Predicting premature delivery--no easy task

Genomics for health in preconception and prenatal periods

PURPOSE

To review and report changes in genomic-based knowledge and care during the preconception and prenatal periods.

DESIGN

Integrative review of relevant medical and nursing literature.

FINDINGS

Client education and counseling are needed to understand genomic information and provide guidance in interpreting this information and making decisions. The factors that influence decision-making about testing and acting on test results constitute a complex process that has not been well studied. Family history is an important tool for obtaining genomic information and can assist women and families in understanding risk preconceptionally and prenatally. Genomic research has enhanced understanding of the mechanisms of birth defects such as neural tube defect and will likely provide research opportunities to better understand complex perinatal outcomes such as preterm birth.

CONCLUSIONS

Research, education, advocacy, and anticipatory guidance are needed as women and families obtain more genetic and genomic information before and during pregnancy. All nurses will be involved in helping patients use genetic and genomic information to understand risk and to develop strategies to modify risk, and in translating the expanding array of genomic information to improve birth outcomes.

The association of chronic endometritis with preterm birth

OBJECTIVE

The purpose of this study was to determine whether chronic endometritis (CE) that is diagnosed by endometrial biopsy is associated with preterm birth at <37 weeks of gestation.

STUDY DESIGN

Pathology reports for women aged 18-45 years who underwent clinically indicated endometrial biopsy between 1992 and 2002 were solicited from 3 participating clinical pathology laboratories. Reports were dichotomized into those with and those without CE by a standard definition. Results were linked to birth certificates at the Ohio Department of Health. Women who delivered singleton infants (1992-2002) within 3 years of biopsy were included. Biopsy specimens that were obtained from women with conditions that were associated with indicated preterm birth were excluded. Statistical analysis included logistic regression, Student's t-test, Fisher's exact test, and chi-square test, where appropriate. A probability value of <.05 was considered significant.

RESULTS

The 1603 endometrial biopsy reports were identified and forwarded. The Ohio Department of Health linked birth certificate data to 193 reports, 157 of which met inclusion criteria and comprised the study group. Twenty-six of 157 women (16.6%) who were studied had CE. The odds of delivering at <37 weeks of gestation were not significantly higher for women with CE (odds ratio, 2.51; 95% CI, 0.86-7.29; P = .091). Infants who were born at <37 weeks of gestation were more likely to be black (P < .001); to have intrapartum fever, meconium, or fetal distress (P = .026) and to require assisted ventilation (P = .016).

CONCLUSION

In our study group, women with CE were not more likely to deliver an infant at <37 weeks of gestation.

Increased recurrence of preterm delivery with early cessation of 17-alpha-hydroxyprogesterone caproate

OBJECTIVE

The purpose of this study was to identify the effect of early cessation of 17-alpha-hydroxyprogesterone caproate (17P) on the incidence of spontaneous recurrent preterm delivery (PTD).

STUDY DESIGN

Retrospective analysis of data from women who were enrolled for outpatient 17P administration between January 2004 and May 2006 included women with previous PTD and current singleton pregnancy who were beginning weekly 17P injections (250 mg intramuscularly) at 16-20.9 weeks. The study group was comprised of patients who were electively terminating 17P at <32.0 weeks and who delivered >10 days from the last injection. The control group consisted of patients who received weekly 17P injections until PTD or 36.9 weeks of gestation. The primary study outcome was the rate of recurrent spontaneous PTD.

RESULTS

Study group patients were significantly more likely to have spontaneous recurrent PTD at <37 weeks of gestation (48.1% vs 33.3%; P = .011), at <35 weeks of gestation (30.9% vs 14.0%; P < .001), and at <32 weeks of gestation (16.0% vs 7.0%; P = .020).

CONCLUSION

Early cessation of 17P treatment is associated with an increased risk for spontaneous recurrent PTD.

