Amniotic Fluid Embolism

LaboratoryAmniotic fluid embolism (AFE) is a rare but serious complication that can happen during delivery or shortly after birth. AFE only affects an estimated 1 in 40,000 deliveries but is still a leading cause of maternal death during labor. This condition occurs when the baby's amniotic fluid (the fluid that surrounds the baby in the placenta), fetal cells, or hair makes its way into the mother's bloodstream. AFE can rapidly develop into a life-threatening situation that puts both the baby and mother's life at risk. Emergency medical intervention is needed to stabilize the mother and deliver the baby as quickly as possible to avoid permanent complications. In most cases, an immediate emergency C-section is the safest option for the baby.

What are the Causes of Amniotic Fluid Embolism?

AFE is more common in vaginal delivery but can occur during a C-section as well. It can also happen shortly after birth while the placenta is still inside the mother's body. AFE occurs when the amniotic fluid or fetal material passes the placental barrier, enters the mother's bloodstream and starts moving throughout the circulatory system. The underlying cause for this is not fully understood, but doctors believe it can stem from a breakdown in the placental barrier. This break of the placental barrier can be triggered by trauma during labor.

When the fetal material enters the mother's bloodstream, her immune system recognizes is as a foreign substance in the body and which triggers an acute inflammatory response. This immune response activates abnormal clotting in the mother's lungs and blood vessels, which can lead to a serious blood-clotting condition called disseminated intravascular coagulation. While this condition is rare, amniotic fluid entering the bloodstream is not uncommon. Many mothers during labor will absorb small amounts of amniotic fluid without any complications. It's not clear why some mothers have such an extreme immune response.

What are the Risk Factors for Amniotic Fluid Embolism?

The causes and specific risk factors for AFE are not well understood, partly because the condition is so rare. With the small amount of research that we already have, several factors have been associated with an increased risk of amniotic fluid embolism. These factors include:

  • Advanced maternal age: Mothers who are 35 years and older are at a much higher risk of pregnancy and labor complications, including AFE.
  • Placenta abnormalities: Abnormalities in the placenta can possibly lead to AFE. Placental abruption and placenta previa can break the natural barrier between your baby and your body.
  • Preeclampsia: High blood pressure during pregnancy and labor has been linked to an increased risk of AFE.
  • Medically induced labor: Some research has suggested that there are certain labor induction methods that could contribute to the development of AFE.
  • Excessive force during delivery: C-sections, using forceps, or using vacuum extraction to deliver the baby can all cause damage to the physical barriers separating the baby from the woman's body. However, it has not been firmly established that this is can be a direct cause of AFE since these procedures are implemented after the condition has already been presented.
  • Polyhydramnios: Excessive amniotic fluid might increase the risk of AFE as well.
  • Intense contractions during labor
  • Tears in the uterus or cervix
What are the Possible Complications from Amniotic Fluid Embolism?

The effects of AFE can be devastating. The maternal mortality rate for this condition can be as high as 80%, with 50% of mothers dying within the first hour of symptom onset. For patients that do survive the embolism, the majority of them will experience long-term neurological deficits. The survival rate for infants, however, is much more promising, with 70% of infants being successfully delivered.

Still, there are several complications that can occur from AFE:

  • Brain injury to mother: The blood clots in the lungs from the embolism can reduce the amount of oxygen traveling to the mother's brain, which can result in permanent brain damage.
  • Fetal distress: AFE can prolong the labor process, which can cause the fetus to become distressed. Fetal distress can greatly increase the risk of several complications, including hypoxia, which can also result in permanent brain damage and conditions like cerebral palsy.
  • Infant death: If the baby is deprived of oxygen for too long or is not delivered quickly enough, the baby can die during delivery.
  • Sudden cardiac arrest: The effects of AFE can develop so rapidly that the blood clots in the lungs send the mother into cardiac arrest.
  • Multiple organ failure: As the condition progresses, it can start to cause the organs to fail from lack of adequate oxygen in the blood.
  • Maternal death

Long-term effects for the mother from AFE include:

  • memory loss
  • organ failure
  • heart damage that can be temporary or permanent
  • nervous system problems
  • a partial or complete hysterectomy
  • damage to the pituitary gland
  • emotional problems if the baby does not survive
What are the Symptoms of Amniotic Fluid Embolism?

The symptoms of AFE can be obvious once fetal material enters the bloodstream because of how sudden the immune response is. The mother will have difficulty breathing or will start to lose consciousness. Other possible symptoms include:

  • fetal distress
  • vomiting
  • nausea
  • seizures
  • severe anxiety, agitation
  • skin discoloration

If the mother survives AFE, she can experience a second stage of the condition known as the hemorrhagic phase. This is when there is excessive bleeding from where the placenta was attached or the location of the cesarean incision.

What is the Treatment of Amniotic Fluid Embolism?

Treatment mainly focuses on stabilizing the mother and preventing the condition from progressing and causing severe complications. Doctors can administer oxygen therapy or a ventilator to assist with breathing. A pulmonary artery catheter may be inserted so doctors can monitor the mother's heart. There are also some medications that can help control blood pressure. If the mother survives the condition, she will most likely need blood, platelets, and plasma transfusions to replace the amount of blood loss from hemorrhaging.

For the baby, the doctors will continuously monitor for any signs of distress. It's critical that doctors deliver the baby as soon as possible. A delayed C-section increases the risk of birth injury. After they are delivered, they will be sent to the intensive care unit (ICU) for evaluation and close observation.

Outlook

Amniotic fluid embolism cannot be prevented and is hard to predict. The condition has the potential to be fatal for both the mother and the baby, so immediate medical intervention is necessary to ensure they survive. If you've previously experienced AFE, it's important to talk to your doctor before you decide to get pregnant again so you can put measures in place to protect your health. This condition is very rare, but mothers should be aware of the possible risks involved.

Sources and Additional Literature

Nawaz, N., & Buksh, A. R. (2018). Amniotic Fluid Embolism. Journal Of The College Of Physicians And Surgeons, 28(6), S107-S109.

Elsey R.J., et al., (2019). Amniotic fluid embolism: A case study and literature review. Southwest Journal of Pulmonary and Critical Care, (4), 94.

Kramer, M. S., et al., (2013). Incidence, risk factors, and consequences of amniotic fluid embolism. Pediatric And Perinatal Epidemiology, 27(5), 436-441.

Angharad Price, C. (2012). The silent killer: exploring amniotic fluid embolism. British Journal of Midwifery, 20(5), 312-315.
Kaur K., et al. (2016). Amniotic fluid embolism. Journal of Anaesthesiology Clinical Pharmacology, 32(2):153-159.

Woo, Y.S., Hong, S.C., Park, S.M., & Cho, K.H. (2015). Ischemic stroke related to an amniotic fluid embolism during labor. Journal Of Clinical Neuroscience: Official Journal Of The Neurosurgical Society Of Australasia, 22(4), 767-768.

Tuffnell, D. J., & Slemeck, E. (2017). Amniotic fluid embolism. Obstetrics, Gynaecology & Reproductive Medicine, 27(3), 86-90.

McDonnell, N. J., Percival, V., & Paech, M. J. (2013). Amniotic fluid embolism: a leading cause of maternal death yet still a medical conundrum. International Journal Of Obstetric Anesthesia, 22(4), 329-336.