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Biomedical subjects

Russell S Kirby

Publications and source records attributed to Russell S Kirby.

At least 19 recordsLinked to original sources
PubMed2006

SGA subtypes and mortality risk among singleton births.

OBJECTIVES: To determine whether early mortality (first year of life) risks among small for gestational age (SGA) neonates were similar regardless of SGA subtype based on three chronological classifications (term, preterm and post-term). STUDY DESIGN: Retrospective cohort study on all singleton live births in the United States from 1995 to 1999 inclusive. Adjusted risk estimates were computed from logistic regression models using non-SGA infants as the referent. RESULTS: When SGA infants were compared as a homogeneous entity to non-SGA infants, the risks for infant, neonatal and post-neonatal mortality were significantly greater in SGA infants [AOR (adjusted odds ratio)=3.0, 95% CI (confidence interval)=2.9-3.0 for infant mortality; AOR=3.2, 95% CI=3.1-3.2 for neonatal mortality; and AOR=2.6, 95% CI=2.6-2.7 for post-neonatal mortality]. However, heterogeneity existed in terms of mortality risk thresholds across SGA babies. The most remarkable risk magnitude was observed among preterm SGA infants [infant mortality AOR=13.8, 95% CI=13.6-14.1; neonatal death AOR=17.4, 95% CI=17.0-17.7; and post-neonatal death AOR=7.4, 95% CI=7.1-7.6]. The adjusted odds ratio for term and post-term SGA infants were comparable regardless of the period during infancy, and were much less than those observed for preterm SGA infants. CONCLUSIONS: SGA is a heterogeneous disease in terms of prognosis for survival. Preterm SGA infants bear an extremely high risk for mortality during infancy, and counseling of affected parents should reflect this risk divergence.

Cohort Studies↗
PubMed2006

Fetal growth risk curves: defining levels of fetal growth restriction by neonatal death risk.

OBJECTIVE: We developed a fetal growth risk curve that delineates the birth weight values for gestational age that reflect a 2-, 2.5-, and 3-fold neonatal death risk relative to infants with normal fetal growth. STUDY DESIGN: We analyzed 18,085,052 single gestation infants (25-42 weeks) who were born to US resident mothers from 1996 to 2000. Multivariate models were used to predict the relationship between neonatal death and birth weight percentile. Fetal risk curves were derived on the basis of birth weight percentile-specific neonatal mortality rates that were relative to an average rate of neonatal death for a comparison group that was representative of typical growth (ie, infants between 45th-55th birth weight percentiles for gestational age). RESULTS: The 10th percentile of birth weight for gestational age is associated with an increased but variable risk of neonatal death relative to the comparison group across the spectrum of gestational ages. At 26 weeks of gestation, infants at the 10th percentile experienced a 3-fold risk of dying within the first 28 days of life (relative to the comparison group); whereas at 40 weeks, the risk was 1.13. CONCLUSION: Fetal growth risk curves facilitate the identification of populations of infants whose risk of death are deemed excessive compared with that of infants at the norm of fetal growth and may be useful for counseling pregnant women.

Birth Weight↗
PubMed2006

National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999-2001.

BACKGROUND: In the United States, birth defects affect approximately 3% of all births, are a leading cause of infant mortality, and contribute substantially to childhood morbidity. METHODS: Population-based data from the National Birth Defects Prevention Network were combined to estimate the prevalence of 21 selected defects for 1999-2001, stratified by surveillance system type. National prevalence was estimated for each defect by pooling data from 11 states with active case-finding, and adjusting for the racial/ethnic distribution of US live births. We also assessed racial/ethnic variation of the selected birth defects. RESULTS: National birth defect prevalence estimates ranged from 0.82 per 10,000 live births for truncus arteriosus to 13.65 per 10,000 live births for Down syndrome. Compared with infants of non-Hispanic (NH) white mothers, infants of NH black mothers had a significantly higher birth prevalence of tetralogy of Fallot, lower limb reduction defects, and trisomy 18, and a significantly lower birth prevalence of cleft palate, cleft lip with or without cleft palate, esophageal atresia/tracheoesophageal fistula, gastroschisis, and Down syndrome. Infants of Hispanic mothers, compared with infants of NH white mothers, had a significantly higher birth prevalence of anencephalus, spina bifida, encephalocele, gastroschisis, and Down syndrome, and a significantly lower birth prevalence of tetralogy of Fallot, hypoplastic left heart syndrome, cleft palate without cleft lip, and esophageal atresia/tracheoesophageal fistula. CONCLUSIONS: This study can be used to evaluate individual state surveillance data, and to help plan for public health care and educational needs. It also provides valuable data on racial/ethnic patterns of selected major birth defects.

