Risk Factors of Low Birth Weight Infants in Multnomah County, Oregon in 1997 and 1998

Abstract

Objective To identify risk factors for low birth weight infants in Multnomah County, Oregon.
Study design Case-control study
Methods All single live births with birth weight less than 4,000 g. were analyzed from the 1997
and 1998 Oregon birth certificate records. The dependent variable was low birth weight,
classified as low birth weight (less than 2,500g.), normal birth weight (2,500g. - 4,000g.).
Independent variables included maternal, paternal, and infant characteristics. Among the
maternal variables examined were race, education, age, complications of pregnancy,
complications of labor and delivery, illnesses during pregnancy, prenatal care, Hispanic origin,
public health care coverage, tobacco use, alcohol use, illicit drug use, heroin use, cocaine use,
methamphetamine use, marijuana use, antenatal procedures, intrapartum procedures, marital
status, birth order, birth space, and maternal weight gain. Paternal variables were race,
education, age, and Hispanic origin. Infant variable included gestational age and sex.
Results Pre-term infants were 17 times more likely than normal term infants to have low birth
weights. Mothers who used cocaine were seven times more likely to have low birth weight
infants than were mothers who did not use cocaine. Mothers who had complications during
pregnancy were three times more likely to have low birth weight infants than were mothers
who had no complications during pregnancy. Mothers who had complications of labor and
delivery were twice as likely to have low birth weight infants than were mothers who had no
complications of labor and delivery. Mothers who had inadequate prenatal care were twice as
likely to have low birth weight infants than were mothers who had adequate prenatal care.
Conclusion Pre-term infants, cocaine use, having complications during pregnancy, having
complications of labor and delivery, and having inadequate prenatal care were significantly
related to low birth weight infants in Multnomah County, Oregon.