435 TRENDS IN BIRTH WEIGHT OVER TWENTY-FIVE YEARS AMONG WOMEN OFDIFFERING ETHNICITIES LINDA M. HOPKINS1, AARON B. CAUGHEY1,DAVID GLIDDEN2, RUSSELL K. LAROS JR1, 1University of California, SanFrancisco, Obstetrics, Gynecology and Reproductive Sciences, San Francisco,California, 2University of California, San Francisco, Epidemiology andBiostatistics, San Francisco, California

OBJECTIVE: To examine whether birth weights have increased among infantsof differing ethnicities.

STUDY DESIGN: Retrospective cohort study of all women who underwenta term (37-42 weeks) delivery of a live, nonanomalous singleton at a singleinstitution. Predictor variables were ethnicity and delivery year with the primaryoutcome variable birth weight. Multivariate regression analysis was used todetect trends in birth weight and risk of birth weight !2500 g, >4000 g, and>4500 g. Potential confounders controlled for included gender, nulliparity,gestational age, maternal age, induction, diabetes, preeclampsia, chronichypertension, tobacco use, socioeconomic status, pregnancy weight gain, andbody mass index.

RESULTS: 33,581 births met criteria. Linear regression analysis of yearlytrends in birth weight revealed a 5 g/year increase in African-American infants(P = .004) and 6.5 g/year increase in Filipino infants (P = .007) with a trend forincreasing weight (1.7 g/year) for Caucasians (P = .077). Logistic regressionanalysis for risk of birth weight !2500 g, >4000, and >4500 g by 5-yearincrements is depicted in the Table.

CONCLUSION: When potential confounders are controlled for, only African-American and Filipino women are noted to have significantly increasing birthweights over time. Also, only the latter are experiencing greater numbers of birthweights >4000 g. These results are novel and expand upon previous studiesemphasizing the importance of considering individual ethnicities and maternalfactors in this type of study.

Birth weight by categories (reference group Caucasian)

Ethnicity !2500 g O4000 g O4500 gOR (P value) OR (P value) OR (P value)

Study population .92 (.126) .95 (.030) .97 (.549)African-American .91 (.417) .99 (.948) 1.21 (.431)Chinese .58 (.010) .99 (.918) 1.28 (.388)Filipino .86 (.413) 1.40 (.012) 1.85 (.049)Latina .87 (.505) .95 (.471) .97 (.892)

SMFM Abstracts S125

433 RACIAL DISPARITY IN PERINATAL MORTALITY - RESULTS FROM THE FASTER TRIALANDREW HEALY1, FERGAL MALONE1, GINA PELOSO2, ROBERT BALL3, DAVID LUTHY4,CHRISTINE H. COMSTOCK5, RADEK BUKOWSKI6, RICHARD BERKOWITZ7, SUSAN GROSS8,LORRAINE DUGOFF9, SABRINA CRAIGO10, ILAN TIMOR11, STEPHEN CARR12,HONOR WOLFE13, MARY D’ALTON1, 1Columbia University, New York, New York,2DM-STAT, Boston, Massachusetts, 3University of Utah Health SciencesCenter, Salt Lake City, Utah, 4Swedish Medical Center, Seattle, Washington,5William Beaumont Hospital, Royal Oak, Michigan, 6UTMB, Galveston, Texas,7Mount Sinai Medical Center, New York, New York, 8Albert Einstein Collegeof Medicine, New York, New York, 9University of Colorado Health SciencesCenter, Denver, Colorado, 10Tufts University, Boston, Massachusetts, 11NewYork University, New York, New York, 12Brown University, Providence,Rhode Island, 13UNC, Chapel Hill, North Carolina

OBJECTIVE: Does access to prenatal care correct the disparity in perinatalmortality between white and minority populations in contemporary obstetricpractice?

STUDY DESIGN: A prospective database from a large multicenter investiga-tion of singleton pregnancies, the FASTER trial, was studied. This databasecontains detailed antenatal, birth and pediatric outcomes on a large unselectedobstetric population. Elective terminations were excluded from this analysis(n = 36,068). Inclusion in the trial necessitated early first trimester access toprenatal care. Multivariable logistic regression analysis was used to assess thepersistent effect of race on perinatal loss in the presence of prenatal care,adjusting for potential confounding factors.

RESULTS: Despite controlling for access to prenatal care, minority pregnan-cies experienced more perinatal mortality when compared to pregnancies in thewhite population. This disparity was most evident in the black population. Whenodds ratios were adjusted for demographic differences calculated valuesremained significant for the black race (OR 3.2 [1.7, 5.8]) and ‘‘others’’ (OR2.2 [1.1, 4.3]) (Table).

CONCLUSION: These findings strongly suggest improving access to prenatalcare alone is not sufficient to correct this disparity. Clinicians must strive toidentify the etiologies of this adverse outcome within minority populations sothat prenatal care systems can be directed toward eliminating racial disparities inperinatal mortality.

