1
|
Maghsoudlou S, Beyene J, Yu ZM, McDonald SD. Phenotypic Classification of preterm Birth Among Multiparous Women: A Population-Based Cohort Study. J Obstet Gynaecol Can 2019; 41:1433-1443.e12. [PMID: 31281043 DOI: 10.1016/j.jogc.2019.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/12/2019] [Accepted: 03/18/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The Global Alliance to Prevent Prematurity and Stillbirth developed a phenotypic classification for preterm birth using clinical presentation (rather than risk factors) to improve surveillance. The objective of this study was to determine distributions of preterm birth phenotypes and associations with Caesarean section, low Apgar score, and neonatal death in multiparous women, stratifying by first versus recurrent preterm births. METHODS This population-based cohort study used the Better Outcomes Registry and Network (BORN) of multiparous women giving birth in hospital with a singleton after 20 weeks in Ontario from 2012 to 2014 (Canadian Task Force Classification II-2). RESULTS In multiparous women with preterm birth, 29.6% had a history of recurrence, of whom 66.2% had at least one clinical condition associated with the phenotypic model, compared with 63.5% of first preterm births. In recurrent preterm births, criteria for maternal, fetal, and placental conditions were met in 44.5%, 37.9%, and 8.2%, respectively, compared with 36.8%, 39.0%, and 10.4%, respectively, of first preterm births. Associations of preterm birth with Caesarean section, low Apgar score, and neonatal death varied across clinical conditions but were similar between first and recurrent preterm births; for example, for recurrent preterm birth, Caesarean section for maternal, fetal, and placental conditions had odds ratios of 1.66 (95% confidence interval [CI] 1.32-2.07), 1.09 (95% CI 0.80-1.49), and 3.92 (95% CI 1.98-7.78), compared with first preterm birth odds ratios of 1.21 (95% CI 1.03-1.41), 0.92 (95% CI 0.77-1.10), and 6.24 (95% CI 4.07-9.56). CONCLUSION This study provides novel evidence of the utility of the preterm birth phenotypic classification model by using stratification for previous preterm birth, a robust predictor-with variation in phenotypes in initial and recurrent preterm births.
Collapse
Affiliation(s)
- Siavash Maghsoudlou
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON; Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institute, Stockholm, Sweden
| | - Joseph Beyene
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON
| | - Zhijie Michael Yu
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON
| | - Sarah D McDonald
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON; Department of Radiology, McMaster University, Hamilton, ON.
| |
Collapse
|
2
|
Manuck TA, Esplin MS, Biggio J, Bukowski R, Parry S, Zhang H, Huang H, Varner MW, Andrews W, Saade G, Sadovsky Y, Reddy UM, Ilekis J. The phenotype of spontaneous preterm birth: application of a clinical phenotyping tool. Am J Obstet Gynecol 2015; 212:487.e1-487.e11. [PMID: 25687564 DOI: 10.1016/j.ajog.2015.02.010] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/19/2014] [Accepted: 02/09/2015] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Spontaneous preterm birth (SPTB) is a complex condition that is likely a final common pathway with multiple possible causes. We hypothesized that a comprehensive classification system appropriately could group women with similar STPB causes and could provide an explanation, at least in part, for the disparities in SPTB that are associated with race and gestational age at delivery. STUDY DESIGN This was a planned analysis of a multicenter, prospective study of singleton SPTBs. Women with SPTB at <34 weeks' gestation were included. We defined 9 potential SPTB phenotypes based on clinical data: infection/inflammation, maternal stress, decidual hemorrhage, uterine distention, cervical insufficiency, placental dysfunction, premature rupture of the membranes, maternal comorbidities, and familial factors. Each woman's condition was evaluated for each phenotype. Delivery gestational age was compared between those with and without each phenotype. Phenotype profiles were also compared between women with very early (20.0-27.9 weeks' gestation) SPTB vs those with early SPTB (28.0-34.0 weeks' gestation) and between African American and white women. Statistical analysis was by t test and χ(2) test, as appropriate. RESULTS The phenotyping tool was applied to 1025 women with SPTBs who delivered at a mean 30.0 ± 3.2 (SD) weeks' gestation. Of these, 800 women (78%) had ≥2 phenotypes. Only 43 women (4.2%) had no phenotypes. The 281 women with early SPTBs were more likely to have infection/inflammation, decidual hemorrhage, and cervical insufficiency phenotypes (all P ≤ .001). African American women had more maternal stress and cervical insufficiency but less decidual hemorrhage and placental dysfunction compared with white women (all P < .05). Gestational age at delivery decreased as the number of phenotypes that were present increased. CONCLUSION Precise SPTB phenotyping classifies women with SPTBs and identifies specific differences between very early and early SPTB and between African American and white women.
