Prospects of the collaborative small-for-gestational-age birth study for the five year old follow-up study.
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Biomedical subjects
Publications and source records attributed to R L Goldenberg.
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BACKGROUND: Although a large body of evidence suggests that prenatal weight gain is an important determinant of fetal growth, 23 to 38 percent of nonobese women have low prenatal weight gain. Determination of potential risk factors for low gain is essential to develop targeted intervention programs. This study examined the association of maternal sociodemographic, lifestyle, and reproductive characteristics with the actual occurrence of low gain among 536 black and 270 white low-income, nonobese women. METHODS: Sociodemographic, pregnancy wantedness, reproductive, and anthropometric data were obtained by interview during the first prenatal visit. A 72-item questionnaire, administered at 24 to 26 weeks' gestation, assessed residential and household characteristics, housing characteristics, income, transportation, physical activity, employment, and institutional support. Variables associated with low gain in bivariate analyses were included in logistic regression analysis to determine the adjusted odds ratios for low gain. RESULTS: Three characteristics were associated with increased adjusted odds ratios for low prenatal weight gain among black women: having a mistimed or unwanted pregnancy, caring for more than one preschool child at home, and not using own car for errands. One characteristic, working more than 40 hours per week when employed, was associated with low gain among white women. CONCLUSION: Although these preliminary findings require additional confirmation, they suggest that a variety of sociodemographic and lifestyle features deserve investigations that target the identification and characterization of risk factors for low prenatal weight gain.
OBJECTIVE: To quantitate the potential effectiveness and monetary costs of a policy of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound. DESIGN: A decision analytic model was constructed to compare 3 policies: (1) management without ultrasound; (2) ultrasound and elective cesarean delivery for estimated fetal weight of 4000 g or more (4000-g policy); and (3) ultrasound and elective cesarean delivery for estimated fetal weight of 4500 g or more (4500-g policy). The impact of maternal diabetes was analyzed separately. Probability data used in the decision analytic model were summarized from the literature and supplemented with unpublished data from the Collaborative Trial of Preterm Birth Prevention. Costs were estimated from the literature, regional reimbursements, and clinical practice data. MAIN OUTCOME MEASURES: Rates of shoulder dystocia and permanent brachial plexus injury, and both the number of additional cesarean births and monetary costs per permanent brachial plexus injury averted. RESULTS: In the baseline analysis for nondiabetic women, the ultrasound policies increased both the cesarean delivery rate and costs, while decreasing the rate of shoulder dystocia and brachial plexus injury. For each permanent brachial plexus injury prevented by the 4500-g policy, 3695 cesarean deliveries were performed at an additional cost of $8.7 million, vs 2345 cesarean deliveries and $4.9 million with the 4000-g policy. In the baseline analysis for diabetic women, with all 3 policies, rates of cesarean delivery, shoulder dystocia and brachial plexus injury, and total costs were higher than for nondiabetic women. However, more favorable ratios for both cesarean deliveries and cost per permanent injury avoided were observed: 443 deliveries and $930 000, respectively, with the 4500-g policy, and 489 deliveries and $880 000, respectively, with the 4000-g policy. Sensitivity analysis confirmed the general robustness of these findings. CONCLUSIONS: For the 97% of pregnant women who are not diabetic, a policy of elective cesarean delivery for ultrasonographically diagnosed fetal macrosomia is medically and economically unsound. In pregnancies complicated by diabetes, such a policy appears to be more tenable, although the merits of such an approach are debatable.
