Data linkage methods used in maternally-linked birth and infant death surveillance data sets from the United States (Georgia, Missouri, Utah and Washington State), Israel, Norway, Scotland and Western Australia

A Framework for Neonatal Prematurity Information System Development Based on a Systematic Review on Current Registries: An Original Research

Background

Registries are regarded as a just valuable fount of data on determining neonates suffering prematurity or low birth weight (LBW), ameliorating provided care, and developing studies.

Objective

This study aimed to probe the studies, including premature infants' registries, adapt the needed minimum data set, and provide an offered framework for premature infants' registries.

Material and Methods

For this descriptive study, electronic databases including PubMed, Scopus, Web of Science, ProQuest, and Embase/Medline were searched. In addition, a review of gray literature was undertaken to identify relevant studies in English on current registries and databases. Screening of titles, abstracts, and full texts was conducted independently based on PRISMA guidelines. The basic registry information, scope, registry type, data source, the purpose of the registry, and important variables were extracted and analyzed.

Results

Fifty-six papers were qualified and contained in the process that presented 51 systems and databases linked in prematurity at the popular and government levels in 34 countries from 1963 to 2017. As a central model of the information management system and knowledge management, a prematurity registry framework was offered based on data, information, and knowledge structure.

Conclusion

To the best of our knowledge, this is a comprehensive study that has systematically reviewed prematurity-related registries. Since there are international standards to develop new registries, the proposed framework in this article can be beneficial too. This framework is essential not only to facilitate the prematurity registry design but also to help the collection of high-value clinical data necessary for the acquisition of better clinical knowledge.

National data linkage assessment of live births and deaths in Mexico: Estimating under-five mortality rate ratios for vulnerable newborns and trends from 2008 to 2019

BACKGROUND

Linked datasets that enable longitudinal assessments are scarce in low and middle-income countries.

OBJECTIVES

We aimed to assess the linkage of administrative databases of live births and under-five child deaths to explore mortality and trends for preterm, small (SGA) and large for gestational age (LGA) in Mexico.

METHODS

We linked individual-level datasets collected by National statistics from 2008 to 2019. Linkage was performed based on agreement on birthday, sex, residential address. We used the Centre for Data and Knowledge Integration for Health software to identify the best candidate pairs based on similarity. Accuracy was assessed by calculating the area under the receiver operating characteristic curve. We evaluated completeness by comparing the number of linked records with reported deaths. We described the percentage of linked records by baseline characteristics to identify potential bias. Using the linked dataset, we calculated mortality rate ratios (RR) in neonatal, infants, and children under-five according to gestational age, birthweight, and size.

RESULTS

For the period 2008-2019, a total of 24,955,172 live births and 321,165 under-five deaths were available for linkage. We excluded 1,539,046 records (6.2%) with missing or implausible values. We succesfully linked 231,765 deaths (72.2%: range 57.1% in 2009 and 84.3% in 2011). The rate of neonatal mortality was higher for preterm compared with term (RR 3.83, 95% confidence interval, CI 3.78, 3.88) and for SGA compared with appropriate for gestational age (AGA) (RR 1.22 95% CI, 1.19, 1.24). Births at <28 weeks had the highest mortality (RR 35.92, 95%CI, 34.97, 36.88). LGA had no additional risk vs AGA among children under five (RR 0.92, 95%CI, 0.90, 0.93).

CONCLUSIONS

We demonstrated the utility of linked data to understand neonatal vulnerability and child mortality. We created a linked dataset that would be a valuable resource for future population-based research.

The Association of Race, Ethnicity, and Poverty With Child Maltreatment Reporting

OBJECTIVES

To determine the role of race/ethnicity and poverty in the likelihood of children younger than age 3 years hospitalized because of child abuse and neglect-related injuries being reported to child protective services (CPS) and being assigned a specific maltreatment diagnostic code.

METHODS

We used population-based linked administrative data comprising of birth, hospitalization, and CPS records. Children were identified for maltreatment-related hospitalizations using standardized diagnostic codes. Regression models were used to compute crude and adjusted race/ethnicity estimates regarding the likelihood of being reported to CPS and assigned a specific maltreatment diagnostic code during the maltreatment-related hospitalization.

RESULTS

Of the 3907 children hospitalized because of child maltreatment, those with public health insurance were more likely than those with private insurance (relative risk [RR]: 1.29; 95% confidence interval [CI], 1.16-1.42) and those with Asian/Pacific Islander mothers were less likely than those with White mothers to be reported to CPS (RR: 0.78; 95% CI, 0.65-0.93). No differences were found for children with Black, Hispanic, and Native American mothers compared with those with White mothers for CPS reporting. However, children with Native American mothers (RR: 1.45; 95% CI, 1.11-1.90) and public health insurance (RR: 2.00; 95% CI, 1.63-2.45) were more likely to have a specific maltreatment diagnostic code, the second strongest predictor of a CPS report.

CONCLUSIONS

Race/ethnicity and poverty were factors for CPS reports during a child maltreatment-related hospitalization. It is necessary to implement programs and policies that mitigate implicit bias to prevent inequities in which children receive protective intervention.

Reports and Removals of Child Maltreatment-Related Hospitalizations: A Population-Based Study

Despite U.S. child protective services (CPS) agencies relying on mandated reporters to refer concerns of child maltreatment to them, there is little data regarding which children mandated reporters decide to report and not to report. This study addresses this gap by utilizing a population-based linked administrative dataset to identify which children who are hospitalized for maltreatment-related reasons are reported to CPS and which are removed by CPS. The dataset was comprised of all children born in Washington State between 1999 and 2013 (N = 1,271,416), all hospitalizations for children under the age of three, and all CPS records. We identified maltreatment-related hospitalizations using standardized diagnostic codes. We examined the records for children with maltreatment-related hospitalizations to identify hospitalization-related CPS reports and if the child was removed from their parents. We tested for differences in these system responses using multinomial regression. About two-thirds of children identified as experiencing a child maltreatment-related hospitalization were not reported to CPS. We found differences in responses by maltreatment subtype and the type of diagnostic code. Children whose hospitalizations were related to abuse and associated with a specific maltreatment code had increased odds of being both reported to CPS and subsequently removed by CPS.

Pregnancy Outcomes after Preeclampsia: The Effects of Interpregnancy Weight Change

OBJECTIVE

This study aimed to examine the effects of interpregnancy weight change on pregnancy outcomes, including recurrent preeclampsia, preterm birth, small-for-gestational age (SGA), large-for-gestational age (LGA), and cesarean delivery, among women with a history of preeclampsia. We also evaluated whether these associations were modified by prepregnancy body mass index (BMI) category in the first pregnancy (BMI < 25 vs. ≥25 kg/m²) and if associations were present among women who maintained a healthy BMI category in both pregnancies.

STUDY DESIGN

We conducted a population-based retrospective cohort study including 15,108 women who delivered their first two nonanomalous singleton live births in Missouri (1989-2005) and experienced preeclampsia in the first pregnancy. We performed Poisson regression with robust error variance to estimate relative risks and 95% confidence intervals for outcomes of interest after controlling for potential confounders.

RESULTS

Interpregnancy weight gain was associated with increased risk of recurrent preeclampsia, LGA, and cesarean delivery. These risks increased in a "dose-response" manner with increasing magnitude of interpregnancy weight gain and were generally more pronounced among women who were underweight or normal weight in the first pregnancy. Interpregnancy weight loss exceeding 1 BMI unit was associated with increased risk of SGA among underweight and normal weight women, while interpregnancy weight loss exceeding 2 BMI units was associated with reduced risk of recurrent preeclampsia among overweight and obese women.

