Low birthweight is defined as less than 2500 grams or 5 1/2 pounds. It is also common to classify low birthweight births into moderately low birthweight (1500-2499 grams) and very low birthweight (less than 1500 grams or 3 1/3 pounds). These classifications are useful because they often correspond to clinical characteristics - increasing morbidities or illnesses with decreasing birthweight. Babies born too small are often born too soon. While the causes of low birthweight and preterm birth may be different in some cases, there is significant overlap within these populations of infants.
Last updated:
January 2022
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In 2022, 1 in 13 babies (7.8% of live births) was low birthweight in Arizona.
Black infants (13.2%) were about 2 times as likely as White infants (7.0%) to be born low birthweight during 2020-2022 (average)
Compared with singleton births, multiple births in Arizona were 8 times as likely to be low birthweight in 2022.
Notes: Very low birthweight is less than 1500 grams (3 1/3 pounds). Multiple deliveries include twin, triplet and higher order deliveries.
Sources: National Center for Health Statistics, final natality data. Retrieved March 19, 2024, from www.marchofdimes.org/peristats.
Compared with singleton births, multiple births in Arizona were about 7 times as likely to be very low birthweight in 2022.
Of all live births in Arizona in 2021, 97.0% were singletons and 3.0% were multiple births.