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BACKGROUND: The role of the cervix in the pathogenesis of premature delivery is controversial. In a prospective, multicenter study of pregnant women, we used vaginal ultrasonography to measure the length of the cervix; we also documented the incidence of spontaneous delivery before 35 weeks' gestation. METHODS: At 10 university-affiliated prenatal clinics, we performed vaginal ultrasonography at approximately 24 and 28 weeks of gestation in women with singleton pregnancies. We then assessed the relation between the length of the cervix and the risk of spontaneous preterm delivery. RESULTS: We examined 2915 women at approximately 24 weeks of gestation and 2531 of these women again at approximately 28 weeks. Spontaneous preterm delivery (at less than 35 weeks) occurred in 126 of the women (4.3 percent) examined at 24 weeks. The length of the cervix was normally distributed at 24 and 28 weeks (mean [+/- SD], 35.2 +/- 8.3 mm and 33.7 +/- 8.5 mm, respectively). The relative risk of preterm delivery increased as the length of the cervix decreased. When women with shorter cervixes at 24 weeks were compared with women with values above the 75th percentile, the relative risks of preterm delivery among the women with shorter cervixes were as follows: 1.98 for cervical lengths at or below the 75th percentile (40 mm), 2.35 for lengths at or below the 50th percentile (35 mm), 3.79 for lengths at or below the 25th percentile (30 mm), 6.19 for lengths at or below the 10th percentile (26 mm), 9.49 for lengths at or below the 5th percentile (22 mm), and 13.99 for lengths at or below the 1st percentile (13 mm) (P < 0.001 for values at or below the 50th percentile; P = 0.008 for values at or below the 75th percentile). For the lengths measured at 28 weeks, the corresponding relative risks were 2.80, 3.52, 5.39, 9.57, 13.88, and 24.94 (P < 0.001 for values at or below the 50th percentile; P = 0.003 for values at the 75th percentile). CONCLUSIONS: The risk of spontaneous preterm delivery is increased in women who are found to have a short cervix by vaginal ultrasonography during pregnancy.
BACKGROUND: The American Academy of Pediatrics strategy to prevent early-onset neonatal sepsis with group B streptococcus (GBS) relies on maternal antepartum GBS cultures, while the American College of Obstetrics and Gynecology strategy does not. OBJECTIVE: To evaluate the impact of the 2 strategies on the care of asymptomatic full-term newborns. DESIGN/SETTING: Self-administered survey mailed to a national random sample of US pediatricians who were members of the American Academy of Pediatrics. PARTICIPANTS: A total of 461 members of the American Academy of Pediatrics who routinely care for newborns. MAIN OUTCOME MEASURE: Self-report of diagnostic and treatment strategies for asymptomatic full-term newborns who were born under different clinical scenarios. Maternal risk factors, antepartum maternal GBS screening status, and maternal treatment with intrapartum antibiotics were varied across the scenarios. RESULTS: Pediatricians treating asymptomatic full-term newborns born to risk factor-negative mothers reported ordering tests (63.3% in GBS-positive cases vs 6.7% with GBS unknown; P = .001) and antibiotics (21.5% in GBS-positive cases vs 0.9% with GBS unknown; P = .001) more frequently when presented with a positive maternal GBS screening result. Maternal intrapartum treatment had little impact on pediatric practice when risk factors were absent. In risk factor-positive mothers, pediatricians reported an increase in their antibiotic usage in response to a positive maternal GBS screen (61.8% in GBS-positive cases vs 36.9% with GBS unknown; P = .001). In risk factor-positive mothers with unknown results of GBS screening, use of intrapartum antibiotics increased the number of pediatricians who reported that they would prescribe antibiotic therapy. CONCLUSIONS: Obstetrical strategies to decrease the risk of neonatal GBS sepsis increase pediatric services provided to full-term healthy newborns. This increase in services by pediatric practices is likely to be greater with the screening-based strategy recommended by the American Academy of Pediatrics.
