Infants' length at birth: an independent effect on perinatal mortality.
OBJECTIVE
To investigate whether variations in birth length (crown-heel-length) were associated with perinatal mortality rate independent of birth weight.


METHODS
The study population was singleton live- and stillbirths from 16 weeks of gestation compiled in the Medical Birth Registry of Norway from 1967 to 1997, totaling 1,705,652 births.


METHODS
The total population was analyzed using z-scores for length at birth, birth weight and gestational age. Variation in perinatal mortality by length at birth was studied within birth weight strata (250 g) by logistic regression.


RESULTS
Perinatal mortality varied more by birth length than by birth weight or gestational age, especially for values above the population means. Within birth weight strata, the association between perinatal mortality and length was similar in all 250 g birth weight categories above 1,500 grams: mortality was lowest at birth lengths 0-2 cm below average, with mortality rates increasing exponentially in either direction.


CONCLUSIONS
Within all birth weight strata, and adjusted for gestational age, long infants had the higher risk of perinatal death, suggesting that length at birth may be a valuable predictor when assessing the risk of perinatal mortality.
Melve
K K
KK
Section for Medical Statistics, Locus of Registry-based Epidemiology, University of Bergen, Norway.
Gjessing
H K
HK
Skjaerven
R
R
Oyen
N
N
D001724:Birth Weight; D001827:Body Height; D005260:Female; D005313:Fetal Death / Q000453:epidemiology*; D005544:Forecasting; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009664:Norway / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors