Differential Diagnosis for Loss of Fetal Heart Rate During Labor

Single Most Likely Diagnosis

• Umbilical Cord Compression: This is the most common cause of variable decelerations in fetal heart rate during labor, which can lead to a loss of fetal heart rate if the compression is severe and prolonged. The compression can occur due to the fetus's position or from the umbilical cord being wrapped around the fetus's body.

Other Likely Diagnoses

• Fetal Distress: This can be due to various factors such as hypoxia, which may result from inadequate placental perfusion or other maternal factors like hypertension or infection. Fetal distress can manifest as abnormal fetal heart rate patterns, including a loss of fetal heart rate.
• Placental Abruption: Although less common, placental abruption can cause fetal distress and lead to abnormalities in fetal heart rate monitoring, including loss of fetal heart rate, due to the reduction in placental blood flow and oxygen supply to the fetus.
• Prolonged Uterine Contractions: These can cause fetal hypoxia by reducing blood flow to the placenta during the contraction, potentially leading to a loss of fetal heart rate if the contractions are very frequent and prolonged.

Do Not Miss Diagnoses

• Uterine Rupture: Although rare, uterine rupture is a catastrophic event that can lead to a sudden loss of fetal heart rate. It is more likely in women with a previous uterine scar (e.g., from a cesarean section) or those undergoing a trial of labor after cesarean (TOLAC).
• Amniotic Fluid Embolism: This is a rare but potentially fatal condition for both the mother and the fetus. It can cause sudden cardiovascular collapse and could be associated with a loss of fetal heart rate due to the severe maternal hypoxia and hypotension.
• Maternal Cardiac Arrest: Any condition leading to maternal cardiac arrest will also compromise fetal well-being, potentially resulting in a loss of fetal heart rate. Prompt recognition and intervention are crucial.

Rare Diagnoses

• Fetal Cardiac Anomalies: Pre-existing fetal heart defects could potentially lead to abnormalities in fetal heart rate patterns, including a loss of detectable fetal heart rate during labor, especially if the defect compromises fetal cardiac function.
• Maternal Severe Hypertension or Preeclampsia: While more commonly associated with fetal growth restriction or placental abruption, severe maternal hypertension can directly affect uteroplacental perfusion, potentially leading to fetal distress and loss of fetal heart rate.