OBJECTIVE: To evaluate the influence of acid-base status at birth and Apgar scores on survival in very low birth weight infants. METHODS: We evaluated 1073 infants born alive and weighing 500-1000 g during 1979-1991; 658 had umbilical artery gas values examined. Apgar scores were assigned at 1 and 5 minutes after birth. Umbilical artery blood samples were collected at delivery for pH, carbon dioxide pressure (PCO2), and bicarbonate. Infants were grouped at 23-24, 25-26, 27-28, and 29 weeks or more. Using survival as the dependent variable, multiple logistic regression analyses were performed controlling for gestational age, birth weight, plurality, antenatal glucocorticoid use, mode of delivery, and year of birth, as well as for Apgar scores and cord blood gases. RESULTS: In every gestational age grouping, compared with infants with a pH lower than 7.05, survival was higher in infants with an umbilical artery pH of 7.05 or higher, significantly so at 27-28 weeks. There was no consistent relationship between umbilical artery PCO2 or bicarbonate and survival. However, with the exception of the 1-minute Apgar score at 23-24 weeks, the relationship of Apgar scores to survival was significant in all gestational age periods. Using multiple logistic regression analyses, the only significant relationships between any of the cord blood gases, Apgar scores, and mortality involved low 1-minute (odds ratio [OR] 2.7 [95% confidence interval (CI) 2.0-3.6]) and low 5-minute Apgar scores (OR 2.8 [95% CI 2.0-3.8]) and a bicarbonate less than 21 mEq/L (OR 1.6 [95% CI 1.1-2.4]). CONCLUSION: One- and 5-minute Apgar scores are better predictors of survival than umbilical artery blood gases in neonates weighing 500-1000 g at birth.
OBJECTIVE: To identify biochemical indices for iron and protein nutriture as well as acute-phase reactants as predictors of preterm delivery. METHODS: In this nested case-control study, serum samples were obtained at about 24 weeks' gestation from 94 indigent multiparas. These cases were defined based on having a spontaneous delivery of 32 weeks or less (n = 31) with two control groups, one delivering spontaneously at 33-36 weeks (n = 32) and the other delivering spontaneously at 37 weeks or more (n = 31). The concentrations of iron, ferritin, transferrin, transferrin saturation, and transferrin receptor were measured as indices of iron status. The concentrations of acute-phase reactants, including C-reactive protein, alpha-2-macroglobulin, beta-2-microglobulin and ceruloplasmin, were also measured, along with albumin, prealbumin, retinol-binding protein, copper, and zinc. RESULTS: Serum ferritin concentrations were negatively correlated with gestational age at birth (P = .034). For subjects having serum ferritin levels above the median compared with those below, the odds ratio of having an early spontaneous preterm delivery was 2.99 (95% confidence interval 1.13-7.89). The other indices, including iron status and the acute-phase reactants, were not significantly associated with gestational age at birth. CONCLUSION: Elevated serum ferritin levels during the second trimester are predictive of early spontaneous preterm delivery, possibly because these reflect an acute-phase reaction to subclinical infections that are closely associated with premature delivery.
OBJECTIVE: To compare the cost-effectiveness and cost-benefit of different strategies for managing the presumed susceptible varicella (chickenpox)-exposed gravida. METHODS: Three strategies were evaluated: 1) a do-nothing or observation strategy; 2) a testing strategy, in which immune status was assessed and varicella-zoster immune globulin was administered to those who tested nonimmune; and 3) a universal-administration strategy, in which varicella-zoster immune globulin was given to all exposed, presumed susceptible gravidas. Because precise data are unavailable about varicella mortality and hospitalization rates in pregnancy, a range of potential rates was evaluated, from one to greater than 20 times healthy nonpregnant adult rates. The potential efficacy of varicella-zoster immune globulin varied from 1 to 99%. A strategy was defined as cost-effective if it cost less than $50,000 per life-year gained. RESULTS: If the mortality rate from varicella infection in pregnancy was increased fivefold over the nonpregnant healthy adult rate (ie, from 31/100,000 to 155/100,000 cases), efficacy would have to be at least 49% for the immune-testing strategy to be cost-effective. If pregnancy only doubled the varicella mortality rate, then even with perfect efficacy, the immune-testing strategy would not be cost-effective. Under most assumptions, the universal-administration strategy was cost-ineffective when compared with the immune-testing strategy. Similar results were obtained in the parallel cost-benefit analysis, which considered hospitalization costs and rates. The analysis was sensitive to the varicella transmission rate and the discount rate. CONCLUSION: From a cost-effectiveness/cost-benefit standpoint, management based on immune testing is preferable to universal varicella-zoster immune globulin administration when caring for the varicella-exposed gravida with a negative or indeterminate infection history.