Tumor necrosis factor-alpha and interleukin-1beta regulate interleukin-8 expression in third trimester decidual cells: implications for the genesis of chorioamnionitis

Chorioamnionitis is associated with intense neutrophil infiltration of the decidua. We therefore determined whether chorioamnionitis enhances decidual interleukin-8 (IL-8) expression and examined cytokine-regulated decidual IL-8 expression. Decidua from chorioamnionitis-complicated pregnancies, but not term controls, displayed marked IL-8 immunohistochemical staining and a dense neutrophil infiltrate. Reverse transcriptase-polymerase chain reaction of microdissected decidual cells identified IL-8 mRNA, confirming decidual synthesis of IL-8. Confluent leukocyte-free term decidual cells were primed with 10(-8) mol/L estradiol (E2) or E2 + 10(-7) mol/L medroxyprogesterone acetate to mimic the steroidal milieu of pregnancy. Compared with cultures maintained in E2 alone, E2 + medroxyprogesterone acetate neither significantly affected IL-8 levels nor altered the response to the cytokines. The addition of 1.0 ng/ml tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1beta) increased IL-8 secretion levels by 236.6 +/- 51.4- and 1062.6 +/- 254.3-fold, respectively (n = 8, mean +/- SEM, P < 0.05), as measured by enzyme-linked immunosorbent assay. Concentration-response studies revealed that 0.01 ng/ml TNF-alpha and IL-1beta elevated IL-8 output by 10- and 100-fold, respectively. Western blotting confirmed these results, and quantitative reverse transcriptase-polymerase chain reaction demonstrated parallel changes in mRNA levels. In conclusion, IL-8 is strongly expressed in term decidua during chorioamnionitis, and TNF-alpha and IL-1beta enhance IL-8 expression in term decidual cells, suggesting that these cytokines are important regulators of chorioamnionitis-related decidual neutrophil infiltration.

Deciding When It's Labor: The Experience of Women Who Have Received Antepartum Care at Home for Preterm Labor

OBJECTIVE

To describe how women who had received antepartum care at home for preterm labor managed subsequent episodes of preterm labor symptoms.

DESIGN

Grounded theory method.

SETTING

2 Canadian antepartum home care programs.

PARTICIPANTS

12 women who received antepartum care at home for preterm labor that had been diagnosed in hospital prior to 34 weeks gestation.

RESULTS

The core psychosocial process was reconciling body knowledge and professional knowledge. Study participants reported knowing something's not right and followed decision guides to seek help. If, when they returned to the hospital to see what's going on, they felt dissonance between what their bodies were telling them (body knowledge) and what their health care providers were telling them (professional knowledge) an overriding tension developed between not wanting to take a risk for the baby versus not wanting to overreact. These women reestablished their baselines of nonthreatening symptoms at a higher level by setting a new normal to avoid the humiliation associated with appearing to overreact. Attempting to ignore recurring symptoms of preterm labor delayed help seeking and caused anxiety.

CONCLUSIONS

To avoid delayed help seeking, nursing interventions should be geared to reducing anxiety and validating the experiences of women with recurring preterm labor symptoms.

Thrombin and interleukin-1beta regulate HOXA10 expression in human term decidual cells: implications for preterm labor

CONTEXT

Preterm delivery is commonly caused by intraamniotic infection with expression of proinflammatory cytokines (IL-1beta) or by abruption resulting in generation of decidual thrombin. Although human parturition is not preceded by overt progesterone withdrawal, progesterone resistance likely leads to labor. The uteri of Hoxa10(-/-) mice demonstrate progesterone resistance; several genes, including prostaglandin receptors, are inappropriately regulated in response to progesterone.

OBJECTIVE

We hypothesized that IL-1beta or thrombin would decrease HOXA10 expression, contributing to the progestin-resistant environment. We analyzed expression of HOX genes and their regulation by IL-1beta or thrombin in decidual cells.

DESIGN AND SETTING

We conducted an in vitro experiment at an academic medical center.

INTERVENTION

Term decidual cells were treated with estradiol (E(2)) or E(2) plus medroxyprogesterone acetate followed by addition of thrombin or IL-1beta.

MAIN OUTCOME MEASURE

HOX mRNA was evaluated by microarray and confirmed by quantitative RT-PCR. Protein expression was detected using immunohistochemistry and Western analysis.

