Amniotic Fluid Embolism - Causes, Symptoms, Risk Factors, Complications, Diagnosis and Treatment

What Is Amniotic Fluid Embolism?

Amniotic fluid embolism, otherwise known as the anaphylactoid syndrome of pregnancy, is a rare and life-threatening condition that can occur during pregnancy or soon after birth. It happens when amniotic fluid (fluid surrounding the fetus), fetal cells, hair, or other debris move into the blood vessels. It affects both mother and baby.

How Prevalent Is Amniotic Fluid Embolism?

Amniotic fluid embolism is an uncommon condition; around one to twelve cases of amniotic fluid embolism are reported in 100,000 deliveries, so it is difficult to identify the risk factor. It can occur in healthy women during vaginal delivery, operative delivery, or abortion or after abnormal vaginal delivery. It can also happen within 48 hours post-delivery.

What Is the Pathophysiology of Amniotic Fluid Embolism?

The word "embolism" used to refer to amniotic fluid has historically implied an obstructive, mostly mechanical condition, such as thrombosis or air embolism. Nonetheless, amniotic fluid cannot be obstructed because it is soluble in blood. Moreover, the minute quantities of fetal cells and tissue fragments that might enter the mother's bloodstream with the amniotic fluid are insufficient to restrict a sufficient portion of the pulmonary vascular tree physically, which would result in the noticeable hemodynamic alterations associated with this illness.

Currently, the theory is that exposure to fetal antigens during delivery activates proinflammatory mediators, which in turn cause the release of vasoactive substances (e.g., norepinephrine) and an overwhelming inflammatory cascade akin to the systemic inflammatory response syndrome (SIRS) seen in septic shock and sepsis.

In addition to causing harm to the heart and lungs, the inflammatory reaction also starts the coagulation cascade, which leads to disseminated intravascular coagulation (DIC). The ensuing hypoxia and hypotension in the mother have a profoundly negative impact on the developing fetus.

It is unclear why amniotic fluid embolism affects so few women, given that labor and delivery expose mothers to fetal antigens on a fairly regular basis. It is believed that undiscovered maternal susceptibility factors likely interact with various fetal antigens at varied levels.

What Are the Risk Factors for Amniotic Fluid Embolism?

Here are some of the potential risk factors of amniotic fluid embolism:

• Age Factor - If the mother is above 35 years, there is an advanced risk of amniotic fluid embolism.

• Operative Delivery - Operative procedures like a C-section, a forceps delivery, or a vacuum extraction might increase the risk of amniotic fluid embolism because the physical barriers between the mother and the baby are disrupted, which may cause amniotic fluid embolism.

• Polyhydramnios - This is a condition with too much amniotic fluid around the baby, which is also considered a risk factor for mothers.

• Medically Induced Labor - In some cases, medically induced labor can serve as a risk factor for amniotic fluid embolism.

• Placental Problems - Deformities in the placenta (organ developing in the uterus during pregnancy) also increase the risk of amniotic fluid embolism. Anomalies like the placenta partially or fully covering the cervix (lower, narrow end of the uterus) and peeling away the placenta from the uterus before delivery can damage the barrier between the mother and baby.

• Preeclampsia - Preeclampsia is a condition that occurs after 20 weeks of pregnancy and is characterized by high blood pressure and damage to other internal organs, which may increase the risk of amniotic fluid embolism.

• Cervical Tears or Lacerations - An injury to the upper or lower portion of the vaginal connection is called a cervical tear. Cervical tears are frequently experienced in difficult labor situations requiring foroxep or in early labor when the cervix is not fully dilated, occasionally as a result of big abortions.

• Fetal Distress- The term "fetal distress" describes symptoms that the fetus is not doing well, both before and during birthing. A rare labor complication is fetal discomfort. It usually happens when there is insufficient oxygen reaching the fetus. Postmaturity, or prolonged pregnancy, can cause distress for the fetus.

What Are the Causes of Amniotic Fluid Embolism?

The exact cause of amniotic fluid embolism is still unclear, and many theories have been put forward. Some say it occurs due to the entry of amniotic fluid into the mother's bloodstream because of the breakdown of the placenta. When this happens, there is an overreaction of the immune system, causing inflammation, which activates clotting in the lungs and blood vessels, resulting in disseminated intravascular coagulation (blood clotting throughout the body). However, few studies have shown that many women do not have the same reaction, even when there is an entry of amniotic fluid into the bloodstream during delivery.

What Are the Symptoms of Amniotic Fluid Embolism?

Signs and symptoms of amniotic fluid embolism include,

• Sudden shortness of breath.

• Low blood pressure.

• Chills.

• Altered mental status.

• Nausea and vomiting.

• Loss of consciousness.

• Discoloration of the skin.

• Seizures.

• Increased heart rate.