OBJECTIVE: To determine the relation between vaginal and upper genital tract infection and cervical-vaginal fetal fibronectin levels. METHODS: We screened 2899 women at ten centers every 2 weeks from 23-24 to 30 weeks' gestation for cervical and vaginal fetal fibronectin. A positive test was defined as a level of at least 50 ng/mL. The relation between a positive test and bacterial vaginosis at 23-24 weeks and clinical or histologic chorioamnionitis at delivery plus neonatal sepsis was determined. RESULTS: Fetal fibronectin was present in 4.0% of cervical and/or vaginal samples at 23-24 weeks and was nearly twice as common in women with bacterial vaginosis. Adjusting for the presence of bacterial vaginosis, race, and parity, women positive for fetal fibronectin were much more likely to have clinical chorioamnionitis (mean +/- standard deviation gestational age 30.6 +/- 4.1 weeks), with an odds ratio of 16.4 and 95% confidence interval of 7.1-37.8, and neonatal sepsis (6.3 and 2.0-20.0, respectively), than those who were fetal fibronectin-negative. A positive cervical fetal fibronectin test was a better predictor of clinical chorioamnionitis and neonatal sepsis than was a vaginal test or a combination of vaginal and cervical tests. Among 40 women who delivered before 32 weeks and had placental histology available for evaluation, ten had a positive cervical and/or vaginal fetal fibronectin test before delivery; all ten had histologic evidence of chorioamnionitis, compared with only 13 of 30 women (43%) who were fetal fibronectin-negative (P = .02). CONCLUSION: Women with bacterial vaginosis were more likely to have a positive fetal fibronectin test than uninfected women. Women with a positive fetal fibronectin test who delivered before 32 weeks' gestation all had evidence of histologic chorioamnionitis. Women positive for fetal fibronectin also had a 16-fold increase in clinical chorioamnionitis and a sixfold increase in neonatal sepsis. There is strong evidence that upper genital tract infection and cervical and/or vaginal fetal fibronectin are closely linked.
OBJECTIVE: To evaluate the presence of fetal fibronectin in the cervix and vagina as a screening test for spontaneous preterm birth. METHODS: Two thousand nine hundred twenty-nine women at ten centers were routinely screened every 2 weeks from 22-24 to 30 weeks for cervical and vaginal fetal fibronectin. A positive test was defined as a value equal to or greater than 50 ng/mL. The relation between a positive test at four gestational ages and spontaneous preterm birth at various intervals after the test was determined. RESULTS: In each testing period, 3-4% of the fetal fibronectin tests were positive. The correlation between cervical and vaginal fetal fibronectin at the same visit was always approximately 0.7 (P < .001), and that between cervical or vaginal fetal fibronectin in consecutive visits was between 0.17 and 0.25 (P < .001). The sensitivity of fetal fibronectin at 22-24 weeks to predict spontaneous preterm birth at less than 28 weeks was 0.63, and the relative risk for a positive versus negative test was 59. The specificity was always 96-98%, whereas the positive predictive value rose from 13% to 36% as the upper limit of the definition of preterm birth was increased from less than 28 to less than 37 weeks. The relative risk for spontaneous preterm birth after a positive fetal fibronectin test compared with a negative fetal fibronectin test varied substantially by testing period and by the definition of spontaneous preterm birth, but always remained greater than 4 and statistically significant. CONCLUSION: A positive cervical or vaginal fetal fibronectin test at 22-24 weeks predicted more than half of the spontaneous preterm births at less than 28 weeks (sensitivity 0.63). As the definition of spontaneous preterm birth was extended to include later gestational ages or when the fetal fibronectin test was performed later in pregnancy, the level of association between a positive fetal fibronectin test and spontaneous preterm birth, while remaining highly significant, tended to decrease. Although fetal fibronectin is an excellent test for predicting spontaneous preterm birth, we present no evidence that the use of this test will result in a reduction in spontaneous preterm birth.