RESULTS

HOXA9, HOXA10, and HOXA11 were expressed in decidual cells and regulated by IL-1beta and thrombin. HOXA10 was further analyzed because of its association with progesterone responsiveness. After E(2) treatment, IL-1beta and thrombin decreased HOXA10 mRNA by 94 and 81%, respectively. After E(2) plus medroxyprogesterone acetate treatment, IL-1beta and thrombin resulted in an 86 and 72% decrease in HOXA10 mRNA, respectively. A similar decrease was noted in HOXA10 protein expression.

CONCLUSION

The expression of HOXA10 protein at term indicates that it may have a role in maintaining decidual cell phenotype and pregnancy. The dramatic decrease of HOXA10 in response to IL-1beta or thrombin may contribute to progestin resistance in preterm labor, mimicking progesterone resistance seen in Hoxa10(-/-) mice.

Thrombin-dependent regulation of matrix metalloproteinase (MMP)-9 levels in human fetal membranes

OBJECTIVE

Amniochorion matrix metalloproteinase (MMP)-9 levels increase during labor, reaching a maximum in patients with preterm premature rupture of membranes (PPROM). Bleeding is a major risk factor for PPROM. Since such hemorrhage into the tissue factor-enriched decidua induces intense thrombin formation, we determined whether thrombin stimulates MMP levels in amniochorionic membranes.

STUDY DESIGN

Fetal membrane (amniochorion) cultures were maintained in media with and without thrombin, lipopolysaccharide (LPS), thrombin receptor agonist peptide (TRAP)-14, and the anti-inflammatory steroid, dexamethasone (DEX). Concentrations of MMP-9, MMP-1, and tissue inhibitor of metalloproteinase (TIMP)-1 in culture media were measured by ELISA and normalized to total cell protein.

RESULTS

The presence of thrombin induced MMP-9 levels. TRAP-14, a thrombin receptor agonist, also significantly increased MMP-9 levels, suggesting that thrombin-induced changes in MMP-9 expression were mediated through the thrombin receptor. Conversely, levels of MMP-1 and TIMP-1 were not affected by thrombin treatment, indicative of specificity of its action. The presence of LPS increased the concentration of MMP-9 and MMP-1. In contrast, DEX treatment significantly reduced MMP-9 levels.

CONCLUSION

Our findings clearly demonstrated that thrombin treatment selectively increased the concentration of MMP-9 in culture media of amniochorionic membranes. Our results provide a potential mechanism through which alterations in hemostasis promote PPROM through thrombin-dependent stimulation of MMP-9.

Detection of intra-amniotic infection in a rabbit model by proteomics-based amniotic fluid analysis

OBJECTIVE

This study was undertaken to identify intra-amniotic infection caused by several different organisms in a rabbit model by using proteomics.

STUDY DESIGN

Twenty infected and 18 uninfected amniotic fluid samples were subjected to proteomic analysis by surface-enhanced laser desorption ionization (SELDI-TOF, Ciphergen Biosystems, Fremont, Calif), 1- and 2-dimensional gel electrophoresis, and tandem mass spectrometry (MS/MS).

RESULTS

Detailed SELDI-TOF spectra revealed a constitutive 4.0 kd peak in all animals. Infected samples also displayed a signature double peak at 3.6 kd. A SELDI-TOF signature profile for intra-amniotic infection predicted positive amniotic fluid and/or fetal cultures with a sensitivity of 90% and specificity of 83%. Similar proteomic profiles were obtained regardless of the infecting organism. The 3.6 kd peak appeared to contain rabbit calgranulin C and rabbit calcyclin, members of the S100 family of calcium binding proteins.

CONCLUSION

Amniotic fluid proteomic analysis was able to detect intra-amniotic infection in this experimental rabbit model. S100 proteins may be involved in the host inflammatory response to intra-amniotic infection.

Infection and Preterm Birth

As many as 50% of spontaneous preterm births are infection-associated. Intrauterine infection leads to a maternal and fetal inflammatory cascade, which produces uterine contractions and may also result in long-term adverse outcomes, such as cerebral palsy. This article addresses the prevalence, microbiology, and management of intrauterine infection in the setting of preterm labor with intact membranes. It also outlines antepartum treatment of infections for the purpose of preventing preterm birth.

