Reliability and validity of birth certificate prepregnancy weight and height among women enrolled in prenatal WIC program: Florida, 2005

Prospective transitions in hemoglobin A1c following gestational diabetes using multistate Markov models

We characterized the state-to-state transitions in postpartum hemoglobin A1c levels after gestational diabetes, including remaining in a state of normoglycemia or transitions between prediabetes or diabetes states of varying severity. We used data from the APPLE Cohort, a postpartum population-based cohort of individuals with gestational diabetes between 2009 and 2011, and linked A1c data with up to 9 years of follow-up (n = 34 171). We examined maternal sociodemographic and perinatal characteristics as predictors of transitions in A1c progression using Markov multistate models. In the first year postpartum following gestational diabetes, 45.1% of people had no diabetes, 43.1% had prediabetes, 4.6% had controlled diabetes, and 7.2% had uncontrolled diabetes. Roughly two-thirds of individuals remained in the same state in the next year. Black individuals were more likely to transition from prediabetes to uncontrolled diabetes (adjusted hazard ratio [aHR] = 2.32; 95% CI, 1.21-4.47) than White persons. Perinatal risk factors were associated with disease progression and a lower likelihood of improvement. For example, hypertensive disorders of pregnancy were associated with a stronger transition (aHR = 2.06; 95% CI, 1.39-3.05) from prediabetes to uncontrolled diabetes. We illustrate factors associated with adverse transitions in incremental A1c stages and describe patient profiles that may warrant enhanced postpartum monitoring.

Association of Prepregnancy Cardiometabolic Health With Hypertensive Disorders of Pregnancy Among Historically Underrepresented Groups in the United States

BACKGROUND

Prepregnancy diabetes and obesity are associated with hypertensive disorders of pregnancy (HDPs). However, the proportion of cases of HDP in the population explained by diabetes and obesity (population attributable fraction), especially among American Indian and Alaska Native and Native Hawaiian and Other Pacific Islander, is not well characterized.

METHODS AND RESULTS

We conducted a cross-sectional analysis of data on individuals with a live singleton birth from the US National Vital Statistics System between 2016 and 2019. We used adjusted logistic regression to estimate the prevalence odds ratios of HDPs and tested interaction for race and ethnicity. We calculated the population attributable fraction for the effect of obesity and diabetes on HDPs. Among 13 201 338 birthing individuals, (mean age, 29±6 years), 7% had HDP. The prevalence of HDP was highest among American Indian and Alaska Native individuals (9.1%). Prepregnancy diabetes (prevalence odds ratio, 2.63 [95% CI, 2.59-2.67]) and obesity (prevalence odds ratio, 2.95 [95% CI, 2.93-2.97]) were associated with HDPs. Compared with non-Hispanic White individuals, the association of diabetes with HDPs was strongest among Native Hawaiian and Other Pacific Islander (prevalence odds ratio, 3.05 [95% CI, 2.48-3.77]), and the association of obesity with HDP was strongest among Asian individuals (prevalence odds ratio, 3.44 [95% CI, 3.35-3.54]; all P for interaction <0.05). Population attributable fractions for diabetes and obesity were highest among Native Hawaiian and Other Pacific Islander individuals (diabetes, 3.7% [95% CI, 3.3%-4.0%]; and obesity, 45% [95% CI, 41.9%-47.8%]).

CONCLUSIONS

Prepregnancy diabetes and obesity are associated with HDP across all racial and ethnic groups. Diabetes and obesity have highest population attributable fractions among Native Hawaiian and Other Pacific Islander individuals and should be aggressively targeted during childhood, adolescence, and young adulthood to reduce risk of HDPs.

Trends in Maternal Weight Disparities: Statewide Differences in Rural and Urban Minnesota Residents From 2012 to 2019

INTRODUCTION

Despite research showing substantial weight disparities along the rural-urban continuum, little work has attempted to identify differences in prepregnancy weight status or gestational weight gain (GWG) outcomes between rural and urban birthing people. As such, the goals of this research were to 1) document the prevalence of prepregnancy overweight and obesity and excessive GWG in rural and urban birthing people and 2) examine changes in rural and urban prepregnancy overweight or obesity and excessive GWG over time.

METHODS

Birth certificate data provided sociodemographic variables, prepregnancy body mass index, GWG, and rurality status on 465,709 respondents who gave birth in Minnesota from 2012 to 2019. A series of regression models estimated risk differences in 1) prepregnancy weight status and 2) excessive GWG between rural and urban respondents over time, controlling for relevant covariates.

RESULTS

Rural individuals had a 4.9 percentage-point (95% confidence interval, 4.5-5.3) higher risk of having prepregnancy overweight or obesity compared with urban individuals, and a 2.6 percentage-point (95% confidence interval, 1.9-3.3) higher risk of gaining excessive gestational weight. The disparities in prepregnancy overweight or obesity and excessive gestational weight between rural and urban individuals widened over time.

CONCLUSIONS

These findings contribute to accumulating evidence documenting notable health disparities between rural and urban individuals during the perinatal period and support the need to develop prevention and treatment efforts focused on improving the weight-related health of individuals living in rural communities.

Maternal and Perinatal Outcomes Associated With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Pregnancy, Florida, 2020-2021: A Retrospective Cohort Study

BACKGROUND

The objective was to estimate risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy and assess adverse maternal and perinatal outcomes.

METHODS

We used a population-based, retrospective cohort of all pregnancies with a live birth or fetal death in Florida from 1 March 2020 to 30 April 2021. Coronavirus disease 2019 (COVID-19) case reports were matched to vital registries. Outcomes assessed were risk of infection in pregnancy, preterm birth, maternal or neonatal admission to an intensive care unit (ICU), perinatal or fetal death, and maternal death. Modified Poisson and multinomial logistic regression models were used to derive relative risk estimates.

RESULTS

Of 234 492 women with a live birth or fetal death during the study period, 12 976 (5.5%) were identified with COVID-19 during pregnancy. Risk factors for COVID-19 in pregnancy included Hispanic ethnicity (relative risk [RR] = 1.89), Black race (RR = 1.34), being unmarried (RR = 1.04), and being overweight or obese pre-pregnancy (RR = 1.08-1.32). COVID-19 during pregnancy was associated with preterm birth (RR = 1.31), Cesarean delivery (RR = 1.04), and neonatal (RR = 1.17) and maternal (RR = 3.10) ICU admission; no association was found with increased risk of perinatal (RR = 0.72) or fetal death (RR = 0.86). Women infected during any trimester showed increased risk of preterm birth. Fourteen maternal deaths were identified among COVID-19 cases; of those who died, 12 were obese. The death rate per 10 000 was 22.09 among obese and 1.22 among non-obese gravida with COVID-19 during pregnancy (RR = 18.99, P = .001).

CONCLUSIONS

Obesity is a risk factor for SARS-CoV-2 infection in pregnancy and for more severe COVID-19 illness among pregnant women. SARS-CoV-2 infection is associated with preterm birth.

Association of types of diabetes and insulin dependency on birth outcomes

BACKGROUND

Diabetes rates among pregnant women in the United States have been increasing and are associated with adverse pregnancy outcomes.

AIM

To investigate differences in birth outcomes (preterm birth, macrosomia, and neonatal death) by diabetes status.

METHODS

Cross-sectional design, using linked Missouri birth and death certificates (singleton births only), 2010 to 2012 (n = 204057). Exposure was diabetes (non-diabetic, pre-pregnancy diabetes-insulin dependent (PD-I), pre-pregnancy diabetes-non-insulin dependent (PD-NI), gestational diabetes- insulin dependent (GD-I), and gestational diabetes-non-insulin dependent (GD-NI)]. Outcomes included preterm birth, macrosomia, and infant mortality. Confounders included demographic characteristics, adequacy of prenatal care, body mass index, smoking, hypertension, and previous preterm birth. Bivariate and multivariate logistic regression assessed differences in outcomes by diabetes status.

RESULTS

Women with PD-I, PD-NI, and GD-I remained at a significantly increased odds for preterm birth (aOR 2.87, aOR 1.77, and aOR 1.73, respectively) and having a very large baby [macrosomia] (aOR 3.01, aOR 2.12, and aOR 1.96, respectively); in reference to non-diabetic women. Women with GD-NI were at a significantly increased risk for macrosomia (aOR1.53), decreased risk for their baby to die before their first birthday (aOR 0.41) and no difference in risk for preterm birth in reference to non-diabetic women.

CONCLUSION

Diabetes is associated with the poor birth outcomes. Clinical management of diabetes during pregnancy and healthy lifestyle behaviors before pregnancy can reduce the risk for diabetes and poor birth outcomes.

Risk of early birth by body mass index in a propensity score-matched sample: A retrospective cohort study

OBJECTIVE

Evaluate the risk of preterm (<37 weeks) or early term birth (37 or 38 weeks) by body mass index (BMI) in a propensity score-matched sample.

DESIGN

Retrospective cohort analysis.

SETTING

California, USA.

POPULATION

Singleton live births from 2011-2017.

METHODS

Propensity scores were calculated for BMI groups using maternal factors. A referent sample of women with a BMI between 18.5 and <25.0 kg/m² was selected using exact propensity score matching. Risk ratios for preterm and early term birth were calculated.

MAIN OUTCOME MEASURES

Early birth.

