Short-term neonatal outcome in low-risk, spontaneous, singleton, late preterm deliveries.
OBJECTIVE
To estimate the effect of gestational age on short-term neonatal morbidity in cases of spontaneous, low-risk singleton late preterm deliveries and to identify predictors of adverse neonatal outcome.


METHODS
This was a retrospective study of all spontaneous, low-risk late preterm deliveries (34 0/7 to 36 6/7 weeks of gestation) during the years 1997 to 2006 (n=2,478). Multiple gestations and pregnancies complicated by preterm premature rupture of membranes (PROM) or maternal or fetal complications were excluded. Short-term neonatal outcome was compared with a control group of full-term deliveries in a 3:1 ratio (n=7,434). Logistic regression analysis was used to identify risk factors for neonatal morbidity among late preterm infants.


RESULTS
Compared with full-term infants, spontaneous late preterm delivery was independently associated with an increased risk of neonatal morbidity, including respiratory distress syndrome (4.2% compared with 0.1%, P<.001), sepsis (0.4% compared with 0.04%, P<.001), intraventricular hemorrhage (0.2% compared with 0.02%, P<.001), hypoglycemia (6.8% compared with 0.4%, P<.001), and jaundice requiring phototherapy (18% compared with 2.5%, P<.001). Cesarean delivery (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.6-2.6), male sex (OR 1.4, 95% CI 1.1-1.8), and multiparity (OR 2.2, 95% CI 1.7-2.8) were independent risk factors for neonatal respiratory morbidity in cases of late preterm deliveries. The relationship between gestational age and neonatal morbidity was of continuous nature with a nadir at about 39 weeks rather than a term-preterm threshold phenomenon and was unrelated to birth weight.


CONCLUSIONS
Late prematurity is associated with significant neonatal morbidity in cases of spontaneous low-risk singleton deliveries. This information is important for appropriate counseling and should stimulate efforts to decrease the rate of late preterm deliveries.


METHODS
II.
Melamed
Nir
N
From the Helen Schneider Hospital for Women and Nursery, Rabin Medical Center, Department of Neonatal Intensive Care, Schneider Children's Medical Center of Israel Petach Tikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Klinger
Gil
G
Tenenbaum-Gavish
Kinneret
K
Herscovici
Tina
T
Linder
Nehama
N
Hod
Moshe
M
Yogev
Yariv
Y
D000328:Adult; D002543:Cerebral Hemorrhage / Q000209:etiology; D002585:Cesarean Section / Q000009:adverse effects; D005260:Female; D005865:Gestational Age; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000209:etiology; D007567:Jaundice, Neonatal / Q000209:etiology; D008297:Male; D010298:Parity; D011247:Pregnancy; D047928:Premature Birth; D012044:Regression Analysis; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors