Biomedical subjects

Greg R Alexander

Publications and source records attributed to Greg R Alexander.

51 records · Page 3Linked to original sources

PubMed2003

Childbearing beyond maternal age 50 and fetal outcomes in the United States.

OBJECTIVE: To estimate whether achieving pregnancy beyond maternal age of 50 years compromises fetal well-being and survival. METHODS: This was a retrospective study on all deliveries in the United States from 1997 to 1999. Four maternal age groups of 20-29 (young), 30-39 (mature), 40-49 (very mature), and 50 or more years (older) were constructed to assess risk gradients for fetal morbidity and mortality. RESULTS: A total of 539 deliveries among older mothers (aged 50 and above) were documented (four per 100,000). Among singleton gestations, the risks for low birth weight, preterm, and very preterm were tripled among older mothers, whereas the occurrence of very low birth weight, small size for gestational age, and fetal mortality were approximately doubled compared with those for young mothers. Older mothers also had greater risks for fetal morbidity and mortality than their immediate younger counterparts (40-49 year olds) except for very low birth weight. Among multiple gestations, the differences in risk between older and young mothers were lower than those noted among singletons. Still, compared with young mothers, older mothers had significantly higher risks of low birth weight, very low birth weight, very preterm, and small size for gestational age. Older mothers also had higher risk estimates for multiples than 40-49-year-old gravidas in terms of all fetal morbidity and mortality indices. CONCLUSION: Pregnancy beyond age 50 was associated with increased risks for the fetus. Our findings suggest that this age group is a distinct obstetric high-risk entity that requires special counseling before and after conception.

Adult↗

PubMed2003

Potentially preventable excess mortality among higher-order multiples.

OBJECTIVE: To estimate the level of potentially preventable excess mortality achievable by avoiding the creation of higher-order multiple gestation with assisted reproductive technologies. METHODS: This was a retrospective cohort study of multiple pregnancies delivered in the United States between 1995 and 1997 involving 304,466 twins, 16,068 triplets, 1448 quadruplets, and 180 quintuplets. We used the generalized estimating equation framework to compute adjusted relative risks for combined perinatal and infant mortality (early mortality). We then calculated potentially preventable excess mortality among higher-order gestations, using twins and triplets sequentially as the referent category. RESULTS: Early mortality increased significantly with each additional fetus in a dose-dependent fashion (P <.001), corresponding to relative risks (95% confidence interval) of 2.4 (2.2, 2.6) for triplets, 3.3 (2.5, 4.4) for quadruplets, and 10.3 (5.0, 21.4) for quintuplets. The creation of twin rather than quadruplet pregnancies would be associated with a substantially higher level of preventable excess mortality (70%) than the creation of triplet pregnancies (28%). By contrast, limiting quintuplets to twins or triplets did not exhibit a similar level of difference (89% versus 75%, respectively). CONCLUSIONS: Our findings support the need for regulating the number of transferred embryos that result in quadruplet and quintuplet pregnancies.

Adult↗

PubMed2003

Our legacy for leadership in MCH.

The history of Maternal and Child Health (MCH) in the United States provides some important lessons for us today. Emerging from the child labor abolition and progressive reform movements of the late 1800s, the basis of MCH in the United States can be traced to fundamental concerns regarding how our society should protect children from a host of threats, including abuse, the adverse practices of childhood labor, disease, and the ill effects of unclean milk and water, poor sanitation, and an unsafe environment. These and additional concerns about how to assure that children and families have access to adequate healthcare and to health and social systems that understand the special developmental needs of children persist to this day. A review of the history of MCH fosters an appreciation of the many accomplishments made by early MCH leaders during some very difficult times in this country. Today, with the advent of war and an unclear economic forecast, to say nothing of continuing health care reforms and the reinvention of the roles and purposes of public health, it may offer modest comfort to know that our predecessors faced grim circumstances too and prevailed. As MCH continues to evolve in response to the major social events of the times, there is an ongoing need to revisit and reflect upon the role and purpose of MCH in the society. Our inherited legacy of leadership in MCH both inspires and challenges us as we strive to responsibly advocate, align constituencies, build and use data capacities for need assessment and evaluation, question our premises, identify and courageously confront pressing health and social issues, and continue our efforts to formulate and articulate a vision for the future of MCH.