RESULTS

Women with a BMI <18.5 kg/m² were at elevated risk of birth of 28-31 weeks (relative risk [RR] 1.2, 95% CI 1.1-1.4), 32-36 weeks (RR 1.3, 95% CI 1.2-1.3), and 37 or 38 weeks (RR 1.1, 95% CI 1.1-1.1). Women with BMI ≥25.0 kg/m² were at 1.2-1.4-times higher risk of a birth <28 weeks and were at reduced risk of a birth between 32 and 36 weeks (RR 0.8-0.9) and birth during the 37th or 38th week (RR 0.9).

CONCLUSION

Women with a BMI <18.5 kg/m² were at elevated risk of a preterm or early term birth. Women with BMI ≥25.0 kg/m² were at elevated risk of a birth <28 weeks. Propensity score-matched women with BMI ≥30.0 kg/m² were at decreased risk of a spontaneous preterm birth with intact membranes between 32 and 36 weeks, supporting the complexity of BMI as a risk factor for preterm birth.

Association of Gestational Weight Gain With Infant Morbidity and Mortality in the United States

IMPORTANCE

The associations of gestational weight gain (GWG) with infant morbidity and mortality are unclear, and the existing recommendations for GWG have not been stratified by the severity of obesity.

OBJECTIVES

To identify optimal GWG ranges associated with reduced risks of infant morbidity and mortality across maternal body mass index (BMI) categories.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used US nationwide, linked birth and infant death data between 2011 and 2015 to assess the associations of GWG in 2.0-kg groups with infant morbidity and mortality and identified optimal GWG ranges associated with reduced risks of both outcomes, using multivariable logistic regression models. Statistical analysis was performed from February 11 to October 14, 2021.

EXPOSURE

Gestational weight gain equivalent to 40 weeks.

MAIN OUTCOMES AND MEASURES

The 2 main outcomes were (1) significant morbidity of the newborn infant, defined as any presence of assisted ventilation, admission to the neonatal intensive care unit, surfactant therapy, antibiotic therapy, or seizures; and (2) infant mortality younger than 1 year of age (<1 hour, 1-23 hours, 1-6 days, 7-27 days, or 28-365 days after birth).

RESULTS

In this study of 15 759 945 mother-infant dyads, the mean (SD) age of the women was 28.1 (5.9) years. Women gained a mean (SD) of 14.1 (7.3) kg during pregnancy, and the mean (SD) GWG decreased with BMI categories (underweight, 15.7 [6.4] kg; normal weight, 15.4 [6.2] kg; overweight, 14.2 [7.4] kg; obesity class 1, 12.2 [8.0] kg; obesity class 2, 10.3 [8.4] kg; obesity class 3, 8.2 [9.2] kg; P < .001). A total of 8.8% of the newborns experienced significant morbidity, with the lowest prevalence among infants delivered by women in the normal weight BMI class (8.0%) and the highest among infants delivered by women with class 3 obesity (12.4%); 0.34% of infants died within 1 year of birth, with the lowest prevalence among infants delivered by women in the normal weight BMI class (0.28%) and the highest among infants delivered by women with class 3 obesity (0.58%). Optimal GWG ranges were 12.0 to less than 24.0 kg for underweight and normal weight women, 10.0 to less than 20.0 kg for overweight women, 8.0 to less than 16.0 kg for women with class 1 obesity, 6.0 to less than 16.0 kg for class 2 obesity, and 6.0 to less than 10.0 kg for class 3 obesity. The lower bounds of the optimal GWG ranges appeared to be higher than the existing recommendations for overweight women (10.0 vs 7.0 kg) and for those with class 1 (8.0 vs 5.0 kg), class 2 (6.0 vs 5.0 kg), and class 3 (6.0 vs 5.0 kg) obesity.

CONCLUSIONS AND RELEVANCE

This study analyzed the associations of GWG with infant morbidity and mortality across BMI categories and found that inadequate GWG was associated with increased risks of adverse infant outcomes even for women with obesity. The results suggested that weight maintenance or weight loss should not be used as routine guidelines.

Gestational weight gain disparities in South Carolina: Temporal trends, 2004-2015

BACKGROUND

Few studies have examined secular trends in gestational weight gain (GWG) and findings are inconsistent. Parallel to increasing trends in pre-pregnancy obesity, we hypothesised similar increasing GWG trends.

OBJECTIVES

The study examined trends in GWG in South Carolina (SC), using methods to reduce bias. We also examined whether the 12-year trends in GWG varied according to race/ethnicity and pre-pregnancy weight.

METHODS

Data came from SC birth certificates, 2004 to 2015. We calculated standardised GWG z-scores (GWGZ), using smoothed reference values to account for gestational age and pre-pregnancy body mass index. Quantile regression was used to examine trends in GWGZ, adjusting for pre-pregnancy weight status, race/ethnicity, parity, WIC participation, smoking during pregnancy, residence, age, and birth cohort.

RESULTS

Among 615 093 women, the mean GWGZ was -0.4 (SD = 1.3), which increased from -0.4 in 2004-2005 to -0.2 in 2014-2015. GWGZ increased at the 5th, 10th, 25th, 50th, and 75th percentiles (ranging 0.04 to 0.73 units), with differential trends observed in sub-groups by pre-pregnancy weight and racial/ethnic group. Notably, non-Hispanic White women showed larger increasing trends (0.89 units) compared to non-Hispanic Black (0.55 units) and Hispanic (0.76 units) women in the 5th percentile. Decreasing trends were seen overall for the 90th (-0.02) and 95th percentile (-0.06 units) but positive trends were not seen among women experiencing obese class 1 (no change in 90th and 95th), and 2 (0.01 units in 90th, -0.02 units in 95th).

CONCLUSIONS

This study shows increasing GWGZ trends from the 5th to the 75th percentiles and decreasing trends in 90th and 95th percentiles in SC for the last decade. Racial/ethnic and pre-pregnancy weight disparities did not improve over the study period. Future research is needed to confirm these findings in other states and to develop strategies to narrow racial and pre-pregnancy weight disparities at the highest and lowest percentiles.

Agreement between self-reported pre-pregnancy weight and measured first-trimester weight in Brazilian women

Background

Self-reported pre-pregnancy weight and weight measured in the first trimester are both used to estimate pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) but there is limited information on how they compare, especially in low- and middle-income countries, where access to a weight scale can be limited. Thus, the main goal of this study was to evaluate the agreement between self-reported pre-pregnancy weight and weight measured during the first trimester of pregnancy among Brazilian women so as to assess whether self-reported pre-pregnancy weight is reliable and can be used for calculation of BMI and GWG.

Methods

Data from the Brazilian Maternal and Child Nutrition Consortium (BMCNC, n = 5563) and the National Food and Nutritional Surveillance System (SISVAN, n = 393,095) were used to evaluate the agreement between self-reported pre-pregnancy weight and weights measured in three overlapping intervals (30–94, 30–60 and 30–45 days of pregnancy) and their impact in BMI classification. We calculated intraclass correlation and Lin’s concordance coefficients, constructed Bland and Altman plots, and determined Kappa coefficient for the categories of BMI.

Results

The mean of the differences between self-reported and measured weights was < 2 kg during the three intervals examined for BMCNC (1.42, 1.39 and 1.56 kg) and about 1 kg for SISVAN (1.0, 1.1 and 1.2 kg). Intraclass correlation and Lin’s coefficient were > 0.90 for both datasets in all time intervals. Bland and Altman plots showed that the majority of the difference laid in the ±2 kg interval and that the differences did not vary according to measured first-trimester BMI. Kappa coefficient values were > 0.80 for both datasets at all intervals. Using self-reported pre-pregnancy or measured weight would change, in total, the classification of BMI in 15.9, 13.5, and 12.2% of women in the BMCNC and 12.1, 10.7, and 10.2% in the SISVAN, at 30–94, 30–60 and 30–45 days, respectively.

Conclusion

In Brazil, self-reported pre-pregnancy weight can be used for calculation of BMI and GWG when an early measurement of weight during pregnancy is not available. These results are especially important in a country where the majority of woman do not initiate prenatal care early in pregnancy.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12884-020-03354-4.

In-Hospital Formula Feeding and Breastfeeding Duration

BACKGROUND

In-hospital formula feeding (IHFF) of breastfed infants is associated with shorter duration of breastfeeding. Despite evidence-based guidelines on when IHFF is appropriate, many infants are given formula unnecessarily during the postpartum hospital stay. To account for selection bias inherent in observational data, in this study, we estimate liberal and conservative bounds for the association between hospital formula feeding and duration of breastfeeding.

METHODS

Infants enrolled in the Minnesota Special Supplemental Nutrition Program for Women, Infants, and Children were selected. Breastfed infants given formula were matched with infants exclusively breastfed (n = 5310) by using propensity scoring methods to adjust for potential confounders. Cox regression of the matched sample was stratified on feeding status. A second, more conservative analysis (n = 4836) was adjusted for medical indications for supplementation.

RESULTS

Hazard ratios (HR) for weaning increased across time. In the first analysis, the HR across the first year was 6.1 (95% confidence interval [CI] 4.9-7.5), with HRs increasing with age (first month: HR = 4.1 [95% CI 3.5-4.7]; 1-6 months: HR = 8.2 [95% CI 5.6-12.1]; >6 months: HR = 14.6 [95% CI 8.9-24.0]). The second, more conservative analysis revealed that infants exposed to IHFF had 2.5 times the hazard of weaning compared with infants who were exclusively breastfed (HR = 2.5; 95% CI 1.9-3.4).