OBJECTIVE: To evaluate the effect of angiotensin-converting enzyme (ACE) genotypes on pregnancy outcome, the incidence of pregnancy-induced hypertension, and changes in blood pressure (BP) during pregnancy; and the relationship between plasma ACE activities and plasma and erythrocyte zinc concentrations in each genotype. METHODS: The subjects (n = 191) were selected from 580 indigent African-American pregnant women who enrolled toward the end of a trial to evaluate the effect of zinc supplementation on pregnancy outcome. This selection resulted in 93 subjects who received zinc and 98 who received placebo. Sample size was calculated with a 0.50 correlation coefficient between plasma ACE activities and zinc levels and a power of 80%. This calculation indicated that the sample size in each ACE genotype should be more than 28. Angiotensin-converting enzyme genotypes were identified using polymerase chain reaction. Blood pressure, plasma ACE activities, and plasma and erythrocyte zinc concentrations were measured at each prenatal clinical visit. RESULTS: Pregnancy outcome, the incidence of pregnancy-induced hypertension, and BP were not different among the three ACE genotypes. There was no significant correlation between plasma ACE activities and zinc concentrations. Zinc supplementation did not have a significant effect on either plasma ACE activities or zinc concentrations, probably because of the small sample size in our study. CONCLUSION: There was no effect of ACE gene polymorphism on pregnancy outcome, the incidence of pregnancy-induced hypertension, or changes in BP during pregnancy. Among each ACE genotype, plasma ACE activities did not correlate significantly with plasma zinc concentrations.
OBJECTIVE: To examine the association between prenatal weight gain patterns and birth weight, using Institute of Medicine (IOM) guidelines. METHODS: Data from a prospective follow-up study of risk factors for fetal growth restriction were used to examine the impact of low weight gain on mean birth weight. A total of 415 nonobese (body mass index [BMI] less than 26) black (n = 275) and white (n = 140) women who delivered at term were included in this analysis. Linear regression analysis was used to examine the impact of low first-trimester gain (less than 2.3 kg with low BMI [less than 19.8]; less than 1.6 kg with normal BMI [19.8-26.0]) and low second- and third-trimester rates of gain (less than 0.38 kg/week with low BMI; less than 0.37 kg/week with normal BMI) on mean birth weight while controlling for selected sociodemographic and reproductive variables. RESULTS: Patterns with low gain in the first and second or in the second and third trimesters were associated with significant decreases in mean birth weight, ranging from 206 to 265 g; low gain in only the first or third trimester was not associated with a significant decrease in mean in birth weight. The impact of low gain on mean birth weight varied by ethnic group. CONCLUSION: These observations suggest that inadequate patterns of prenatal weight gain, defined by IOM guidelines, are associated with decreased birth weight, particularly when the patterns involve low second-trimester gain.
OBJECTIVE: Our purpose was to determine whether various measures of poor psychosocial status in pregnancy are associated with spontaneous preterm birth, fetal growth restriction, or low birth weight. STUDY DESIGN: Anxiety, stress, self-esteem, mastery, and depression were assessed at 25 to 29 weeks in 2593 gravid women by use of a 28-item Likert scale. Scores for each psychosocial subscale were determined, and an overall psychosocial score was calculated. Scores were divided into quartiles, and the lowest quartile scores were used to define poor psychosocial status. The percent spontaneous preterm birth, low birth weight, and fetal growth restriction in women with low and high psychosocial scores were compared. Logistic regression analyses provided the odds ratios and 95% confidence intervals. RESULTS: Analyses revealed that stress was significantly associated with spontaneous preterm birth and with low birth weight with odds ratios of 1.16, p = 0.003, and 1.08, p = 0.02, respectively, for each point on the scale. A low score on the combined scale or on any subscale other than stress did not predict spontaneous preterm birth, fetal growth restriction, or low birth weight. After multivariate adjustment was performed for psychosocial status, substance use, and demographic traits, black race was the only variable significantly associated with spontaneous preterm birth, fetal growth restriction, and low birth weight; stress and low education were associated with spontaneous preterm birth and low birth weight. CONCLUSION: Stress was associated with spontaneous preterm birth and low birth weight even after adjustment for maternal demographic and behavioral characteristics. Black race continues to be a significant predictor of spontaneous preterm birth, fetal growth restriction, and low birth weight even after adjustment for stress, substance use, and other demographic factors.
