Characteristics of acidotic vs non-acidotic cases of low Apgar scores at 5 minutes in term infants

Abstract

AT 5 MINUTES IN TERM INFANTS ALESSANDRO GHIDINI, MADDALENA INCERTI, ANNA LOCATELLI, ANNA LONGONI, ELENA CIRIELLO, GIUSEPPE PATERLINI, University of Milan-Bicocca, Obstetrics and Gynecology, Monza, Italy, University of Milan-Bicocca, Neonatology, Monza, Italy OBJECTIVE: Low Apgar scores are frequently considered to be indicators of perinatal asphyxia. We have evaluated the prenatal and perinatal characteristics of term infants with low Apgar scores at 5 minutes in relation to the results of cord blod gas analysis to evaluate the strength of this association. STUDY DESIGN: From a cohort of 26,838 consecutive singleton neonates born after 37 weeks from 1/1993 to 12/2003, we selected those with 5-minute Apgar score !7. Demographic, obstetric (gestational age, pregnancy complications, induction of labor, sentinel events during labor, fetal heart rate monitoring pattern, meconium-stained fluid, oligohydramnios or polyhydramnios, mode of delivery) and neonatal variables (sex, weight, multisystem organ dysfunction) were evaluated in reference to umbilical artery evidence of fetal acidemia, defined as pH !7.0 or base excess O 12. Excluded were stillbirths and congenital anomalies. Statistical analysis included Fisher’s exact test and Student t-test with P!0.05 considered significant. RESULTS: Apgar score at 5 minutes !7 was present in 87/26838 infants (0.3%). Cord gas analysis was not performed in 8 cases, and 27 of the remaining cases (34%) had acidosis. Acidotic babies differed from nonacidotic babies with low 5-minute Apgar score only in rates of preeclampsia (11% vs 0%, P=0.03), but not in rates of other obstetric complications, labor, delivery, or neonatal characteristics. CONCLUSION: Umbilical artery evidence of acidosis is present in only about 1/3 of babies with low Apgar scores at 5 minutes, and preeclampsia is the only prenatal or perinatal variable associated with greater risk of acidosis among such cases.