CONCLUSIONS

IHFF was associated with earlier weaning, with infants exposed to IHFF at 2.5 to 6 times higher risk in the first year than infants exclusively breastfed. Strategies to reduce IHFF include prenatal education, peer counseling, hospital staff and physician education, and skin-to-skin contact.

Change in prepregnancy body mass index and gastroschisis

PURPOSE

Maternal body mass index (BMI) is inversely associated with gastroschisis, but a causal relationship has not been established. As data demonstrating that a change in exposure status is related to a change in the frequency of the outcome can add to the evidence for causality, we conducted a case-control study of change in maternal BMI, assessed using interpregnancy change in BMI (IPC-BMI), and gastroschisis.

METHODS

Data for 258 gastroschisis cases and 2561 controls were obtained from the Texas Birth Defects Registry and vital records (2006-2012). Logistic regression was used to estimate the adjusted association between IPC-BMI and gastroschisis.

RESULTS

The continuous IPC-BMI variable was inversely associated with gastroschisis (adjusted odds ratio [aOR] = 0.90, 95% confidence interval [CI]: 0.86, 0.95). When assessed as a six-level categorical variable, with weight stable women as the referent, the odds of gastroschisis were higher following a BMI decrease of greater than 1 unit (aOR = 1.37, 95% CI: 0.91, 2.06) and lower after a BMI increase of ≥3 units (aOR = 0.62, 95% CI: 0.42, 0.94).

CONCLUSIONS

Our findings suggest that maternal change in BMI is associated with gastroschisis and, thus, add to the epidemiological evidence that can be used to inform our understanding of the relationship between BMI and gastroschisis.

Effect of Maternal Body Mass Index on Postpartum Hemorrhage

BACKGROUND

It is unclear whether obesity is a risk factor for postpartum hemorrhage. The authors hypothesized that obese women are at greater risk of hemorrhage than women with a normal body mass index.

METHODS

The authors conducted a cohort study of women who underwent delivery hospitalization in California between 2008 and 2012. Using multilevel regression, the authors examined the relationships between body mass index with hemorrhage (primary outcome), atonic hemorrhage, and severe hemorrhage (secondary outcomes). Stratified analyses were performed according to delivery mode.

RESULTS

The absolute event rate for hemorrhage was 60,604/2,176,673 (2.8%). In this cohort, 4% of women were underweight, 49.1% of women were normal body mass index, 25.9% of women were overweight, and 12.7%, 5.2%, and 3.1% of women were in obesity class I, II, and III, respectively. Compared to normal body mass index women, the odds of hemorrhage and atonic hemorrhage were modestly increased for overweight women (hemorrhage: adjusted odds ratio [aOR], 1.06; 99% CI, 1.04 to 1.08; atonic hemorrhage: aOR, 1.07; 99% CI, 1.05 to 1.09) and obesity class I (hemorrhage: aOR, 1.08; 99% CI, 1.05 to 1.11; atonic hemorrhage; aOR, 1.11; 99% CI, 1.08 to 1.15). After vaginal delivery, overweight and obese women had up to 19% increased odds of hemorrhage or atonic hemorrhage; whereas, after cesarean delivery, women in any obesity class had up to 14% decreased odds of severe hemorrhage.

CONCLUSIONS

The authors' findings suggest that, at most, maternal obesity has a modest effect on hemorrhage risk. The direction of the association between hemorrhage and body mass index may differ by delivery mode.

Interpregnancy change in body mass index and infant outcomes in Texas: a population-based study

Background

Maternal prepregnancy body mass index (BMI) is associated with several infant outcomes, but it is unclear whether these associations reflect causal relationships. We conducted a study of interpregnancy change in BMI (IPC-BMI) to improve understanding of the associations between BMI and large for gestational age (LGA), small for gestational age (SGA), and preterm birth (PTB).

Methods

Birth certificate data from 2481 linked sibling pairs (Texas, 2005–2012) were used to estimate IPC-BMI and evaluate its association with LGA, SGA, and PTB in the younger sibling of the pair. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) using data from the full sample and within strata defined by prepregnancy BMI for the older sibling.

Results

On average, women gained 1.1 BMI units between pregnancies. In the full sample, interpregnancy BMI decreases were associated with reduced odds of LGA and increased odds of SGA and PTB (IPC-BMI < -1 versus 0 to < 1: LGA aOR 0.7, 95% CI 0.4, 1.1; SGA aOR 1.6, 95% CI 1.0, 2.7; PTB aOR 1.9, 95% CI 1.3, 2.8). In stratified analyses, similar associations were observed in some, but not all, strata. Findings for interpregnancy BMI increases were less consistent, with little evidence for associations between these outcomes and the most extreme IPC-BMI increases.

Conclusions

There is growing evidence that interpregnancy BMI decreases are associated with LGA, SGA, and PTB. However, taken as a whole, the literature provides insufficient evidence to establish causal links between maternal BMI and these outcomes.

Examining interpregnancy intervals and maternal and perinatal health outcomes using U.S. vital records: Important considerations for analysis and interpretation

BACKGROUND

Numerous studies use birth certificate data to examine the association between interpregnancy interval (IPI) and maternal and perinatal health outcomes. Substantive changes from the latest birth certificate revision have implications for examining this relationship.

METHODS

We provide an overview of the National Vital Statistics System and recent changes to the national birth certificate data file, which have implications for assessing IPI and perinatal health outcomes. We describe the calculation of IPI using birth certificate information and related measurement issues. Missing IPI values by maternal age, race and education using 2016 birth certificate data were also compared. Finally, we review and summarise data quality studies of select covariate and outcome variables (sociodemographic, maternal health and health behaviours, and infant health) conducted after the most recent 2003 birth certificate revision.

RESULTS

Substantive changes to data collection, dissemination and quality have occurred since the 2003 revision. These changes impact IPI measurement, trends and associations with perinatal health outcomes. Missing values of IPI were highest for older ages, lower education and non-Hispanic black women. Minimal differences were found when comparing IPI using different gestational age measures. Recent data quality studies pointed to substantial variation in data quality by item and across states.

CONCLUSION

Future studies examining the association of IPI with maternal and perinatal data using vital records should consider these aspects of the data in their research plan, sensitivity analyses and interpretation of findings.

Using appropriate pre-pregnancy body mass index cut points for obesity in the Chinese population: a retrospective cohort study

BACKGROUND

Appropriate classification of obesity is vital for risk assessment and complication prevention during pregnancy. We aimed to explore which pre-pregnancy BMI cut-offs of obesity, either BMI ≥ 25 kg/m² as recommended by the WHO for Asians or BMI ≥ 28 kg/m² as suggested by the Working Group on Obesity in China (WGOC), best predicts the risk of adverse maternal and perinatal outcomes.

METHODS

We retrospectively reviewed 11,494 medical records for live singleton deliveries in a tertiary center in Guangzhou, China, between January 2013 and December 2016. The primary outcomes included maternal obesity prevalence, adverse maternal and perinatal outcomes. Data were analyzed using the Chi-square test, logistic regression, and diagnostics tests.

RESULTS

Among the study population, 824 (7.2%) were obese according to the WHO criteria for Asian populations, and this would be reduced to 198 (1.7%) based on the criteria of WGOC. Obesity-related adverse maternal and perinatal outcomes were gestational diabetes mellitus, preeclampsia, cesarean section, and large for gestational age (P < 0.05). Compared to the WGOC criterion, the WHO for Asians criterion had a higher Youden index in our assessment of its predictive value in identifying risk of obesity-related adverse outcomes for Chinese pregnant women. Women in the BMI range of 25 to 28 kg/m² are at high risks for adverse maternal and perinatal outcomes, which were similar to women with BMI ≥ 28 kg/m².

CONCLUSIONS

A lower pre-pregnancy BMI cutoff at 25 kg/m² for defining obesity may be appropriate for pregnant women in South China. If WGOC standards are applied to pregnant Chinese populations, a significant proportion of at-risk patients may be missed.

Achieving Appropriate Gestational Weight Gain: The Role of Healthcare Provider Advice

BACKGROUND

The Institute of Medicine (IOM) revised gestational weight gain recommendations in 2009. We examined associations between healthcare provider advice about gestational weight gain and inadequate or excessive weight gain, stratified by prepregnancy body mass index category.

MATERIALS AND METHODS

We analyzed cross-sectional data from women delivering full-term (37-42 weeks of gestation), singleton infants from four states that participated in the 2010-2011 Pregnancy Risk Assessment Monitoring System (unweighted n = 7125). Women reported the weight gain range (start and end values) advised by their healthcare provider; advice was categorized as follows: starting below recommendations, starting and ending within recommendations (IOM consistent), ending above recommendations, not remembered, or not received. We examined associations between healthcare provider advice and inadequate or excessive, compared with appropriate, gestational weight gain using adjusted prevalence ratios (aPR) and 95% confidence intervals (CIs).

RESULTS

Overall, 26.3% of women reported receiving IOM-consistent healthcare provider advice; 26.0% received no advice. Compared with IOM-consistent advice, advice below recommendations was associated with higher likelihood of inadequate weight gain among underweight (aPR 2.22, CI 1.29-3.82) and normal weight women (aPR 1.57, CI 1.23-2.02); advice above recommendations was associated with higher likelihood of excessive weight gain among all but underweight women (aPR range 1.36, CI 1.08-1.72 to aPR 1.42, CI 1.19-1.71). Not remembering or not receiving advice was associated with both inadequate and excessive weight gain.