Research agenda for preterm birth: recommendations from the March of Dimes

Preterm birth (PTB) is a common, serious, and costly health problem affecting nearly 1 in 8 births in the United States. Burdens from PTB are especially severe for the very preterm infant (<32 weeks' gestation), comprising 2% of all US births. Successful prevention needs to include newly focused and adequately funded research, incorporating new technologies and recognition that genetic, environmental, social, and behavioral factors interact in complex pathogeneses and multiple pathways leading to PTB. The March of Dimes Scientific Advisory Committee created this prioritized research agenda, which is aimed at garnering serious attention and expanding resources to make major inroads into the prevention of PTB, targeting six major, overlapping categories: epidemiology, genetics, disparities, inflammation, biologic stress, and clinical trials. Analogous to other common, complex disorders, progress in prevention will require incorporating multipronged risk reduction strategies that are based on sound scientific discovery, as well as on effective translation into clinical care.

Trends in maternal and infant health in poor urban neighborhoods: good news from the 1990s, but challenges remain

OBJECTIVES

During the 1990s, numerous public policy changes occurred that may have affected the health of mothers and infants in low-income neighborhoods. This article examines trends in key maternal and child health indicators to determine whether disparities between high-poverty neighborhoods and other neighborhoods have declined.

METHODS

Using neighborhood-level vital statistics and U.S. Census data, we categorized "neighborhoods" (Census tracts) as being high poverty (greater than 30% of population below the federal poverty level in 1990) or not. We compared trends in four key indicators--births to teenagers, late prenatal care, low birth-weight; and infant mortality--over the 1990s among high-poverty and other neighborhoods in Cuyahoga County, Ohio; Denver, Colorado; Marion County, Indiana; and Oakland, California.

RESULTS

In all four metropolitan areas, trends in high-poverty neighborhoods were more favorable than in other neighborhoods. The most consistently positive trend was the reduction in the rate of teen births. The metropolitan areas with the most intensive programs to improve maternal and child health--Cuyahoga County and Oakland-saw the most consistent improvement across all indicators. Still, great disparities between high-poverty and other neighborhoods remain, and only Oakland shows promise of achieving some of the Healthy People 2010 maternal and child health goals in its high-poverty neighborhoods.

CONCLUSIONS

While there has been a reduction in maternal and infant health disparities between high-poverty and other neighborhoods, much work remains to eliminate disparities and achieve the 2010 goals. Small area data are useful in isolating the neighborhoods that should be targeted. Experience from the 1990s suggests that a combination of several intensive interventions can be effective at reducing disparities.

TOCOX--a randomised, double-blind, placebo-controlled trial of rofecoxib (a COX-2-specific prostaglandin inhibitor) for the prevention of preterm delivery in women at high risk

OBJECTIVE

To assess the safety and efficacy of the long term prophylactic use of rofecoxib (a COX-2-specific inhibitor) in women at high risk of preterm delivery.

DESIGN

A randomised, double-blind, placebo-controlled trial.

SETTING

Queen Charlotte's and Chelsea Hospital, London and Guys and St Thomas' Hospitals, London.

POPULATION

Ninety-eight singleton pregnancies at high risk of preterm labour.

METHODS

Treatment from 16 to 32 weeks. Weekly ultrasound surveillance.

MAIN OUTCOME MEASURES

Fetal renal function and ductus arteriosus blood flow changes. Preterm delivery rates and neonatal outcome.

RESULTS

Rofecoxib caused a reduction in hourly fetal urine production rates (-34%, 95% CI -13 to -50%, P = 0.004) and amniotic fluid index (-2.2, 95% CI -3.2 to -1.2, P < 0.001). This effect did not increase with time on treatment and reversed in all cases on discontinuation of treatment. Rofecoxib had an effect on the ductus arteriosus, increasing maximum systolic velocity (0.1 m/s, 95% CI 0.03-0.16, P = 0.02) and minimum diastolic velocity (0.007 m/s, 95% CI 0.0007-0.013, P= 0.03). This effect increased with time on treatment but was reversed with discontinuation of treatment and had no long term clinical sequelae. There was no difference in preterm delivery rates <30 weeks (28% on placebo vs 33% on rofecoxib, Mantel-Haensel [M-H]-adjusted risk 1.11, 95% CI 0.67-1.87). There were more deliveries <37 weeks in those on rofecoxib (40%vs 67%, M-H-adjusted risk 1.59, 95% CI 1.09-2.32). Rates of preterm prelabour rupture of membranes (PPROM) were higher in those on rofecoxib (RR 2.5, 95% CI 1.3-4.7).