Black or African American↗
PubMed2006

Role of geographic information systems in birth defects surveillance and research.

BACKGROUND: With the significant advancement of geographic information systems (GIS), mapping and evaluating the spatial distribution of health events has become easier. We examine the role of GIS in birth defects surveillance and research. METHODS: We briefly describe the geocoding process and potential problems in accuracy of the obtained geocodes, and some of the capabilities and limitations of GIS. We illustrate how GIS has been applied using the Metropolitan Atlanta Congenital Defects Program geocoded dataset. We provide some comments on potential data quality and confidentiality issues with birth defects in relation to GIS. RESULTS: It is desirable to geocode addresses using a multistrategy approach to achieve a high-quality and accurate GIS dataset. Beyond the basic but important function of mapping, sophisticated statistical approaches and software are available to analyze the spatial or spatial-temporal occurrence of birth defects, alone or in association with environmental hazards, and to present this information without compromising the confidentiality of the subjects. CONCLUSIONS: We recommend a broad and systematic use of GIS in birth defects spatial surveillance and research.

Congenital Abnormalities↗
PubMed2006

Childhood pregnancy (10-14 years old) and risk of stillbirth in singletons and twins.

OBJECTIVE: To clarify the association between childhood pregnancy and risk of stillbirth. STUDY DESIGN: We analyzed singleton and twin pregnancies that occurred in children (10-14 years old) in the United States from 1989 to 2000. We estimated the absolute and relative risks of stillbirth by using 15- to19-year-old and 20- to 24-year-old mothers as comparison groups. RESULTS: The analysis involved 17.8 million singletons and 337,904 individual twins. The rate of stillbirth was highest in pediatric mothers for both singletons (12.8/1000) and twins (56/1000) compared with adolescent (6.8/1000 in singletons and 29/1000 in twins) and mature (5.5/1000 in singletons and 20/1000 in twins) mothers. After adjusting for confounding characteristics, pediatric mothers continued to exhibit significantly elevated risk for stillbirth in both singletons (odds ratio, 1.57; 95%CI, 1.49-1.66) and twins (odds ratio, 1.97; 95%CI, 1.42-2.73). Preterm birth rather than small size for gestational age was revealed by means of sequential modeling to account for the excess risk of stillbirth observed in pediatric gravidas. CONCLUSION: Pregnancy in childhood is a risk factor for stillbirth; shortened gestation rather than reduction in fetal growth is the mediating pathway.

Adolescent↗
PubMed2006

Risk of stillbirth following a cesarean delivery: black-white disparity.

OBJECTIVE: We examine the association between prior cesarean delivery and risk of stillbirth in a subsequent pregnancy. METHODS: The Missouri maternally linked cohort data set containing births from 1978 through 1997 was used. We identified a cohort of women who delivered live births by cesarean delivery and a comparison cohort of women who delivered live births vaginally in their first pregnancies. We then compared the risks of stillbirth in the second pregnancy between the 2 groups. RESULTS: We analyzed 396,441 women with information on first and second pregnancies, comprising 71,950 (18.1%) in the cesarean arm, and 324,491 (81.9%) in the vaginal birth arm. Rates of stillbirth among women with and those without history of cesarean delivery were 4.4 and 4.1 per 1,000 births, respectively (P = .2). The adjusted estimates also showed no difference in risk for stillbirth between the 2 groups (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.0-1.3). Among whites, the stillbirth rates in women with and those without history of cesarean delivery were 3.7 and 3.6 per 1,000 births, respectively (OR 1.0, 95% CI 0.9-1.2). Among blacks, both the absolute and the adjusted relative risks for stillbirth were elevated in mothers with history of cesarean delivery (stillbirth rate 9.3 versus 6.8 per 1,000 births; OR 1.4, 95% CI 1.1-1.7). CONCLUSION: Overall, our analysis did not detect an association between cesarean history and subsequent stillbirth. However, cesarean delivery may increase the risk for subsequent stillbirth among black mothers, a group with the highest cesarean delivery rate in the country. LEVEL OF EVIDENCE: III.