CONCLUSIONS

Few women reported receiving IOM-consistent advice; not receiving IOM-consistent advice put women at-risk for weight gain outside recommendations. Strategies that raise awareness of IOM recommendations and address barriers to providing advice are needed.

The role of obesity in the risk of gestational diabetes among immigrant and U.S.-born women in New York City

PURPOSE

To examine if the role of obesity in the risk of gestational diabetes differs between immigrant and U.S.-born women.

METHODS

We used New York City-linked 2010-2014 birth certificate and hospital data. We created four racial/ethnic groups (non-Hispanic black, Hispanic, non-Hispanic white, and Asian) and three subgroups (Mexican, Indian, and Chinese). Gestational diabetes mellitus (GDM) was ascertained by the birth certificate checkbox and discharge ICD-9 codes. We calculated relative risks for immigrant status and body mass index with GDM using covariate-adjusted log-binomial regression. We calculated multivariable population attributable risk to estimate the proportion of GDM that could be eliminated if overweight/obesity were eliminated by immigrant status.

RESULTS

Immigrant women had higher risk of GDM than U.S.-born women, with adjusted relative risks ranging from 1.2 among non-Hispanic black women (95% confidence interval, 1.2-1.3) to 1.6 among Hispanic women (95% confidence interval, 1.4-1.8). Increasing body mass index was associated with GDM risk in all groups, but relative risks were weaker among immigrants (P for interaction <.05). The population attributable risk for overweight/obesity was lower in immigrant women than in U.S.-born women in all racial/ethnic groups.

CONCLUSIONS

The lower proportion of GDM attributable to overweight/obesity among immigrant women may point to early life and migration influences on risk of GDM.

The impact of maternal body mass index on external cephalic version success

OBJECTIVE

The purpose of this study is to determine the association between body mass index (BMI) and success of ECV.

METHODS

This is a cross-sectional analysis of singleton live births in the USA from 2010 to 2014 using birth certificate data. Patients were assigned a BMI category according to standard WHO classification. Comparisons of success of ECV between the BMI categories were made using chi-square analysis with normal BMI as the reference group. Cochran-Armitage test was performed to look for a trend of decreasing success of ECV as BMI increased. The odds for successful ECV were estimated using multivariate logistic regression analysis, adjusting for possible confounders.

RESULTS

A total of 51,002 patients with documented ECV were available for analysis. There was a decreased success rate for ECV as BMI increased (p < .01). Women with a BMI of 40 kg/m² or greater had a 58.5% success rate of ECV; women with a normal BMI had 65.0% success rate of ECV. Multivariate analyses demonstrated significant decrease in success of ECV in women with BMI of 40 kg/m² or greater (OR 0.621, CI 0.542-0.712). Among women with BMI of 40 kg/m² or greater with successful ECV, 59.5% delivered vaginally. In contrast, 81.0% of women with normal BMI and successful ECV delivered vaginally.

CONCLUSIONS

Morbidly obese women have decreased success rate of ECV as BMI increases and decreased vaginal delivery rates after successful ECV.

Parental Body Mass Index and Behavioral Problems in Their Offspring: A Danish National Birth Cohort Study

Maternal obesity has been associated with increased risk of offspring behavioral problems. We examined whether this association could be explained by familial factors by comparing associations for maternal body mass index (BMI) with associations for paternal BMI. We studied 38,314 children born to mothers enrolled in the Danish National Birth Cohort during 1996-2002. Data on maternal BMI was collected at 15 weeks of gestation, and paternal BMI was assessed when the child was 18 months old. When the child was 7 years old, the Strengths and Difficulties Questionnaire was completed by the parents. We estimated odds ratios for behavioral problems in offspring born to overweight/obese parents, and we found that maternal BMI was associated with offspring behavioral problems. Maternal BMI of 25.0-29.9 was associated with a 33% (odds ratio = 1.33, 95% confidence interval: 1.13, 1.57) higher risk of total difficulties in offspring, and maternal BMI of ≥30.0 was associated with an 83% (odds ratio = 1.83, 95% confidence interval: 1.49, 2.25) higher risk. Paternal obesity was also associated with higher risk of offspring behavioral problems, but stronger associations were observed with maternal prepregnancy obesity. Our results suggest that part of the association between maternal BMI and behavioral problems can be accounted for by genetic and social factors, but environmental risk factors may also contribute to the etiology of behavioral problems.

Antenatal and postnatal depression in women with obesity: a systematic review

Obesity and depression are prevalent complications during pregnancy and associated with severe health risks for the mother and the child. The co-occurrence of both conditions may lead to a particular high-risk group. This review provides a systematic overview of the association between pre-pregnancy obesity and antenatal or postnatal depression. We conducted a systematic electronic literature search for English language articles published between January 1990 and March 2017. Inclusion criteria were (a) adult pregnant women, (b) women with pre-pregnancy obesity and normal weight controls, (c) definition of obesity according to the IOM 1990/2009 criteria, (d) established depression measure, and (e) report on the association between pre-pregnancy obesity and antenatal or postnatal depression. Fourteen (eight prospective (PS), six cross-sectional (CS)) studies were included. One study reported data from a large community-based sample, and one reported cross-national data. Of 13 studies examining pre-pregnancy obesity and antenatal depression, 9 found a higher risk or higher levels of antenatal depression among women with obesity relative to normal weight (6 PS, 3 CS), while 4 studies found no association (2 PS, 2 CS). Of four studies examining pre-pregnancy obesity and postnatal depression, two studies found a positive association (two PS), one study (CS) reported different findings for different obesity classes, and one study found none (PS). The findings suggest that women with obesity are especially vulnerable to antenatal depression. There is a need to develop appropriate screening routines and targeted interventions to mitigate negative health consequences for the mother and the child. Research addressing the association between obesity and postnatal depression is too limited to draw solid conclusions. Results are mainly based on selective samples, and there is a need for further high-quality prospective studies examining the association between pre-pregnancy obesity and antenatal and postnatal depression.

Geographic variability in gestational weight gain: a multilevel population-based study of women having term births in Florida (2005-2012)

PURPOSE

We examined the extent of geographic variability in gestational weight gain (GWG), identified areas where women have suboptimal GWG, and evaluated whether individual- and area-level factors account for such variability.

METHODS

We conducted a population-based cohort study including 1,385,574 women delivering term, singleton, and live births in Florida. We used a Bayesian, structured additive regression with a spatial function to analyze data from Florida's birth certificates (2005-2012) and ZIP code tabulation areas (ZCTAs; 2010 Census).

RESULTS

The prevalence of insufficient (7.7%-42.9%) and excessive (17.1%-82.4%) GWG varied widely within Florida. Geographic variability was not explained by risk factors under study. Clusters in Orlando, Tampa, and Miami exhibited increased likelihood of insufficient GWG, whereas clusters in the Northwest of Florida exhibited increased likelihood of excessive GWG.

CONCLUSIONS

We identified areas in Florida with high likelihood of suboptimal GWG that policy-makers should prioritize in the implementation of programs for optimizing GWG.

Maternal Supplementation with Small-Quantity Lipid-Based Nutrient Supplements Compared with Multiple Micronutrients, but Not with Iron and Folic Acid, Reduces the Prevalence of Low Gestational Weight Gain in Semi-Urban Ghana: A Randomized Controlled Trial

Background: It is unclear whether maternal supplementation with small-quantity lipid-based nutrient supplements (SQ-LNSs; 118 kcal/d) affects maternal weight.Objective: We compared several secondary anthropometric measures between 3 groups of women in the iLiNS (International Lipid-based Nutrient Supplements)-DYAD trial in Ghana.Methods: Women (n = 1320; <20 wk of gestation) were randomly assigned to receive 60 mg Fe + 400 μg folic acid/d (IFA), 18 vitamins and minerals/d [multiple micronutrients (MMNs)], or 20 g SQ-LNSs with 22 micronutrients/d (LNS) during pregnancy and a placebo (200 mg Ca/d), MMNs, or SQ-LNSs, respectively, for 6 mo postpartum. Weight, midupper arm circumference (MUAC), and triceps skinfold (TSF) thickness at 36 wk of gestation and 6 mo postpartum were analyzed, as were changes from estimated prepregnancy values. We assessed the adequacy of estimated gestational weight gain (GWG) by using Institute of Medicine (IOM) and International Fetal and Newborn Growth Standards for the 21st Century (INTERGROWTH-21st) guidelines.Results: The estimated prepregnancy prevalence of overweight or obesity was 38.5%. By 36 wk of gestation, women (n = 1015) had a mean ± SD weight gain of 7.4 ± 3.7 kg and changes of -1.0 ± 1.7 cm in MUAC and -2.8 ± 4.1 mm in TSF thickness. The LNS group had a lower prevalence of inadequate GWG on the basis of IOM guidelines (57.4%) than the MMN (67.2%) but not the IFA (63.1%) groups (P = 0.030), whereas the prevalence of adequate (26.9% overall) and excessive (10.4% overall) GWG did not differ by group. The percentages of normal-weight women (in kg/m²: 18.5 < body mass index < 25.0; n = 754) whose GWG was less than the third centile of the INTERGROWTH-21st standards were 23.0%, 28.7%, and 28.5% for the LNS, MMN, and IFA groups, respectively (P = 0.36). At 6 mo postpartum, the prevalence of overweight or obesity was 45.3%, and the risk of becoming overweight or obese did not differ by group.Conclusion: SQ-LNS supplementation is one potential strategy to address the high prevalence of inadequate GWG in women in settings similar to Ghana, without increasing the risk of excessive GWG. This trial was registered at clinicaltrials.gov as NCT00970866.