Collapse
Affiliation(s)
- Tracy A Manuck
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah School of Medicine, and Department of Maternal-Fetal Medicine, Intermountain Healthcare, Salt Lake City, UT.
| | - M Sean Esplin
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah School of Medicine, and Department of Maternal-Fetal Medicine, Intermountain Healthcare, Salt Lake City, UT
| | - Joseph Biggio
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, and Center for Women's Reproductive Health, University of Alabama at Birmingham School of Medicine, Birmingham, AL
| | - Radek Bukowski
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX
| | - Samuel Parry
- Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Heping Zhang
- Collaborative Center for Statistics in Science, Yale University School of Public Health, New Haven, CT
| | - Hao Huang
- Collaborative Center for Statistics in Science, Yale University School of Public Health, New Haven, CT
| | - Michael W Varner
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah School of Medicine, and Department of Maternal-Fetal Medicine, Intermountain Healthcare, Salt Lake City, UT
| | - William Andrews
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, and Center for Women's Reproductive Health, University of Alabama at Birmingham School of Medicine, Birmingham, AL
| | - George Saade
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX
| | - Yoel Sadovsky
- Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Uma M Reddy
- Pregnancy and Perinatology Branch, Center for Developmental Biology and Perinatal Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD
| | - John Ilekis
- Pregnancy and Perinatology Branch, Center for Developmental Biology and Perinatal Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD
| |
Collapse
|
3
|
Laughon SK, Albert PS, Leishear K, Mendola P. The NICHD Consecutive Pregnancies Study: recurrent preterm delivery by subtype. Am J Obstet Gynecol 2014; 210:131.e1-8. [PMID: 24036403 PMCID: PMC3934564 DOI: 10.1016/j.ajog.2013.09.014] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/08/2013] [Accepted: 09/10/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Attention for recurrent preterm delivery has primarily focused on spontaneous subtypes with less known about indicated preterm delivery. STUDY DESIGN In a retrospective cohort of consecutive pregnancies among 51,086 women in Utah (2002-2010), binary relative risk regression was performed to examine the risk of preterm delivery (PTD; <37 weeks) in the second observed delivery by PTD in the first, adjusting for maternal age, race/ethnicity, prepregnancy body mass index, insurance, smoking, alcohol and/or drug use, and chronic disease. Analyses were also performed stratified by prior preterm delivery subtype: spontaneous, indicated, or no recorded indication. RESULTS There were 3836 women who delivered preterm in the first observed pregnancy (7.6%), of which 1160 repeated in the second (30.7%). Rate of recurrent PTD was 31.6% for prior spontaneous, 23.0% for prior indicated delivery, and 27.4% for prior elective delivery. Prior spontaneous PTD was associated with a relative risk (RR) of 5.64 (95% confidence interval [CI], 5.27-6.05) of subsequent spontaneous and RR of 1.61 (95% CI, 0.98-2.67) of subsequent indicated PTD. Prior indicated PTD was associated with an RR of 9.10 (95% CI, 4.68-17.71) of subsequent indicated and RR of 2.70 (95% CI, 2.00-3.65) of subsequent spontaneous PTD. CONCLUSION Prior indicated PTD was strongly associated with subsequent indicated PTD and with increased risk for subsequent spontaneous PTD. Spontaneous PTD had the highest rate of recurrence. Some common pathways for different etiologies of preterm delivery are likely, and indicated PTD merits additional attention for recurrence risk.
