Racial disparities in recurrent preterm delivery risk: mediation analysis of prenatal care timing.

OBJECTIVES: We estimated the degree to which the association between race and spontaneous recurrent preterm delivery is mediated by the timing of the first prenatal care visit. METHODS: A retrospective population-based cohort study was conducted using the U.S. National Center for Health Statistics Natality Files. We identified 644,576 women with a prior PTB who delivered singleton live neonates between 2011 and 2017. A mediation analysis was conducted using log-binomial regression to evaluate the mediating effect of timing of first prenatal care visit. RESULTS: During the seven-year period, 349,293 (54.2%) White non-Hispanic women, 131,296 (20.4%) Black non-Hispanic women, 132,367 (20.5%) Hispanic women, and 31,620 (4.9%) Other women had a prior preterm delivery. The risk of late prenatal care initiation was higher in Black non-Hispanic women, Hispanic women, and Other women (women of other racial/ethnic backgrounds) compared to White non-Hispanic women, and the risk of preterm delivery was higher in women with late prenatal care initiation. Between 8 and 15% of the association between race and spontaneous recurrent preterm delivery acted through the delayed timing of the first prenatal care visit. CONCLUSIONS: Racial disparities in spontaneous recurrent preterm delivery rates can be partly, but not primarily, attributed to timing of first prenatal care visit.

Direct and Vicarious Racial Discrimination at Three Life Stages and Preterm Labor: Results from the African American Women's Heart & Health Study.

INTRODUCTION: Health disparities research has demonstrated a negative relationship between racial discrimination and African American women's maternal health outcomes. Yet, the relationship between racial discrimination and preterm labor, a key measure of maternal health, remains understudied. This study sought to examine the associations between preterm labor and direct and vicarious racial discrimination among African American women at three life stages: childhood, adolescence, and adulthood. METHODS: Logistic regression methods were used to analyze cross-sectional data from the African American Women's Heart & Health Study (AAWHHS; N = 173). The AAWHHS includes detailed maternal health information on a community sample of African American women residing in the San Francisco Bay Area. RESULTS: Findings indicated each unit increase in adolescent direct racial discrimination was associated with a 48% increase in the odds of preterm labor (OR: 1.480, 95% CI 1.002-2.187, p < 0.05) and each unit increase in childhood vicarious racial discrimination was associated with a 45% increase in the odds of preterm labor (OR: 1.453, 95% CI 1.010-2.092, p < 0.05) after adjusting for number of pregnancies and socioeconomic variables. DISCUSSION: This study provides evidence of an association between life-stage racial discrimination and preterm labor risk among African American women, underscoring a need to consider how both directly and vicariously experienced racial discrimination at different developmental periods impact racial disparities in birth outcomes.

Early gestational weight gains within current recommendations result in increased risk of gestational diabetes mellitus among Korean women.

BACKGROUND: We prospectively assessed whether maternal weight gain at 24-28 weeks of gestation (MWG24) influences the risk of developing gestational complications, such as gestational diabetes mellitus (GDM) and other adverse pregnancy outcomes, in pregnant Korean women. METHODS: Maternal weight gain from self-reported pre-pregnancy weight until 24-28 weeks of gestation was measured in 731 pregnant women, and an expected MWG24 was determined using the Institute of Medicine 2009 guidelines. Glucose tolerance, insulin resistance, insulin secretory capacity, anthropometric measurements, lipid profiles, nutrient intakes and pregnancy outcomes were evaluated at 24-28 weeks of gestation. The adjusted odds ratios (ORs) for GDM, large-for-gestational-age infants, small-for-gestational-age infants and preterm delivery were determined according to maternal weight gain by logistic regression analysis after adjusting for covariates. RESULTS: Compared with a normal MWG24, an inadequate MWG24 reduced the OR (0.565) for GDM, but an excessive MWG24 did not affect the OR (0.854). However, ORs for preterm delivery were significantly higher in both inadequate and excessive MWG24 groups in comparison with the normal MWG24. There were no other adverse pregnancy outcomes due to the inadequate MWG24. MWG24 was not associated with a significant increase in ORs for delivering large-for-gestational-age or small-for-gestational-age infants or delivery by caesarean section. Although energy intake was less than the estimated energy requirement in all groups, MWG24 was linearly associated with energy intake such that energy balance was positive in the excessive MWG24 group. CONCLUSIONS: This study suggests that both target weight gain and energy intake recommendations for early pregnancy may not be optimal for Korean women and that race-specific recommendations are needed to decrease the risk of GDM without increasing adverse pregnancy outcomes.

Attitudes of healthcare providers towards non-initiation and withdrawal of neonatal resuscitation for preterm infants in Mongolia.

Antenatal parental counselling by healthcare providers is recommended to inform parents and assist with decision-making before the birth of a child with anticipated poor prognosis. In the setting of a low-income country, like Mongolia, attitudes of healthcare providers towards resuscitation of high-risk newborns are unknown. The purpose of this study was to examine the attitudes of healthcare providers regarding ethical decisions pertaining to non-initiation and withdrawal of neonatal resuscitation in Mongolia. A questionnaire on attitudes towards decision-making for non-initiation and withdrawal of neonatal resuscitation was administered to 113 healthcare providers attending neonatal resuscitation training courses in 2009 in Ulaanbaatar, the capital and the largest city of Mongolia where -40% of deliveries in the country occur. The questionnaire was developed in English and translated into Mongolian and included multiple choices and free-text responses. Participation was voluntary, and anonymity of the participants was strictly maintained. In total, 113 sets of questionnaire were completed by Mongolian healthcare providers, including neonatologists, paediatricians, neonatal and obstetrical nurses, and midwives, with 100% response rate. Ninety-six percent of respondents were women, with 73% of participants from Ulaanbaatar and 27% (all midwives) from the countryside. The majority (96%) of healthcare providers stated they attempt pre-delivery counselling to discuss potential poor outcomes when mothers present with preterm labour. However, most (90%) healthcare providers stated they feel uncomfortable discussing not initiating or withdrawing neonatal resuscitation for a baby born alive with little chance of survival. Religious beliefs and concerns about long-term pain for the baby were the most common reasons for not initiating neonatal resuscitation or withdrawing care for a baby born too premature or with congenital birth-defects. Most Mongolian healthcare providers provide antenatal counselling to parents regarding neonatal resuscitation. Additional research is needed to determine if the above-said difficulty with counselling stems from deficiencies in communication training and whether these same counselling-related issues exist in other countries. Future educational efforts in teaching neonatal resuscitation in Mongolia should incorporate culturally-sensitive training on antenatal counselling.

National trends and racial differences in late preterm induction.

OBJECTIVE: The objective of the study was to determine the trends and racial differences in late preterm induction (LPI) of labor in the United States. STUDY DESIGN: Data from the National Vital Statistics System were used to identify women eligible for induction between 34 and 42 weeks' gestation from 1991 to 2006. Annual LPI rates were calculated, and maternal race/ethnicity was classified into 4 groups. Changes in the frequency and odds of LPI, stratified by race/ethnicity, were assessed using logistic regression. RESULTS: Among the 42.0 million eligible women, LPI rates increased from 0.46% to 1.37% (P < .01) over 16 years. LPI rates were highest for black women (P < .01) each year, and after adjusting for confounding factors, the odds of LPI were highest (P < .01) and rose most rapidly (P < .01) for black women (non-Hispanic white: odds ratio [OR], 1 [referent]; Hispanic white: OR, 0.76; black: OR, 1.31; other: OR, 0.81; P < .01). CONCLUSION: LPI rates were persistently highest and rose most rapidly for black women.

Optimal gestational age of delivery to decrease neonatal morbidity in preterm pregnancies in Korea.

AIMS: Preterm birth is the most common cause of neonatal morbidity and mortality. Neonatal morbidity and mortality are known to decrease significantly after 34 weeks in preterm births following preterm labor, and after 32 weeks in preterm births following preterm rupture of the membranes. However, these outcomes may not apply to Korean preterm neonates. This study analyzed the morbidity of preterm neonates based on gestational age to determine the optimal gestational age of delivery following preterm labor. MATERIALS AND METHODS: We retrospectively analyzed the medical records of preterm neonates and their mothers who delivered at Seoul St. Mary's Hospital between January 1995 and December 2007. RESULTS: Among 1234 preterm neonates, 1008 were singletons and 226 were multiple births. In both singleton and multifetal pregnancies, the maternal characteristics did not differ based on gestational age. The 1- and 5-min Apgar scores were significantly lower than at 35 weeks in singleton births, and at 33 weeks in multiple births. Major complications, such as intraventricular hemorrhage and the use of a respirator, decreased significantly after 35 weeks in singleton births, and after 33 weeks in multiple births. CONCLUSIONS: The optimal gestational age for decreasing the morbidity of major complications in preterm neonates was 1 week later than the American College of Obstetricians and Gynecologists recommendations. For Korean mothers with preterm labor, delivery needs to be delayed until 35 weeks in singletons, 33 weeks in twins, and 32 weeks in singletons with preterm rupture of the membranes.

Disparate rates of persistent smoking and drug use during pregnancy of women of Hawaiian ancestry.

BACKGROUND: Significant disparity in smoking rates has been previously reported in pregnant and non-pregnant women of Native Hawaiian ancestry. Disparities in drug use rates have also been reported in non-pregnant women of Native Hawaiian ancestry. OBJECTIVE: We undertook this study to compare rates of smoking and drug use during pregnancy among women in Hawaii to see if these differences are associated with disparities in pregnancy complications among Native Hawaiian women. METHODS: Women were enrolled in the Pacific Research Center on Early Human Development study from July 2007 to January 2008, according to approved protocols. Persistent smoking was defined as self-reported smoking within 1 week of admission for labor. Drug use data was assessed by self-report, or if available, toxicology tests at the time of labor. RESULTS: There were 868 women enrolled in the study during this period. Women of Hawaiian/part-Hawaiian ancestry comprised 22% of the study population. Rates of persistent smoking and drug use among Hawaiian women were significantly higher than the remainder of the study population (21% and 8.3% vs. 7.8% and 2.1%, respectively, P < .001 for both). Methamphetamine use was associated with an almost 5-fold increase in preterm birth and smoking a 3.4% decrease in birth weights. DISCUSSION AND CONCLUSION: Women of Hawaiian ancestry continue to smoke and use illicit drugs during pregnancy at significantly higher rates than women of other ethnic groups in Hawaii. In addition to the immediate effects on pregnancy, long-term adverse outcomes of in utero exposures of the offspring remain an important health disparity.

Skipping meals and less walking among African Americans diagnosed with preterm labor.

PURPOSE: The aim was to compare meal frequency, macronutrient intake, and physical activity between African Americans with preterm labor and those without preterm labor. DESIGN: A descriptive comparative study was used with 80 pregnant African Americans. METHODS: Three 24-hour diet recalls, the Block 2005 food frequency questionnaire, International Physical Activity Questionnaire, and Perceived Stress Scale were collected at 24 to 34 weeks of gestation. FINDINGS: The odds of skipping meals for women in the preterm labor group was 3.57 times the odds of skipped meals for women in the term labor group (95% confidence interval [CI] 1.28-10.16, p=.006). The association was increased to 6.86 (95% CI 2.13-22.12, p<.001) after adjustment for age, prepregnancy body mass index, education, and income. Walking was significantly less in terms of total amount of walking in the preterm labor group (p=.03). CONCLUSIONS: Results have implications for prenatal counseling regarding the importance of frequent meal and snack consumption throughout the day. Further research is necessary to establish the mechanisms by which energy consumption contributes to risk for preterm labor. CLINICAL RELEVANCE: Pregnancy is a time when health professionals monitor women regularly and presents a unique opportunity for practitioners to communicate the importance of frequent meals and snacks throughout pregnancy, as well as the health benefits of walking as a form of physical activity.

Maternal height and length of gestation: does this impact on preterm labour in Asian women?

BACKGROUND: Both maternal height and ethnicity may influence the gestation length, but their independent effect is unclear. AIM: This study was performed to examine the relationship between maternal height and gestational length in women with singleton pregnancies in a Chinese and southeast Asian population. METHODS: A retrospective cohort study was performed on women carrying singleton pregnancies with spontaneous labour in a 48-month period managed under our department to determine the relationship between maternal height, expressed in quartiles, with the mean gestational age and incidence of preterm labour. RESULTS: Of the 16 384 women who delivered within this period, the 25th, 50th and 75th percentile values of maternal height were 153 cm, 156 cm and 160 cm respectively. Excluded from analysis were 6597 women because of multifetal pregnancy, teenage pregnancy (maternal age < or = 19 years old), induction of labour or elective caesarean section, or incomplete data due to no antenatal booking in our hospital. Significant differences were found in the maternal weight and body mass index, incidences of multiparity and smokers, gestational age and birthweight among the four quartiles. There was significantly increased incidence of preterm birth between 32 and 37 weeks gestation in women with shorter stature. CONCLUSIONS: In our population, maternal height has an influence on gestational length, and the lower three quartiles was associated with increased odds of labour at > 32 to < 37 weeks. This effect should be taken into consideration in the adoption of international recommendations in obstetric management and intervention.

Perinatal outcomes among different Asian-American subgroups.

OBJECTIVE: The objective of the study was to investigate the differences in perinatal outcomes between various Asian ethnic subgroups at a national level. STUDY DESIGN: This is a retrospective cohort study of all non-Hispanic Chinese, Japanese, Filipino, Asian Indian, Korean, Vietnamese, Samoan, Guamanian, and Hawaiian women whose deliveries were recorded by US birth certificates within the year 2003. Perinatal outcomes were compared between groups and potential confounders controlled for with multivariable logistic regression. RESULTS: We found significant differences (P < .001) in the incidence of all perinatal outcomes of interest among the different Asian subgroups. These differences persisted after adjusting for potential confounders. The incidence of diabetes in pregnancy varied from 2.9% (Korean) to 5.7% (Filipina). CONCLUSION: Our study demonstrates significant differences in preterm labor, primary cesarean delivery, pregnancy-associated hypertension, eclampsia, diabetes in pregnancy, low birthweight, macrosomia, and cephalopelvic disproportion among Asian subgroups at a national level, affirming the importance of examining these subgroups separately.

Racial differences in birth outcomes: the role of general, pregnancy, and racism stress.

OBJECTIVE: This study examined the role of psychosocial stress in racial differences in birth outcomes. DESIGN: Maternal health, sociodemographic factors, and 3 forms of stress (general stress, pregnancy stress, and perceived racism) were assessed prospectively in a sample of 51 African American and 73 non-Hispanic White pregnant women. MAIN OUTCOME MEASURES: The outcomes of interest were birth weight and gestational age at delivery. Only predictive models of birth weight were tested as the groups did not differ significantly in gestational age. RESULTS: Perceived racism and indicators of general stress were correlated with birth weight and tested in regression analyses. In the sample as a whole, lifetime and childhood indicators of perceived racism predicted birth weight and attenuated racial differences, independent of medical and sociodemographic control variables. Models within each race group showed that perceived racism was a significant predictor of birth weight in African Americans, but not in non-Hispanic Whites. CONCLUSIONS: These findings provide further evidence that racism may play an important role in birth outcome disparities, and they are among the first to indicate the significance of psychosocial factors that occur early in the life course for these specific health outcomes.

Symptoms described by African American women evaluated for preterm labor.

OBJECTIVE: To describe symptoms, self-care for symptoms, and lay consultations of African American women later diagnosed with a likelihood of preterm labor (PTL). DESIGN: Qualitative descriptive study. SETTING: Two sites within the United States, one urban and one suburban high-risk maternity referral center. PARTICIPANTS: Twenty-five African American women presenting for emergent care and subsequently diagnosed as "rule out PTL." Five of the women later delivered before 37 weeks gestation, of whom 4 had a preterm low-birthweight infant (

Paternal race is a risk factor for preterm birth.

OBJECTIVE: The purpose of this study was to test the hypothesis that paternal race influences the risk for preterm birth. STUDY DESIGN: We conducted a population-based cohort study to examine the association of paternal race with preterm birth using the Missouri Department of Health's birth registry from 1989-1997. Birth outcomes were analyzed in 4 categories: white mother/white father, white mother/black father, black mother/white father, and black mother/ black father. RESULTS: We evaluated 527,845 birth records. The risk of preterm birth at <35 weeks of gestation increased when either parent was black (white mother/black father: adjusted odds ratio, 1.28 [95% CI, 1.13, 1.46], black mother/white father: adjusted odds ratio, 2.10 [95% CI, 1.68, 2.62], and black mother/black father: adjusted odds ratio, 2.28 [95% CI, 2.18, 2.39]) and was even higher for extreme preterm birth (<28 weeks of gestation) in pregnancies with a nonwhite parent. CONCLUSION: Paternal black race is associated with an increased risk of preterm birth in white mothers, which suggests a paternal contribution to fetal genotype that ultimately influences the risk for preterm delivery.

Preterm delivery and cytokine gene polymorphisms.

OBJECTIVE: To investigate the association of preterm delivery with polymorphisms of IL-6, IL-10, IFN-gamma, TGFbeta1 and TNF-alpha genes. STUDY DESIGN: The study group consisted of 45 Caucasian, 81 mixed race and 13 black women with a history of preterm labor, consecutively referred. All of them had delivered before 37 weeks' gestation. The control group was composed of 56 Caucasian, 48 mixed race and 15 black women with successful pregnancy. DNA was extracted from whole blood, and cytokine genotyping was performed using the Cytokine Genotyping Tray (One-Lambda, Canoba Park, California). The polymorphisms analyzed were: TNF-alpha (-08 G --> A), IL-10 (-1082 G --> A), IL-6 (-174 G --> C), TGFbeta1 (+10 T --> C e 25 C --> G) and IFN-gamma (+874 A --> T). RESULTS: There were no differences in genotype frequencies of IL-10, TGF-beta, TNF-alpha or IL-6 polymorphisms between the groups. In the Caucasian group there was a trend toward increased frequencies of the TT genotype of IFN-gamma in controls. CONCLUSION: Preterm delivery is not associated with TNF-alpha (-308), IL-10 (-1082), IL-6 (-174), TGFbeta1 (+10 e 25) or IFN-gamma (+874) polymorphisms.

The impact of fetal gender and ethnicity on the risk of spontaneous preterm delivery in women with symptoms of preterm labor.

OBJECTIVE: The objective of this study is to evaluate the relation among fetal gender, ethnicity, and preterm labor (PTL) and preterm delivery (PTD). METHODS: A secondary analysis was performed of a prospective cohort study including women with symptoms of PTL between 24 and 34 weeks. The proportion of women carrying a male or female fetus at the onset of PTL was calculated. Gestational age at delivery and risk of PTD of both fetal genders was compared and interaction of fetal gender and maternal ethnicity on the risk of PTD was evaluated. RESULTS: Of the 594 included women, 327 (55%) carried a male fetus. Median gestational age at delivery in women pregnant with a male fetus was 37 5/7 (IQR 34 4/7-39 1/7) weeks compared with 38 1/7 (IQR 36 0/7-39 5/7) weeks in women pregnant with a female fetus (p = 0.032). The risk of PTD did not differ significantly. In Caucasians, we did find an increased risk of PTD before 37 weeks in women pregnant with a male fetus (OR 1.9 (95% CI 1.2-3.0)). CONCLUSIONS: The majority of women with PTL are pregnant with a male fetus and these women deliver slightly earlier. Race seems to affect this disparity.

The Association Between Socio-demographic Factors, Dental Problems, and Preterm Labor for Pregnant Women Residing in Hawai'i.

Periodontal disease during pregnancy has the potential to increase the risk of adverse perinatal outcomes including preterm labor (PTL), prematurity, and low birth weight (LBW). Despite professional recommendations on the importance and safety of dental assessments and treatments, the rate of dental care utilization during pregnancy remains low. The purpose of this study was to document the utilization of dental services and explore the relationships among socio-demographic factors, dental problems, and PTL in pregnant women residing in Hawai'i. Hawai'i Pregnancy Risk Assessment Monitoring System (PRAMS) survey results were analyzed from 4,309 women who experienced live births between the years 2009-2011. Results revealed that 2 in 5 women in Hawai'i had their teeth cleaned during pregnancy, while 1 in 5 reported seeing a dentist for a dental problem. Women who reported having a dental problem during pregnancy were more likely to experience PTL (OR=1.46, 95% CI=1.10-1.94, P=.008) compared to women without a dental problem. In addition, Native Hawaiian and Part-Hawaiian women were more likely to experience PTL (OR=1.73, 95% CI=1.22-2.46, P=.002) compared to Caucasian women. These findings document the underutilization of dental services in pregnant women in Hawai'i and reveal an association between poor dental care and PTL. Identification of groups at risk for maternal complications may assist in the development of programs that are sensitive to the diverse cultures and variability of community resources that exist throughout Hawai'i.

Post-hoc analysis of vitamin D status and reduced risk of preterm birth in two vitamin D pregnancy cohorts compared with South Carolina March of Dimes 2009-2011 rates.

BACKGROUND: Two vitamin D pregnancy supplementation trials were recently undertaken in South Carolina: The NICHD (n=346) and Thrasher Research Fund (TRF, n=163) studies. The findings suggest increased dosages of supplemental vitamin D were associated with improved health outcomes of both mother and newborn, including risk of preterm birth (<37 weeks gestation). How that risk was associated with 25(OH)D serum concentration, a better indicator of vitamin D status than dosage, by race/ethnic group and the potential impact in the community was not previously explored. While a recent IOM report suggested a concentration of 20 ng/mL should be targeted, more recent work suggests optimal conversion of 25(OH)D-1,25(OH)2D takes place at 40 ng/mL in pregnant women. OBJECTIVE: Post-hoc analysis of the relationship between 25(OH)D concentration and preterm birth rates in the NICHD and TRF studies with comparison to Charleston County, South Carolina March of Dimes (CC-MOD) published rates of preterm birth to assess potential risk reduction in the community. METHODS: Using the combined cohort datasets (n=509), preterm birth rates both for the overall population and for the subpopulations achieving 25(OH)D concentrations of ≤20 ng/mL, >20 to <40 ng/mL, and ≥40 ng/mL were calculated; subpopulations broken down by race/ethnicity were also examined. Log-binomial regression was used to test if an association between 25(OH)D serum concentration and preterm birth was present when adjusted for covariates; locally weighted regression (LOESS) was used to explore the relationship between 25(OH)D concentration and gestational age (weeks) at delivery in more detail. These rates were compared with 2009-2011 CC-MOD data to assess potential risk reductions in preterm birth. RESULTS: Women with serum 25(OH)D concentrations ≥40 ng/mL (n=233) had a 57% lower risk of preterm birth compared to those with concentrations ≤20 ng/mL [n=82; RR=0.43, 95% confidence interval (CI)=0.22,0.83]; this lower risk was essentially unchanged after adjusting for covariates (RR=0.41, 95% CI=0.20,0.86). The fitted LOESS curve shows gestation week at birth initially rising steadily with increasing 25(OH)D and then plateauing at ∼40 ng/mL. Broken down by race/ethnicity, there was a 79% lower risk of preterm birth among Hispanic women with 25(OH)D concentrations ≥40 ng/mL (n=92) compared to those with 25(OH)D concentrations ≤20 ng/mL (n=29; RR=0.21, 95% CI=0.06,0.69) and a 45% lower risk among Black women (n=52 and n=50; RR=0.55, 95% CI=0.17,1.76). There were too few white women with low 25(OH)D concentrations for assessment (n=3). Differences by race/ethnicity were not statistically significant with 25(OH)D included as a covariate. Compared to the CC-MOD reference group, women with serum concentrations ≥40 ng/mL in the combined cohort had a 46% lower rate of preterm birth overall (n=233, p=0.004) with a 66% lower rate among Hispanic women (n=92, p=0.01) and a 58% lower rate among black women (n=52, p=0.04). CONCLUSIONS: In this post-hoc analysis, achieving a 25(OH)D serum concentration ≥40 ng/mL significantly decreased the risk of preterm birth compared to ≤20 ng/mL. These findings suggest the importance of raising 25(OH)D levels substantially above 20 ng/mL; reaching 40 ng/mL during pregnancy would reduce the risk of preterm birth and achieve the maximal production of the active hormone.

Precursors of preterm birth: comparison of three ethnic groups in the middle East and the United States.

OBJECTIVE: To examine factors related to preterm birth in three ethnic groups and in three different countries. DESIGN: Data were obtained on a convenience sample of 118 Lebanese mothers, 104 Egyptian mothers, 40 Mexican American mothers, and 32 White American mothers from Southern California. About half of each cohort had delivered a preterm newborn and half a full-term newborn. Mothers with premature or full-term newborns completed a questionnaire by interview. Analysis compared ethnic groups and preterm- versus full-term birth groups. Multiple logistic regression determined relatedness to outcome. RESULTS: Descriptive factors differed among groups, but not for preterm versus full-term newborn groups. Significant factors for premature birth were vaginal infections, stress, smoking, drug use, and protein intake. Factors significantly related to preterm birth in the Middle-Eastern and American groups were almost identical: social support, stress, and exercise. Smoking was related only in the American group. CONCLUSIONS: These data suggest risk factors are similar across nations and ethnic groups. Prenatal counseling and programs should address these four issues.

Neighborhood socioeconomic status, maternal race and preterm delivery: a case-control study.

PURPOSE: To explore associations between neighborhood socioeconomic context and preterm delivery, independent of maternal and family socioeconomic status, in African-American and white women. METHODS: A case-control study of African-American (n = 417) and white (n = 1244) women delivering infants at the University of California, San Francisco's Moffitt Hospital, between 1980 and 1990. RESULTS: Neighborhood socioeconomic contexts were associated with preterm delivery but associations were non-linear and varied with race/ethnicity. For African-American women, living in a neighborhood with either high or low median household income was associated with an increased risk of spontaneous preterm delivery, as was living in a neighborhood with large increases or decreases in the proportion of African-American residents during the study decade. Residence in neighborhoods with high and low rates of male unemployment was associated with a decreased risk of preterm delivery. Among white women only large positive and negative changes in neighborhood male unemployment were associated with risk of preterm delivery. CONCLUSIONS: Neighborhood factors and changes in neighborhoods over time are related to preterm delivery, although the mechanisms linking local environments to maternal risk remain to be specified.

Variation in vaginal breech delivery rates by hospital type.

OBJECTIVE: To relate vaginal breech delivery rates to the following hospital types: public, health maintenance organization, private teaching, or private nonteaching. METHODS: In a retrospective study using administrative discharge data from Los Angeles County, California, we calculated the vaginal breech delivery rates of singleton breech deliveries during calendar years 1988 and 1991. RESULTS: Ten thousand four hundred breech deliveries were identified, 8988 (86.4%) term and 1412 (13.6%) preterm. Twelve percent (1252 of 10,400) were vaginal deliveries (10.1% term and 24.5% preterm). Term vaginal breech deliveries varied by hospital type and were more frequent in public hospitals (28.4%, 95% confidence interval [CI] 26.1%, 30.7%) and less frequent in private nonteaching hospitals (5.4%, 95% CI 4.8%, 5.9%). Term vaginal deliveries were 2.4 to 11.3 times more likely among black women and 1.3 to 6.3 times more likely for Hispanic women across all hospital types, compared with white women in private nonteaching hospitals. There was no difference in the proportion of preterm vaginal breech deliveries by hospital type (mean 24.5%). However, with the exception of public hospitals, the proportion of vaginal breech deliveries for both term and preterm deliveries varied significantly by ethnicity. CONCLUSION: The use of vaginal breech delivery varied by hospital type and patient ethnicity. Within private teaching and nonteaching hospitals, vaginal breech delivery was more likely for black women than for women of other ethnic groups. Further study is needed to understand the hospital policies or organizational factors, as well as the patient-related sociocultural and clinical factors, that contribute to those differences.