African-American teens are twice as likely to deliver
low birth weight babies and 1.5 times more likely to have
premature babies than white adolescents, according to a
study by researchers at the Johns Hopkins
Bloomberg School of Public
Health. The study, conducted by the school's
Center for
Human Nutrition, examined birth outcomes of 1,120
pregnant African-American teens age 17 and younger living
in Baltimore and compared them with national data on their
white counterparts. When compared with pregnant black women
of all ages in Maryland, the study found the younger group
had almost twice the infant mortality rate (2.3 percent vs.
1.3 percent). The study appears in the August edition of
The Journal of Pediatrics.
"This study shows the need for effective intervention
programs to reduce the risk factors contributing to low
birth weight and other poor pregnancy outcomes in this
population," said principal investigator Kimberly O'Brien,
associate professor with CHN and the school's
Department of International
Health. "In the long run, it costs more to pay for the
health care costs associated with low birth weight and
premature babies than to focus on prevention. There's not
enough attention given to this vulnerable group."
Babies born weighing less than 5 pounds, 8 ounces and
premature babies born before 37 weeks of gestation may face
serious health problems and suffer developmental problems
later in life. Babies born to teen mothers of all races are
at a higher risk of low birth weight, preterm delivery and
infant mortality than those born to older mothers. Previous
studies also have documented that black women in general
have a higher risk of factors associated with adverse
pregnancy outcomes than white or Hispanic women. Yet, until
now, the risk factors for adverse birth outcomes in black
teens had not been well-studied.
Baltimore led the nation with the highest percent of
births to teens with 22.4 percent in 1998, which was nearly
twice the national average of 12.5 percent (source:
Population Connection, Kid Friendly Cities Report Card,
2002). CHN investigators identified several characteristics
and risk factors related to adverse birth outcomes in the
group of urban black teens, including low prepregnancy body
mass index, inadequate weight gain during pregnancy,
inadequate utilization of prenatal care, the presence of
sexually transmitted diseases and a history of cigarette
smoking.
Nutritional status and weight gain during pregnancy
had a significant impact on the risk of preterm birth.
Adolescents in the study who were underweight before
pregnancy had twice the risk for preterm birth than those
of a healthy weight. More than two-thirds of all the study
participants did not have appropriate weight gain during
pregnancy. Nearly 30 percent gained too little weight, and
40 percent gained more than the recommended amount (25-35
pounds for women of normal weight). Those who did not gain
adequate weight had three times the risk for preterm birth
than those who had appropriate weight gain during
pregnancy.
Inadequate utilization of prenatal care was evident in
more than half the girls under age 15 in the study and 35
percent of those ages 15 to 17. Among these girls, the
number of preterm births was twice the national rate.
Infant birth weight also was affected by risk-taking
behaviors during pregnancy. Girls with a history of
cigarette smoking had babies who weighed on average 110
grams less than those of nonsmokers. Rates of cigarette
smoking among blacks is typically lower than among white
adolescents but is increasing and is of great concern to
the study investigators.
Sexually transmitted diseases were also common in this
group. During pregnancy, more than 20 percent of the
adolescents had chlamydia, nearly 7 percent had gonorrhea,
and 30 percent had at least one vaginal infection during
pregnancy. No single sexually transmitted disease was
associated with preterm delivery or low birth weight, but
girls who had a vaginal infection during pregnancy had
babies with a slightly decreased birth weight.
The paper was written by Shih-Chen Chang, Kimberly
O'Brien, Maureen Schulman Nathanson, Jeri Mancini and Frank
R. Witter.
Funding for this research study was provided by
National Institutes of Health/NICHD.
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