Collapse
Affiliation(s)
- S. Katherine Laughon
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD
| | - Paul S. Albert
- Biostatistics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD
| | - Kira Leishear
- Division of Intramural Population Health Research, NICHD, National Institutes of Health, Rockville, MD
| | - Pauline Mendola
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD
| |
Collapse
|
4
|
Affiliation(s)
- Catherine Y Spong
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland
| |
Collapse
|
5
|
Affiliation(s)
- James M Nicholson
- Department of Family and Community Medicine, Pennsylvania State College of Medicine, Hershey
| | | | | |
Collapse
|
6
|
Affiliation(s)
- Catherine Y Spong
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Blvd, Room 4B03, MSC 7510, Bethesda, MD 20892, USA.
| |
Collapse
|
7
|
Kamath-Rayne BD, DeFranco EA, Chung E, Chen A. Subtypes of preterm birth and the risk of postneonatal death. J Pediatr 2013; 162:28-34.e2. [PMID: 22878113 PMCID: PMC3628608 DOI: 10.1016/j.jpeds.2012.06.051] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 05/23/2012] [Accepted: 06/26/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To examine the differences in postneonatal death risk among 3 clinical subtypes of preterm birth: preterm premature rupture of membranes (PROM), indicated preterm birth, and spontaneous preterm labor. STUDY DESIGN We analyzed the 2001-2005 US linked birth/infant death (birth cohort) datasets. The preterm birth subtypes were classified using information on the birth certificate: reported PROM, induction of labor, cesarean section, and complications of pregnancy and labor. Cox proportional hazard models were used to estimate covariate-adjusted hazard ratios and 95% CIs for postneonatal death (from days 28 to 365). Estimation was given for preterm birth subtypes in a week-by-week analysis. Causes of death were analyzed by preterm birth subtype and then separately at 24-27, 28-31, and 32-36 weeks of gestation. RESULTS For the total of 1895350 singleton preterm births who survived the neonatal period, the postneonatal mortality rate was 1.11% for preterm PROM, 0.78% for indicated preterm birth, and 0.53% for spontaneous preterm labor. Preterm PROM was associated with significantly higher risk of postneonatal death compared with spontaneous preterm labor in infants born at 27 weeks gestation or later. Similarly, indicated preterm birth was associated with a significantly higher risk of postneonatal death than spontaneous preterm labor in infants born at 25 weeks gestation or later. Preterm PROM and indicated preterm birth were associated with greater risk of death in the postneonatal period compared with spontaneous preterm labor, irrespective of the cause of death. CONCLUSION Subtypes of preterm birth carry different risks of postneonatal mortality. Prevention of preterm-related postneonatal death may require more research into the root causes of preterm birth subtypes.
Collapse
Affiliation(s)
- Beena D Kamath-Rayne
- Division of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
| | | | | | | |
Collapse
|
8
|
Landry JS, Croitoru D, Menzies D. Validation of ICD-9 diagnostic codes for bronchopulmonary dysplasia in Quebec's provincial health care databases. Chronic Dis Inj Can 2012; 33:47-52. [PMID: 23294921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
INTRODUCTION Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease caused by neonatal lung injury. The aim of this study was to validate the use of ICD-9 diagnostic codes for BPD in administrative databases to allow for their use in health care utilization analyses. METHODS The validation process used a retrospective cohort composed of preterm infants, with or without respiratory complications, admitted to the Montréal Children's Hospital, Montréal, Quebec, between 1983 and 1992. BPD subjects were identified using ICD-9 diagnostic codes in the provincial administrative databases (medical services and MED-ECHO) and then matched with subjects with confirmed BPD from the validation cohort. We examined concordance and estimated sensitivity and specificity associated with the use of these diagnostic codes for BPD. RESULTS True positive and false negative BPD subjects did not differ significantly according to gestational age, birth weight and Apgar scores. False positive BPD subjects were found to have significantly lower gestational age than true negative subjects. The use of the ICD-9 diagnostic codes for BPD was associated with a specificity between 97.6% and 98.0%. The sensitivity was lower at 45.0% and 52.4% for the medical services and MED-ECHO databases, respectively. Milder cases of BPD tended to be missed more frequently than more severe cases. CONCLUSION The specificity of the use of ICD-9 diagnostic codes for BPD in the Quebec provincial health care databases is adequate to allow its routine use. Its lower sensitivity for milder cases will likely result in an underestimation of the impacts of BPD on the long-term health care utilization of preterm infants.