Child↗

PubMed2003

Levels of excess infant deaths attributable to maternal smoking during pregnancy in the United States.

OBJECTIVES: The objectives of the study were: 1) To determine the risk of infant mortality associated with prenatal cigarette smoking; 2) To assess whether the relationship, if existent, was dose-dependent; 3) To explore the morbidity pathway that explains the effect of tobacco smoke on infant mortality, and 4) to compute excess infant deaths attributable to maternal smoking in the United States. METHODS: Retrospective cohort study on 3,004,616 singleton live births that occurred in 1997 in the United States using the US national linked birth/infant death data. Excess infant deaths due to maternal smoking were computed using the population-attributable risk (PAR). RESULTS: Overall, 13.2% of pregnant women who delivered live births in 1997 smoked during pregnancy. The rate of infant mortality was 40% higher in this group as compared to nonsmoking gravidas (P < 0.0001). This risk increased with the amount of cigarettes consumed prenatally in a dose-dependent fashion (p for trend < 0.0001). Small-for-gestational age rather than preterm birth is the main mechanism through which smoking causes excess infant mortality. We estimated that about 5% of infant deaths in the United States were attributable to maternal smoking while pregnant, with variations by race/ethnicity. The proportion of infant deaths attributable to maternal smoking was highest among American Indians at 13%, almost three times the national average. If pregnant smokers were to halt tobacco use a total of 986 infant deaths would be averted annually. CONCLUSIONS: Smoking during pregnancy accounts for a sizeable number of infant deaths in the United States. This highlights the need for infusion of more resources into existing smoking cessation campaigns in order to achieve higher quit rates, and substantially diminish current levels of smoking-associated infant deaths.

Adolescent↗

PubMed2003

Macrosomic births in the united states: determinants, outcomes, and proposed grades of risk.

OBJECTIVE: We describe maternal risk factors for macrosomia and assess birth weight categories to determine predictive thresholds of adverse outcomes. STUDY DESIGN: We analyzed linked live birth and infant death cohort files from 1995 to 1997 for the United States with the use of selected term (37-44 weeks of gestation) single live births to mothers who were US residents. We compared macrosomic infants (4000-4499 g, 4500-4999 g, and >5000 g infants) with a normosomic control group of infants who weighed 3000 to 3999 g. RESULTS: Maternal risk factors for macrosomia included nonsmoking, advanced age, married, diabetes mellitus, hypertension, and previous macrosomic infant or pregnancy loss. The risks of labor complications, birth injuries, and newborn morbidity rose with each gradation of macrosomic birth weight. Infant mortality rates increased significantly among infants weighing >5000 g. CONCLUSION: Although a definition of macrosomia as >4000 g (grade 1) may be useful for the identification of increased risks of labor and newborn complications, >4500 g (grade 2) may be more predictive of neonatal morbidity, and >5000 g (grade 3) may be a better indicator of infant mortality risk.

Adolescent↗

PubMed2003

Placenta previa: neonatal death after live births in the United States.

OBJECTIVE: The purpose of this study was to describe neonatal mortality rates among live births that were complicated by placenta previa in the United States. STUDY DESIGN: This was a population-based retrospective cohort study of 1997 United States singleton live births. Neonatal deaths among pregnancies that were complicated by placenta previa were compared with deaths among pregnancies with no placenta previa. Adjusted and unadjusted hazard ratios were generated from a proportional hazards regression model. RESULTS: Of 3,773,369 live births, 9656 were complicated by placenta previa (2.6 cases per 1000). Among cases of placenta previa, 114 neonatal deaths occurred (11.8 per 1000) versus 14951 (4 per 1000) among non-placenta previa neonates (P <.0001). The adjusted relative risk of death was three times higher among placenta previa neonates (hazard ratio, 3.06; 95% CI, 2.40-3.94). Placenta previa-related death was mediated through preterm delivery rather than small for gestational age. CONCLUSION: Placenta previa triples the rate of neonatal mortality, which is mediated mainly through preterm birth.