Optimal gestational weight gain: prepregnancy BMI specific influences on adverse pregnancy and infant health outcomes

OBJECTIVE

The Institute of Medicine (IOM) 2009 gestational weight gain (GWG) guidelines are based on prepregnancy body mass index (BMI) categories. We intended to refine optimal GWG for each prepregnancy BMI unit in relation to the risk of small- and large-for-gestational-age (SGA and LGA) births, cesarean section (C-section) and infant death.

STUDY DESIGN

We used data from 836,841 Ohio birth records from 2006 to 2012, and applied generalized additive models to calculate optimal GWG by prepregnancy BMI unit.

RESULTS

The suggested optimal GWG was generally similar to IOM 2009 GWG guidelines for prepregnancy BMIs <25 kg m^-2, but higher for prepregnancy BMIs 25 to 32 kg m^-2 and lower for BMIs 38 to 50 kg m^-2. The suggested optimal GWG was 14 to 18.5, 13 to 17, 11.5 to 16, 8.5 to 12.5, 4 to 10, 3 to 7, 1.5 to 6 and 1.5 to 4.5 kg for prepregnancy BMIs 15, 20, 25, 30, 35, 40, 45 and 50 kg m^-2, respectively.

CONCLUSION

This research suggests that GWG recommendations may be refined at individual prepregnancy BMI levels.

The accuracy of self-reported pregnancy-related weight: a systematic review

Self-reported maternal weight is error-prone, and the context of pregnancy may impact error distributions. This systematic review summarizes error in self-reported weight across pregnancy and assesses implications for bias in associations between pregnancy-related weight and birth outcomes. We searched PubMed and Google Scholar through November 2015 for peer-reviewed articles reporting accuracy of self-reported, pregnancy-related weight at four time points: prepregnancy, delivery, over gestation and postpartum. Included studies compared maternal self-report to anthropometric measurement or medical report of weights. Sixty-two studies met inclusion criteria. We extracted data on magnitude of error and misclassification. We assessed impact of reporting error on bias in associations between pregnancy-related weight and birth outcomes. Women underreported prepregnancy (PPW: -2.94 to -0.29 kg) and delivery weight (DW: -1.28 to 0.07 kg), and over-reported gestational weight gain (GWG: 0.33 to 3 kg). Magnitude of error was small, ranged widely, and varied by prepregnancy weight class and race/ethnicity. Misclassification was moderate (PPW: 0-48.3%; DW: 39.0-49.0%; GWG: 16.7-59.1%), and overestimated some estimates of population prevalence. However, reporting error did not largely bias associations between pregnancy-related weight and birth outcomes. Although measured weight is preferable, self-report is a cost-effective and practical measurement approach. Future researchers should develop bias correction techniques for self-reported pregnancy-related weight.

Parental Obesity and Early Childhood Development

BACKGROUND

Previous studies identified associations between maternal obesity and childhood neurodevelopment, but few examined paternal obesity despite potentially distinct genetic/epigenetic effects related to developmental programming.

METHODS

Upstate KIDS (2008-2010) recruited mothers from New York State (excluding New York City) at ∼4 months postpartum. Parents completed the Ages and Stages Questionnaire (ASQ) when their children were 4, 8, 12, 18, 24, 30, and 36 months of age corrected for gestation. The ASQ is validated to screen for delays in 5 developmental domains (ie, fine motor, gross motor, communication, personal-social functioning, and problem-solving ability). Analyses included 3759 singletons and 1062 nonrelated twins with ≥1 ASQs returned. Adjusted odds ratios (aORs) and 95% confidence intervals were estimated by using generalized linear mixed models accounting for maternal covariates (ie, age, race, education, insurance, marital status, parity, and pregnancy smoking).

RESULTS

Compared with normal/underweight mothers (BMI <25), children of obese mothers (26% with BMI ≥30) had increased odds of failing the fine motor domain (aOR 1.67; confidence interval 1.12-2.47). The association remained after additional adjustment for paternal BMI (1.67; 1.11-2.52). Paternal obesity (29%) was associated with increased risk of failing the personal-social domain (1.75; 1.13-2.71), albeit attenuated after adjustment for maternal obesity (aOR 1.71; 1.08-2.70). Children whose parents both had BMI ≥35 were likely to additionally fail the problem-solving domain (2.93; 1.09-7.85).

CONCLUSIONS

Findings suggest that maternal and paternal obesity are each associated with specific delays in early childhood development, emphasizing the importance of family information when screening child development.

Prepregnancy Body Mass Index and Infant Mortality in 38 U.S. States, 2012-2013

OBJECTIVE

To estimate whether prepregnancy body mass index (BMI) is related to infant mortality and whether adherence to weight gain recommendations mitigates the relationship between BMI and infant mortality.

METHODS

This was a cohort study using 2012-2013 U.S. national linked birth certificate and infant death files for 38 states and the District of Columbia with the BMI measure, including 6,419,836 singleton births and 36,691 infant deaths (infant mortality rate 5.72/1,000). Prenatal weight gain in three categories was based on adherence to Institute of Medicine recommendations. The outcome measure was infant deaths in the first year of life subdivided into two time periods: neonatal (less than 28 days) and postneonatal (28 days to 1 year).

RESULTS

With normal prepregnancy weight as a reference, after adjustment, the odds ratio (OR) for an infant death rose from 1.32 (95% confidence interval [CI] 1.27-1.37) for mothers in the obese I category to 1.73 (95% CI 1.64-1.83) for obese III. Higher BMI was related to higher rates of both neonatal and postneonatal mortality. The adjusted OR for the risk of an infant death among singleton, term, vertex births for those gaining less than the recommended weight was 1.07 (95% CI 1.01-1.12) and 1.04 (95% CI 0.99-1.09) for those gaining more than recommended.

CONCLUSION

Even after controlling for multiple risks, prepregnancy BMI was strongly related to infant mortality. Efforts to lower the infant mortality rate may benefit from a focus on reducing obesity among women of reproductive age.

Maternal pre-pregnancy and gestational diabetes, obesity, gestational weight gain, and risk of cancer in young children: a population-based study in California

PURPOSE

We aimed to examine the influence of pre-pregnancy diabetes, pre-pregnancy body mass index (BMI), gestational diabetes, and gestational weight gain on childhood cancer risk in offspring.

METHODS

We identified cancer cases (n = 11,149) younger than age 6 years at diagnosis from the California Cancer Registry registered between 1988 and 2013. Controls (n = 270,147) were randomly sampled from California birth records, and frequency matched by year of birth to all childhood cancers during the study period. Exposure and covariate information were extracted from birth records. Unconditional logistic regression models were generated to assess the importance of pre-pregnancy diabetes, pre-pregnancy BMI, gestational diabetes, and gestational weight gain on childhood cancer risk.

RESULTS

We observed increased risks of acute lymphoblastic leukemia and Wilms' tumor in children of mothers with pre-pregnancy diabetes [odds ratio (OR) 95 % confidence interval (CI) 1.37 (1.11, 1.69); OR (95 % CI) 1.45 (0.97, 2.18), respectively]. When born to mothers who were overweight prior to pregnancy (BMI 25-<30), children were at increased risk of leukemia [OR (95 % CI) 1.27 (1.01, 1.59)]. Insufficient gestational weight gain increased the risk of acute myeloid leukemia [OR (95 % CI) 1.50 (0.92, 2.42)] while excessive gestational weight gain increased the risk of astrocytomas [OR (95 % CI) 1.56 (0.97, 2.50)]. No associations were found between gestational diabetes and childhood cancer risk in offspring.

CONCLUSIONS

We estimated elevated risks of several childhood cancers in the offspring of mothers who had diabetes and were overweight prior to pregnancy, as well as mothers who gained insufficient or excessive weight. Since few studies have focused on these factors in relation to childhood cancer, replication of our findings in future studies is warranted.

Preventing large birth size in women with preexisting diabetes mellitus: The benefit of appropriate gestational weight gain

OBJECTIVE

To estimate the percentage of infants with large birth size attributable to excess gestational weight gain (GWG), independent of prepregnancy body mass index, among mothers with preexisting diabetes mellitus (PDM).

STUDY DESIGN

We analyzed 2004-2008 Florida linked birth certificate and maternal hospital discharge data of live, term (37-41weeks) singleton deliveries (N=641,857). We calculated prevalence of large-for-gestational age (LGA) (birth weight-for-gestational age≥90th percentile) and macrosomia (birth weight>4500g) by GWG categories (inadequate, appropriate, or excess). We used multivariable logistic regression to estimate the relative risk (RR) of large birth size associated with excess compared to appropriate GWG among mothers with PDM. We then estimated the population attributable fraction (PAF) of large birth size due to excess GWG among mothers with PDM (n=4427).