Collapse
Affiliation(s)
- J S Landry
- Respiratory Epidemiology and Clinical Research Unit, McGill University, Montréal, Quebec, Canada.
| | | | | |
Collapse
|
9
|
Abstract
Preterm birth affects 12.5% of all births in the USA. Infants of Black mothers are disproportionately affected, with 1.5 times the risk of preterm birth and 3.4 times the risk of preterm-related mortality. The preterm birth rate has increased by 33% in the last 25 years, almost entirely due to the rise in late preterm births (34-36 weeks' gestation). Recently attention has been given to uncovering the often subtle morbidity and mortality risks associated with moderate (32-33 weeks' gestation) and late preterm delivery, including respiratory, infectious, and neurocognitive complications and infant mortality. This section summarizes the epidemiology of moderate and late preterm birth, case definitions, risk factors, recent trends, and the emerging body of knowledge of morbidity and mortality associated with moderate and late preterm birth.
Collapse
Affiliation(s)
- Carrie K Shapiro-Mendoza
- Maternal and Infant Health Branch, Division of Reproductive Health, Centers for Disease Control and Prevention, Mailstop K-23, 4770 Buford Highway, NE, Atlanta, GA 30341-3717, USA.
| | | |
Collapse
|
10
|
Goldenberg RL, Gravett MG, Iams J, Papageorghiou AT, Waller SA, Kramer M, Culhane J, Barros F, Conde-Agudelo A, Bhutta ZA, Knight HE, Villar J. The preterm birth syndrome: issues to consider in creating a classification system. Am J Obstet Gynecol 2012; 206:113-8. [PMID: 22177186 DOI: 10.1016/j.ajog.2011.10.865] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 08/27/2011] [Accepted: 10/19/2011] [Indexed: 11/30/2022]
Abstract
A comprehensive classification system for preterm birth requires expanded gestational boundaries that recognize the early origins of preterm parturition and emphasize fetal maturity over fetal age. Exclusion of stillbirths, pregnancy terminations, and multifetal gestations prevents comprehensive consideration of the potential causes and presentations of preterm birth. Any step in parturition (cervical softening and ripening, decidual-membrane activation, and/or myometrial contractions) may initiate preterm parturition, and should be recorded for every preterm birth, as should the condition of the mother, fetus, newborn, and placenta, before a phenotype is assigned.
