Fetal scalp stimulation test: an adjunct to intermittent auscultation in non-reassuring fetal status during labor.

AIMS: To evaluate fetal scalp stimulation test (FSST) as an adjunct to intermittent auscultation in diagnosis of intrapartum fetal acidosis and associate result of FSST with cord blood pH and immediate neonatal outcome.

MATERIAL &

METHODS

This study was conducted at a tertiary hospital in India. Digital FSST was performed in seven hundred and fifty women in labor with singleton gestation ≥37 weeks, cephalic presentation and fetal heart abnormalities and/or thick meconium stained amniotic fluid. Intermittent auscultation was used for fetal monitoring during labor. The outcome measure was cord blood pH < 7.20 and neonatal morbidity.

RESULTS

The non-reactive FSST is associated with lower umbilical cord blood pH, lower Apgar scores and higher asphyxia related neonatal morbidity (P-value < 0.001). The non-reactive FSST had 41% sensitivity and 84% specificity to detect pH < 7.20. The positive predictive value of FSST for fetal acidosis is 44% and negative predictive value is 83%. The likelihood ratio for acidosis with noncreative FSST is 2.57.

CONCLUSIONS

Non-reactive FSST is associated with adverse neonatal outcomes. The positive and negative predictive values of FSST to diagnose fetal cord blood pH < 7.20 during labor are 44% & 83%, respectively.