Adult↗

PubMed2003

US birth weight/gestational age-specific neonatal mortality: 1995-1997 rates for whites, hispanics, and blacks.

OBJECTIVE: In recent years, gains in neonatal survival have been most evident among very low birth weight, preterm, and low birth weight (LBW) infants. Most of the improvement in neonatal survival since the early 1980s seems to be the consequence of decreasing birth weight-specific mortality rates, which occurred during a period of increasing preterm and LBW rates. Although the decline in neonatal mortality has been widely publicized in the United States, research suggests that clinicians may still underestimate the chances of survival of an infant who is born too early or too small and may overestimate the eventuality of serious disability. So that clinicians may have current and needed ethnic- and race-specific estimates of the "chances" of early survival for newborn infants, we examined birth weight/gestational age-specific neonatal mortality rates for the 3 largest ethnic/racial groups in the United States: non-Hispanic whites, Hispanics, and non-Hispanic blacks. Marked racial variation in birth weight and gestational age-specific mortality has long been recognized, and growing concerns have been raised about ongoing and increasing racial disparities in pregnancy outcomes. Our purpose for this investigation was to provide an up-to-date national reference for birth weight/gestational age-specific neonatal mortality rates for use by clinicians in care decision making and discussions with parents. METHODS: The National Center for Health Statistics linked live birth-infant death cohort files for 1995-1997 were used for this study. Singleton live births to US resident mothers with a reported maternal ethnicity/race of non-Hispanic white, non-Hispanic black, or Hispanic (n = 10 610 715) were selected for analysis. Birth weight/gestational age-specific neonatal mortality rates were calculated using 250 g/2-week intervals for each ethnic/racial group. RESULTS: The overall neonatal mortality rates for whites, Hispanics, and blacks were 3.24, 3.45, and 8.16 neonatal deaths per 1000 live births, and the proportion of births <28 weeks was 0.35%, 0.45%, and 1.39%, respectively. Newborns who weighed <1500 g comprised <2.5% of all births in each racial/ethnic group but accounted for >50% of neonatal deaths. For whites, Hispanics, and blacks, >50% of newborns 24 to 25 weeks of gestational age survived. For most combinations of birth weights <3500 g and gestational ages of <37 weeks, the neonatal mortality rate was lowest among blacks, compared with whites or Hispanics. At these same gestational age/birth weight combinations, Hispanics have slightly lower mortality rates than whites. For combinations of birth weights >3500 g and gestational ages of 37 to 41 weeks, Hispanics had the lowest neonatal mortality rate. In these birth weight/gestational age combinations, where approximately two thirds of births occur, blacks had the highest neonatal mortality rate. CONCLUSIONS: Compared with earlier reports, these data suggest that a substantial improvement in birth weight/gestational age-specific neonatal mortality has occurred in the United States. Regardless of ethnicity/race, the risk of a neonatal death does not exceed 50% (the suggested definition for the limit of viability), except for birth weights below 500 g and gestational ages <24 weeks. Notwithstanding, ethnic/racial variations in neonatal mortality rates continue to persist, both in overall rates and within birth weight/gestational age categories. Blacks continue to have higher proportions for preterm and LBW births, compared with either whites or Hispanics. At the same time, blacks experience lower risks of neonatal mortality for preterm and LBW infants, while having higher risks of mortality among term, postterm, normal birth weight, and macrosomic births.

Black or African American↗

PubMed2003

Infant mortality among twins born to teenagers in the United States. Black-white disparity.