Adult↗
PubMed2006

Is race a determinant of stillbirth recurrence?

BACKGROUND: A history of stillbirth may result in an increased risk for recurrence, although information regarding this remains scanty. It is also uncertain whether race is a determinant of stillbirth recurrence given that the risk of stillbirth varies across racial and ethnic populations. METHODS: The Missouri maternally linked cohort data set containing births from 1978 through 1997 was used. We identified the study group (women who experienced a stillbirth in the first pregnancy) and a comparison group (women who delivered a live birth in their first pregnancy) and compared the outcome (stillbirth) in the second pregnancy between the 2 groups. RESULTS: We analyzed 404,180 women with information on first and second pregnancies (1,979 [0.5%] in the study arm, and 402,201 [99.5%] in the comparison arm). Of the 1,929 cases of stillbirths in the second pregnancy, 45 cases occurred in mothers with a history of stillbirth (stillbirth rate = 22.7/1000) and 1,884 in the comparison group (stillbirth rate 4.7/1,000, P < .001). The adjusted risk of stillbirth was almost 5-fold as high in women with a prior stillbirth (odds ratio 4.7, 95% confidence interval 3.3-6.6). Analysis across racial groups revealed that whites had lower absolute risk for stillbirth recurrence than African Americans (19.1/1,000 compared with 35.9/1,000, P < .05). The elevated stillbirth recurrence risk was confirmed after adjusting for potential confounders (odds ratio 2.6, 95% confidence interval 1.2-5.7). CONCLUSION: History of stillbirth is associated with a 5-fold increase for subsequent stillbirth. The recurrence of stillbirth is almost tripled in African Americans as compared with whites. LEVEL OF EVIDENCE: II-2.

Adult↗
PubMed2006

Is small for gestational age a marker of future fetal survival in utero?

OBJECTIVE: We sought to assess whether small for gestational age is a risk factor for stillbirth of a subsequent sibling. METHODS: The Missouri maternally linked cohort data set, containing data on births from 1978 through 1997, was used. We identified the study group (women who delivered a SGA infant in the first pregnancy) and a comparison group (women who delivered a non-SGA infant in their first pregnancy) and compared the outcome (stillbirth) in the second pregnancy between both groups. RESULTS: We analyzed information on the first and second pregnancies of 402,015 women (43,549 [10.8%] in the study arm and 358,466 [89.2%] in the comparison arm). Of the 1,883 cases of stillbirth in the second pregnancy, 314 cases occurred in mothers with a history of SGA (stillbirth rate 7.2/1,000) and 1,569 in the comparison group (stillbirth rate 4.4/1,000), P < .001. The adjusted risk of stillbirth was 60% higher in women with a prior SGA (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.4-1.8). The risk for stillbirth in the second pregnancy increased with decreasing gestational age at birth of the SGA infant in the first pregnancy (term: OR 1.4, 95% CI 1.2-1.6; preterm: OR 2.8, 95% CI 2.0-3.8; and very preterm: OR 4.2, 95% CI 2.4-7.3), P for trend < .001. CONCLUSION: Small for gestational age is a marker for subsequent stillbirth, and the risk rises with decreasing gestational age of the SGA birth. This information is potentially useful for counseling parents of SGA infants. LEVEL OF EVIDENCE: II-2.

Adult↗
PubMed2006

Back to the future? A critical commentary on the 2003 U.S. National standard certificate of live birth.

Vital statistics documents for the United States have been revised approximately decennially throughout the past century. In this commentary we review the contents of the 2003 revision of the national standard certificate of live birth, focusing on changes from the certificates in use nationally since 1989, and identifying strengths and weaknesses of key data elements. Additional federal-state partnership funding is imperative to support the transition to the new standard certificates, and to ensure a focus on data quality at the state and national levels.

