Labor Induction and Fetal Heart Rate Pattern
A 32-year-old primigravida at 41 weeks gestation is admitted for induction of labor due to post-term pregnancy. She has no significant medical history. Her cervix is 2 cm dilated, 50% effaced, and -2 station. Oxytocin infusion is started at 2 mU/min and titrated every 30 minutes. After 6 hours, the oxytocin rate is 12 mU/min, and contractions are every 2-3 minutes, lasting 60 seconds, strong by palpation. The fetal heart rate (FHR) baseline is 140 bpm with moderate variability. Suddenly, a deceleration to 90 bpm occurs, lasting 90 seconds, and is not related to contractions. The maternal blood pressure is 110/70 mmHg, and she is lying supine.
1. What is the category of this FHR pattern according to the NICHD classification? What are the immediate nursing actions?
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This is a Category II FHR pattern (prolonged deceleration) because it is a deceleration lasting >2 minutes but <10 minutes, with moderate variability and baseline 140 bpm. Immediate nursing actions:
- Stop oxytocin infusion immediately.
- Reposition the mother to left lateral position to relieve aortocaval compression.
- Administer oxygen via nonrebreather mask at 10 L/min.
- Increase IV fluid rate (if ordered) to improve uteroplacental perfusion.
- Notify the obstetric provider immediately.
- Perform a vaginal exam to assess for cord prolapse.
- Continue monitoring FHR and maternal vital signs. If the deceleration does not resolve, prepare for emergency cesarean delivery.
2. What are potential causes of this prolonged deceleration?
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Prolonged decelerations can be caused by:
- Uteroplacental insufficiency: e.g., maternal hypotension, uterine hyperstimulation (oxytocin), abruption.
- Cord compression/prolapse: especially if membranes ruptured.
- Maternal hypoxia: e.g., supine position causing aortocaval compression.
- Fetal factors: e.g., fetal anemia, infection, or cardiac arrhythmia. In this case, the oxytocin may be causing hyperstimulation (contractions every 2-3 minutes may be borderline; strong contractions can impair perfusion). Also, supine position may cause hypotension. The deceleration is not related to contractions, so it's not a typical variable or late deceleration.
3. After stopping oxytocin and repositioning, the FHR returns to baseline 140 bpm with moderate variability. The obstetrician orders to restart oxytocin at half the previous rate. What is the nurse's response?
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The nurse should advocate for patient safety. Restarting oxytocin at half the previous rate (6 mU/min) may be appropriate, but the nurse must ensure:
- Contractions are not excessive: Assess contraction frequency and duration; if tachysystole (>5 contractions in 10 minutes averaged over 30 minutes), oxytocin should not be restarted until contractions normalize.
- FHR is reassuring: Confirm baseline 140 bpm, moderate variability, no decelerations.
- Maternal position: Keep mother in lateral position.
- Informed consent: Discuss with the provider the rationale for restarting and the plan for monitoring. The nurse should clarify the order if concerned and document the event. If the provider insists, the nurse should restart at the lowest effective rate and monitor closely. The nurse has the right to refuse to administer a medication if they believe it is unsafe, but should escalate through the chain of command.