OBJECTIVE: To determine the magnitude of the disparity in infant mortality between twins born to black and white teenagers in the United States. STUDY DESIGN: Analysis was performed on twins born to adolescents in the United States within the period 1995-1997. The generalized estimating equations framework was used to generate relative risks after capturing the effects of sibling correlations within twin pairs. RESULTS: Infant mortality was 20% higher among black twins as compared to their white counterparts (adjusted OR = 1.20, 95% CI = 1.04-1.39). The black-white disparity in infant mortality occurred exclusively in the neonatal period (adjusted OR = 1.31, 95% CI = 1.11-1.54), with postneonatal estimates comparable (adjusted OR = 0.86, 95% CI = .63-1.17). The higher proportion of low-birth-weight infants--more specifically, those small for gestational age as opposed to preterm--among black twins was the most likely explanation for the lower survival probability among twins born to black teenagers. CONCLUSION: Black-white disparity in infant mortality among twins occurred exclusively during the first 28 days of life rather than throughout infancy. Efforts to bridge the gap should be focused on this critical period and should preferentially target those twins who are small for gestational age.

Adolescent↗

PubMed2003

An evaluation of a Medicaid managed maternity program: the impact of comprehensive care coordination on utilization and pregnancy outcomes.

The purpose of this study is to evaluate the effectiveness of the implementation of a Medicaid managed maternity care program in a public health department service population, analyzing race-specific models of WIC participation and risk of small-for-gestational age of term. There were 13,095 singleton deliveries during the period 1987-1990 to women with prenatal care in this managed maternity care program. The research design entailed comparison of the intervention group (those receiving regular prenatal care plus comprehensive care coordination in 1989-90) with an historical comparison group of women who received only regular prenatal care in the two years (1987-88). For the intervention groups, black women were 1.7 times and white women 2.1 times more likely to participate in WIC than their comparison groups. The impact of care coordination on term-SGA births indicates a protective odds ratio of 0.851 for black women. Results for white women were not significant. These findings suggest that care coordination is associated with an increase in WIC participation and with lower risk of term-SGA births for black women but not for white women. The overall results add to growing evidence regarding the efficacy of comprehensive care coordination in improving specific pregnancy outcomes and inform our understanding of the evaluation of a comprehensive approach in preventive, community-based intervention.

Adolescent↗

PubMed2002

Prematurity at birth: trends, racial disparities, and epidemiology.

While infant mortality rates have continued to decline in the U.S., low birth weight and preterm rates have dramatically increased. Although the combination of factors that underlies these trends has not been fully described, there is growing concern that an appreciable part of the rise in prematurity rates stems from efforts taken to improve the survival of these high-risk infants. While advancements in medical technology and practice, augmented by improvements in prenatal care use, may have adversely effected prematurity rates and played a role in broadening racial disparities in pregnancy outcomes, they have positively impacted infant survival. Although many risk factors for prematurity have been identified, there are presently few areas for effective prevention. Accordingly, there is little encouragement for a downturn in prematurity rates in the near future. The prospect of continuing growth in the annual number of surviving preterm infants in the U.S. highlights the need for early detection and treatment of developmental problems for these high-risk survivors, and emphasizes the importance of assuring that needed support services are available to these children and their families.

Humans↗

PubMed2002

A comparison of risk factors for twin preterm birth in the United States between 1981-82 and 1996-97.

OBJECTIVE: This paper examines risk factors for twin preterm birth in 1981-82 and 1996-97 in the United States in order to see if they have changed over time. METHODS: We studied all U.S. twin births for the years examined (N = 346, 567). Since the gestational age distributions for twins differs from singletons, the risk of preterm birth was examined at <33, 33-34, and 35-36 weeks. Logistic regression was used to examine the contributions of sociodemographic and obstetric factors at each period. RESULTS: While the <33 week twin preterm rate rose 7% from 1981-82 to 1996-97, the 33-34-week rate rose 31%, and the 35-36-week rate rose 51%. Women with less education, teenagers, unmarried women, primiparas, and blacks were more likely to deliver preterm across all three preterm birth levels. However, the effect of these low socioeconomic status markers diminished over the study period. Additionally, the odds of preterm birth among blacks increased with earlier gestational ages. Women who had intensive prenatal care utilization as compared with less than adequate utilization were more likely to deliver preterm (35-36 weeks) in 1996-97 (odds ratio (OR) = 2.05) compared with 1981-82 (OR = 1.44). Smaller increases were noted for <33 and 33-34 weeks. CONCLUSIONS: Obstetric factors appear to be playing a greater role in the rise of twin preterm births at 35-36 weeks gestation. Temporal sociodemographic changes do not explain the rise in the preterm rate. Changing clinical practices may be having unintended consequences on the public health goals of reducing preterm and low birthweight rates in the United States.