CONCLUSION

Rofecoxib has a significant but reversible effect on fetal renal function and the ductus arteriosus. It does not reduce the incidence of early preterm delivery <30 weeks and is associated with an increased risk of delivery before 37 weeks in women at high risk.

Timing of Enhanced Prenatal Care and Birth Outcomes in New Jersey’s HealthStart Program

OBJECTIVE

This study examined the effects of prenatal care and the timing of its initiation on birth weight and gestational age outcomes among women in a state-wide Medicaid enhanced prenatal care program.

METHODS

Ordinary Least Squares and logistic regression analyses were performed using data on 88,196 births in New Jersey between 1988 and 1996. A large number of potentially confounding factors were included.

RESULTS

Initiating prenatal care in the first trimester was associated with a 56 g advantage in birth weight (p = .01) compared to no care. Initiating prenatal care in the first or second trimester was associated with a 1 day advantage in gestational age (p = .05). There were no significant effects of prenatal care, initiated in any trimester, on low-birth weight. Initiating care in the first versus the second trimester had no effect on the probability of delivering preterm. The findings did not vary by sociodemographic subgroup.

CONCLUSION

This study provides support for claims that there is little that prenatal care can do to improve aggregate birth outcomes because most pregnancy complications are the result of behaviors and life circumstances that precede the pregnancy and are very difficult to reverse. Prenatal care, even with enhanced services, appears to offer too little, too late.

Dose response of RU486 in a novel rabbit model of noninfectious preterm birth: comparative efficacy of 3 routes of administration

OBJECTIVE

The purpose of this study was to examine whether the pregnant rabbit model can be used as a viable model for the study of non-infection-mediated preterm birth.

STUDY DESIGN

Timed pregnant New Zealand rabbits were injected with a single dose of RU486 on day 22 of gestation. Three doses (50 mg, 75 mg, and 100 mg) were administered intramuscularly, intraperitoneally, or subcutaneously. The rabbits were monitored for preterm delivery. Progesterone, cortisol, and cytokine levels were examined before the induction and after delivery. Uterine and cervical progesterone, cortisol, and cytokine levels were determined after delivery.

RESULTS

RU486 resulted in 100% preterm delivery in all doses and modes of administration, compared with 0% of controls. Intramuscular administration appeared to generate the most favorable preterm delivery time. Rabbits that received 100 mg RU486 intramuscularly showed significantly decreased serum progesterone levels and uterine progesterone levels, compared with 100 mg subcutaneously and intraperitoneally.

CONCLUSION

RU486 that was administered intramuscularly appears to be a potent and effective method for inducing preterm birth. This model of hormonally mediated preterm birth might serve as a useful model for the investigation of the possible mechanisms of preterm labor.

Use of uterine EMG and cervical LIF in monitoring pregnant patients

OBJECTIVES

Review the uterine electromyography (EMG) and cervical light-induced fluorescence (LIF) devices and their role in the evaluation of uterine and cervical function in comparison with present methods.

DESIGN

Review of recent studies.

SETTING

University of Texas Medical Branch Labour and Delivery Clinics.

POPULATION

Various groups of pregnant women.

METHODS

We have developed and recently improved non-invasive methods to evaluate quantitatively uterine electrical signals from the abdominal surface and cervical collagen.

MAIN OUTCOME MEASURES

Uterine EMG utilised power density spectrum (PDS) peak frequency and total power (P(0)) and cervical LIF utilising LIF ratio.

