1B. NATALITY: MATERNAL CHARACTERISTICS ANDNEWBORN?SHEALTH
Figure1B-9
Risk forMultipleBirths byMother?sAgeGroup, Arizona, 2013
In 2013, the proportion of multiple
births gradually increased with
maternal age among mothers
below 45 years of age and sharply
increased among mothers age 45
years and older. Among women
aged 45 years and older, 19.9
percent of all births were twins,
triplets, or quadruplets (
Figure
1B-9
). The percent of all births
that weremultiple births towomen
age 45 and over decreased from
25 percent in 2010, to 16.8
percent in 2011, and dropped to
6.2 percent in 2012. Continued
monitoring of multiple births
among older mothers will help
better understand the recent
variation that has been found in
thismeasure.
Figure 1B-10
Infants Born tooEarly (Preterm)
a
and Infants Born tooSmall (LBW)
b
amongMultiple andSingleBirths, Arizona, 2013
Notes:
a
Preterm is < 37weeks of gestation;
b
Low birthweight is less than 2,500 grams or 5 pounds 8 ounces.
Infants born in multiple deliveries
tend to be born at shorter
gestations and smaller than those
born in singleton deliveries
(
Figure 1B-10
). In 2013, infants
born in multiple deliveries were
12.7 times more likely (45.6 vs.
3.6 percent) to be born earlier
than expected (at less than 37
completed weeks of gestation) and
smaller (at less than 2,500 grams)
than singleton births.
Preterm birth is a leading cause of
infant morbidity and mortality,
accounting for almost two-thirds of
infant deaths (59.0 percent;
Figure 2C-4
in section 2C on Age-
Specific Mortality). The weight of
the newborn also is an important
predictor of future morbidity and
mortality. Infants born at low birth
weight (< 1,500 grams) account
for 47.9 percent of all infant
deaths (
Figure2C-3
).
22
Arizona Health Status and Vital Statistics 2013