Estimation of loss by race (adjusted odds ratios, white population (n = 24,388)as referent population)

RaceBlack(n = 1836) P value

Hispanic(n = 8076) P value

Other(n = 1768)

Pvalue

Fetal loss!24 wk

2.0 (0.9, 4.4) .08 1.2 (0.6, 2.4) .6 1.9 (0.8, 4.5) .15

Fetal lossR24 wk

4.5 (1.7, 11.6) .002 1.2 (0.4, 3.5) .7 2.8 (0.8, 10.0) .11

Neonataldeath

5.0 (2.2, 11.7) .0002 1.0 (0.4, 2.3) .9 3.0 (1.0, 8.9) .04

Perinatalmortality

3.2 (1.7, 5.8) .0002 1.3 (0.8, 2.3) .3 2.2 (1.1, 4.3) .02

434 ARE THERE ETHNIC DIFFERENCES IN LENGTH OF LABOR? LINDA M. HOPKINS1,CHRISTINA WASSEL FYR2, MARA GREENBERG1, JEANETTE BROWN1, DAVID THOM3,STEPHEN K. VAN DEN EEDEN4, ARONA I. RAGINS2, AARON B. CAUGHEY1, 1Universityof California, San Francisco, Obstetrics, Gynecology and ReproductiveSciences, San Francisco, California, 2University of California, San Francisco,Epidemiology and Biostatistics, San Francisco, California, 3University ofCalifornia, San Francisco, Family and Community Medicine, San Francisco,California, 4Kaiser Permanente Division of Research, Oakland, California

OBJECTIVE: To determine predictors of labor length among a diversepopulation-based group of women.

STUDY DESIGN: Retrospective study of a population-based cohort ofethnically diverse women using information derived from detailed interviewsand chart abstracted labor and delivery records archived since 1946. Womenwith a singleton vertex presentation who completed at least the first stage oflabor were included in the study. Predictors of labor length included ethnicity(Caucasian, African-American, Latina, Asian, Native American), anesthesia,fetal position, oxytocin use, years since last delivery, type of delivery, birthweight, maternal weight, diabetes, education and income. Outcome variableswere length of first, second and total labor. Regression analysis was performedcontrolling for potential confounders with stratification by parity.

RESULTS: Among 1307 nulliparous births, African-American women hada significantly longer first stage of labor (+92 minutes, P = .013) as comparedto Caucasians. Occiput posterior or transverse positions were also associatedwith significantly longer first stage (+83 minutes, P = .036) compared toocciput anterior position. For the second stage of labor, significant variablesincluded maternal age (2.4% increase per year, P = .003) and birth weight(.02% change per gram, P ! .001). Among 2577 multiparous births, African-American women again had a significantly longer first stage of labor (+37minutes, P = .035). Length of second stage was significantly longer for occiputposterior or transverse position (36% increase, P ! .001), and regionalanesthesia (44% increase, P ! .001).

CONCLUSION: African-American ethnicity, occiput posterior and occiputtransverse position were associated with a longer length of first stage of labor.Birth weight, maternal age, regional anesthesia and occiput posterior ortransverse position were associated with an increased second stage of labor.Ethnic differences in length of labor were limited to differences in the first stageand only for African-American women.

436 INCREASED RISK OF ADVERSE PERINATAL OUTCOME AMONG SOMALI IMMIGRANTSIN WASHINGTON STATE BLAIR JOHNSON1, SUSAN REED2, JANE HITTI2,MANEESH BATRA3, 1University of Washington, Obstetrics and Gynecology,Seattle, Washington, 2University of Washington, Obstetrics and Gynecology,Epidemiology, Seattle, Washington, 3University of Washington, Pediatrics,Seattle, Washington

OBJECTIVE: To compare maternal and neonatal morbidity among Somaliimmigrants, US-born Blacks and US-born Whites in Washington state.Secondly, to address concerns of the Somali community that obstetricinterventions occur too quickly, frequently and unnecessarily in the UnitedStates.

STUDY DESIGN:Washington State birth certificate data was linked to hospitaldischarge records comparing singleton deliveries among Somali immigrants toUS-born Blacks and US-born Whites between 1993 and 2001 in a 1:4 ratio.Outcomes were compared using unconditional multiple logistic regressionmodels, calculating odds ratios and 95% confidence intervals.

RESULTS: 579 pregnancies from Somali women were compared with 2384and 2435 pregnancies from US-born Black and White women, respectively.Somali women were more likely to deliver after 42 weeks gestation (OR = 9.0*,OR= 9.0**) and during labor were more likely to have intrapartum oligohy-dramnios (OR = 3.7*, OR = 7.9**), meconium (OR = 2.6*, OR = 6.4**) andfetal distress (OR= 1.9*, OR = 3.1**), even after controlling for gestationalage. Nulliparous Somali women were more likely to have a cesarean delivery(OR = 1.6*, OR = 2.0**); and, cesarean delivery, among both nulliparous andmultiparous Somalis, was more commonly associated with fetal distress. Somaliwomen were at increased risk of perineal lacerations, febrile illness, andtransfusion. Their newborns were at increased risk for prolonged hospitalization(OR = 1.7*, OR= 2.3**), lower 5-minute Apgar scores (OR = 3.1*,OR= 5.2**), assisted ventilation (OR = 3.8*, OR = 11.1**), and meconiumaspiration (OR = 14.4*, OR= 27.7**).

*OR comparing Somali to US-born Blacks.**OR comparing Somali to US-born Whites.CONCLUSION: Pregnancy outcomes should be evaluated within ethnically and

culturally unique groups. Somali immigrants represent a high-risk subpopula-tion. In response to our research, several community-wide educational forumshave been organized to educate the Somali community about their uniqueperinatal risks and to address their specific obstetric concerns.