Adolescent↗

PubMed2002

Maternal and child health graduate and continuing education needs: a national assessment.

OBJECTIVES: The purpose of this report is to describe the methodology and results of a recent national assessment of long-term graduate and short-term continuing education needs of public health and health care professionals who serve or are administratively responsible for the U.S. maternal and child health population and also to offer recommendations for future training initiatives. METHODS: The target of this needs assessment was all directors of state MCH, CSHCN and Medicaid agencies, as well as a 20% random sample of local public health departments. A 7-page needs assessment form was used to assess the importance of and need for supporting graduate and continuing education training in specific skill and content areas. The needs assessment also addressed barriers to pursuing graduate and continuing education. Respondents (n = 274) were asked to indicate the capacity of their agency for providing continuing education as well as their preferred modalities for training. RESULTS: Regardless of agency type, i.e., state MCH, CSHCN, Medicaid or local health department, having employees with a graduate education in MCH was perceived to be of benefit by more than 70% of the respondents. Leadership, systems development, management, administration, analytic, policy and advocacy skills, as well as genetics, dentistry, nutrition and nursing, were all identified as critical unmet needs areas for professionals with graduate training. Education costs, loss of income, and time constraints were the identified barriers to graduate education. More than 90% of respondents from each agency viewed continuing education as a benefit for their staff, although the respondents indicated that their agencies have limited capacity to either provide such training or to assess their staffs need for continuing education. Program managers and staff were perceived in greatest need of continuing education and core public health skills, leadership, and administration were among the most frequently listed topics to receive continuing education training support dollars. Time away from work, lack of staff to cover functions, and cost were the top barriers to receiving continuing education. While attending on-site, in-state, small conferences was the continuing education modality of first preference, there was also considerable interest expressed in web-based training. CONCLUSIONS: Six recommendations were developed on the basis of the findings and address the following areas: the ongoing need for continued support of both graduate and continuing education efforts; the development of a national MCH training policy analysis center; the incorporation of routine assessments of training needs by states as part of their annual needs assessments; the promotion of alternative modalities for training, i.e., web-based; and, the sponsorship of academic/practice partnerships for cross-training.

Child↗

PubMed2002

Racial differences in prenatal care use in the United States: are disparities decreasing?

OBJECTIVES: We examined trends and racial disparities (White, African American) in trimester of prenatal care initiation and adequacy of prenatal care utilization for US women and specific high-risk subgroups, e.g., unmarried, young, or less-educated mothers. METHODS: Data from 1981-1998 US natality files on singleton live births to US resident mothers were examined. RESULTS: Overall, early and adequate use of care improved for both racial groups, and racial disparities in prenatal care use have been markedly reduced, except for some young mothers. CONCLUSIONS: While improvements are evident, it is doubtful that the Healthy People 2000 objective for prenatal care will soon be attained for African Americans or Whites. Further efforts are needed to understand influences on and to address barriers to prenatal care.

Adolescent↗

PubMed2002

The impact of the increasing number of multiple births on the rates of preterm birth and low birthweight: an international study.

OBJECTIVES: We studied the effects of twins and triplets on perinatal health indicators in the overall population in the 1980s and 1990s in Canada, England and Wales, France, and the United States. METHODS: Data were derived mostly from live birth registration. We used rates, relative risks, and population attributable risks for twins and triplets separately. RESULTS: In each country, the increase in multiple births, and the increase in preterm delivery among multiple births, contributed almost equally to the rise in or stabilization of the overall rates of preterm delivery. Twins contributed a much larger proportion of the preterm deliveries and low-birthweight newborns than did triplets. CONCLUSIONS: Twins have a major population-based impact on the trends of perinatal health indicators.

Canada↗

PubMed2002

An evaluation of a Medicaid managed maternity program: the impact of comprehensive care coordination on utilization and pregnancy outcome.

Alabama↗