OBJECTIVE: Our purpose was to determine whether various demographic, behavioral, housing, psychosocial, or medical characteristics explain the difference in pregnancy outcome between black and white women. STUDY DESIGN: A sample of 1491 multiparous women with singleton pregnancies, 69% of whom were black and 31% of whom were white and who enrolled for care between Oct. 1, 1985, and March 30, 1988, participated in the study. The frequencies of various demographic, medical environmental, and psychosocial risk factors among black and white women were determined. The outcome measures were birth weight, gestational age, fetal growth restriction, preterm delivery and low birth weight. RESULTS: White infants were heavier and born later than black infants. The white women in this sample smoked more cigarettes, moved more frequently, and had worse psychosocial scores. The black women had lower incomes, were less likely to be married, and had more hypertension, anemia, and diabetes. Besides race, only maternal height, weight, blood pressure, diabetes, and smoking had a consistent impact on outcome and did not explain the difference in outcome between the two groups. CONCLUSION: In this low-income population, many of the risk factors for low birth weight were more common among white women than black women. Nevertheless, black women had more infants born preterm, with growth restriction, and with low birth weight than did white women. The various maternal characteristics studied did not explain these differences.
OBJECTIVE: Plasma ferritin is considered the best measure of total body iron, with low levels diagnostic of iron deficiency. High levels have been associated with inflammation and infection. We determined the relationship between plasma ferritin, birth weight, and preterm delivery. STUDY DESIGN: Plasma ferritin and hematocrit values were measured at 19, 26, and 36 weeks' gestational age and correlated with birth weight and preterm delivery (< or = 32 and < 37 weeks) in 580 indigent black women. RESULTS: Hematocrit levels measured at any gestational age did not correlate significantly with birth weight or preterm delivery. Regardless of the gestational age of sampling, ferritin levels in the lowest quartile did not correlate significantly with subsequent preterm delivery. However, at 26 weeks, compared with the three lower quartiles, ferritin levels in the highest quartile were significantly associated with preterm delivery < or = 32 weeks, 6.5% versus 2.3% (p = 0.02), with preterm delivery < 37 weeks, 14% versus 8% (p = 0.04), and with birth weight < 1500 gm, 6.5% versus 2.0% (p = 0.01). Plasma ferritin levels in the highest quartile at 19, 26, and 36 weeks were associated with birth weight < or = 2500 gm, 14% versus 8% (p = 0.03), 12% versus 7% (p = 0.05), and 10% versus 2% (p = 0.0001), respectively, compared with the lower quartiles. Ferritin levels in the highest quartile were always associated with a lower mean birth weight than were those in the lower three quartiles: 19 weeks, 2999 gm versus 3225 gm, (p = 0.002); 26 weeks, 3065 gm versus 3257 gm, (p = 0.005); and 36 weeks, 3182 gm versus 3323 gm, (p = 0.009). Regression analyses controlling for multiple potential confounders confirmed that at 26 weeks ferritin levels in the highest quartile had an odds ratio and 95% confidence interval for preterm birth < 37 weeks of 2.0 (1.1 to 3.8), preterm delivery < or = 32 weeks of 2.7 (0.99 to 7.6), birth weight < or = 1500 gm of 3.9 (1.2 to 12.2), and birth weight < or = 2500 gm of 2.0 (1.0 to 4.0) compared with the three lower ferritin quartiles. CONCLUSION: High, but not low, plasma ferritin levels, especially at 26 weeks, were strongly associated with subsequent preterm delivery and birth weight.