RESULTS

Human studies indicate that uterine and cervical performance can be successfully monitored during pregnancy using EMG and LIF, respectively, and the assessment of uterine and cervical function can both be used to influence patient management in a variety of conditions associated with labour, more than can currently available methods.

CONCLUSIONS

The potential benefits of the proposed instrumentation include the following: a reduction in the rate of preterm birth, improved maternal and perinatal outcome, better monitoring of treatment, decreased caesarean section rate and better research methods for understanding uterine and cervical function.

The initiation of parturition at term

This article discusses the initiation of parturition at term.

Perspectives in the prevention of premature birth

Obstetric and neonatal interventions have improved the survival of preterm infants, but there has not been an equivalent reduction in long-term neurological disability. Thus, some effort must be invested in finding ways of preventing preterm birth. Numerous programmes have been promoted to address the matter of how the frequency of preterm birth could be prevented. Most interventions intended to prevent preterm labour do not have the desired effect, except for antibiotic treatment in cases of asymptomatic bacteriuria or bacterial vaginosis and progesterone administered prophylactically in high-risk women. Tocolytic drugs appear to delay delivery long enough for successful administration of corticosteroids in women in preterm labour, but without decreasing the risk of preterm birth. Some authors promote public health approaches that address all risk factors and affect the entire population of pregnant women, given that prevention programmes directed only at high-risk women have had little effect in preventing preterm births. However, the lack of progress in reducing the frequency of preterm births is also due to our limited understanding of the aetiology of preterm delivery. Although there is growing evidence that infection and neuroendocrine processes are involved, progress has remained slow. Recently, the hypothesis of a genetic predisposition to preterm delivery has been set up. Additional research exploring the pathophysiology of preterm labour is obviously needed, which will hopefully lead to the development of new therapeutic approaches.

Elevated interleukin-8 in cervical mucus as an indicator for treatment to prevent premature birth and preterm, pre-labor rupture of membranes: a prospective study

PROBLEM

We investigated whether cervical shortening and high interleukin (IL)-8 in cervical mucus were valuable indications for treatment to prevent premature birth and preterm, pre-labor rupture of membranes (pPROM).

METHOD OF STUDY

Pregnant women were divided into group A, in which neither cervical IL-8 nor cervical length was measured in the middle trimester; and groups B and C, in which cervical length and cervical IL-8 were measured, and bed rest or cerclage was performed when cervical shortening was detected. In group B, vaginal washing with povidone iodine and insertion of chloramphenicol vaginal tablets were carried out in women with IL-8 elevations.

RESULTS

In group B, duration of pregnancy was significantly prolonged compared with group A and C, and occurrence of pPROM was significantly lower. No significant differences were found in those rates between groups A and C.

CONCLUSION

Successful treatment for women with IL-8 elevations in cervical mucus decreased rates of premature birth or pPROM.

Use of microbial cultures and antibiotics in the prevention of infection-associated preterm birth

OBJECTIVE

The purpose of this study was to summarize recent evidence regarding infection-associated preterm birth and to make appropriate recommendations. Antepartum treatment of lower genital tract infection or bacterial colonization has been found to reduce the incidence of preterm birth in the case of asymptomatic bacteriuria and bacterial vaginosis in selected patients but has been proved to be ineffective for vaginal colonization with organisms such as Ureaplasma urealyticum and group B streptococcus.

STUDY DESIGN

This is a clinical opinion based on a review of recent data related to 1) the association between lower genital tract infection and preterm birth and 2) antibiotic trials to prevent preterm birth.

RESULTS

Antepartum treatment of lower genital tract infection or bacterial colonization has been found to reduce the incidence of preterm birth in the case of asymptomatic bacteriuria and bacterial vaginosis in selected patients, but has been proven to be ineffective for vaginal colonization with organisms such as Ureaplasma urealyticum and group B streptococcus. Large well-designed trials have shown that the routine administration of antibiotics to women with preterm labor and intact membranes is not beneficial; however, antibiotic regimens including macrolides are recommended for preterm premature rupture of the membranes.

CONCLUSION

Large well-designed trials have shown that the routine administration of antibiotics to women with preterm labor and intact membranes is not beneficial; however, antibiotic regimens that include macrolides are recommended for preterm premature rupture of the membranes.