RESULTS

Regardless of diabetes status, half of mothers (51.2%) gained weight in excess of recommendations. Large birth size was higher in infants of mothers with PDM than in infants of mothers without diabetes (28.8% versus 9.4% for LGA, 5.8% versus 0.9% for macrosomia). Among women with PDM, the adjusted RR of having an LGA infant was 1.7 (95% CI 1.5, 1.9) for women with excess GWG compared to those with appropriate gain; the PAF was 27.7% (95% CI 22.0, 33.3). For macrosomia, the adjusted RR associated with excess GWG was 2.1 (95% CI 1.5, 2.9) and the PAF was 38.6% (95% CI 24.9, 52.4).

CONCLUSION

Preventing excess GWG may avert over one-third of macrosomic term infants of mothers with PDM. Effective strategies to prevent excess GWG are needed.

Body Mass Index as a Measure of Obesity: Racial Differences in Predictive Value for Health Parameters During Pregnancy

BACKGROUND

As a measure of obesity, body mass index (BMI; kg/m²) is an imperfect predictor of health outcomes, particularly among African Americans. However, BMI is used to guide prenatal care. We examined racial differences in the predictive value of maternal BMI for physiologic correlates of obesity, serum interleukin (IL)-6 and C-reactive protein (CRP), as well as cesarean section and infant birth weight.

METHODS

One hundred five pregnant women (40 European American, 65 African American) were assessed during the second trimester. BMI was defined as per prepregnancy weight. Electrochemiluminescence and enzyme-linked immunosorbent assays were used to quantify IL-6 and CRP, respectively. Birth outcomes were determined by medical record review.

RESULTS

Women of both races classified as obese had higher serum IL-6 and CRP than their normal-weight counterparts (ps ≤ 0.01). However, among women with overweight, elevations in IL-6 (p < 0.01) and CRP (p = 0.06) were observed among European Americans, but not African Americans (ps ≥ 0.61). Maternal obesity was a significantly better predictor of cesarean section among European Americans versus African Americans (p = 0.03) and BMI was associated with infant birth weight among European Americans (p < 0.01), but not African Americans (p = 0.94). Effects remained after controlling for gestational age at delivery, gestational diabetes, and gestational weight gain as appropriate.

CONCLUSIONS

BMI may be a less valid predictor of correlates of overweight/obesity among African Americans versus European Americans during pregnancy. This should be considered in epidemiological studies of maternal-child health. In addition, studies examining the comparative validity of alternative/complementary measures to define obesity in pregnancy are warranted to inform clinical care.

Validity of birth certificate-derived maternal weight data in twin pregnancies

Birth certificates are an important source of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) data for surveillance and aetiologic studies, but little is known about their validity in twin pregnancies. Twins experience high rates of adverse perinatal outcomes that have been associated with BMI and GWG in singletons. Our objective was to evaluate the accuracy of birth certificate-derived pre-pregnancy BMI and GWG compared with medical record-derived data in a sample of 186 twin pregnancies at a teaching hospital in Pennsylvania (2003-2010). Twelve strata were created by simultaneous stratification on pre-pregnancy BMI (underweight, normal weight/overweight, obese class 1, obese classes 2 and 3) and GWG (<20th, 20-80th, >80th percentile). The agreement of birth certificate-derived pre-pregnancy BMI category with medical record BMI category was lowest among underweight mothers [75% (95% confidence interval 51-91%) ] and highest among normal/overweight [97% (90-99%) ] and obese classes 2 and 3 mothers [97% (85-99%) ]. Agreement for GWG category from the birth certificate varied from 57% (41-70%) for GWG >80th percentile to 80% (65-91%) and 82% (72-89%) for GWG <20th and 20th-80th percentiles, respectively. The misclassification of BMI and GWG was primarily due to error in pre-pregnancy weight rather than weight at delivery or height. Agreement proportions for twins were not meaningfully different from the proportions in a comparable sample of singleton pregnancies. These data suggest that birth certificate-based BMI and GWG data are prone to error in twin pregnancies. Those who use these data should conduct internal validation studies and adjust their results using bias analyses.

Educational Attainment and Gestational Weight Gain among U.S. Mothers

BACKGROUND

Education is an important social determinant of many health outcomes, but the relationship between educational attainment and the amount of weight gained over the course of a woman's pregnancy (gestational weight gain [GWG]) has not been established clearly.

METHODS

We used data from 1979 through 2010 for women in the National Longitudinal Survey of Youth (1979) cohort (n = 6,344 pregnancies from 2,769 women). We used generalized estimating equations to estimate the association between educational attainment and GWG adequacy (as defined by 2009 Institute of Medicine guidelines), controlling for diverse social factors from across the life course (e.g., income, wealth, educational aspirations and expectations) and considering effect measure modification by race/ethnicity and prepregnancy overweight status.

RESULTS

In most cases, women with more education had increased odds of gaining a recommended amount of gestational weight, independent of educational aspirations and educational expectations and relatively robust to sensitivity analyses. This trend manifested itself in a few different ways. Those with less education had higher odds of inadequate GWG than those with more education. Among those who were not overweight before pregnancy, those with less education had higher odds of excessive GWG than college graduates. Among women who were White, those with less than a high school degree had higher odds of excessive GWG than those with more education.

CONCLUSION

The relationship between educational attainment and GWG is nuanced and nonlinear.

Discrimination and excessive weight gain during pregnancy among Black and Latina young women

RATIONALE

Excessive weight gain during pregnancy is a major determinant of later life obesity among both Black and Latina women and their offspring. However, psychosocial determinants of this risk, including everyday discrimination, and potential moderators of such effects remain unexplored.

OBJECTIVE

We examined the influence of discrimination, a culturally relevant stressor, on odds of gaining weight beyond Institute of Medicine recommendations during pregnancy. Whether the effect was moderated by race/ethnicity, age, or depressive symptoms was also examined.

METHOD

Participants were 413 Black and Latina pregnant young women, ages 14-21 years. Experience with discrimination and all moderators were assessed in the second trimester. Last weight recorded in the third trimester was abstracted from medical records and used to determine excessive weight gain.

RESULTS

Ever experiencing discrimination was associated with a 71% increase in the odds of excessive weight gain. The effect of discrimination was primarily present among women who attributed this treatment to membership in a historically oppressed group (e.g., ethnic minority, female) or to membership in other stigmatized groups (e.g., overweight). The effect of ever experiencing discrimination was not moderated by race/ethnicity or age but was moderated by depressive symptoms. Supporting the perspective of the environmental affordances model, discrimination strongly predicted excessive weight gain when women were low in depressive symptoms but had no effect when women were high in depressive symptoms. The moderating role of depressive symptoms was equivalent for Black and Latina women.

CONCLUSION

Results highlight the role of discrimination in perpetuating weight-related health disparities and suggest opportunities for improving health outcomes among young pregnant women.

Association of Provider Advice and Pregnancy Weight Gain in a Predominantly Hispanic Population

OBJECTIVES

This study sought to determine whether women's report of gestational weight gain (GWG) advice from a health care provider is consistent with the Institute of Medicine (IOM) guidelines and the association between provider advice and women's weight gain during pregnancy.

METHODS

Data came from the 2007 Los Angeles Mommy and Baby study (n = 3,402). The 1990 IOM GWG guidelines were used to define whether the provider's advice on weight gain and women's weight gain were below, within, or above the guidelines.

RESULTS

Approximately 4 months after delivery, 18.8% of the women reported having not discussed weight gain with any health care providers during pregnancy. Among those who reported such discussions, 42% reported receiving weight gain advice from a health care provider within IOM guidelines, 16.5% below guidelines, and 10% above. An additional 13.5% reported the discussion but did not report the recommended weight gain amount. Compared with women who reported provider advice on weight gain within guidelines, women who reported advice below guidelines were 1.7 times (95% confidence interval [CI], 1.3-2.2) more likely to gain less than the IOM recommended amount. Women who reported provider advice above IOM guidelines were 2.0 times (95% CI, 1.4-2.9) more likely to exceed guidelines.

CONCLUSIONS

There is a need for more women to receive advice consistent with the IOM GWG guidelines from their prenatal care providers. Intervention strategies are needed to educate providers about IOM guidelines and how to counsel on GWG.

Postpartum Weight Retention and Subsequent Pregnancy Outcomes

The effects of postpartum weight retention on gestational weight gain in successive pregnancies require elucidation. The purpose of the study was (1) to examine the association between postpartum weight retention and subsequent adherence to the Institute of Medicine gestational weight gain guidelines and (2) to determine whether the association varies by body mass index status and affects birth outcomes. Florida vital records for 2005-2010 were analyzed using χ tests and multivariable Poisson regression, adjusted for interpregnancy interval, tobacco use, maternal age, and race/ethnicity. Obese women who gained inadequate weight were more likely to retain weight between pregnancies than obese women who met or exceeded the recommended weight gain. Risks for preterm birth increased among women with inadequate weight and decreased among women with excessive weight gain. Gaining excessive weight was protective for small-for-gestational age infants in all body mass index categories but increased the risks for large-for-gestational age infants. Underweight and normal weight women who gained in excess were 40% more likely to develop hypertension than normal weight women who gained within the recommended amount. Obese women who retain or gain weight postpartum are at increased risk for inadequate weight gain in a successive pregnancy. Achieving Institute of Medicine-recommended gestational weight gain is essential for preventing adverse maternal and infant outcomes.

