The use of ST Analysis as an adjunct to CTG, has during recent years, reduced the frequency of vaginal operative deliveries, the necessity of fetal blood sampling and the number of neonates transferred to NICU.
The aim of this prospective observational study was to assess the effect of the time interval from indication of hypoxia to delivery on neonatal outcome.
Six thousand and ten women with singleton high risk pregnancies with a gestational age above 35+6 monitored with CTG and ST Analysis were included at a Norwegian University Hospital. An indication to intervene was found in 19% of the cases for fetal distress according to Stan Clinical Guidelines.
The study showed that the monitoring of high-risk deliveries with CTG and ST Analysis enabled the selection of fetuses at risk of adverse outcome for intervention and the risk of an adverse neonatal outcome was dependent on the time frame between the indication of hypoxia and delivery, which may reflect a higher specificity for the detection of intrapartum hypoxia than use of CTG alone. The risk increased further if the delivery was delayed more than 20 minutes.
Conclusion
- Users of the Stan method should support and follow the time frame given in the Stan Clinical Guidelines to prevent neonatal morbidity.
- CTG + ST Analysis may reflect a higher specificity for the detection of intrapartum hypoxia than CTG alone.
- ST Analysis enables to select fetuses at risk of adverse outcome.
- The occurrence of a significant ST Event provide an exact time indicating hypoxia, requests a necessary intervention within a certain time frame.
