Factors associated with umbilical artery acidemia in term infants with low Apgar scores at 5 min.
OBJECTIVE
To evaluate predictors of umbilical artery acidemia in term neonates with low Apgar score.


METHODS
From a cohort of term singleton deliveries over a 13-year period, we selected neonates with 5-min Apgar score < 7. Acidemia was defined as umbilical artery pH < 7.00 or base excess (BE) < or = -12 mmol/L. Three pathogenic processes of neonatal acidemia were evaluated: (1) intrauterine vascular disease, defined as preeclampsia, clinical diagnosis of placental abruption, birth weight < 10th centile, or histologic evidence of placental infarction or severe vascular pathology, (2) intrauterine infection, defined as clinical chorioamnionitis, histologic chorioamnionitis, or early neonatal sepsis, and (3) acute intrapartum events, which included cases of cord prolapse, amniotic fluid embolism, uterine rupture, sudden and sustained fetal bradycardia or absence of FHR variability with a previously normal pattern, shoulder dystocia or complicated breech extraction. The associations of such processes with umbilical artery evidence of acidemia were tested using chi(2), Fisher's exact test, Student's t-test, and logistic regression, with P < 0.05 or odds ratio (OR) with 95% confidence interval (CI) not inclusive of the unity considered significant.


RESULTS
Among the 27,395 neonates in the cohort, an Apgar score at 5 min < 7 was recorded in 94 (0.32%) and it was associated with umbilical artery acidemia in 33 cases. Logistic regression analysis showed that intrauterine vascular disease was independently associated with umbilical cord acidemia (P=0.035, OR=3.2, 95% CI=1.1-9.7) whereas intrauterine infection (OR=1.1, 95% CI 0.4-3.4) and acute intrapartum events (OR=2.1 95% CI 0.6-7.0) were not.


CONCLUSIONS
Umbilical artery evidence of acidemia is present in 38% of term babies with low Apgar score and it is predominantly associated with chronic antepartum vascular disease. Neither intrauterine infection nor acute intrapartum events are significantly associated with umbilical artery acidemia.
Locatelli
Anna
A
Department of Obstetrics and Gynecology, San Gerardo Hospital, University of Milano-Bicocca, Via Solferino 16, 20052 Monza (MI), Italy. anna.locatelli@unimib.it
Incerti
Maddalena
M
Ghidini
Alessandro
A
Greco
Massimiliano
M
Villa
Elisabetta
E
Paterlini
Giuseppe
G
D000138:Acidosis / Q000175:diagnosis* / Q000503:physiopathology; D000328:Adult; D001034:Apgar Score; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012044:Regression Analysis; D012189:Retrospective Studies; D047929:Term Birth; D014469:Umbilical Arteries / Q000737:chemistry*; D014652:Vascular Diseases / Q000175:diagnosis / Q000503:physiopathology