Snapshot A 35-year-old woman at 42 weeks of gestation presents for an induction of labor due to postterm pregnancy. She reports positive fetal movement, and denies vaginal bleeding. After amniotomy is performed, a change in fetal heart monitor is noted. Maternal repositioning is performed. (Variable decelerations) Biophysical Profile (BPP) Five measurements of fetal well being, each rated on scale of 1-2 measure fetal breathing gross body movements fetal tone extremity extension and flexion amniotic fluid volume nonstress test (NST) Scoring 8-10 is reassuring 6 is equivocal delivery if > 36 weeks repeat BPP in 24 hours if < 36 weeks ≤ 4 is abnormal requires immediate intervention Fetal Heart Rate (FHR) Normal FHR 120-160/min Tachycardia is FHR > 160/min causes include maternal fever fetal hypoxia prematurity anemia (maternal or fetal) chorioamnionitis hyperthyroidism Bradycardia is FHR < 110/min for > 10 minutes causes include congenital heart block maternal β-blockers FHR variability reliable indicator of fetal well being causes of decreased variability include fetal hypoxia congenital heart anomalies Electronic Fetal Heart Rate Monitoring (EFM) Tracing Interpretation Accelerations ↑ FHR at least 15/min above baseline for ≥ 15 seconds in a 20 minute period considered a reactive NST (needs the presence of at least 2 accelerations) suggests fetal well being Early decelerations ↓ FHR (not below 100/min) that coincide with uterine contraction results from pressure on fetus head resulting in vagus nerve stimulation and reflex bradycardia physiologic and not harmful to fetus Variable decelerations may not coincide with uterine contractions rapid ↓ in FHR (often < 100/min) with variable recovery reflex mechanism due to umbilical cord compression rupture of membrane can lead to umbilical artery compression correct by shifting maternal position or amnioinfusion if membranes ruptured considered first-line if maternal repositioning does not improve FHR tracing, amnioinfusion can be considered Late decelerations begins after uterine contraction has started associated with uteroplacental insufficiency and viewed as potentially dangerous causes include placental abruption maternal diabetes maternal anemia maternal sepsis postterm pregnancy hyperstimulated uterus repetitive late develerations require intervention Sinusoidal tracing sine-wave like pattern associated with increased morbidity and mortality indicative of severe fetal anemia e.g., severe hypoxia and Rh disease