Possible involvement of inositol phosphoglycan-P in human parturition

Preterm labour is a major cause of neonatal morbidity and mortality but the pathophysiology that underlies preterm labour is unknown. Inositolphosphoglycans (IPGs) comprise a ubiquitous family of putative carbohydrate second messengers and they have been linked to the pathogenesis of various conditions, including diabetes and pre-eclampsia. Studying IPG-P levels in normal and pre-eclamptic pregnancies, we noticed a constant rise of urinary IPG-P levels in all women at the time of delivery. A prospective pilot study of urinary IPG-P levels in 23 non-labouring and labouring women with uncomplicated pregnancies has, therefore, been performed. Levels of urinary IPG-P were significantly higher in labour than in the non-labouring group (P<0.0001). These higher levels have been found in both spontaneous and induced labour. The clinical significance of this observation with particular reference to the onset of labour itself is discussed.

The anatomy of a disparity in infant mortality

This article suggests that while disparities in infant mortality have been longstanding, the mechanisms of disparity creation are undergoing intense change. This dynamic character is explored by first developing an analytic model that examines the interaction between social factors and the public health and clinical capacity to intervene. Disparities in infant mortality are then broken down into their component parts and linked to specific arenas of intervention. Disparities in postneonatal mortality are being shaped by differential access to interventions designed to prevent infant death from congenital anomalies and the Sudden Infant Death Syndrome. Disparities in neonatal mortality are primarily determined by factors that influence the birthrate of extremely premature infants and access to specialized obstetrical and pediatric care. This analysis suggests that the epidemiology and social meaning of disparities in infant mortality are intensely dynamic and increasingly reflect the interaction between social forces and technical innovation.

A risk assessment screening test for very low birth weight

OBJECTIVES

To develop a risk-assessment screening tool for very low birth weight (VLBW) and to compare our empirically derived tool to the nonempirically derived screening tool used by the State of Florida.

METHODS

Birth records from the State of Florida Vital Statistics between 04/01/92 and 12/07/94 were matched with State Healthy Start prenatal records, reported from 04/01/92 through 03/31/94. Known and additional potentially important risk factors were identified from both sources. Generalized Linear Modeling techniques were used to estimate associations between risk factors and VLBW. A risk assessment system was then developed using the estimated model. The resulting screening test was compared with the one used by the Florida State Department of Health in terms of sensitivity and specificity on an independent validation sample.

RESULTS

The proposed screening tool had comparable specificity to the Healthy Start screening tool but significantly better sensitivity. Both instruments are simple and easy to implement.

CONCLUSIONS

Identification of women at high risk for VLBW would be improved using the model-based screening tool developed in this paper. Public health policy makers should use statistical methods in addition to expert opinion to improve existing risk assessment methods. The actual value of an improved screening instrument is dependent on the availability of effective intervention programs.

Public perceptions about prematurity: a national survey

BACKGROUND

More than 460,000 preterm babies are born annually in the United States, with rates varying depending on the mother's race/ethnicity. Preliminary evidence suggests that the general public may have a lack of knowledge and misconceptions about preterm birth.

METHODS

A national telephone survey of U.S. adults, over-sampling for black and Hispanic women, was conducted in 2002 to assess people's knowledge, attitudes, and beliefs related to preterm birth (N=1967). Analyses included racial/ethnic differences among women's responses and comparisons to men's responses.

RESULTS

Prematurity was named by <1% of women as the most important issue facing pregnant women and infants. Overall, 34% of women and 31% of men felt that prematurity is a common problem in the United States, and 38% of women and 25% of men believed prematurity to be a serious problem in the United States. More black and Hispanic women considered prematurity to be common and serious. A majority of women (65%) and men (59%) attributed preterm births to risky prenatal maternal behaviors.

CONCLUSIONS

Although nearly one in eight babies is born prematurely, most U.S. adults do not consider prematurity to be a serious public health problem. While the etiology can be identified in only half of spontaneous preterm births, the public largely blames the mother's prenatal behavior. Misperceptions are prevalent and may impede future research and prevention efforts if not corrected.