摘要：Objectives. We examined low-birthweight (LBW) rates among participants in Colorado’s Prenatal Plus program by prenatal risk factors (smoking, inadequate weight gain during pregnancy, and psychosocial problems) and the effect of successful resolution of these risks during pregnancy. Methods. Data for 3569 Medicaid-eligible women who received care coordination, nutritional counseling, or psychosocial counseling through the Prenatal Plus Program in 2002 were analyzed to determine the prevalence of specific risks, the proportion of women who resolved each specific risk, and the low birthweight rates for births to women who did and did not resolve risk. LBW rates were analyzed with χ2 tests of significance. Results. Women who quit smoking had an LBW rate of 8.5%, compared with an LBW rate of 13.7% among women who did not. Women with adequate weight gain had an LBW rate of 6.7%, compared with 17.2% among women with inadequate weight gain. Women who resolved all of their risks had a low-birthweight rate of 7.0%, compared with a rate of 13.2% among women who resolved no risks. Women who had at least 10 Prenatal Plus visits were more likely to resolve their risks than were women who had fewer visits. Conclusions. Multidisciplinary prenatal interventions targeted toward specific risks demonstrate success at significantly improving infant birthweight. Low birthweight (LBW)—weight of less than 2500 g—has long been recognized as a critical risk factor for infant mortality and neurologic and developmental disabilities. 1 For this reason, Healthy People 2010, the health objectives for the nation, includes as a goal the reduction of the low-birthweight rate to 5.0% of live births by 2010, from a baseline rate of 7.6% in 1998. 2 Despite this ambitious goal, the reduction of low birthweight presents a vexing problem. Although the national low-birthweight rate reached a low of 6.8% in 1985, it has risen steadily since that time and reached 7.8% in 2002. Colorado has experienced this rise in low-birthweight rates as well, with 8.9% of women delivering low-birthweight babies in 2002. In addition, Colorado has had one of the highest low-birthweight rates in the nation for many years. Much of the increase in low birthweight is attributable to an increase in the proportion of multiple births, because these infants face a much higher risk of low birthweight than do singleton infants. However, the rate of low birthweight among singleton births has risen as well, although not as rapidly as that of the population as a whole. The trend in low birthweight also varies by race and ethnicity. Although the LBW rate among non-Hispanic Whites has increased > 20% since 1990, that for Hispanics has risen much less steeply, and that for non-Hispanic Blacks has declined slightly. Nonetheless, the LBW rate among Blacks remains nearly twice that of Whites. 3 Low birthweight can be attributed to two major phenomena: intrauterine growth retardation and preterm delivery. The primary risk factor for intrauterine growth retardation is smoking, which accounts for 20% to 30% of all LBW births in the United States, 4 followed by low maternal weight gain and low prepregnancy weight. 5 Risk factors for pre-term delivery include maternal or fetal stress, infections, and violence; 6 – 8 however, a clear etiology or effective intervention for preterm delivery has not yet been identified. 9 Low birthweight has also been associated with socioeconomic indicators such as education and income 10 as well as with stress during pregnancy; 11 in addition, high-risk behaviors, such as smoking, may themselves be associated with psychosocial stress. 12 Much research to date has focused on the effectiveness of early, consistent prenatal care in preventing low birthweight and preterm delivery; however, this research has not shown that standard prenatal care itself prevents low birthweight. 13 To address the risk factors related to low birthweight that may be modifiable, many programs have been developed with the goal of reducing low-birthweight rates by providing psychosocial support services to high-risk women in the prenatal period. Evaluation results from these programs have found that low-birthweight rates for specific high-risk populations can be reduced with enhanced psychosocial prenatal care programs. Various programs have shown reductions in low birthweight among HIV-infected women, 14 medically high-risk women, 15 low-income women, 16 women pregnant with twins, 17 and pregnant adolescents. 18 Our study contributes to the literature on LBW by examining (1) prenatal interventions and their impact on specific risk factors associated with low birthweight, and (2) by examining the association of these risks with infant birthweight.