Adult↗
PubMed2006

Survival of infants with neural tube defects in the presence of folic acid fortification.

OBJECTIVE: Neural tube defects (NTDs) are preventable through preconceptional and periconceptional folic acid intake. Although decreases in the prevalence of NTDs have been reported since folic acid fortification of United States grain products began, it is not known whether folic acid plays a role in reducing the severity of occurring NTDs. Our aim was to determine whether survival among infants born with spina bifida and encephalocele has improved since folic acid fortification and to measure the effects of selected maternal, pregnancy, and birth characteristics on first-year (infant) survival rates. METHODS: A retrospective cohort study was conducted and included 2841 infants with spina bifida and 638 infants with encephalocele who were born between 1995 and 2001 and were registered in any of 16 participating birth defects monitoring programs in the United States. First-year survival rates for both spina bifida and encephalocele cohorts were measured with Kaplan-Meier estimation; factors associated with improved chances of first-year survival, including birth before or during folic acid fortification, were measured with Cox proportional-hazards regression analysis. RESULTS: Infants with spina bifida experienced a significantly improved first-year survival rate of 92.1% (adjusted hazard ratio: 0.68; 95% confidence interval: 0.50-0.91) during the period of mandatory folic acid fortification, compared with a 90.3% survival rate for those born before fortification. Infants with encephalocele had a statistically nonsignificant increase in survival rates, ie, 79.1% (adjusted hazard ratio: 0.76; 95% confidence interval: 0.51-1.13) with folic acid fortification, compared with 75.7% for earlier births. CONCLUSIONS: Folic acid may play a role in reducing the severity of NTDs in addition to preventing the occurrence of NTDs. This phenomenon contributes to our understanding of the efficacy of folic acid. Additionally, as survival of NTD-affected infants improves, health care, education, and family support must expand to meet their needs.

Dietary Supplements↗
PubMed2005

Parity effect on preterm birth and growth outcomes among infants with isolated omphalocele.

OBJECTIVE: To assess the association between parity and fetal morbidity outcomes among omphalocele-affected fetuses. STUDY DESIGN: We carried out a retrospective study of 498 cases of isolated omphalocele (210 born to nulliparous and 288 to multiparous mothers) in New York State from 1983 through 1999. Infants of nulliparous mothers were compared to those of multiparous gravidas using adjusted odds ratios generated from a logistic regression. RESULTS: Omphalocele-affected fetuses of nulliparous mothers had a lower risk of being delivered preterm (odds ratio (OR)=0.49; 95% CI=0.27-0.90) but comparable risks for low birth weight (OR=1.01; 95% CI=0.60-1.72), very low birth weight (OR=0.33; 95% CI=0.09-1.20), very preterm birth (OR=0.42; 95% CI=0.15-1.16), and small size for gestational age (SGA) [OR=0.61; 95% CI=0.23-1.63]. CONCLUSION: Omphalocele-affected fetuses of multiparous mothers have double the risk for preterm birth compared to their nulliparous counterparts. This information is potentially useful in counseling parents whose fetuses have omphaloceles.

Adult↗
PubMed2005

Omphalocele, advanced maternal age, and fetal morbidity outcomes.

In this study we wanted to determine if the risk for adverse neonatal outcome among omphalocele-affected fetuses is increased among older gravidas. This was a retrospective cohort study on live-born infants with omphalocele delivered in New York State from 1983 through 1999. We compared infants of older (>or=35 years) with those of younger (<35 years) mothers with respect to the following fetal morbidity indices: low birth weight and very low birth weight, preterm and very preterm, and small for gestational age. We used adjusted odds ratios to approximate relative risks. Data on a total of 1,010 infants with omphalocele were analyzed. Mean gestational age and birth weight were similar in both maternal age categories: mean+/-standard deviation (SD) for infants with omphalocele born to older mothers=37.4 weeks+/-3.9 versus 38.0 weeks+/-5.1 for those of younger mothers (P=0.2); mean birth weights+/-SD for infants with omphalocele born to older mothers=2,813+/-871.1 versus 2,958+/-809.9 for those of younger mothers (P=0.08). Also, the two maternal age sub-groups did not differ with respect to the fetal morbidity outcome: low birth weight (OR=0.95; 95% CI=0.60-1.51), very low birth weight (OR=0.78; 95% CI=0.36-1.69), preterm (OR=0.95; 95% CI=0.58-1.57), very preterm (OR=0.73; 95% CI=0.34-1.58), and SGA (OR=1.00; 95% CI=0.44-2.27). Thus, advanced maternal age does not appear to be a risk factor for fetal morbidity outcomes among omphalocele-affected fetuses. This information is potentially useful in counseling affected parents.

