Differences In Preterm Birth Research Articles

Examining the Starting Dose of Glyburide in Gestational Diabetes.

The aim of this study was to determine the impact of initial glyburide dosing on pregnancy outcomes. STUDY DESign: Retrospective cohort of singleton pregnancies complicated by gestational diabetes mellitus (GDM) from 2007 to 2013. Women who received glyburide were compared by initial dose: 2.5 mg (n = 170) versus 5 mg (n = 154) total daily dose. The primary maternal outcome was hypoglycemia, defined as a blood glucose < 60 mg/dL. The primary neonatal outcome was birth weight. Secondary maternal outcomes included time to blood glucose control, preeclampsia, and cesarean delivery. Secondary neonatal outcomes included macrosomia (>4,000 g), hypoglycemia (<40 mg/dL), shoulder dystocia, and preterm delivery. The 5 mg/day glyburide dose did not increase maternal hypoglycemia (26% in the 2.5 mg/day group vs. 27% in the 5 mg/day group; adjusted odds ratio [AOR] 0.67; confidence interval [CI] 0.30-1.49). An increase in macrosomia in the 5 mg/day group was not significant after adjusting for maternal obesity (AOR 2.16; CI 0.96-4.88). Differences in preterm birth and large for gestational age were not significant after adjusting for prior preterm birth and maternal obesity, respectively. A higher starting dose of glyburide for the management of GDM was not associated with increased maternal hypoglycemia or decreased adverse neonatal outcomes.

The impact of postpartum contraception on reducing preterm birth: findings from California

Family planning is recommended as a strategy to prevent adverse birth outcomes. The potential contribution of postpartum contraceptive coverage to reducing rates of preterm birth is unknown. In this study, we examine the impact of contraceptive coverage and use within 18 months of a birth on preventing preterm birth in a Californian cohort. We identified records for second or higher-order births among women from California's 2011 Birth Statistical Master File and their prior births from earlier Birth Statistical Master Files. To identify women who received contraceptive services from publicly funded programs, we applied a probabilistic linking methodology to match birth files with enrollment records for women with Medi-Cal or Family Planning, Access, Care, and Treatment Program (PACT) claims. The length of contraceptive coverage was determined through applying an algorithm based on the specified method and the quantity dispensed. Preterm birth was defined as a birth occurring <37 weeks' gestation, and calculated from the medical record. We further examined differences in preterm birth using subcategories defined by the World Health Organization: extremely preterm (<28 weeks); very preterm (28 to <32 weeks); and moderate to late preterm (32 to <37 weeks). We built a multivariable regression model to examine the effect of contraceptive coverage on the odds of a preterm birth and control for key covariates. The cohort consisted of 111,948 women who were seen at least once by a Medi-Cal or Family PACT provider within 18 months of delivery. Of the cohort, 9.75% had a preterm birth. Contraceptive coverage was found to be protective against preterm birth. For every month of contraceptive coverage, odds of a preterm birth <37 weeks decrease by 1.1% (odds ratio, 0.989; 95% confidence interval, 0.986-0.993). Improving postpartum contraceptive use has the potential to reduce preterm births.

IgA Deficiency, Autoimmunity &amp; Pregnancy: A Population-Based Matched Cohort Study

