduated blood sack. Postpartum blood loss between 1,000 and 2,000 mL and >2,000 mL were classified as moderate and severe PPH, respectively.

Results

A total of 74,144 patients were available for analysis. According to the color of amniotic fluid (AF), two groups of patients were identified: MSAF (n=10,997) and clear AF (n=63,147). The rates of severe and massive PPH were found to be significantly higher in the MSAF group than that of clear AF group (OR=1.3, 95% CI: 1.2-1.5, p<0.001 and OR=2.5, 95% CI: 1.5-4.2, p<0.001). Operative vaginal delivery rate was found to be higher in the MSAF group than that of clear AF group, but the difference was only borderline significant (OR=1.5, 95% CI: 1.0-2.2, p=0.05). There were no significant differences between the MSAF and the clear AF groups with respect to episiotomies, second- or third-degree perineal tears, vaginal-perineal thrombus, cervical lacerations, vaginal births after cesarean section, twin deliveries, and placental retention rates.

Conclusion

To the best of our knowledge, this is the first clinical study that has investigated the role of MSAF as a risk factor for PPH after vaginal delivery in an unselected population. Our results suggest that MSAF is significantly associated with higher risk of moderate and severe PPH than clear AF.

Clinical course of disseminated intravascular coagulopathy-type amniotic fluid embolism: A report of three cases

Amniotic fluid embolism (AFE) is a rare complication of pregnancy and its mortality rate is high. There have been few reports of AFE with presence of severe coagulopathy and incoagulable bleeding, and absence of cardiopulmonary symptoms or limited cardiopulmonary symptoms, followed by massive blood loss during delivery. Such cases have been referred to as disseminated intravascular coagulopathy-type AFE, and the characteristics of this condition have been presented previously. Here we report three cases that fulfilled the diagnostic characteristics of disseminated intravascular coagulopathy-type AFE.

Amniotic fluid embolism

Amniotic fluid embolism (AFE) is an unpredictable and as-of-yet unpreventable complication of maternity. With its low incidence it is unlikely that any given practitioner will be confronted with a case of AFE. However, this rare occurrence carries a high probability of serious sequelae including cardiac arrest, ARDS, coagulopathy with massive hemorrhage, encephalopathy, seizures, and both maternal and infant mortality. In this review the current state of medical knowledge about AFE is outlined including its incidence, risk factors, diagnosis, pathophysiology, and clinical manifestations. Special attention is paid to the modern aggressive supportive care that resulted in an overall reduction in the still alarmingly high mortality rate of this devastating entity. The key factors for successful management and resolution of this disease process continue to be sharp vigilance, a high level of clinical suspicion, and rapid all-out resuscitative efforts on the part of all clinicians involved in the medical care of the parturient.

Current concepts of immunology and diagnosis in amniotic fluid embolism

Amniotic fluid embolism (AFE) is one of the leading causes of maternal mortality and morbidity in developed countries. Current thinking about pathophysiology has shifted away from embolism toward a maternal immune response to the fetus. Two immunologic mechanisms have been studied to date. Anaphylaxis appears to be doubtful while the available evidence supports a role for complement activation. With the mechanism remaining to be elucidated, AFE remains a clinical diagnosis. It is diagnosed based on one or more of four key signs/symptoms: cardiovascular collapse, respiratory distress, coagulopathy, and/or coma/seizures. The only laboratory test that reliably supports the diagnosis is the finding of fetal material in the maternal pulmonary circulation at autopsy. Perhaps the most compelling mystery surrounding AFE is not why one in 20,000 parturients are afflicted, but rather how the vast majority of women can tolerate the foreign antigenic presence of their fetus both within their uterus and circulation?

Maternal death analysis from the Japanese autopsy registry for recent 16 years: significance of amniotic fluid embolism

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.

Amniotic fluid embolism: an evidence-based review

We conducted an evidence-based review of information about [corrected] amniotic fluid embolism (AFE). The estimated incidence of AFE is 1:15,200 and 1:53,800 deliveries in North America and Europe, respectively. The case fatality rate and perinatal mortality associated with AFE are 13-30% and 9-44%, respectively. Risk factors associated with an [corrected] increased risk of AFE include advanced maternal age, placental abnormalities, operative deliveries, eclampsia, polyhydramnios, cervical lacerations, [corrected] and uterine rupture. The hemodynamic response in [corrected] AFE is biphasic, with initial pulmonary hypertension and right ventricular failure, followed by left ventricular failure. Promising therapies include selective pulmonary vasodilators and recombinant activated factor VIIa. Important topics for future research are presented.

FETAL BRADYCARDIA. A PRACTICAL APPROACH

Fetal bradycardia may herald fetal demise. This article highlights arrhythmic fetal bradycardia rather than bradycardia caused by perinatal distress. We briefly examine the embryonic conduction system's development and physiology and we review the classification, aetiology, evaluation, and approach to fetal bradycardia. Our aim is to provide the clinician with practical information about fetal bradycardia that enlightens causative conditions and aids management.