CONCLUSION

Even small changes in interpregnancy weight may significantly affect pregnancy outcomes among formerly preeclamptic women. Appropriate weight management between pregnancies has the potential to attenuate such risks.

KEY POINTS

· Interpregnancy weight change among formerly preeclamptic women significantly affects pregnancy outcomes.. · Interpregnancy weight gain is associated with increased risk of recurrent preeclampsia, large-for-gestational-age and cesarean delivery.. · Interpregnancy weight loss is associated with increased risk of small-for-gestational age and recurrent preeclampsia..

Prevalence of Births and Interactions with Child Protective Services of Children Born to Mothers Diagnosed with an Intellectual and/or Developmental Disability

OBJECTIVES

Concerns have been raised that parents with intellectual and/or developmental disabilities (IDD) interact with child protective services (CPS) at disproportionate rates than the general population as a result of bias and discrimination. However, there has been little empirical evidence to ascertain if these concerns are grounded. This study's objectives were to identify (a) the prevalence and sociodemographic characteristics of children born to mothers diagnosed with IDD diagnoses, (b) how many of these children interact with CPS (reports and removals) and (c) when these CPS interactions are occurring.

METHODS

The dataset was comprised of linked administrative birth, hospital discharge, and CPS records for all children born in one U.S. state between 1999 and 2013 (N = 1,271,419). CPS records were available through the first quarter of 2018 and CPS reports and removals at the child's first and fourth birthdays were identified. We conducted chi-square tests and multivariate survival Cox regression models.

RESULTS

A total of 567 children were identified as born to mothers with IDD diagnoses, which is 4.5 per 10,000 births. Of these children, 21.7% were the subject of a CPS report within 1 year and 35.8% within 4 years. In terms of removals, 6.5% experienced removals by 1 year and 8.6% by 4 years.

CONCLUSIONS FOR PRACTICE

This study provides population-based knowledge about how and when the children born to mothers diagnosed with IDD interact with CPS. These children have higher rates of CPS interactions than the general population, but these rates are not as high as previously reported.

Smallness at Birth and Neonatal Death: Reexamining the Current Indicator Using Sibling Data

OBJECTIVE

The similarity in size among siblings has implications for neonatal death, but research in this area is lacking in the United States. We examined the association between small-for-gestational age (SGA), defined as a birthweight <10th percentile for gestational age, and neonatal death, defined as death within the first 28 days of life, among second births who had an elder sibling with SGA ("repeaters") versus those whose elder sibling did not have SGA ("nonrepeaters").

STUDY DESIGN

We conducted a population-based retrospective cohort study including 179,436 women who had their first two nonanomalous singleton live births in Missouri (1989-2005). Logistic regression was used to evaluate the association between SGA and neonatal death among second births, stratified by whether the elder sibling was SGA.

RESULTS

Out of 179,436 second births, 297 died in the neonatal period. There was a significant interaction between birthweight-for-gestational age of first and second births in relation to neonatal death (p = 0.001). Second births with SGA had increased odds of neonatal death by 2.15-fold if they were "repeaters," and 4.44-fold if they were "nonrepeaters," as compared with non-SGA second births.

CONCLUSION

Our findings suggest that referencing sibling birthweight may be warranted when evaluating infant size in relation to neonatal death.

The Incidence of Child Maltreatment Resulting in Hospitalizations for Children Under Age 3 Years

OBJECTIVE

To assess the incidence of child maltreatment-related hospitalizations for children under 3 years for the population of Washington State.

STUDY DESIGN

A population-based study using retrospective linked administrative data for all children born in Washington State from 2000 through 2013 (n = 1 191 802). The dataset was composed of linked birth and hospitalization records for the entire state. Child maltreatment-related hospitalizations were identified using diagnostic codes, both specifically attributed to and suggestive of maltreatment. Incidence were calculated for the population, by birth year, by sex, and by maltreatment subtype.

RESULTS

A total of 3885 hospitalizations related to child maltreatment were identified for an incidence of 10.87 per 10 000 person-years. Hospitalizations related to child maltreatment accounted for 2.1% of all hospitalizations for children under the age of 3 years. This percentage doubled over time, reaching a high in 2012 (3.6%). More than one-half of all hospitalizations were related to neglect. Maltreatment-related hospitalizations occurred most frequently in the first year of life for all subtypes except for neglect, which occurred the most between 1 and 2 years of age. Male children had higher incidence than female children in general (11.97 vs 9.70 per 10 000 person-years) and across all subtypes.

CONCLUSIONS

Hospitalizations can be a useful source of population-based child maltreatment surveillance. The identification of neglect-related hospitalizations, likely the result of supervisory neglect, because the most common subtype is an important finding for the development of prevention programming.

Birthweight and all-cause mortality after childhood and adolescent leukemia: a cohort of children with leukemia from Denmark, Norway, Sweden, and Washington State

Background: High birthweight may predispose children to acute lymphoid leukemia, whereas low birthweight is associated with childhood morbidity and mortality. Low and high birthweight have been inconsistently associated with mortality in children with leukemia.Material and methods: In a cohort of childhood and adolescent leukemia (0-19 years) patients from registries in Denmark, Norway, Sweden, and Washington State in the United States (1967-2015), five-year all-cause mortality was assessed by birthweight and other measures of fetal growth using the cumulative incidence function and Cox regression with adjustment for sex, diagnosis year, country, the presence of Down's syndrome or other malformations, and type of leukemia.Results: Among 7148 children and adolescents with leukemia (55% male), 4.6% were low (<2500 g) and 19% were high (≥4000 g) birthweight. Compared with average weight, hazard ratios (HRs) of death associated with low birthweight varied by age at leukemia diagnosis: 1.5 (95% confidence interval (CI): 0.7, 3.2) for patients 0-1 year old, 1.6 (95% CI: 1.0, 2.6) for >1-2 years old; 1.0 (95% CI: 0.6, 1.5) for 3-8 years old; 1.0 (95% CI: 0.6, 1.8) for 9-13 years old; and 1.2 (95% CI: 0.7, 2.1) for 14-19 years old, and were similar for size for gestational age and Ponderal index. In analyses restricted to children born full term (37-41 weeks of gestation), results were only slightly attenuated but risk was markedly increased for infants aged ≤1 year (HR for low birthweight = 3.2, 95% CI: 1.2, 8.8).Conclusion: This cohort study does not suggest that low birthweight or SGA is associated with increased five-year all-cause mortality risk among children with any type of childhood leukemia or acute lymphoblastic leukemia, specifically, beyond infancy.

Advances in Epidemiological Methods and Utilisation of Large Databases: A Methodological Review of Observational Studies on Central Nervous System Drug Use in Pregnancy and Central Nervous System Outcomes in Children

INTRODUCTION

Studies have used various epidemiological approaches to study associations between central nervous system (CNS) drug use in pregnancy and CNS outcomes in children. Studies have generally focused on clinical adverse effects, whereas variations in methodologies have not received sufficient attention.

OBJECTIVE

Our objective was to review the methodological characteristics of existing studies to identify any limitations and recommend further research.

METHODS

A systematic literature search was conducted on observational studies listed in PubMed from 1 January 1946 to 21 September 2017. Following independent screening and data extraction, we conducted a review addressing the trends of relevant studies, differences between various data sources, and methods used to address bias and confounders; we also conducted statistical analyses.

RESULTS

In total, 111 observational studies, 25 case-control studies, and 86 cohort studies were included in the review. Publications dating from 1978 to 2006 mainly focused on antiepileptic drugs, but research on antidepressants increased from 2007 onwards. Only one study focused on antipsychotic use during pregnancy. A total of 46 studies obtained data from an administrative database/registry, 20 from ad hoc disease registries, and 41 from ad hoc clinical samples. Most studies (58%) adjusted the confounding factors using general adjustment, whereas only a few studies used advanced methods such as sibling-matched models and propensity score methods; 42 articles used univariate analyses and 69 conducted multivariable regression analyses.

CONCLUSION

Multiple factors, including different study designs and data sources, have led to inconsistent findings in associations between CNS drug use in pregnancy and CNS outcomes in children. Researchers should allow for study designs with clearly defined exposure periods, at the very least in trimesters, and use advanced confounding adjustment methodology to increase the accuracy of the findings.

Comparison of Parametric and Nonparametric Estimators for the Association Between Incident Prepregnancy Obesity and Stillbirth in a Population-Based Cohort Study

While prepregnancy obesity increases risk of stillbirth, few studies have evaluated the role of newly developed obesity independent of long-standing obesity. Additionally, researchers have relied almost exclusively on parametric models, which require correct specification of an unknown function for consistent estimation. We estimated the association between incident obesity and stillbirth in a cohort constructed from linked birth and death records in Pennsylvania (2003-2013). Incident obesity was defined as body mass index (weight (kg)/height (m)2) greater than or equal to 30. We used parametric G-computation, semiparametric inverse-probability weighting, and parametric/nonparametric targeted minimum loss-based estimation (TMLE) to estimate the association between incident prepregnancy obesity and stillbirth. Compared with pregnancies from women who stayed nonobese, women who became obese prior to their next pregnancy were estimated to have 2.0 (95% confidence interval (CI): 0.5, 3.5) more stillbirths per 1,000 pregnancies using parametric G-computation. However, despite well-behaved stabilized inverse probability weights, risk differences estimated from inverse-probability weighting, nonparametric TMLE, and parametric TMLE represented 6.9 (95% CI: 3.7, 10.0), 0.4 (95% CI: 0.1, 0.7), and 2.9 (95% CI: 1.5, 4.2) excess stillbirths per 1,000 pregnancies, respectively. These results, particularly those derived from nonparametric TMLE, were highly sensitive to covariates included in the propensity score models. Our results suggest that caution is warranted when using nonparametric estimators to quantify exposure effects.

Effect of interpregnancy interval after a first pregnancy complicated by placental abruption, on adverse maternal and fetal outcomes in a second pregnancy

Background: For women who suffer from abruption in the first pregnancy, the extent to which birth spacing has an impact on maternal and fetal outcomes in a second pregnancy remains unclear.Objectives: To examine the effect of interpregnancy interval (IPI) after a first pregnancy complicated by placental abruption, on adverse maternal and fetal outcomes in a subsequent pregnancy.Study design: This was a population-based retrospective cohort study using maternally-linked Missouri birth registry from 1989 to 2005 (n = 2069). Exposure of interest was IPI and outcomes were placental abruption, preeclampsia, preterm birth, small for gestational age, cesarean delivery, and neonatal plus fetal deaths (neofetal death) in a second pregnancy. Logistic regressions were used to assess the association between IPI and the outcomes.Results: Compared with women with an IPI of 1-2 years, those with short IPI (<1 year) were more likely to experience preterm birth (aOR 3.01, 95% CI 1.71-5.28) and neonatal death (aOR 3.52, 95% CI 1.24-10.02) in their subsequent pregnancy. No significant associations between IPI and recurrent placental abruption or preeclampsia were detected.Conclusions: Women who become pregnant in less than a year's time of an initial placental abruption are at increased risk for preterm birth and neofetal death in a subsequent pregnancy. Other ischemic placental disease conditions are also shown to have serious health implications for a woman's next pregnancy.

Revisiting the low birthweight paradox using sibling data with implications for the classification of low birthweight

Background

We examined the birthweight threshold for increased odds of neonatal death among second births based on their elder sibling's birthweight category.

Methods

This population-based cohort study included 190 575 women who delivered their first two non-anomalous singleton live births in Missouri (1989-2005). We examined the birthweight distribution and neonatal mortality curves of second births whose elder sibling had low versus adequate/high birthweight. We determined the optimal cut-off point for the classification of low birthweight among infants in each group based on the Youden index.

Results

Infants whose elder sibling had low birthweight had a lower mean birthweight and a higher percentage of low birthweight infants versus those whose elder sibling had adequate/high birthweight, but low birthweight infants in the former group had a lower rate of neonatal mortality. Upon standardizing the birthweight distribution to a Z-scale, neonatal mortality rates became comparable between the two groups at every rescaled birthweight for Z-scores ≥-3.7. The optimal cut-off point for low birthweight was 2500 and 3000 g among infants whose elder sibling had low and adequate/high birthweight, respectively.

Conclusions

Using sibling data for the classification of LBW may enable the identification of average-sized infants who may be at increased risk of neonatal mortality.

Evaluation of identifier field agreement in linked neonatal records

OBJECTIVE

To better address barriers arising from missing and unreliable identifiers in neonatal medical records, we evaluated agreement and discordance among traditional and non-traditional linkage fields within a linked neonatal data set.

STUDY DESIGN

The retrospective, descriptive analysis represents infants born from 2013 to 2015. We linked children's hospital neonatal physician billing records to newborn medical records originating from an academic delivery hospital and evaluated rates of agreement, discordance and missingness for a set of 12 identifier field pairs used in the linkage algorithm.

RESULTS

We linked 7293 of 7404 physician billing records (98.5%), all of which were deemed valid upon manual review. Linked records contained a mean of 9.1 matching and 1.6 non-matching identifier pairs. Only 4.8% had complete agreement among all 12 identifier pairs.

CONCLUSION

Our approach to selection of linkage variables and data formatting preparatory to linkage have generalizability, which may inform future neonatal and perinatal record linkage efforts.

Gestational Weight Gain in the First Two Pregnancies and Perinatal Outcomes in the Second Pregnancy

BACKGROUND

Gestational Weight Gain (GWG) below or above the Institute of Medicine (IOM) recommendations increases the risk of adverse pregnancy outcomes. However, it remains unknown whether the risk of adverse outcomes is affected by GWG in a previous pregnancy. We examined associations between GWG in the index (second) pregnancy and pregnancy outcomes, including preterm delivery and small for gestational age (SGA), while taking into consideration GWG in the first pregnancy.

METHODS

In a population-based cohort study (n = 210 564), using the Missouri maternally-linked birth registry (1989-2005), we used multivariable Poisson regression with robust error variance stratified by prepregnancy body mass index (BMI) to evaluate associations between GWG in the index pregnancy and a composite indicator of GWG in the first and second pregnancies and our outcomes of interest, after controlling for sociodemographic and pregnancy-related confounders.

RESULTS

Associations between GWG in the index pregnancy and pregnancy outcomes were moderated by GWG in the first pregnancy. Despite having GWG within recommendations in the index pregnancy, women had increased risk of preterm delivery and SGA if they had suboptimal GWG in their first pregnancy. Also, women having suboptimal GWG in the index pregnancy had increased risk of preterm delivery only if their GWG in the first pregnancy was also suboptimal.

