compounded by poverty and related adverse socio-
economic factors.
High Birthweight
High birthweight (HBW), or macrosomia (large
body), in an infant also increases the risk to the infant
and mother. A widely agreed upon definition of
macrosomia has yet to be established but often-used
definitions include a birthweight equal to or exceed-
ing 4,000 grams (8 pounds, 12 ounces), 4,250 grams
(9 pounds, 4 ounces), or 4,500 grams (9 pounds, 14
ounces), as well as a birth weighing at or above the
ninetieth percentile of birthweights for the infant’s
gestational age. While one-third of macrosomic births
are still unexplained, several factors are known to
contribute to excessive fetal size, including large size
of parents (especially the mother), multiparity diabe-
tes in the mother, and prolonged gestation. Older
maternal age, male infants, and previous delivery of
a high birthweight infant also seem to be indicative of
macrosomic births. Babies of diabetic women are usu-
ally large at birth, but they behave clinically as if they
are immature. These infants are not longer in average
length but have increased fetal weight. Because glu-
cose, a substance necessary for fetal growth, is elevat-
ed in both diabetic and obese women, these mothers
are more likely to have macrosomic births.
Risks for birth injuries rise rapidly for heavier ba-
bies, with vaginal deliveries being related to higher
morbidity and mortality for both the infant and the
mother. Lacerations of the birth canal and hemor-
rhaging may occur to the mother, fetal death may
occur due to asphyxia (lack of oxygen), and infants
may suffer broken clavicles and neurological damage.
While cesarean delivery has been prescribed as the
best delivery method to prevent fetal death or injury,
others suggest that vaginal birth is still possible for
some macrosomic infants.
See also: INFANT MORTALITY; PREMATURE INFANTS
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