Collapse
Affiliation(s)
- Robert L Goldenberg
- Department of Obstetrics and Gynecology, Drexel University, Philadelphia, PA, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Parra-Saavedra M, Gómez L, Barrero A, Parra G, Vergara F, Navarro E. Prediction of preterm birth using the cervical consistency index. Ultrasound Obstet Gynecol 2011; 38:44-51. [PMID: 21465603 DOI: 10.1002/uog.9010] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVES To assess the diagnostic power of a new cervical consistency index (CCI) obtained using transvaginal sonography for the prediction of spontaneous preterm birth (PTB) and to establish reference ranges for this new variable. METHODS Included in this prospective cross-sectional study were 1115 singleton pregnancies at 5-36 weeks of gestation. Anteroposterior cervical diameter was measured before (AP) and after (AP') application of pressure on the cervix using the transvaginal probe. The index was calculated using the formula: CCI=((AP'/AP) × 100). Cervical length was also measured. The outcomes evaluated were spontaneous PTB before 32, 34 and 37 weeks. Logistic regression and analysis of receiver-operating characteristics (ROC) curves were performed to evaluate the diagnostic power of CCI and cervical length (adjusted for gestational age). Intraclass correlation coefficients (ICCs) and Bland-Altman analysis were used to evaluate intra- and interobserver variability. RESULTS In the 1031 women with follow-up, the rate of spontaneous PTB before 32 weeks was 0.87%, before 34 weeks was 2.13% and before 37 weeks was 7.76% (n=80). There were 31 (3.01%) iatrogenic PTBs before 37 weeks. An inverse linear correlation between gestational age and CCI was observed, with regression equation: CCI (in %)=89.8 - 1.35 × (GA in weeks); r(2)=0.66, P<0.001. Cervical length showed an inverse quadratic, though non-significant, relationship with gestational age: CL (in mm)=31.084 - 0.0278× (GA in weeks)(2) + 1.0772× (GA in weeks); r(2)=0.076, P<0.14. The intra- and interobserver ICCs for CCI were 0.99 (95% CI, 0.988-0.994) and 0.98 (95% CI, 0.973-0.987), respectively. The area under the ROC curve for CCI in the prediction of spontaneous PTB before 32 weeks was 0.947, for spontaneous PTB before 34 weeks it was 0.943 and for spontaneous PTB before 37 weeks it was 0.907. For a 5% screen-positive rate, CCI had a sensitivity of 67%, 64% and 45% for prediction of spontaneous PTB before 32, 34 and 37 weeks, respectively, with equivalent values of 11%, 9% and 11% for cervical length. CONCLUSIONS CCI shows a clear inverse linear relationship with GA. Assessment of CCI is reproducible and is effective in the prediction of spontaneous PTB. This new variable appears to provide better prediction of spontaneous PTB than does cervical length.
Collapse
Affiliation(s)
- M Parra-Saavedra
- Maternal-Fetal Unit, CEDIFETAL, Centro de Diagnóstico de Ultrasonido e Imágenes, CEDIUL, Barranquilla, Colombia.
| | | | | | | | | | | |
Collapse
|
12
|
Abstract
Preterm birth (<37 weeks) complicates 12.5% of all deliveries in the USA, and remains the leading cause of perinatal mortality and morbidity, accounting for as many as 75% of perinatal deaths. Despite the recent temporal increase in preterm birth, efforts to understand the problem of prematurity have met with little success. This may be attributable to the under-appreciation of the etiologic heterogeneity of preterm birth as well as the heterogeneity in its underlying clinical presentations--spontaneous onset of labor, preterm premature rupture of membranes, and medically indicated preterm birth. In this paper, we review data regarding preterm births with particular focus on its incidence, temporal trends, and recurrence. Studies of births from the USA indicate that the recent temporal increase in the overall preterm birth rate is driven by an impressive concomitant increase in medically indicated preterm birth. However, the largest temporal decline in perinatal mortality has also occurred among medically indicated preterm births (relative to other clinical subtypes), suggesting that these obstetric interventions at preterm gestational ages are associated with a reduction in perinatal mortality. Recent data indicate that spontaneous preterm birth is not only associated with increased recurrence of spontaneous, but also medically indicated, preterm birth, and vice versa. This suggests that the clinical subtypes may share common underlying etiologies. Since medically indicated preterm birth accounts for as many as 40% of all preterm births, efforts to understand the reasons for such interventions and their impact on short- and long-term morbidity in newborns is compelling. Further research is necessary in order to understand the mechanisms and etiology of preterm birth, thus leading to the possibility of effective preventive or therapeutic strategies.