CONCLUSIONS

The observation that women who have GWG within recommendations in a current pregnancy may still have increased risk of adverse outcomes if they had suboptimal GWG in the first pregnancy has considerable clinical and public health implications.

Probabilistic Matching Approach to Link Deidentified Data from a Trauma Registry and a Traumatic Brain Injury Model System Center

OBJECTIVE

There is no civilian traumatic brain injury database that captures patients in all settings of the care continuum. The linkage of such databases would yield valuable insight into possible care interventions. Thus, the objective of this article is to describe the creation of an algorithm used to link the Traumatic Brain Injury Model System (TBIMS) to trauma data in state and national trauma databases.

DESIGN

The TBIMS data from a single center was randomly divided into two sets. One subset was used to generate a probabilistic linking algorithm to link the TBIMS data to the center's trauma registry. The other subset was used to validate the algorithm. Medical record numbers were obtained and used as unique identifiers to measure the quality of the linkage. Novel methods were used to maximize the positive predictive value.

RESULTS

The algorithm generation subset had 121 patients. It had a sensitivity of 88% and a positive predictive value of 99%. The validation subset consisted of 120 patients and had a sensitivity of 83% and a positive predictive value of 99%.

CONCLUSIONS

The probabilistic linkage algorithm can accurately link TBIMS data across systems of trauma care. Future studies can use this database to answer meaningful research questions regarding the long-term impact of the acute trauma complex on health care utilization and recovery across the care continuum in traumatic brain injury populations.

Cystic Fibrosis is Associated with Adverse Neonatal Outcomes in Washington State, 1996-2013

OBJECTIVE

To determine whether cystic fibrosis (CF) is associated with adverse neonatal outcomes in a recent birth cohort in the US.

STUDY DESIGN

A retrospective matched cohort study of infants born in Washington State from 1996 to 2013 was identified through birth certificate data and linked to statewide hospital discharge data. Infants with CF were identified by hospitalization (through age 5 years) in which a CF-specific International Classification of Diseases, Ninth Revision code was recorded. "Unexposed" infants lacked CF-related International Classification of Diseases, Ninth Revision codes and were randomly selected among births, frequency-matched to "exposed" infants on birth year. Associations of CF with adverse neonatal outcomes (low birth weight [LBW], small for gestational age [SGA], preterm birth, and infant mortality) were estimated through Poisson regression. We performed extreme value imputation to address possible ascertainment bias.

RESULTS

We identified 170 infants with CF and 3400 unexposed infants. CF was associated with increased relative risk (95% CI) of 3.5 (2.5-4.9), 1.6 (1.1-2.4), 3.0 (2.2-4.0), and 6.8 (1.7-26.5) for LBW, SGA, preterm birth, and infant death, respectively. The estimated relative risks were similar among infants born from 2006 to 2013, except SGA was no longer associated with CF diagnosis. Results were robust to extreme value imputation and exclusion of infants with meconium ileus.

CONCLUSIONS

Observed associations of CF with LBW, preterm birth, and infant death are unlikely to be due to ascertainment bias. Further work is needed to determine how to prevent these adverse neonatal outcomes.

Morbidity and Mortality Differences Between Hematopoietic Cell Transplantation Survivors and Other Cancer Survivors

Purpose To compare the risks of serious health outcomes among hematopoietic cell transplantation (HCT) survivors versus a matched population of patients with cancer who did not undergo HCT, where the primary difference may be exposure to HCT. Methods Two-year HCT survivors treated at a comprehensive cancer center from 1992 through 2009 who were Washington State residents (n = 1,792; 52% allogeneic and 90% hematologic malignancies) were frequency matched by demographic characteristics and underlying cancer diagnosis (as applicable) to non-HCT 2-year cancer survivors, using the state cancer registry (n = 5,455) and the general population (n = 16,340) using driver's license files. Late outcomes for all three cohorts were ascertained from the state hospital discharge and death registries; subsequent cancers were ascertained from the state cancer registry. Results After median follow-up of 7.1 years, HCT survivors experienced significantly greater rates of hospitalization compared with matched non-HCT cancer survivors (280 v 173 episodes per 1,000 person-years, P < .001) and greater all-cause mortality (hazard ratio [HR], 1.1; 95% CI, 1.01 to 1.3). HCT survivors had more hospitalizations or death with infections (10-year cumulative incidence, 31% v 22%; HR, 1.4; 95% CI, 1.3 to 1.6) and respiratory complications (cumulative incidence, 27% v 20%; HR, 1.4; 95% CI, 1.2 to 1.5). Risks of digestive, skin, and musculoskeletal complications also were greater among HCT versus non-HCT cancer survivors. The two groups had similar risks of circulatory complications and second cancers. Both HCT and non-HCT cancer survivors had significantly greater 10-year cumulative incidences of all major organ-system outcomes versus the general population. Conclusion History of HCT was associated with late morbidity and mortality among cancer survivors. In particular, clinicians who care for HCT survivors should be aware of their high rates of late respiratory and infectious complications.

Bacterial vaginosis and adverse outcomes among full-term infants: a cohort study

Background

Bacterial vaginosis (BV) during pregnancy is a well-established risk factor for preterm birth and other preterm pregnancy complications. Little is known about adverse neonatal outcomes associated with BV exposure in full-term births, nor its influence on adverse outcomes independent of its effect on gestational age. The purpose of this study was to examine the relationship between BV during pregnancy and adverse neonatal outcomes among full-term and preterm infants.

Methods

We conducted a retrospective cohort study of Washington State mother/infant pairs from 2003-2013, stratified by full-term (primary outcomes) and preterm births (secondary outcomes). BV-exposed and unexposed women were frequency-matched based on year of delivery. BV exposure and adverse outcomes [assisted ventilation/respiratory distress, neonatal intensive care unit (NICU) admission, neonatal sepsis, fetal mortality, and infant mortality] were identified using birth certificates, ICD-9 codes from linked hospital records, and death certificates. Associations between BV exposure and outcomes were assessed using multivariable Poisson regression, adjusted for maternal demographics, gestational age, and other pregnancy complications, including infections.

Results

A total of 12,340 mother/infant pairs were included: 2,468 BV-exposed (2198 term, 267 preterm) and 9,872 BV unexposed (9156 term, 708 preterm). Among full-term infants, BV-exposed mothers were younger, more likely to be Black or Hispanic, more likely to have had a sexually transmitted infection, and less likely to have a college degree than unexposed mothers. Term BV exposed infants were more likely to have meconium at delivery. Following adjustment, BV was associated with an increased risk of assisted ventilation/respiratory distress at birth (aRR = 1.28, 95 % CI 1.02-1.61), NICU admission (aRR = 1.42, 95 % CI 1.11-1.82), and neonatal sepsis (aRR = 1.60, 95 % CI 1.13-2.27) among full-term infants. These associations were independent of the presence of chorioamnionitis or meconium. Among preterm infants, BV-exposure was associated with an increased risk for NICU admissions only (aRR = 1.24, 95 % CI 1.04-1.46).

Conclusions

BV exposure during pregnancy is associated with adverse neonatal outcomes even among infants born full-term. These findings amongst full-term infants are novel, and highlight neonatal implications of BV in pregnancy independent of BV’s effect on preterm birth.

A Longitudinal Study of Changes in Prenatal Care Utilization Between First and Second Births and Low Birth Weight

OBJECTIVES

Because previous analyses of prenatal care (PNC) utilization and risk of low birth weight (LBW) may have been influenced by selection bias, we conducted a study using longitudinal data of women with repeat pregnancies.