Adult↗
PubMed2005

Gastroschisis, low maternal age, and fetal morbidity outcomes.

OBJECTIVE: To determine if the risk for fetal growth inhibition among gastroschisis-afflicted fetuses is heightened among younger gravidas (teen mothers). METHOD: This was a retrospective cohort study on live-born infants with isolated gastroschisis delivered in New York State from 1983 through 1999. We compared infants of mature (>20 years) mothers with those of younger (<20 years) mothers with respect to the following indices of fetal morbidity outcomes: low birth weight and very low birth weight, preterm and very pre-term, and small for gestational age. We used adjusted odds ratios to approximate relative risks. RESULTS: A total of 368 infants with isolated gastroschisis were analyzed. The two groups differed in terms of mean gestational age at delivery [Mean + standard deviation(SD) for infants with gastroschisis born to mature mothers = 37.2 weeks +/- 2.8 versus 36.3 weeks + 3.6 for those of teenage mothers(p = 0.01)], as well as mean birth weight [mean birth weight +/- SD for infants with gastroschisis born to mature mothers = 2562.4 grams +548.8 versus 2367.9 grams +/- 645.2 for those of younger mothers (p = 0.004)]. Infants of teen mothers were about twice as likely to be of low birth weight (OR = 1.70; 95% CI = 1.05-2.77) and about three times as likely to be born very preterm when compared to those of mature mothers (OR = 2.80; 95% Cl = 1.02-8.00). No significant differences were observed with respect to very low birth weight, pre-term and small for gestational age. CONCLUSION: Low maternal age appears to be a risk factor for low birth weight and very preterm birth among gastroschisis-affected fetuses. This information is potentially useful for planning by care providers and in counseling affected parents.

Adolescent↗
PubMed2005

Changes in the birth prevalence of selected birth defects after grain fortification with folic acid in the United States: findings from a multi-state population-based study.

BACKGROUND: Observational studies and clinical trials have suggested that periconceptional use of folic acid can reduce the risk of birth defects other than neural tube defects (NTDs). Using data reported by states to the National Birth Defects Prevention Network, we examined whether folic acid fortification might have decreased the prevalence of other specific birth defects. METHODS: For each of 16 birth defect categories selected for study, birth prevalence for two time periods was calculated with data submitted from a number of states in 1995-1996 ("pre-fortification") and 1999-2000 ("post-fortification"). Changes in birth prevalence between the two time periods were assessed by calculating prevalence ratios and 95% confidence intervals for each defect, and compared by maternal race/ethnicity and availability of prenatally diagnosed cases. RESULTS: We confirmed previously reported reductions in the birth prevalence of NTDs. In addition, we found modest, yet statistically significant, decreases in the birth prevalence for transposition of the great arteries(12%), cleft palate only (12%), pyloric stenosis (5%), upper limb reduction defects (11%), and omphalocele (21%). More substantial subgroup decreases were observed for renal agenesis among programs that conduct prenatal surveillance (28%), for common truncus among Hispanics (45%), and for upper limb reduction defects among Hispanics (44%). There were modest yet significant increases in the prevalence of obstructive genitourinary defects (12%) and Down syndrome (7%), but not among programs conducting prenatal surveillance for these defects. CONCLUSIONS: These results suggest some modest benefit from the folic acid fortification on the prevalence of a number of non-NTD birth defects.

Congenital Abnormalities↗