The association of hypotonia and depression in the term and near-term neonate with metabolic acidemia.
OBJECTIVE
To determine the association of hypotonia and depression in neonates at or near term with metabolic acidemia at birth (umbilical arterial pH<7.0 and base excess <-12 mM).


METHODS
This case-control study identified 87 infants without chromosomal or congenital abnormalities born at a single university hospital between 7/91 and 10/04 with hypotonia at birth requiring resuscitation and admission to the neonatal intensive care unit that had a cord gas at delivery. Controls were the subsequent delivery with a cord gas matched by gestational age.


RESULTS
Cases and controls did not differ in gestational age (38.7+/-1.9, 38.6+/-1.9 weeks) or birth weight (3,066+/-664, 3,171+/-655 g, P=0.20). Cases were more likely to have a cord pH<7.0 [17 (20%) vs. 1 (1.1%), P=0.0001] and cord pH 7.0-7.1 [13 (14.9%) vs. 2 (2.3%), P=0.003]. Among the hypotonic infants, 31 (35.6%) also were depressed at birth with a 5-min Apgar <7. In the depressed subset of hypotonic neonates 14/31 (45%) had a pH<7.0. Of the 12 hypotonic neonates with seizures, 3 (25%) had pH<7.0. Multivariate analysis showed a significant association between neonatal hypotonia and hypoglycemia, umbilical arterial pH, and nucleated red blood cell count.


CONCLUSIONS
Although metabolic acidemia is significantly associated with hypotonia at the time of birth, the majority of neonates with hypotonia and depression or seizures do not have objective evidence of asphyxia as measured by a cord gas at the time of delivery.
Silva
Anadir M
AM
Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Cootauco
Alice C
AC
Aina-Mumuney
Abimbola
A
Donohue
Pamela K
PK
Graham
Ernest M
EM
D000138:Acidosis / Q000150:complications*; D001238:Asphyxia Neonatorum / Q000209:etiology*; D001784:Blood Gas Analysis; D016022:Case-Control Studies; D005312:Fetal Blood / Q000737:chemistry*; D005865:Gestational Age; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D009123:Muscle Hypotonia / Q000209:etiology*; D012640:Seizures / Q000209:etiology*