The mutual effect of pregestational body mass index, maternal hyperglycemia and gestational weight gain on adverse pregnancy outcomes

OBJECTIVE

To investigate the mutual effect of obesity, gestational diabetes (GDM) and gestational weight gain (GWG) on adverse pregnancy outcomes.

METHODS

Charts of patients who delivered in our hospital between June 2001 and June 2006 singleton, live births  >24 weeks gestation were reviewed. Univariate and multivariate logistic regression were used to assess pregnancy outcomes defined as large for gestational age (LGA), primary cesarean section (PCS) and a composite outcome of LGA and/or PCS.

RESULTS

A total of 8595 women were included. Frequency of composite outcome increased with increasing body mass index (BMI), increasing hyperglycemia and above-recommended GWG. In the multivariate logistic regression analysis compared to women with normal BMI, odds ratio (OR) for composite outcome was 1.23 (95% confidence interval [CI] 1.06-1.44) in overweight women, OR = 1.86 (1.51-2.31) in obese women and in severe obesity OR = 2.97 (2.15-4.11). Compared to normoglycemic women, odds for composite outcome in women with abnormal glucose challenge test OR = 1.46 (1.20-1.79), impaired glucose tolerance OR = 1.65 (1.14-2.4) and GDM OR = 1.56 (1.16-2.10). Women with GWG above recommended had OR = 1.58, (1.37-1.81) for composite outcome.

CONCLUSIONS

Higher pregestational BMI, maternal hyperglycemia and above-recommended GWG independently contribute to adverse pregnancy outcomes. Furthermore, there is mutual effect between these three factors and adverse outcomes. Appropriate pregestational weight and adequate GWG might reduce risk of adverse pregnancy outcomes.

Prepregnancy Obesity and Primary Cesareans among Otherwise Low-Risk Mothers in 38 U.S. States in 2012

BACKGROUND

The United States has recently experienced increases in both its rate of obesity and its cesarean rate. Our objective was to use a new item measuring prepregnancy body mass index (BMI) on the U.S. Standard Certificate of Live Birth to examine at a population level the relationship between maternal obesity and primary cesarean delivery for women at otherwise low risk for cesarean delivery.

METHODS

By 2012, 38 states with 86 percent of United States births had adopted the U.S. Standard Certificate. The sample was limited to the 2,233,144 women who had a singleton, vertex, term (37-41 weeks) birth in 2012 and no prior cesarean. We modeled the likelihood of a primary cesarean by BMI category, controlling for maternal socio-demographic and medical characteristics.

RESULTS

Overall, 46.4 percent of otherwise low-risk mothers had a prepregnancy BMI in the overweight (25.1%) or obese (21.3%) categories, with the obese category distributed as follows: obese I (BMI 30.0-34.9, 12.4%); obese II (BMI 35.0-39.9, 5.5%); and obese III (BMI 40+, 3.5%). Obesity rates were highest among American Indian and Alaska Native (32.5%) and non-Hispanic black mothers (30.5%). After adjustment for demographic and medical risks, the adjusted risk ratios (95% confidence intervals) of cesarean for low-risk primiparas were: 1.61 (1.60-1.63) for obese I, 1.86 (1.83-1.88) for obese II, and 2.21 (2.18-2.25) for obese III mothers compared with mothers in the normal weight category.

DISCUSSION

A relationship between prepregnancy obesity and primary cesarean delivery among relatively low-risk mothers remained even after controlling for social and medical risk factors.

Proportion of gestational diabetes mellitus attributable to overweight and obesity among non-Hispanic black, non-Hispanic white, and Hispanic women in South Carolina

Objective was to estimate race-specific proportions of gestational diabetes mellitus (GDM) attributable to overweight and obesity in South Carolina. South Carolina birth certificate and hospital discharge data were obtained from 2004 to 2006. Women who did not have type 2 diabetes mellitus before pregnancy were classified with GDM if a diagnosis was reported in at least one data source. Relative risks (RR) and 95 % confidence intervals were calculated using the log-binomial model. The modified Mokdad equation was used to calculate population attributable fractions for overweight body mass index (BMI: 25.0-29.9 kg/m(2)), obese (30.0-34.9 kg/m(2)), and extremely obese (≥35 kg/m(2)) women after adjusting for age, gestational weight gain, education, marital status, parity, tobacco use, pre-pregnancy hypertension, and pregnancy hypertension. Overall, the adjusted RR of GDM was 1.6, 2.3, and 2.9 times higher among the overweight, obese, and extremely obese women compared to normal-weight women in South Carolina. RR of GDM for extremely obese women was higher among White (3.1) and Hispanic (3.4) women than that for Black women (2.6). The fraction of GDM cases attributable to extreme obesity was 14.0 % among White, 18.1 % among Black, and 9.6 % among Hispanic women. The fraction of GDM cases attributable to obesity was about 12 % for all racial groups. Being overweight (BMI: 25.0-29.9) explained 8.8, 7.8, and 14.4 % of GDM cases among White, Black, and Hispanic women, respectively. Results indicate a significantly increased risk of GDM among overweight, obese, and extremely obese women. The strength of the association and the proportion of GDM cases explained by excessive weight categories vary by racial/ethnic group.

Effects of race/ethnicity and BMI on the association between height and risk for spontaneous preterm birth

OBJECTIVE

Short height and obesity have each been associated with increased risk for preterm birth (PTB). However, the effect of short height on PTB risk, across different race/ethnicities and body mass index (BMI) categories, has not been studied. Our objective was to determine the influence of maternal height on the risk for PTB within race/ethnic groups, BMI groups, or adjusted for weight.

STUDY DESIGN

All California singleton live births from 2007 through 2010 were included from birth certificate data (vital statistics) linked to hospital discharge data. Prepregnancy BMI (kg/m(2)) was categorized as underweight (<18.5), normal (18.5-24.9), overweight (25.0-29.9), or obese (≥30.0). Maternal race/ethnicity was categorized as: non-Hispanic white, non-Hispanic black, Hispanic, and Asian. Maternal height was classified into 5 categories (shortest, short, middle, tall, tallest) based on racial/ethnic-specific height distributions, with the middle category serving as reference. Poisson regression models were used to estimate relative risks for the association between maternal height and risk of spontaneous PTB (<37 weeks and <32 weeks). Models were stratified on race/ethnicity and BMI. Generalized additive regression models were used to detect nonlinearity of the association. Covariates considered were: maternal age, weight, parity, prenatal care, education, medical payment, previous PTB, gestational and pregestational diabetes, pregestational hypertension, preeclampsia/eclampsia, and smoking.

RESULTS

Among 1,655,385 California singleton live births, 5.2% were spontaneous PTB <37 weeks. Short stature (first height category) was associated with increased risk for PTB for non-Hispanic whites and Hispanics across all BMI categories. Among obese women, tall stature (fifth category) was associated with reduced risk for spontaneous PTB for non-Hispanic whites, Asians, and Hispanics. The same pattern of association was seen for height and risk for spontaneous PTB <32 weeks. In the generalized additive regression model plots, short stature was associated with increased risk for spontaneous PTB of <32 and <37 weeks of gestation among whites and Asians. However, this association was not observed for blacks and Hispanics.

CONCLUSION

Maternal shorter height is associated with a modest increased risk for spontaneous PTB regardless of BMI. Our results suggest that PTB risk assessment should consider race/ethnicity-specific height with respect to the norm in addition to BMI assessment.

Relationship between maternal obesity and prenatal, metabolic syndrome, obstetrical and perinatal complications of pregnancy in Indiana, 2008-2010

BACKGROUND

Obesity is a serious medical condition affecting more than 30% of Indiana, and 25% of Unites States pregnant women. Obesity is related to maternal complications, and significantly impacts the health of pregnant women. The objective of this study was to describe the relationship between maternal complications and pre-pregnancy maternal weight.

METHODS

Using logistic regression models, we analyzed 2008 to 2010 birth certificate data, for 255,773 live births abstracted from the Indiana Vital Statistics registry. We examined the risk of reproductive factors, obstetrical complications and perinatal (intrapartum) complications for underweight, healthy weight, overweight and obese women for this population.

RESULTS

Women who received prenatal care were more likely to be obese [adjusted odds ratio (AOR) = 1.82 (1.56-2.13)]. While women with parity of zero (0) were less likely to be obese [AOR = 0.89, 95% CI (0.86-0.91)]. Women giving birth to twins [AOR = 1.25, 95% CI (1.17- 1.33)], women delivering by Caesarian section [AOR = 2.31, 95% CI ( 2.26-2.37)], and women who previously had a Caesarian section [AOR = 1.95, 95% CI (1.88-2.02)] were more likely to be obese. There was evidence of metabolic like complication in this population, due to obesity. Obesity was significantly associated with obstetrical conditions of the metabolic syndrome, including pre-pregnancy diabetes, gestational diabetes, pre-pregnancy hypertension, pregnancy-induced hypertension and eclampsia [AOR = 5.12, 95% CI (4.47-5.85); AOR = 3.87, 95% CI (3.68-4.08); AOR = 7.66, 95% CI (6.77-8.65); AOR = 3.23, 95% CI (3.07-3.39); and AOR = 1.77, 95% CI (1.31-2.40), respectively. Maternal obesity modestly increased the risk of induction, epidural, post-delivery bleeding, and prolonged labor [AOR = 1.26, 95% CI (1.23-1.29); AOR = 1.15, 95% CI (1.13-1.18); AOR = 1.20, 95% CI (1.12-1.28); and AOR = 1.44, 95% CI (1.30-1.61)], respectively. Obese women were less likely to have blood transfusions [AOR = .74, 95% CI (0.58-96)], vaginal tears [AOR = 0.51, 95% CI (0.44-0.59)], or infections [AOR = 86, 95% CI (0.80-0.93)].