METHODS

We analyzed Washington State birth certificates of first and second live births (2003-2012). We estimated relative risk (RR) of LBW at second birth associated with Kotelchuck Index PNC level among women stratified by level of PNC in their first birth (n = 67,571).

RESULTS

Among women with inadequate PNC prior to their first birth (n = 10,355), women with intermediate or adequate PNC before their second birth (n = 7464) had a reduced risk of LBW (adjusted RR 0.61, 95% CI: 0.48, 0.78) compared to those whose PNC level remained inadequate. Likewise, among women with intermediate or adequate PNC prior to their first birth (n = 57,216), those with inadequate PNC before the second birth (n = 7095) had higher risk of LBW (adjusted RR 1.59, 95% CI: 1.36, 1.85) compared to those who remained at intermediate or adequate PNC.

CONCLUSIONS

Our findings support the hypothesis that PNC decreases LBW risk at second birth, independent of factors related to the utilization of PNC at first birth.

Risk of Adverse Infant Outcomes Associated with Maternal Tuberculosis in a Low Burden Setting: A Population-Based Retrospective Cohort Study

Background. Maternal tuberculosis (TB) may be associated with increased risk of adverse infant outcomes. Study Design. We examined the risk of low birth weight (LBW), small for gestational age (SGA), and preterm birth (<37 weeks) associated with maternal TB in a retrospective population-based Washington State cohort using linked infant birth certificate and maternal delivery hospitalization discharge records. We identified 134 women with births between 1987 and 2012 with TB-associated ICD-9 diagnosis codes at hospital delivery discharge and 536 randomly selected women without TB, frequency matched 4 : 1 on delivery year. Multinomial logistic regression analyses were performed to compare the risk of LBW, SGA, and preterm birth between infants born to mothers with and without TB. Results. Infants born to women with TB were 3.74 (aRR 95% CI 1.40–10.00) times as likely to be LBW and 1.96 (aRR 95% CI 0.91–4.22) as likely to be SGA compared to infants born to mothers without TB. Risk of prematurity was similar (aRR 1.01 95% CI 0.39–2.58). Conclusion. Maternal TB is associated with poor infant outcomes even in a low burden setting. A better understanding of the adverse infant outcomes associated with maternal TB, reflecting recent trends in US TB epidemiology, may inform potential targeted interventions in other low prevalence settings.

Poor record linkage sensitivity biased outcomes in a linked cohort analysis

OBJECTIVES

To examine the validity of deterministic compared to probabilistic record linkage in the ascertainment of hospitalizations in two linked cohorts.

STUDY DESIGN AND SETTING

HIV-negative (HIV-ve) (n = 1,325) and HIV-positive (HIV+ve) gay and bisexual men (n = 557) recruited in Sydney, Australia, were probabilistically and deterministically linked to a statewide hospital registry (July 2000-June 2012).

RESULTS

Using probabilistic linkage as the reference standard, deterministic linkage had higher specificity but much lower sensitivity [34.67% (95% confidence interval: 33.44, 35.92)]. A disproportionate number of links missed were individuals with poorer socioeconomic and health indicators, including HIV status. Risk of hospitalization compared to the general male population [HIV+ve standardized incidence ratio (SIR) = 1.45 (1.33-1.59); HIV-ve SIR = 0.72 (0.67-0.78)] was significantly underestimated when deterministic linkage was used [HIV+ve SIR = 0.46 (0.37-0.58); HIV-ve SIR = 0.29 (0.24-0.35)]. The impact of linkage strategy on the calculation of incidence rate ratios (IRRs) was less, but a greater discrepancy in IRRs was seen for diagnostic categories where event rates were low or where the sensitivity of the deterministic linkage was differential between the two cohorts.

CONCLUSION

Linkage without proven high sensitivity and specificity should be carefully considered. In circumstances of undetermined sensitivity, SIRs should not be calculated as the extent of underestimation is unknown. The comparison of linked events within or between cohorts is more robust to linkage misclassification; however, selection bias does affect estimates and should be considered before linkage.

Prepregnancy body mass index in a first uncomplicated pregnancy and outcomes of a second pregnancy

OBJECTIVE

This study examined the effect of body mass index (BMI) before a first uncomplicated pregnancy on maternal and fetal outcomes in a subsequent pregnancy, including preterm births, preeclampsia, cesarean delivery, small for gestational age, large for gestational age, and neonatal deaths.

STUDY DESIGN

We conducted a population-based cohort study (n = 121,092) using the Missouri maternally linked birth registry (1989 through 2005). Multivariable binary logistic regression models were fit to estimate odds ratios and 95% confidence intervals for the parameters of interest after controlling for sociodemographic and pregnancy-related confounders in the second pregnancy.

RESULTS

Compared to women with a normal BMI in their first pregnancy, those who were underweight prepregnancy had increased odds for preterm birth by 20% and small for gestational age by 40% in their second pregnancy, while those with prepregnancy obesity had increased odds for large for gestational age, preeclampsia, cesarean delivery, and neonatal deaths in their second pregnancy by 54%, 156%, 85%, and 37%, respectively.

CONCLUSION

Women starting a first pregnancy with suboptimal BMI may be at risk of adverse maternal and fetal outcomes in a subsequent pregnancy, even if their first pregnancy was uncomplicated or if they reached a normal weight by their second pregnancy. The long-term consequences of suboptimal BMI carry considerable public health implications.

Development of a linked perinatal data resource from state administrative and community-based program data

To demonstrate a generalizable approach for developing maternal-child health data resources using state administrative records and community-based program data. We used a probabilistic and deterministic linking strategy to join vital records, hospital discharge records, and home visiting data for a population-based cohort of at-risk, first time mothers enrolled in a regional home visiting program in Southwestern Ohio and Northern Kentucky from 2007 to 2010. Because data sources shared no universal identifier, common identifying elements were selected and evaluated for discriminating power. Vital records then served as a hub to which other records were linked. Variables were recoded into clinically significant categories and a cross-set of composite analytic variables was constructed. Finally, individual-level data were linked to corresponding area-level measures by census tract using the American Communities Survey. The final data set represented 2,330 maternal-infant pairs with both home visiting and vital records data. Of these, 56 pairs (2.4 %) did not link to either maternal or infant hospital discharge records. In a 10 % validation subset (n = 233), 100 % of the reviewed matches between home visiting data and vital records were true matches. Combining multiple data sources provided more comprehensive details of perinatal health service utilization and demographic, clinical, psychosocial, and behavioral characteristics than available from a single data source. Our approach offers a template for leveraging disparate sources of data to support a platform of research that evaluates the timeliness and reach of home visiting as well as its association with key maternal-child health outcomes.

Preterm birth in the first pregnancy and risk of neonatal death in the second pregnancy: a propensity score-weighted matching approach

The study purpose was to assess the relationship between various grades of preterm birth (moderate preterm: 33-36 weeks; severe preterm: 27-32 weeks; extreme preterm: ≤ 26 weeks) in the first pregnancy and neonatal mortality (death within 28 days of birth; early: 0-7 days; late: 8-28 days) in the second pregnancy. Using the Missouri maternally-linked dataset (1989-2005), a population-based, retrospective cohort analysis with propensity score-weighted matching was conducted on mothers with two consecutive singleton live births (n = 310,653 women). Women with a prior preterm birth were more likely to subsequently experience neonatal death. The odds increased in a dose-dependent pattern with ascending severity of the preterm event in the first pregnancy (moderate preterm: AOR = 1.32; 95% CI: 1.10-1.60; severe preterm: AOR = 2.62; 95% CI: 2.01-3.41; extreme preterm: AOR = 5.84; 95% CI: 4.28-7.97; p value for trend < 0.001). However, the pathway for the relationship between prior preterm birth and subsequent neonatal mortality may be the recurrence of preterm birth.

