Intrapartum Care
Core concepts
Labor is staged by cervical change and fetal descent, not by clock time alone. Contemporary definitions place the active phase at 6 cm; active-phase arrest requires ≥6 cm with ruptured membranes and either ≥4 hours of adequate contractions or ≥6 hours of inadequate contractions. Second-stage arrest thresholds are longer for nulliparas and with epidural analgesia.
Fetal surveillance drives many questions. Category I is a normal baseline (110–160), moderate variability, no late or variable decelerations. Category III includes absent variability with recurrent late or variable decelerations, bradycardia, or a sinusoidal pattern-an expedited-delivery signal. Everything else is Category II, which calls for intrauterine resuscitation (position change, oxygen if hypoxic, IV fluid bolus, stop or reduce oxytocin, treat tachysystole) and reassessment rather than reflex operative delivery.
Be fluent in induction methods and Bishop scoring, labor dystocia, amniotomy, GBS prophylaxis, and emergency management: shoulder dystocia (McRoberts, suprapubic pressure, then internal maneuvers), cord prolapse (elevate the presenting part, knee-chest, emergent delivery), uterine rupture, and postpartum hemorrhage. Interpret decelerations by mechanism: early = head compression, variable = cord compression, late = uteroplacental insufficiency.
Traps
Tachysystole means more than five contractions in 10 minutes averaged over 30 minutes-do not count a single 10-minute window. A prolonged deceleration is defined by duration, not depth.
Worked example
Category II tracing with recurrent variables after an epidural bolus: reposition, bolus fluids, consider ephedrine for hypotension, reassess in 15–30 minutes before escalating.
Rule of thumb
Treat the tracing and the mother together-resuscitate first, then decide.