Several autoimmune disorders have been linked to adverse pregnancy outcome. IgA deficiency shares many autoimmune traits, but its association with pregnancy outcome is unknown. Prospective population-based cohort study in Sweden of 613 mothers with IgA deficiency (IgA levels < .07 g/L) diagnosed in 1980-2010 in six university hospitals. In 1973-2010, these women delivered 1,172 singleton infants registered in the Swedish Medical Birth Register. Each delivery to a woman with IgA deficiency was matched on maternal age, parity, early pregnancy smoking status, education level, and delivery year with up to 5 control births (n = 5,758). Offspring to women with IgA deficiency had 79 g lower birth weight than controls (mean ± SD: 3,457 ± 559 vs 3,537 ± 553 g, P < 0.001), and 1.4 days shorter gestational age (mean ± SD: 278 ± 13 vs 280 ± 14 days, P = 0.001). No difference in preterm birth (<37 weeks) could be detected in deliveries to women with IgA deficiency vs control deliveries (5.8 % vs 5.2 %; odds ratio (OR) = 1.13, 95%CI = 0.85-1.49), but small for gestational age birth was more common (4.3 % vs 2.8 %; OR = 1.48, 95%CI = 1.04-2.10). Women with IgA deficiency also delivered more often by caesarean section (16.9 % vs 11.9 %; OR = 1.51, 95%CI = 1.26-1.82), while no difference was observed regarding low Apgar score (<7 at 5 min; 1.1 % vs 1.0 %; OR = 1.18; 95%CI = 0.62-2.27). When excluding women with autoimmune diseases, the excess risks of adverse pregnancy outcome diminished. There is a small excess risk of certain adverse delivery and perinatal outcomes among offspring to women with IgA deficiency. These excess risks are attenuated when considering the presence of autoimmune diseases.

OUTCOMES OF LATINA WOMEN IN CENTERINGPREGNANCY GROUP PRENATAL CARE COMPARED WITH INDIVIDUAL PRENATAL CARE

Introduction CenteringPregnancy is a client-centered model of group prenatal care that brings women together into small groups to receive care through assessment, education, and support. As Spanish-speaking CenteringPregnancy groups become more common, outcomes of Latinas who attend these groups must be assessed. The purpose of this retrospective cohort study was to compare pregnancy outcomes of Latina women who completed CenteringPregnancy in a public health clinic with women who completed individual care in the same clinic during the same time. Methods Medical charts were reviewed retrospectively to examine differences in pregnancy outcomes and maternal factors in both prenatal care groups. Latina Spanish-speaking women who completed CenteringPregnancy were matched with Latina Spanish-speaking women who completed individual care within the same time frame. Logistic regression analysis was conducted to examine maternal and birth outcomes. Results A total of 487 patient charts were obtained for data collection (CenteringPregnancy n = 247, individual n = 240). No differences in low-birth-weight or preterm births were observed between the groups. Compared with women in individual care, women in CenteringPregnancy had higher odds of giving birth vaginally (adjusted odds ratio [aOR], 2.57; 95% confidence interval [CI], 1.23-5.36), attending prenatal care visits (aOR, 11.03; 95% CI, 4.53-26.83), attending postpartum care visits (aOR, 2.20; 95% CI, 1.20-4.05), and feeding their infants formula only (aOR, 6.07; 95% CI, 2.57-14.3). Women in CenteringPregnancy also had lower odds of gaining below the recommended amount of gestational weight (aOR, 0.41; 95% CI, 0.22-0.78). Discussion Women in CenteringPregnancy had higher health care utilization, but there were no differences in preterm birth or low birth weight. Randomized studies are needed to eliminate selection bias.

Outcomes of Latina Women in CenteringPregnancy Group Prenatal Care Compared With Individual Prenatal Care

CenteringPregnancy is a client-centered model of group prenatal care that brings women together into small groups to receive care through assessment, education, and support. As Spanish-speaking CenteringPregnancy groups become more common, outcomes of Latinas who attend these groups must be assessed. The purpose of this retrospective cohort study was to compare pregnancy outcomes of Latina women who completed CenteringPregnancy in a public health clinic with women who completed individual care in the same clinic during the same time. Medical charts were reviewed retrospectively to examine differences in pregnancy outcomes and maternal factors in both prenatal care groups. Latina Spanish-speaking women who completed CenteringPregnancy were matched with Latina Spanish-speaking women who completed individual care within the same time frame. Logistic regression analysis was conducted to examine maternal and birth outcomes. A total of 487 patient charts were obtained for data collection (CenteringPregnancy n = 247, individual n = 240). No differences in low-birth-weight or preterm births were observed between the groups. Compared with women in individual care, women in CenteringPregnancy had higher odds of giving birth vaginally (adjusted odds ratio [aOR], 2.57; 95% confidence interval [CI], 1.23-5.36), attending prenatal care visits (aOR, 11.03; 95% CI, 4.53-26.83), attending postpartum care visits (aOR, 2.20; 95% CI, 1.20-4.05), and feeding their infants formula only (aOR, 6.07; 95% CI, 2.57-14.3). Women in CenteringPregnancy also had lower odds of gaining below the recommended amount of gestational weight (aOR, 0.41; 95% CI, 0.22-0.78). Women in CenteringPregnancy had higher health care utilization, but there were no differences in preterm birth or low birth weight. Randomized studies are needed to eliminate selection bias.

Racial and ethnic disparities in preterm births in infants conceived by in vitro fertilization in the United States

The objective of the study was to examine racial and ethnic differences in preterm births in infants conceived by in vitro fertilization (IVF). A retrospective cohort study was conducted of 97,288 singleton and 40,961 twin pregnancies resulting from fresh, nondonor IVF cycles using 2006-2010 data from the Society for Assisted Reproductive Technology Clinic Online Reporting System. Rates of very early preterm (<28 weeks), early preterm (<32 weeks), and preterm birth (<37 completed weeks) varied across racial and ethnic groups in both singleton and twin pregnancies. In singletons, with white women as the referent, after adjustment of confounding variables, the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of very early preterm birth, early preterm birth, and preterm birth in black women were 4.8 (95% CI, 4.1-5.7), 3.9 (95% CI, 3.4-4.4), and 2.1 (95% CI, 1.9-2.3). Hispanic women had a significantly lower rate of preterm births as compared with black women and similar or slightly higher rates as compared with white women. Native American women were not at an increased risk of any types of preterm births; Asian women were at a reduced risk of preterm twin births (adjusted OR, 0.8; 95% CI, 0.7-0.9). There exist notable racial and ethnic disparities in preterm births in infants conceived by IVF, suggesting that mechanisms other than socioeconomic disparities contribute to this difference.

Cervical assessment by ultrasound for preventing preterm delivery.

Measurement of cervical length (CL) by transvaginal ultrasound (TVU) is predictive of preterm birth (PTB). It is unclear if this screening test is effective for prevention of PTB. To assess the effectiveness of antenatal management based on transvaginal ultrasound of cervical length (TVU CL) screening for preventing PTB. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2012), reviewed the reference lists of all articles and contacted experts in the field for additional and ongoing trials. Published and unpublished randomized controlled trials including pregnant women between the gestational ages of 14 to 32 weeks screened with TVU CL for risk of PTB. This review focuses exclusively on studies based on knowledge versus no knowledge of TVU CL results. All potential studies identified from the search were independently assessed for inclusion by three review authors. We also analyzed studies for quality measures and extracted data. Of the 13 trials identified, five were eligible for inclusion (n = 507). Three included singleton gestations with preterm labor (PTL); one included singleton gestations with preterm premature rupture of membranes (PPROM); and one included twin gestations with or without PTL.In the three trials of singleton gestations with PTL, 290 women were randomized; 147 to knowledge and 143 to no knowledge of TVU CL. Knowledge of TVU CL results was associated with a non-significant decrease in PTB at less than 37 weeks (22.3% versus 34.7%, respectively; average risk ratio 0.59, 95% confidence interval (CI) 0.26 to 1.32; two trials, 242 women) and at less than 34 weeks (6.9% verus 12.6%; RR 0.55, 95% CI 0.25 to 1.20; three trials, 256 women). Delivery occurred at a later gestational age in the knowledge versus no knowledge groups (mean difference (MD) 0.64 weeks, 95% CI 0.03 to 1.25; three trials, 290 women). For all other outcomes for which there were available data (PTB at less than 34 or 28 weeks; birthweight less than 2500 grams; perinatal death; maternal hospitalization; tocolysis; and steroids for fetal lung maturity), there was no evidence of a difference between groups.The trial of singleton gestations with PPROM (n = 92) evaluated as its primary outcome safety of TVU CL in this population, and not its effect on management. There was no evidence of a difference in incidence of maternal and neonatal infections between the TVU CL and no TVU CL groups.In the trial of twin gestations with or without PTL (n = 125), there was no evidence of a difference in PTB at less than 36, 34, or 30 weeks, gestational age at delivery, and other perinatal and maternal outcomes between the TVU CL and the no TVU CL groups. Life-table analysis revealed significantly less PTB at less than 35 weeks in the TVU CL group compared with the no TVU CL group (P = 0.02). Currently, there is insufficient evidence to recommend routine screening of asymptomatic or symptomatic pregnant women with TVU CL. Since there is a non-significant association between knowledge of TVU CL results and a lower incidence of PTB at less than 37 weeks in symptomatic women, we encourage further research. Future studies should look at specific populations separately (e.g., singleton versus twins; symptoms of PTL or no such symptoms), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU CL results, so that it can be easily evaluated and replicated.

Preterm Birth Among American Indian/Alaskan Natives in Washington and Montana: Comparison with Non-Hispanic Whites

Preterm birth is the single most important cause of perinatal mortality in North America. Given that American Indians/Alaskan Natives (AI/ANs) in the United States continue to have adverse birth outcomes, the purpose of this study is to compare the risk of preterm birth among AI/AN mothers to Non-Hispanic White mothers living in Washington and Montana from 2003 to 2009. A population-based retrospective cohort study was conducted examining the association between AI/AN mothers (self-reported) and the risk of preterm birth (gestational age <37 weeks) using birth certificate data from Washington and Montana. All AI/AN singleton lives births (n = 26,648) from residents of Washington and Montana from 2003 to 2009 were identified and included in our study. An identical number of Non-Hispanic White singleton infants (n = 26,648) born to residents of Washington and Montana were randomly selected as a comparison group and logistic regression was used to analyze the data. AI/AN mothers living in Washington and Montana between 2003 and 2009 were 1.34 times (95 % CI 1.25-1.44) as likely to have a preterm birth compared to Non-Hispanic Whites after adjusting for maternal and paternal characteristics as well as pregnancy risk factors. AI/AN mothers residing in Washington and Montana from 2003 to 2009 were at a significantly increased risk of having a preterm birth compared to Non-Hispanic Whites. Identifying etiologic differences in preterm birth experienced by AI/ANs is essential in targeting future interventions.

12: Genetic variation associated with preterm birth in black women

Black race is one of the strongest risk factors for preterm birth (PTB). Recently published data supports the hypothesis that genetic variation is a critical component in the pathogenesis of PTB and may account, in part, for the differences in PTB among different racial groups. We sought to identify single nucleotide polymorphisms (SNPs) associated with PTB within a cohort of black women.

Francophone and Anglophone perinatal health: temporal and regional inequalities in a Canadian setting, 1981–2008

We evaluated temporal and regional inequalities in adverse birth outcomes between Anglophones and Francophones of a Canadian province. Odds ratios and rate differences in preterm birth (PTB, <37 gestational weeks) and small-for-gestational-age (SGA) birth were computed for Anglophones relative to Francophones for singleton live births in Québec from 1981 to 2008 (N = 2,292,237), adjusting for maternal characteristics. Trends over time and residential region were evaluated. Rates of PTB and SGA birth overall were lower for Anglophones relative to Francophones, but temporal and regional trends varied by outcome. Although PTB rates increased over time, inequalities between Francophones and Anglophones were relatively stable. In contrast, inequalities in SGA birth narrowed over time as Francophone rates declined more than Anglophones. Inequalities in SGA birth favored Anglophones overall, but the gap gradually reversed in Montréal (the largest metropolitan center) to currently favor Francophones. PTB and SGA birth rates favored Anglophones over Francophones. The linguistic gap was generally stable over time for PTB, but narrowed or reversed for SGA birth. Language may be used to capture inequalities in perinatal health in countries where different linguistic groups predominate.

Does Time Since Immigration Modify Neighborhood Deprivation Gradients in Preterm Birth? A Multilevel Analysis

Immigrants’ health is jointly influenced by their pre- and post-migration exposures, but how these two influences operate with increasing duration of residence has not been well-researched. We aimed to examine how the influence of maternal country of birth and neighborhood deprivation effects, if any, change over time since migration and how neighborhood effects among immigrants compare with those observed in the Canadian-born population. Birth data from Ontario hospital records (2002–2007) were linked with an official Canadian immigration database (1985–2000). The outcome measure was preterm birth. Neighborhoods were ranked according to a neighborhood deprivation index developed for Canadian urban areas and collapsed into tertiles of approximately equal size. Time since immigration was measured from the date of arrival to Canada to the date of delivery, ranging from 1 to 22 years. We used cross-classified random effect models to simultaneously account for the membership of births (N = 83,233) to urban neighborhoods (N = 1,801) and maternal countries of birth (N = 168). There were no differences in preterm birth between neighborhood deprivation tertiles among immigrants with less than 15 years of residence. Among immigrants with 15 years of stay or more, the adjusted absolute risk difference (ARD%, 95% confidence interval) between high-deprived (tertile 3) and low-deprived (tertile 1) neighborhoods was 1.86 (0.68, 2.98), while the ARD% observed among the Canadian-born (N = 314,237) was 1.34 (1.11, 1.57). Time since migration modifies the neighborhood deprivation gradient in preterm birth among immigrants living in Ontario cities. Immigrants reached the level of inequalities in preterm birth observed at the neighborhood level among the Canadian-born after 14 years of stay, but neighborhoods did not influence preterm birth among more recent immigrants, for whom the maternal country of birth was more predictive of preterm birth.

Increased risk of low birthweight and small for gestational age infants among women with tuberculosis

As the relationship between tuberculosis (TB) and fetal outcomes remains unclear, this study used a 3-year nationwide population-based data set to determine the risk of adverse pregnancy outcomes [low birthweight (LBW), preterm birth and small for gestational age (SGA) infants] among women with TB. A cross-sectional retrospective study. Taiwan. Linking the Taiwan birth certificate registry and the Taiwan National Health Insurance Research Dataset, we identified 761 women who gave birth from 2001 to 2003 and who had received medication treatment for TB during their pregnancy, together with 3805 unaffected women matched in terms of age and year of delivery. Conditional logistic regression analyses were performed to compare the risk of LBW, preterm birth and SGA for mothers with TB and unaffected mothers. The risk of LBW, preterm birth and SGA. Mothers diagnosed with TB had significantly higher percentages of LBW (8.5 versus 6.4%, P = 0.033) and SGA (19.7 versus 16.7%, P = 0.048) infants than unaffected mothers. However, there was no significant difference in preterm birth (8.0 versus 8.0%, P = 0.961) between these two groups. The adjusted odds ratios of having LBW and SGA infants for mothers with TB were 1.35 (95% CI = 1.01-1.81) and 1.22 (95% CI = 1.00-1.49), respectively, compared with unaffected mothers. We concluded that women diagnosed with TB during pregnancy are at increased risk for having LBW and SGA babies, compared with unaffected mothers. We suggest that clinicians should make women with TB aware of the potential risks before planning a child.

Ethnic differences in preterm birth and its subtypes: the effect of a cumulative risk profile

To explore the effect of potentially explanatory risk factors on ethnic differences in the prevalence of preterm birth (PTB) and its subtypes. Prospective population-based cohort study. Pregnant women from Amsterdam attending their first antenatal visit for obstetric care. A total of 8266 women participated (response rate 67%). Ethnicity was based on the country of birth of the pregnant woman's mother: the Netherlands, Surinam, the Antilles, Turkey, Morocco, Ghana and other non-Dutch countries. Exclusion criteria were multiple births and gestational age at delivery less than 24 weeks. Risk factors were obtained using a multilingual questionnaire and from the Dutch Perinatal Registration. Risk factors were summed into a cumulative risk score. Multiple logistic regression analyses were performed. Odds ratios with 95% CIs were calculated for total, spontaneous and iatrogenic (medically indicated) preterm births for the ethnic minority groups versus the Dutch reference group. After adjustment for all risk factors, the Surinamese (OR 1.6, 95% CI 1.2-2.4), Ghanaian (OR 2.0, 95% CI 1.1-3.6) and Antillean (OR 1.6, 95% CI 0.8-3.3) women had a higher risk of PTB compared with the Dutch women, in particular for iatrogenic preterm birth (OR 2.1, 95% CI 1.0-4.4; OR 3.2, 95% CI 1.0-10.4; OR 3.6, 95% CI 1.1-11.2, respectively). The ethnic minority groups had a higher cumulative risk score (ranging from 2.1 to 3.7) compared with the Dutch group (1.8). Adjustment for the cumulative risk score considerably decreased the risk of PTB among the Surinamese (OR 1.2, 95% CI 0.9-1.7), Ghanaian (OR 1.3, 95% CI 0.8-2.3) and Antillean (OR 1.2, 95% CI 0.6-2.4) women. A cumulation of risk factors, mainly observed among the ethnic minority groups, contributes to the explanation of ethnic differences in PTB prevalence.

Shirodkar versus McDonald Cerclage for the Prevention of Preterm Birth in Women with Short Cervical Length

The efficacy of Shirodkar cerclage was compared with that of the McDonald procedure for the prevention of preterm birth (PTB) in women with a short cervix. Secondary analysis using data from all published randomized trials including women with a short cervical length (CL) was performed comparing the use of Shirodkar versus McDonald sutures. Analysis was limited to singletons with short CL on transvaginal ultrasound. The primary outcome measure was PTB < 33 weeks. Statistical analysis was performed using bivariate and multivariable techniques. From 607 women randomly assigned in the study, 277 met our inclusion criteria; 127 received Shirodkar and 150 women received McDonald sutures. The mean ( +/- standard deviation) gestational age at delivery was 35.0 +/- 5.3 versus 36.3 +/- 4.7 for the Shirodkar versus McDonald groups, respectively ( p< 0.02). PTB < 33 weeks was seen in 61 (22%) of 277 women; 26 (20%) of 127 in the Shirodkar and 35 (23%) of 150 in the McDonald groups, respectively (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.5 to 1.6). On adjusting for confounders using logistic regression modeling, no significant difference in PTB < 33 weeks was found between the two groups (OR, 0.55; 95% CI, 0.2 to 1.3). In women with short cervical length randomly assigned to receiving cerclage, no significant difference in prevention of PTB was observed using Shirodkar or McDonald's procedures.

Recent work on the epidemiology of preterm birth

Preterm birth proportions and outcomes are strongly influenced by the criteria for inclusion of births and deaths in national data systems and Registers. The European Commission Health Monitoring Program includes development of indicators to monitor and evaluate perinatal health, and a recent journal supplement provides results from this PERISTAT project. The analysis by subgroups of gestational age, birthweight, and plurality, shown in the supplement (1), demonstrates the impact of these registration differences. The second development is the recognition that the analysis of preterm birth and fetal and infant deaths would best be thought of as occurring within a cohort of conceptions which reach 20 weeks gestation (2). All those still in utero are at risk of being born in any given week. This approach has already provided an explanation for the paradox of intersecting perinatal mortality curves between babies of smokers and non-smokers, and between singleton and twin infants (2, 3). One research group has carried out a series of systematic reviews of the accuracy of methods for predicting preterm birth, either in threatened preterm labor or among asymptomatic women. Their review of published risk-scoring systems found that none could be recommended (4). A systematic review of controlled studies of perinatal outcomes for singletons and twins after assisted conception concluded that singletons had a significantly worse outcome than non-assisted singletons: the relative risk (RR) was 3.27 [95% confidence interval (CI) 2.03–5.28] for birth <32 weeks and 2.04 (95% CI 1.80–2.32) for any preterm birth. There were no differences in preterm birth between assisted and unassisted twin births (5). Evidence that intimate partner violence (IPV) is a major risk factor for preterm birth has been strengthened. IPV reported to police during pregnancy was followed by a large increase in births before 32 weeks [adjusted odds ratio (aOR) 3.71, 95% CI 1.80, 7.63) and 1.61 (95% CI 1.14, 2.28) for any preterm birth (6). A large population-based study found an increased risk of antepartum hemorrhage [aOR 3.79 (95% CI 1.38, 10.4)] and even larger odds of perinatal death [8.06 (95% CI 1.42, 45.6)] (7). The large European case–control study (EUROPOP) found no excess risk of preterm birth among women employed in pregnancy, but an increased risk for women working more than 42 hr a week, standing more than 6 hr a day, and among those with low job satisfaction (8). The possibility of longer term effects has been demonstrated most clearly by the association of a prior cesarean birth with antepartum hemorrhage and placenta praevia, both risks for preterm birth (9). An analysis of linked records from first and second births in Scotland using the fetuses-at-risk approach showed other adverse effects of prior cesarean, including an increased risk of late preterm birth (33–36 weeks) and fetal death at and after 34 weeks (10). EUROPOP took advantage of different patterns of abortion use in three groups of countries to measure a significant association of prior abortion with preterm birth in all three groups. The risk increased with the number of prior abortions and was larger for very preterm birth. The clinical pathways to preterm birth were spontaneous preterm labor, preterm PROM, and antepartum hemorrhage (11) Records of women with cervical dysplasia were linked to subsequent births in New Zealand to compare preterm birth in those treated and untreated. An increase in preterm PROM was seen with the loop electrosurgical excision procedure and laser conization, though not with laser ablation, and the risk increased with the height of tissue removed (12). The findings were not assessed against population-based data. These three examples demonstrate the need for a broader approach to thinking about epidemiology, etiology, and pathways to preterm birth.

Race and ethnic differences in determinants of preterm birth in the USA: broadening the social context

Preterm births occur in 9.7% of all US singleton births. The rate for blacks is double that of whites and the rate is 25% higher for Hispanics than for whites. While a number of individual correlates with preterm birth have been identified, race and ethnic differences have not been fully explained. Influenced by a growing body of literature documenting a relationship among health, individual income, and neighborhood disadvantage, researchers interested in explaining racial differences in preterm birth are designing studies that extend beyond the individual. No studies of adverse birth outcomes have considered contextual effects beyond the neighborhood level. Only a handful of studies, comparing blacks and whites, have evaluated the influence of neighborhood disadvantage on preterm birth. This study examines how preterm birth among blacks, whites and Hispanics is influenced by social context, broadly defined to include measures of neighborhood disadvantage and cumulative exposure to state-level income inequality, controlling for individual risk factors. Neighborhood disadvantage is determined by Census tract data. Cumulative exposure to income inequality is measured by the fraction of the mother's life since age 14 spent residing in states with a state-level Gini coefficient above the median. The results for neighborhood disadvantage are highly sensitive across race/ethnicities to the measure used. We find evidence that neighborhood poverty rates and housing vacancy rates increased the rate of very preterm birth and decreased the rate of moderately preterm birth for blacks. The rate of very preterm increased with the fraction of female-headed households for Hispanics and decreased with the fraction of people employed in professional occupations for whites. We find direct effects of cumulative exposure to income inequality only for Hispanics. However, we do find indirect effects of context broadly defined on behaviors that increased the risk of preterm birth.

Birthweight differences among infants of North African immigrants and Belgians in Belgium

Infants of North African immigrants are reported to have higher birthweights than their Belgian counterparts. It is unclear what mechanism contributes to this difference. Analyses were based on a hospital-based cohort of 1,162 women. Infants of North African immigrants were less likely to be born preterm, compared to infants of Belgian women. After adjusting for sociodemographic and maternal factors, the estimated difference in mean birthweight was 74 g (p=0.05). When limited to term births, this difference was 28 g (p=0.42). The difference in mean birthweight between North African and Belgian infants was explained by differences in preterm birth and other risk factors.

Infant mortality among First Nations versus non-First Nations in British Columbia: temporal trends in rural versus urban areas, 1981-2000

Increasingly more First Nations (FN) people have moved from rural to urban areas. It is unknown how disparities in infant mortality among FN versus non-FN women have changed over time in urban versus rural areas. We conducted a birth cohort-based study of all 877 925 live births (56 771 FN and 821 154 non-FN) registered in British Columbia, 1981-2000. Main outcomes included rates, risk differences, and relative risks of neonatal, postneonatal, and overall infant death. Both neonatal and postneonatal mortality rates for FN infants showed a steady decline in rural areas but a rise-and-fall pattern in urban areas. Relative risks for overall infant death among FN versus non-FN infants declined steadily from 2.75 (95% CI: 2.04, 3.72) to 1.87 (95% CI: 1.24, 2.81) in rural areas from 1981-1984 to 1997-2000, but rose from 1.59 (95% CI: 1.27, 1.99) (1981-1984) to 2.80 (2.33-3.37) (1989-92) and then fell to 1.89 (1.44-2.49) (1997-2000) in urban areas. Risk differences for neonatal death among FN versus non-FN infants declined substantially over time in rural but not urban areas. The disparities in neonatal death among FN versus non-FN were largely explained by differences in preterm birth, while the disparities in postneonatal death were not explained by observed maternal and pregnancy characteristics. Reductions in disparities in infant mortality among FN versus non-FN women have been less substantial and consistent over time in urban versus rural areas of British Columbia, suggesting the need for greater attention to FN maternal and infant health in urban areas.

Preinduction cervical ripening with the Foley catheter and the risk of subsequent preterm birth

Objective The Foley catheter is a safe and effective form of preinduction cervical ripening and is quickly growing in popularity. Its major effect appears to be through mechanical dilation, which has raised the concern that the use of the Foley catheter for cervical ripening may damage the cervix and result in a higher rate of subsequent preterm birth. Study design We conducted a review of all induction of labor at our institution from July 1998 to July 2001 that required preinduction cervical ripening and had a subsequent birth. The primary outcome variable was preterm birth at <35 weeks of gestation. Demographic and potential confounding variables were analyzed. A probability value of <.05 was considered significant. Results The cases of 126 women (63 women in the Foley group and 63 women in the prostaglandin group) were studied. Women in the prostaglandin group had a prostaglandin agent used. There was no difference in maternal age, gravidity, parity, Bishop score, total time of induction, gestational age, oxytocin use, maximum oxytocin level, tobacco or drug use, or type of delivery in the index pregnancy between the groups. In the subsequent pregnancies, there were no differences in maternal age, gravidity, parity, spontaneous abortions, terminations, cone or Loop Electrosurgical Excision Procedure (LEEP) procedures, history of cervical manipulation, tobacco or drug use, stillbirth, need for induction, mode of delivery, episiotomy, gestational age at delivery, Apgar scores, labor duration, use of oxytocin, or birth weight. There were no differences in preterm birth at 37, 35, or 32 weeks of gestation between the groups. Conclusion The use of the Foley catheter for preinduction cervical ripening does not appear to increase the risk of preterm birth in a subsequent pregnancy.

Helicobacter pylori Seropositivity in Patients With Hyperemesis Gravidarum

In theory, increased fluid accumulation resulting from elevated steroid hormones in pregnant women could lead to a pH shift in the gastrointestinal tract, with subclinical Helicobacter pylori infection becoming manifest as a consequence. Hyperemesis gravidarum is relatively frequent in primigravidas with high serum estradiol. This prospective study used an H. pylori–specific fluorescent serum antibody test to find any association between H. pylori infection and hyperemesis gravidarum. Subjects included 95 pregnant women with hyperemesis gravidarum and 116 unaffected women matched for gestational age. H. pylori infection was detected in 91.5 percent of women with hyperemesis gravidarum and in 45 percent of control subjects. The two groups did not differ significantly in age, gravidity, or parity, and there were no substantial differences in preterm births, small-for-gestational-age infants, perinatal deaths, or miscarriages. The hospital stay averaged 5.5 days for women with hyperemesis gravidarum and 1.5 days for control subjects. These findings support the possibility that hyperemesis gravidarum is associated with H. pylori infection. It might seem reasonable to eradicate H. pylori in women with hyperemesis gravidarum to prevent transmitting infection to the fetus, but treating this infection during pregnancy, especially with metronidazole, is problematic. Int J Gynecol Obstet 1999;66:251–254