Electronic fetal heart rate monitoring: Early neonatal outcomes associatedwith normal rate, fetal stress, and fetal distress

OBJECTIVE: The purpose of this study was to test the ability of a clearly d efined classification system for electronic fetal heart rate monitoring to predict early neonatal outcome. STUDY DESIGN: All labors of women with singleton pregnancies greater than o r equal to 32 weeks' gestation electronically monitored at 2 institutions w ere examined. Tracings in the final hour before delivery were defined as no rmal, fetal stress, or fetal distress. After delivery, Apgar scores, cord b lood gas values, and admission to the neonatal intensive care unit were exa mined as measures of early neonatal outcome. RESULTS: Among the 898 patients who qualified for study, 627 (70%) had trac ings classified as normal, 263 (29%) had tracings classified as fetal stres s, and 8 (1%) had tracings classified as fetal distress. There was a signif icant worsening of neonatal outcome across these 3 groups with regard to de pressed Apgar scores 1 minute (5.1%, 18.3%, and 75.0%; P <.05), depressed A pgar scores at 5 minutes (1.0%, 3.8%, and 37.5%; P <.05), and admission to the neonatal intensive care unit (5.6%, 10.6%, and 37.5%; P <.05). There wa s also a progressive worsening of cord blood pH (7.27 +/- 0.06, 7.21 +/- 0. 08, and 7.06 +/- 0.14; P <.05), a progressive increase in P-CO2 (53.39 +/- 8.34 mm Hg, 58.51 +/- 10.55 mm Hg, and 78.31 +/- 20.35 mm Hg; P <.05), and a progressive decline in base excess (-3.18 +/- 2.02 mEq/L, -5.11 +/- 3.11 mEq/L, and -9.07 +/- 4.59 mEq/L; P<.05). CONCLUSION: This simple classification system for interpreting fetal heart rate tracings accurately predicts normal outcomes for fetuses as well discr iminating fetuses in true distress. Further, it identifies an intermediate group of fetuses with a condition labeled fetal stress who might benefit fr om additional evaluation and possibly from expeditious delivery.