Gestational Weight Gain and Maternal and Neonatal Outcomes in Term Twin Pregnancies in Obese Women

Limited data is available that estimates the effect of gestational weight gain on maternal and neonatal outcomes in term twin pregnancies in obese women. A historical cohort study of 831 obese (BMI ≥30.0 kg/m2) women in Missouri delivering 1,662 liveborn, term (≥37 weeks gestation) twin infants in 1998–2005 was conducted. Three gestational weight gain categories were examined: <25 pounds, 25–42 pounds, and >42 pounds. Adjusted odds ratios were calculated with multiple logistic regression, using the 2009 Institute of Medicine provisional guideline of 25–42 pounds as the reference group. Significant increasing trends with gestational weight gain were found for preeclampsia (p < .05), larger twin birth weight (p < .01), smaller twin birth weight (p < .001), and infants weighing >2,500 grams (p < .001). Significant increasing trends for preeclampsia and for cesarean delivery were found in concordant twin pairs (smaller twin >80% of birth weight of larger twin). Women who gained >42 pounds had a borderline significantly higher odds of preeclampsia than women who gained 25–42 pounds (adjusted OR 1.72; 95% CI 1.00–2.99, p = .052). No significant differences were found for 1-min Apgar score <4, 5-min Apgar score <7, or infant mortality ≤1 year. Our study suggests that increasing gestational weight gain is associated with larger infants but increased risk of preeclampsia and cesarean delivery in term twin pregnancies in obese women. Limiting gestational weight gain could reduce the risk of preeclampsia and cesarean delivery. Prospective studies of other study populations and maternal/infant outcomes are needed to evaluate the efficacy of the Institute of Medicine guideline.

Infant mortality and the risk of small size for gestational age in the subsequent pregnancy: a retrospective cohort study

To examine the association between prior infant mortality and subsequent risk for small for gestational age (SGA). This population-based, retrospective cohort study used the Missouri maternally linked, longitudinal dataset (1989-2005). Analyses were restricted to women who had two singleton pregnancies during the study period. Logistic regression was conducted to obtain adjusted odds ratios (AOR) and 95 % confidence intervals (CI) for the association between infant mortality in the first pregnancy and SGA in the second pregnancy. Women with a prior occurrence of infant death were more likely to be black and obese and had lower educational levels and had higher rates of pregnancy-related complications (p < 0.01). White women with previous infant mortality were at 1.46 times greater risk for SGA in the subsequent pregnancy (AOR = 1.46, 95 % CI = 1.24-1.71). For black women with prior infant death, the risk for SGA increased to 2.77 times (AOR = 2.77, 95 % CI = 2.19-3.51). White mothers who experienced infant mortality coupled with SGA in the first pregnancy had a nearly threefold heightened risk for SGA in the second pregnancy (AOR = 2.89, 95 % CI = 2.21-3.78), whereas black women with this history were more than four times as likely to have an infant with SGA (AOR = 4.60 95 % CI = 3.05-6.96). Prior occurrence of infant mortality is associated with increased risk for subsequent SGA. This finding has important implications for health professionals, as targeted inter-conception strategies for women who have experienced infant death, as well as SGA, may be warranted.

Maternal pre-gravid obesity and early childhood respiratory hospitalization: a population-based case-control study

Inflammation in utero is linked to childhood respiratory and infectious complications. Obesity is an increasingly common chronic inflammatory state, yet little is known about its role in childhood respiratory illness. We sought to examine the association between maternal pre-gravid BMI and early childhood respiratory hospitalization. We conducted a population-based case-control study using the Washington State Comprehensive Hospital Abstract Reporting System and linked birth certificate data. Cases were children age 0-5 years, born in Washington state, with a respiratory hospitalization between 2003 and 2008. We identified 15,318 cases, frequency matching each case to two controls by birth year (total 31,060 controls). We used logistic regression to estimate the risk (approximated by odds ratios) of early childhood respiratory hospitalization according to maternal pre-gravid body mass index (BMI) category (underweight, normal, overweight, obese), after adjustment for maternal and infant characteristics. An elevated maternal pre-gravid BMI was associated with increased risk of childhood respiratory hospitalization, with an adjusted odds ratio OR [95 % CI] = 1.08 [1.03-1.14] for overweight mothers (BMI 25-29.9 kg/m(2)), and OR = 1.29 [1.22-1.36] for obese mothers (BMI ≥ 30 kg/m(2)). An elevated maternal pre-gravid BMI was associated with higher risk of early childhood respiratory hospitalization. Childhood respiratory illness may be an important complication of excess maternal weight that should be shared with expectant mothers.

A linked-registry study of gestational factors and subsequent breast cancer risk in the mother

BACKGROUND

Women who were younger at their first live birth have a reduced breast cancer risk. Other pregnancy characteristics, including complications, also may affect risk but because they are rare, require large datasets to study.

METHODS

The association of pregnancy history and breast cancer risk was assessed in a population-based study including 22,646 cases diagnosed in Washington State 1974 to 2009, and 224,721 controls, frequency matched on parity, age, calendar year of delivery, and race/ethnicity. Information on prediagnosis pregnancies derived from linked birth certificate and hospital discharge databases. Adjusted odd ratios (ORs) and 95% confidence intervals (CI) were calculated.

RESULTS

Multiple gestation pregnancies were associated with decreased breast cancer risk (OR, 0.65; 95% CI, 0.57-0.74) as was prepregnancy obesity (OR, 0.76; 95% CI, 0.65-0.90). Infant birth weight was positively associated (6% per 1,000 g; 95% CI, 3%-9%). The ORs for first trimester bleeding (OR, 3.35; 95% CI, 1.48-7.55) and placental abnormality/insufficiency (OR, 2.24; 95% CI, 1.08-4.67) were increased in women diagnosed at age 50+ years and 15+ years after the index pregnancy. Results were similar in analyses restricted to first pregnancies, those closest to diagnosis, and when excluding in situ disease.

CONCLUSION

These data suggest that multiple gestation pregnancies are protective, whereas delivering larger infants increases risk for later development of maternal breast cancer. Placental abnormalities that result in bleeding in pregnancy also may reverse the long-term protection in postmenopausal women associated with parity.

IMPACT

Certain pregnancy characteristics seem to be associated with later maternal breast cancer risk.

The impact of interpregnancy weight change on birthweight in obese women

OBJECTIVE

The purpose of this study was to estimate the impact of interpregnancy weight change from first to second pregnancies in obese women on the risk of large-for-gestational-age (LGA) and small-for-gestational-age (SGA) infants.

STUDY DESIGN

A population-based historical cohort analysis of 10,444 obese women in Missouri who delivered their first 2 singleton live infants from 1998-2005. Interpregnancy weight change was calculated as the difference between prepregnancy body mass index (BMI) of the first and second pregnancies. LGA and SGA births were compared among 3 interpregnancy weight change groups: (1) weight loss (≥2 BMI units), (2) weight gain (≥2 BMI units), and (3) reference group (BMI maintained within 2 units). Adjusted odds ratios (aOR) were calculated for LGA and SGA births with the use of multiple logistic regression. A dose-response relationship was assessed with a linear-by-linear χ(2) test.

