The seven signs of fetal hypoxia include abnormal fetal heart rate at delivery, amniotic fluid-fetal fecal contamination, abnormal fetal movement, acidosis, abnormal prenatal electronic fetal heart rate monitoring, low fetal biophysical scores, and abnormal fetal Doppler ultrasound blood flow.
Fetal hypoxia can be categorized as acute fetal hypoxia and chronic fetal hypoxia. Acute fetal hypoxia occurs mainly during labor and may be manifested by abnormal fetal heart rate at delivery (most often with a class III fetal heart rate pattern), amniotic fluid-fetal fecal contamination with fetal heart rate monitoring abnormalities, decreased fetal movement after frequent fetal movements, and acidosis suggested by blood gas analysis of fetal scalp blood.
Chronic fetal hypoxia occurs mainly in late pregnancy and often continues and worsens until labor. It is characterized by decreased fetal movement, no stress test abnormalities on prenatal fetal cardiac monitoring, a fetal biophysical score of ≤4, suggestive of fetal hypoxia, and elevated s/d ratios on ultrasound of fetal umbilical artery Doppler flow.
The detection of acute fetal hypoxia or chronic hypoxia requires immediate hospitalization and treatment after evaluation by a physician.