Collapse
Affiliation(s)
- Cande V Ananth
- Division of Epidemiology and Biostatistics, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901-1977, USA.
| | | |
Collapse
|
13
|
Vahratian A, Buekens P, Alexander GR. State-specific trends in preterm delivery: are rates really declining among non-Hispanic African Americans across the United States? Matern Child Health J 2006; 10:27-32. [PMID: 16362234 DOI: 10.1007/s10995-005-0032-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES This study sought to examine state-specific trends in preterm delivery rates among non-Hispanic African Americans and to assess whether these rates are influenced by misclassification of gestational age. METHODS The sample population consisted of singleton non-Hispanic White and non-Hispanic African-American infants born in 1991 and 2001 to U.S. resident mothers. For both time periods, state-specific and national preterm delivery rates were calculated for all infants, stratified by infant race/ethnicity. Next, birth-weight distributions within strata of gestational age were studied to explore possible misclassifications of gestational age. Lastly, state-specific and national preterm delivery rates among infants who weighed less than 2,500 g were separately computed. RESULTS National analyses showed that the frequency of preterm delivery increased by 15.8% among non-Hispanic Whites but declined by 10.3% among non-Hispanic African Americans over the same period. For both subgroups, a bimodal distribution of birth weights was apparent among preterm births at 28-31 weeks of gestation. The second peak with its cluster of normal-weight infants was more prominent among non-Hispanic African Americans in 1991 than in 2001. After excluding preterm infants who weighed 2,500 g or more, the national trends persisted. State-specific analyses showed that preterm delivery rates increased for both subgroups in 13 states during this period. Of these 13, 6 states had a number of non-Hispanic African-American births classified as preterm that were apparently term births mistakenly assigned short gestational ages. Such misclassification was more frequent in 1991 than in 2001 and inflated 1991 rates. CONCLUSION There is heterogeneity in state-specific preterm delivery rates. Such differences are often overlooked when aggregate results are presented.
Collapse
Affiliation(s)
- Anjel Vahratian
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, USA.
| | | | | |
Collapse
|
14
|
Abstract
Determination of gestational age is important to assess risks for morbidity and mortality in neonates. Definitions for preterm, term and postterm have been precisely defined although definitions for subgroups of infants within these categories have not been well defined. More precise definitions for the subgroup of infants born "near-term" is especially important because of the rapid increase in percentage of births attributed to this subgroup. It is recommended that "late preterm" replace "near-term" because it better reflects the higher risk for complications of preterm birth experienced by this subgroup of preterm infants. Furthermore, it is proposed that "late preterm" be defined as beginning on the 239th day (34 0/7 weeks' gestation) and ending on the 259th day (36 6/7 weeks' gestation) since the first day of the mother's last normal menstrual period.
Collapse
Affiliation(s)
- William A Engle
- Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| |
Collapse
|
15
|
Abstract
The role of the obstetrician is to help predict and prevent maternal/fetal infection/inflammation related to neonatal mortality and morbidity. Predictive studies have mainly focused on the high-risk phenotype. Currently, there is a scientific drive to analyse the genetic susceptibility of preterm birth (PTB). Studies of the combination of environmental and lifestyle risk factors with the known genotype may result in a better understanding of the causation of PTB. Predictive technical markers such as fibronectin, cervical length measurement and home uterine activity remain largely unproven. Current antenatal care has not achieved primary prevention of PTB. Tocolytics and antibiotics constitute the two key elements of secondary prevention. Tocolytics have a minimal benefit but should not be used to prolong an infected preterm pregnancy. The use of antibiotics in preterm premature rupture of membranes can prolong the pregnancy with a decrease in neonatal morbidity. Anti-inflammatory cytokines, cytokine inhibitors and soluble cytokine receptors are promising treatment options that could modulate the intra-amniotic inflammatory process.
Collapse
Affiliation(s)
- H Logghe
- Academic Unit of Obstetrics and Gynaecology, Clarendon Wing D-Floor, Leeds General Infirmary, Leeds LS2 9NS, UK.
| | | |
Collapse
|