RESULTS

Compared with the reference group, interpregnancy weight loss was associated with lower risk of an LGA infant (aOR, 0.61; 95% confidence interval, 0.52-0.73), whereas interpregnancy weight gain was associated with increased risk of an LGA infant (aOR, 1.37; 95% confidence interval, 1.21-1.54). Interpregnancy BMI change was not related to SGA infant risk, except for weight loss of >8 BMI units. A significant dose-response relationship was observed for LGA infant risk (P < .001), but not SGA infant risk (P = .840).

CONCLUSION

Mild-to-moderate interpregnancy weight loss in obese women reduced the risk of subsequent birth of LGA infants without increasing the risk of SGA infants. The interpregnancy interval may be a crucial period for targeting weight loss in obese women.

Population-based study of risk factors for severe maternal morbidity

BACKGROUND

Severe maternal morbidity (SMM) is a serious health condition potentially resulting in death without immediate medical attention, including organ failure, obstetric shock and eclampsia. SMM affects 20000 US women every year; however, few population-based studies have examined SMM risk factors.

METHODS

We conducted a population-based case-control study linking birth certificate and hospital discharge data from Washington State (1987-2008), identifying 9485 women with an antepartum, intrapartum or postpartum SMM with ≥3-day hospitalisation or transfer from another facility and 41 112 random controls. Maternal age, race, smoking during pregnancy, parity, pre-existing medical condition, multiple birth, prior caesarean delivery, and body mass index were assessed as risk factors with logistic regression to estimate odds ratios (OR) and 95% confidence intervals [CI], adjusted for education and delivery payer source.

RESULTS

Older women (35-39: OR 1.65 [CI 1.52, 1.79]; 40+: OR 2.48 [CI 2.16, 2.81]), non-White women (Black: OR 1.82 [CI 1.64, 2.01]; American Indian: OR 1.52 [CI 1.32, 1.73]; Asian/Pacific Islander: OR 1.30 [CI 1.19, 1.41]; Hispanic: OR 1.17 [CI 1.07, 1.27]) and women at parity extremes (nulliparous: OR 1.83 [CI 1.72, 1.95]; parity 3+: OR 1.34 [CI 1.23, 1.45]) were at greater risk of SMM. Women with a pre-existing medical condition (OR 2.10 [CI 1.88, 2.33]), a multiple birth (OR 2.54 [CI 2.26, 2.82]) and a prior caesarean delivery (OR 2.08 [CI 1.93, 2.23]) were also at increased risk.

CONCLUSION

The risk factors identified are not modifiable at the individual level; therefore, provider and system-level factors may be the most appropriate target for preventing SMM.

Sickle cell disease incidence among newborns in New York State by maternal race/ethnicity and nativity

PURPOSE

Sickle cell disease is estimated to occur in 1:300-400 African-American births, with higher rates among immigrants from Africa and the Caribbean, and is less common among Hispanic births. This study determined sickle cell disease incidence among New York State newborns stratified by maternal race/ethnicity and nativity.

METHODS

Newborns with confirmed sickle cell disease born to New York State residents were identified by the New York State newborn screening program for the years 2000-2008 and matched to birth records to obtain birth and maternal information. Annual incidence rates were computed and bivariate analyses were conducted to examine associations with maternal race/ethnicity and nativity.

RESULTS

From 2000 to 2008, 1,911 New York State newborns were diagnosed with sickle cell disease and matched to the birth certificate files. One in every 1,146 live births was diagnosed with sickle cell disease. Newborns of non-Hispanic black mothers accounted for 86% of sickle cell disease cases whereas newborns of Hispanic mothers accounted for 12% of cases. The estimated incidence was 1:230 live births for non-Hispanic black mothers, 1:2,320 births for Hispanic mothers, and 1:41,647 births for non-Hispanic white mothers. Newborns of foreign-born non-Hispanic black mothers had a twofold higher incidence of sickle cell disease than those born to US-born non-Hispanic black mothers (P < 0.001).

CONCLUSION

This study provides the first US estimates of sickle cell disease incidence by maternal nativity. Women born outside the United States account for the majority of children with sickle cell disease born in New York State. Such findings identify at-risk populations and inform outreach activities that promote ongoing, high-quality medical management to affected children.

Small size for gestational age and the risk for infant mortality in the subsequent pregnancy

PURPOSE

To examine the association between small for gestational age (SGA) in the first pregnancy and risk for infant mortality in the second pregnancy.

METHODS

This is a population-based, retrospective cohort study in which we used the Missouri maternally linked cohort dataset for 1978-2005. Analyses were restricted to women who had two singleton pregnancies during the study period. The exposure was SGA in the first pregnancy, whereas the primary outcome was infant mortality in the second pregnancy. Kaplan-Meier Estimate and Cox proportional hazard regression were conducted.

RESULTS

Infant mortality was significantly greater among mothers with previous SGA (P < .01). A persistent association of previous SGA with subsequent infant mortality was observed (adjusted hazard ratio [AHR] 1.35, 95% confidence interval [95% CI] 1.24-1.48). Race-specific data illustrated that black women with a previous SGA birth were 40% more likely to experience infant mortality (AHR 1.40, 95% CI 1.21-1.63) than their counterparts without a history of SGA, but white women with a previous SGA had an increased risk of 31% (AHR 1.31, 95% CI 1.17-1.46).

CONCLUSIONS

Women with previous SGA bear increased risks for subsequent infant mortality, which was greater among black mothers. Hence, SGA plays an important role in the black-white disparity in infant mortality. Women's previous childbearing experiences could serve as important criterion in determining appropriate interconception strategies to improve infant health and survival.

The effect of paternal age on fetal birth outcomes

Research investigating the role of paternal age in adverse birth outcomes is limited. This population-based retrospective cohort study used the Missouri maternally linked data set from 1989 to 2005 to assess whether paternal age affects fetal birth outcomes: low birth weight (LBW), preterm birth (PTB), stillbirth, and small size for gestational age (SGA). We examined these outcomes among infants across seven paternal age-groups (<20, 20-24, 25-29, 30-34, 35-39, 40-45, and >45 years) using the generalized estimating equation framework. Compared with infants born to younger fathers (25-29 years), infants born to fathers aged 40 to 45 years had a 24% increased risk of stillbirth but a reduced risk of SGA. A 48% increased risk of late stillbirth was observed in infants born to advanced paternal age (>45 years). Moreover, advanced paternal age (>45 years) was observed to result in a 19%, 13%, and 29% greater risk for LBW, PTB, and VPTB (very preterm birth) infants, respectively. Infants born to fathers aged 30 to 39 years had a lower risk of LBW, PTB, and SGA, whereas those born to fathers aged 24 years or younger had an elevated likelihood of experiencing these same adverse outcomes. These findings demonstrate that paternal age influences birth outcomes and warrants further investigation.

Maternal superobesity and perinatal outcomes

OBJECTIVE

The purpose of this study was to determine the effect of maternal superobesity (body mass index [BMI], ≥ 50 kg/m(2)) compared with morbid obesity (BMI, 40-49.9 kg/m(2)) or obesity (BMI, 30-39.9 kg/m(2)) on perinatal outcomes.

STUDY DESIGN

We conducted a retrospective cohort study of birth records that were linked to hospital discharge data for all liveborn singleton term infants who were born to obese Missouri residents from 2000-2006. We excluded major congenital anomalies and women with diabetes mellitus or chronic hypertension.