• Pulmonary edema (collection of fluid in lungs).

• Cardiovascular collapse (sudden failure of the heart to pump blood effectively).

• Bleeding from the uterus.

• Fetal distress (signs of changes in heart rate or decreased movement in the womb).

How Can One Prevent Amniotic Fluid Embolism?

Amniotic fluid embolism was found during the 1920s; since then, researchers have been puzzled about the exact cause and cannot predict who is at significant risk. This makes prevention a problematic task. If a mother has already experienced amniotic fluid embolism and is planning for the next child, it is advisable to consult a high-risk obstetrician first.

How to Diagnose Amniotic Fluid Embolism?

Amniotic fluid embolism diagnosis is difficult because the symptoms have similarities with other severe medical conditions. An amniotic fluid embolism occurs in several stages and phases, which include:

Phase One - It has the highest mortality rate because it is associated with rapid respiratory failure and cardiac arrest.

Phase Two - During this phase, there is increased hemorrhage (bleeding) at the cesarean incision or placental attachment site.

Traditionally, amniotic fluid embolism is diagnosed during autopsy when fetal squamous cells are found in the maternal pulmonary circulation. Nowadays, doing a few tests helps reduce the complications of an amniotic fluid embolism, which include:

• Continuous oximetry (test to measure oxygen level) and arterial blood gas (test to measure oxygen and carbon dioxide level in blood) to determine the degree of hypoxia (low oxygen in the blood).

• Complete blood and coagulation (the process by which blood clot is formed) study to detect early clotting of blood.

• Blood type and screening tests are helpful during transfusion.

• Chest radiographs help detect acute pulmonary edema (fluid accumulation in the lungs).

• An electrocardiogram (ECG) helps to detect heart failure.

• A lung scan is used to detect a blood clot in the lungs.

How Can Amniotic Fluid Embolism Be Treated?

If a physician suspects amniotic fluid embolism during pregnancy, immediate treatment should be started to prevent life-threatening complications. Several methods that doctors practice depending on the situation are:

• Cardiopulmonary resuscitation (CPR).

• Oxygen administration using a tracheal tube or mechanical ventilation.

• Blood, plasma, and platelet transfusions.

• Hysterectomy to stop the bleeding (if it is the source of bleeding).

• Urgent delivery.

• Cardiac catheterization (a thin, flexible tube attached to the heart's blood vessels for problems like blood clots and irregular heartbeat).

• Steroid administration.

Both mother and baby who survived amniotic fluid embolism may have long-term or lifelong medical issues like neurological disorders and permanent organ damage.

What Are the Complications Associated With Amniotic Fluid Embolism?

Statistics show that 80 percent of women do not survive amniotic fluid embolism. The remaining percentage of women who survive have to face many life-threatening complications after survival. The following are the long-term complications that can occur:

• Brain injury or Memory Loss - Less oxygen supply to blood can cause permanent damage to the brain.

• Organ failure.

• Short-term or permanent heart damage.

• Damage to the pituitary gland.

• Complete or partial removal of the uterus.

• Infant death.

• Lengthy hospitalization.

What Are the Long-Term Consequences for Those Who Survive?

It depends on the medical history and how strongly one responds to AFE. Amniotic fluid embolism can have adverse implications that are both physiological and psychological. Among the possible long-term impacts are:

• Damage to the neurons and impairs word recall or memory.

• Irreversible cardiac injury.

• Stroke-related complications (assuming one has experienced one).

• Kidney-related issues.

• Guilt, despair, and anxiety.

• The illness is known as post-traumatic stress disorder (PTSD).

What Are the Differential Diagnosis?

The following conditions can present with symptoms that resemble amniotic fluid embolism. Making comparisons could help with a differential diagnosis.

Amniotic fluid embolism symptoms and indications can be similar to those of a wide range of other diseases or disorders. These include high blood pressure-related seizures during pregnancy (eclampsia); placental abruption, which is the separation of the placenta from the uterine wall; peripartum cardiomyopathy, which is heart failure in the final few months before or after delivery; anaphylaxis; an embolus, which is a blood clot in the lungs; an air embolism; pulmonary aspiration, which is the entry of material into the lungs or lower respiratory tract (pulmonary aspiration); shock caused by abruptly low blood pressure due to widespread infection (septic shock); the loss of more than 20 percent of the blood supply (hemorrhagic shock), which can be brought on by myocardial infarction, a ruptured or inverted uterus, or the toxic effects of some medications, such as an adverse reaction to anesthesia drugs.

Conclusion:

Amniotic fluid embolism is considered a rare but life-threatening condition during pregnancy. Even today, the actual cause of amniotic fluid embolism is unclear, so prevention is a challenging task. When doctors suspect amniotic fluid embolism during pregnancy, emergency treatment planning should be done for the survival of the mother and baby.