OBJECTIVE: Our purpose was to determine the influence of being small for gestational age at term and being preterm < 34 weeks on cognitive functioning at age 5 years. STUDY DESIGN: Five hundred forty-six children of black low-income mothers, nearly all at risk for being small for gestational age, followed up prenatally with early ultrasonographic gestational age dating, were classified as either term appropriate for gestational age, term small for gestational age, or preterm at < 34 weeks. At a mean of 5.5 +/- 0.5 years, a Wechsler Preschool and Primary Scale of Intelligence-Revised intelligence quotient test was administered. An intelligence quotient < 70 was used to define mental retardation. Univariate and multivariate analyses adjusted for maternal age, smoking, education and language skills, home environment, and child gender and preschool attendance were performed. RESULTS: Term small-for-gestational-age and preterm infants at < 34 weeks had 4 and 6 point intelligence quotient reductions compared with term appropriate-for-gestational-age infants. In the regression analyses these differences in intelligence quotient remained significant after confounders were adjusted. High maternal receptive language level (8 points), a positive home environment (5 points), and attendance at preschool (5 points) were each significantly associated with an increase in intelligence quotient. CONCLUSION: Both term small-for-gestational-age infants and those born at < 34 weeks had a significantly lower mean intelligence quotient, and small-for-gestational-age infants had an increased risk of mental retardation at age 5 years. Higher maternal language skills, a positive home environment, and attendance at preschool each were associated with an increase in the mean intelligence quotient of 5 to 7 points.
OBJECTIVE: Our aims were to develop a risk assessment system for the prediction of spontaneous preterm delivery using clinical information available at 23 to 24 weeks' gestation and to determine the predictive value of such a system. STUDY DESIGN: A total of 2929 women were evaluated between 23 and 24 weeks' gestation at 10 centers. Demographic factors, socioeconomic status, home and work environment, drug and alcohol use, and medical history were evaluated. Information regarding symptoms, cultures, and treatments in the current pregnancy were ascertained. Anthropomorphic and cervical examinations were performed. Univariate analysis and multivariate logistic regression were performed in a random selection, constituting 85% of the study population. The derived risk assessment system was applied to the remaining 15% of the population to evaluate its validity. RESULTS: A total of 10.4% of women were delivered of preterm infants. The multivariate models for spontaneous preterm delivery were highly associated with spontaneous preterm delivery (p < 0.0001). A low body mass index (<19.8) and increasing Bishop scores were significantly associated with spontaneous preterm delivery in nulliparous and multiparous women. Black race, poor social environment, and work during pregnancy were associated with increased risk for nulliparous women. Prior obstetric outcome overshadowed socioeconomic risk factors in multiparous women with a twofold increase in the odds of spontaneous preterm delivery for each prior spontaneous preterm delivery. Current pregnancy symptoms, including vaginal bleeding, symptomatic contractions within 2 weeks, and acute or chronic lung disease were variably associated with spontaneous preterm delivery in nulliparous and multiparous women. When the system was applied to the remainder of the population, women defined to be at high risk for spontaneous preterm delivery (> or = 20% risk) carried a 3.8-fold (nulliparous women) and 3.3-fold (multiparous women) higher risk of spontaneous preterm delivery than those predicted to be at low risk. However, the risk assessment system identified a minority of women who had spontaneous preterm deliveries. The sensitivities were 24.2% and 18.2% and positive predictive values were 28.6% and 33.3%, respectively, for nulliparous and multiparous women. CONCLUSIONS: Although it is possible to develop a graded risk assessment system that includes factors that are highly associated with spontaneous preterm delivery in nulliparous and multiparous women, such a system does not identify most women who subsequently have a spontaneous preterm delivery. This system has investigational value as the basis for evaluating new technologies designed to identify at-risk subpopulations.