RESULTS

There were 64,272 births that met the study criteria, which included 1185 superobese mothers (1.8%). Superobese women were significantly more likely than obese women to have preeclampsia (adjusted relative risk [aRR], 1.7; 95% confidence interval [CI], 1.4-2.1), macrosomia (aRR, 1.8; 95% CI, 1.3-2.5), and cesarean delivery (aRR, 1.8; 95% CI, 1.5-2.1). Almost one-half of all superobese women (49.1%) delivered by cesarean section, and 33.8% of superobese nulliparous women underwent scheduled primary cesarean delivery.

CONCLUSION

Women with a BMI of ≥ 50 kg/m(2) are at significantly increased risk for perinatal complications compared with obese women with a lower BMI.

Very low birth weight births in Georgia, 1994-2005: trends and racial disparities

OBJECTIVE

To investigate the nature of very low birth weight (VLBW) births in Georgia-a major contributor to the overall and the black-white disparity in infant mortality-as a step toward elucidating strategies for reducing VLBW births.

METHODS

This population-based retrospective cohort study utilized maternally linked vital records data from Georgia to examine the status of and contributors to the VLBW rate for non-Hispanic blacks and whites by comparing trends in the proportion represented by singleton versus multiple gestations, first versus recurrent events, and specific subtypes over three, consecutive 4-year periods (1994-1996 through 2003-2005); and logistic regression to model the risk of various subtypes of VLBW as a function of maternal and obstetrical characteristics.

RESULTS

Georgia's VLBW rate remained unchanged from 1994-1996 to 2003-2005, although there was a significant decrease in the rates of twin and first VLBW and a significant increase in recurrent VLBW. For both first and recurrent VLBW, there was a statistically significant increase for blacks and a decrease for whites. The strongest risk factor for a VLBW birth of any subtype for blacks and whites was a prior VLBW, with recurrent VLBW accounting for 4.8-16% of all VLBW depending upon the subtype.

CONCLUSION

From 1994-1996 to 2003-2005, the rate of recurrent VLBW increased while the rate of first VLBW decreased in Georgia. For both first and recurrent VLBW, the black-white disparity widened. Because the strongest risk factor for a VLBW birth is a previous one, there is a need to identify strategies to prevent a woman's first VLBW birth and to reduce recurrences.

Risk factors for eclampsia: a population-based study in Washington State, 1987-2007

OBJECTIVE

We sought to investigate whether previously identified risk factors are associated with eclampsia in a contemporary, heterogeneous cohort of women.

STUDY DESIGN

Data were collected from birth certificate and hospital discharge records and used to conduct a population-based case-control study among women giving birth to singletons in Washington State from 1987 through 2007. We used multivariable logistic regression to estimate odds ratios and 95% confidence intervals. Multiple imputation procedures were used to address missing data.

RESULTS

Risk of eclampsia was greater in nulliparous compared to parous women. Being a young mother (< 20 years) or an older mother (≥ 35 years) were each associated with elevated eclampsia risk. Longer birth interval, low socioeconomic status, gestational diabetes, prepregnancy obesity, and weight gain during pregnancy above or below recommended guidelines were positively associated with eclampsia. Multiparity and smoking were inversely associated with eclampsia risk.

CONCLUSION

Exposures identified more than a decade ago continue to be associated with eclampsia in contemporary birth cohorts.

Birth injury in a subsequent vaginal delivery among women with a history of shoulder dystocia

AIM

To examine risk factors for birth injury in a subsequent vaginal delivery among women with a prior delivery complicated by shoulder dystocia.

METHODS

Population-based retrospective cohort study, Washington State (1987-2007). Logistic regression was used to assess risk factors associated with subsequent birth injury.

RESULTS

Of 9232 women who met inclusion criteria, 223 (2.4%) had a subsequent vaginal delivery with birth injury. Birth injury in an index delivery, adjusted odds ratio (aOR) 2.6 [95% confidence interval (CI) 1.7-4.1] and factors in subsequent delivery: birth weight ≥4000 g, aOR 4.4 (95% CI: 3.0-6.3), gestational diabetes, aOR 1.9 (95% CI: 1.2-3.2), Hispanic ethnicity aOR 1.9 (95% CI: 1.2-2.9), and maternal obesity, aOR 1.8 (95% CI: 1.3-2.6) were associated with birth injury.

CONCLUSION

Among women with prior delivery complicated by shoulder dystocia, the risk factors identified in this study should be carefully considered prior to deciding upon route of delivery - cesarean vs. vaginal delivery.

Alcohol consumption during pregnancy and risk of placental abruption and placenta previa

The purpose of this study was to examine the association between prenatal alcohol consumption and the occurrence of placental abruption and placenta previa in a population-based sample. We used linked birth data files to conduct a retrospective cohort study of singleton deliveries in the state of Missouri during the period 1989 through 2005 (n = 1,221,310). The main outcomes of interest were placenta previa, placental abruption and a composite outcome defined as the occurrence of either or both lesions. Multivariate logistic regression was used to generate adjusted odd ratios, with non-drinking mothers as the referent category. Women who consumed alcohol during pregnancy had a 33% greater likelihood for placental abruption during pregnancy (adjusted odds ratio (OR), 95% confidence interval (CI) = 1.33 [1.16-1.54]). No association was observed between prenatal alcohol use and the risk of placenta previa. Alcohol consumption in pregnancy was positively related to the occurrence of either or both placental conditions (adjusted OR [95% CI] = 1.29 [1.14-1.45]). Mothers who consumed alcohol during pregnancy were at elevated risk of experiencing placental abruption, but not placenta previa. Our findings underscore the need for screening and behavioral counseling interventions to combat alcohol use by pregnant women and women of childbearing age.

Stillbirth as a risk factor for subsequent infant mortality

BACKGROUND

Infant mortality is an important indicator of the health and wellness of a society. Multiple risk factors for infant mortality have been identified and investigated; however, the influence of prior pregnancy experience on subsequent infant mortality is under-researched.

AIMS

To examine the association between stillbirth in the first pregnancy and risk for infant mortality in the second pregnancy in a large population-based dataset.

STUDY DESIGN

Population-based, retrospective cohort study

SUBJECTS

Missouri maternally linked cohort data files were utilized from 1989 through 2005. Analyses were restricted to women who had two singleton pregnancies during the study period.

OUTCOME MEASURES

The exposure was stillbirth in the first pregnancy, while the primary outcome was infant mortality in the second pregnancy.

RESULTS

Women who experienced stillbirth in their first pregnancy were more likely to be of advanced age, black, and obese and had higher rates of pregnancy-related complications (p<0.01). Previous stillbirth was associated with an elevated risk for subsequent infant mortality (AHR=2.51, 95% CI: 1.73-3.65) and neonatal mortality (AHR=3.04, 95% CI: 1.99-4.65), after adjustment for socio-demographic variables and pregnancy complications. Risk estimates for mortality in the second pregnancy were most profound among black mothers with a history of stillbirth in the first pregnancy [risk for infant mortality: (AHR=2.68, 95% CI: 1.41-5.09) and neonatal death: (AHR=4.25, 95% CI: 2.34-7.60)].

CONCLUSIONS

Women with prior stillbirth bear elevated risks for subsequent infant mortality. Women's previous childbearing experiences could serve as important criteria in determining appropriate interconception strategies to improve subsequent feto-infant health and survival.