Immediate Cesarean Section
At 33 weeks gestation with type 2 (late) decelerations during active labor at +2 station, proceed immediately with cesarean section rather than operative vaginal delivery or fetal scalp sampling. 1, 2
Rationale for Cesarean Delivery
Type 2 (late) decelerations indicate chemoreceptor-mediated fetal hypoxia from placental insufficiency, which is particularly concerning at 33 weeks gestation. 3 This pattern suggests the fetus cannot tolerate the ongoing stress of labor contractions due to inadequate uteroplacental oxygen transfer. 4
Why Not Operative Vaginal Delivery
Forceps and ventouse are contraindicated at 33 weeks gestation - these instruments are designed for term deliveries and should not be used on preterm fetuses due to increased risk of intracranial hemorrhage and skull fractures in the softer, more fragile preterm skull. 5
Even at term, operative vaginal delivery with pre-existing fetal compromise (as evidenced by late decelerations) carries 75-95% risk of requiring emergency cesarean for worsening intrapartum heart rate abnormalities. 6
The mechanical effects of forceps or vacuum on the fetal head cause additional vagal stimulation and increased intracranial pressure, which would worsen the existing hypoxic state indicated by late decelerations. 3
Why Not Fetal Scalp Sampling
Fetal scalp sampling delays definitive management when the CTG already demonstrates a pathologic pattern requiring immediate delivery. 4
Late decelerations represent chemoreceptor-mediated hypoxia - waiting for scalp pH confirmation risks progression to terminal bradycardia (prolonged deceleration >10 minutes), which increases risk of hypoxic-ischemic brain injury to the basal ganglia and thalami, predisposing to dyskinetic cerebral palsy. 4
At 33 weeks with established fetal compromise, there is no benefit to delaying delivery for additional testing. 1
Critical Pre-Delivery Interventions
While preparing for cesarean section, implement intrauterine resuscitation measures: 4
Stop any oxytocin infusion immediately and consider acute tocolysis if uterine hypertonus is present. 4
Position the mother in left lateral decubitus to relieve aortocaval compression. 7
Administer supplemental oxygen and ensure adequate IV hydration to optimize maternal blood pressure and placental perfusion. 4
Administer antenatal corticosteroids if not previously given, as delivery before 34 weeks is imminent. 8, 2
Do not administer magnesium sulfate for neuroprotection - this is only indicated before 32 weeks gestation, and this patient is already at 33 weeks. 1, 2
Common Pitfalls to Avoid
Never attempt labor augmentation or continued expectant management when late decelerations are present at preterm gestation - this represents established placental insufficiency that will only worsen with continued contractions. 1, 4
Do not delay delivery beyond 3-5 minutes if late decelerations persist despite intrauterine resuscitation measures, as prolonged deceleration >10 minutes significantly increases risk of permanent neurologic injury. 4
Ensure neonatal team is present at delivery given the 33-week gestation and evidence of intrapartum compromise requiring immediate neonatal assessment and potential resuscitation. 2