CONCLUSIONS

Our results suggest that maternal obesity in Indiana, like other populations in the USA, is associated with high risks of maternal complications for pregnant women. Pre-pregnancy obesity prevention efforts should focus on targeting children, adolescent and young women, if the goal to reduce the risk of maternal complications related to obesity, is to be reached.

Prepregnancy Obesity and Risks of Stillbirth

BACKGROUND

We examined the association of maternal obesity with risk of stillbirth, focusing on whether the pattern of results varied by gestational age or maternal race-ethnicity or parity.

METHODS

Analyses included 4,012 stillbirths and 1,121,234 liveborn infants delivered in California from 2007-2010. We excluded stillbirths due to congenital anomalies, women with hypertensive disorders or diabetes, and plural births, to focus on fetuses and women without these known contributing conditions. We used Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CI). Separate models were run for stillbirths delivered at 20-23, 24-27, 28-31, 32-36, 37-41 weeks, relative to liveborn deliveries at 37-41 weeks.

RESULTS

For stillbirth at 20-23 weeks, RRs were elevated for all race-ethnicity and parity groups. The RR for a 20-unit change in BMI (which reflects the approximate BMI difference between a normal weight and an Obese III woman) was 3.5 (95% CI 2.2, 5.6) for nulliparous white women and ranged from 1.8 to 5.0 for other sub-groups. At 24-27 weeks, the association was significant (p<0.05) only for multiparous non-Hispanic whites; at 28-31 weeks, for multiparous whites and nulliparous whites and blacks; at 32-36 weeks, for multiparous whites and nulliparous blacks; and at 37-41 weeks, for all groups except nulliparous blacks. The pattern of results was similar when restricted to stillbirths due to unknown causes and somewhat stronger when restricted to stillbirths attributable to obstetric causes.

CONCLUSION

Increased risks were observed across all gestational ages, and some evidence of heterogeneity of the associations was observed by race-ethnicity and parity.

Validity of prepregnancy weight status estimated from self-reported height and weight

The Institute of Medicine's gestational weight gain guidelines are intended to reduce pregnancy complications, poor birth outcomes and excessive postpartum weight retention. The specific weight gain guidelines vary by prepregnancy weight status. We evaluated the validity of prepregnancy weight status (underweight, normal weight, overweight and obesity) classified from self-reported prepregnancy height and weight in reference to those from measured data during the first trimester of pregnancy and imputed data for both pregnant and age-matched non-pregnant women included in the National Health and Nutrition Examination Survey 2003-2006. Self-reported prepregnancy weight status was validated by two ideal references: imputed data with the number of imputations as 10 (n = 5,040) using the data of age-matched non-pregnant women who had both self-reported and measured data, and weight status based on height and weight measured during the first trimester (n = 95). Mean differences, Pearson's correlations (r), and Kappa statistics (κ) were used to examine the strength of agreement between self-reported data and the two reference measures. Mean (standard error of the mean) differences between self-reported versus imputed prepregnancy weight was -1.7 (0.1) kg with an r = 0.98 (p < 0.001), and κ = 0.78 which indicate substantial agreement for the 504 pregnant women. Mean (SEM) differences between self-reported prepregnancy weight versus measured weight in the first trimester was -2.3 (0.7) kg with r = 0.98 (p < 0.001), and κ = 0.76, which also showed substantial agreements in 95 pregnant women. Prepregnancy weight status classified based on self-reported prepregnancy height and weight was valid.

Prevalence and characteristics associated with gestational weight gain adequacy

OBJECTIVE

To estimate the prevalence of gestational weight gain adequacy according to the 2009 Institute of Medicine recommendations and examine demographic, behavioral, psychosocial, and medical characteristics associated with inadequate and excessive gain stratified by prepregnancy body mass index (BMI) category.

METHODS

We used cross-sectional, population-based data on women delivering full-term (37 weeks of gestation or greater), singleton neonates in 28 states who participated in the 2010 or 2011 Pregnancy Risk Assessment Monitoring System. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for inadequate and excessive compared with adequate gain, stratified by prepregnancy BMI.

RESULTS

Overall, 20.9%, 32.0%, and 47.2% of women gained inadequate, adequate, and excessive gestational weight, respectively. Prepregnancy BMI was strongly associated with weight gain outside recommendations. Compared with normal-weight women (prevalence 51.8%), underweight women (4.2%) had decreased odds of excessive gain (adjusted OR 0.50, CI 0.40-0.61), whereas overweight and obese class I, II, and III (23.6%, 11.7%, 5.4%, and 3.5%, respectively) women had increased odds of excessive gain (adjusted OR range 2.07, CI 1.63-2.62 to adjusted OR 2.99, CI 2.63-3.40). Underweight and obese class II and III women had increased odds of inadequate gain (adjusted OR 1.25, CI 1.01-1.55 to 1.86, CI 1.45-2.36). Most characteristics associated with weight gain adequacy were demographic such as racial or ethnic minority status and education and varied by prepregnancy BMI. Notably, one behavioral characteristic-smoking cessation-was associated with excessive gain among normal-weight and obese women.

CONCLUSION

Most women gained weight outside recommendations. Understanding characteristics associated with inadequate or excessive weight gain may identify potentially at-risk women and inform much-needed interventions.

Gestational weight gain and perinatal outcomes of subgroups of Asian-American women, Texas, 2009

BACKGROUND

Asian-American subgroups are heterogeneous, but few studies had addressed differences on gestational weight gain (GWG) and perinatal outcomes related to GWG among this growing and diverse population. The purposes of this study were to examine whether Asian-American women are at higher risk of inadequate or excessive GWG and adverse perinatal outcomes than non-Hispanic White (NH-White) women, and to compare those risks among Asian-American subgroups.

METHODS

This retrospective study included all singleton births to NH-Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnam, and NH-White women documented in 2009 Texas birth certificate data (N = 150,674). Data were analyzed using the χ(2) test, t test, multinomial logistic regression, and binary logistic regression. Chinese women were the reference group in the comparisons among Asian subgroups.

FINDINGS

Asian women had a higher risk of inadequate GWG and gestational diabetes mellitus (GDM) than NH-White women. No difference in the odds of excessive GWG was found among Asian subgroups, although Japanese women had the highest risk of inadequate GWG. After adjusting for confounders, Korean women had the lowest risk of GDM (adjusted odds ratio [AOR], 0.49), whereas Filipino women and Asian Indian had the highest risks of gestational hypertension (AOR, 2.01 and 1.61), cesarean birth (AOR, 1.44 and 1.39), and low birth weight (AOR, 1.94 and 2.51) compared with Chinese women.

CONCLUSIONS

These results support the heterogeneity of GWG and perinatal outcomes among Asian-American subgroups. The risks of adverse perinatal outcomes should be carefully evaluated separately among Asian-American subpopulations.

Validation of selected items on the 2003 U.S. standard certificate of live birth: New York City and Vermont

OBJECTIVE

We assessed the validity of selected items on the 2003 revised U.S. Standard Certificate of Live Birth to understand the accuracy of new and existing items.

METHODS

We calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of select variables reported on the birth certificate using the medical record as the gold standard for a representative sample of live births in New York City (n=603) and Vermont (n=664) in 2009.

RESULTS

In both sites, sensitivity was excellent (>90%) for Medicaid coverage at delivery, any previous live births, and current method of delivery; sensitivity was moderate (70%-90%) for gestational diabetes; and sensitivity was poor (<70%) for premature rupture of the membranes and gestational hypertension. In both sites, PPV was excellent for Medicaid coverage, any previous live births, previous cesarean delivery, and current method of delivery, and poor for premature rupture of membranes. In both sites, almost all items had excellent (>90%) specificity and NPV.

CONCLUSION

Further research is needed to determine how best to improve the quality of data on the birth certificate. Future revisions of the birth certificate may consider removing those items that have consistently proven difficult to report accurately.

Are gestational diabetes mellitus and preconception diabetes mellitus less common in non-Hispanic black women than in non-Hispanic white women?

Based on their higher risk of type 2 diabetes, non-Hispanic blacks (NHBs) would be expected to have higher gestational diabetes mellitus (GDM) risk compared to non-Hispanic whites (NHWs). However, previous studies have reported lower GDM risk in NHBs versus NHWs. We examined whether GDM risk was lower in NHBs and NHWs, and whether this disparity differed by age group. The cohort consisted of 462,296 live singleton births linked by birth certificate and hospital discharge data from 2004 to 2007 in Florida. Using multivariable regression models, we examined GDM risk stratified by age and adjusted for body mass index (BMI) and other covariates. Overall, NHBs had a lower prevalence of GDM (2.5 vs. 3.1%, p < 0.01) and a higher proportion of preconception DM births (0.5 vs. 0.3%, p ≤ 0.01) than NHWs. Among women in their teens (risk ratio 0.56, p < 0.01) and 20-29 years of age (risk ratio 0.85, p < 0.01), GDM risk was lower in NHBs than NHWs. These patterns did not change with adjustment for BMI and other covariates. Among women 30-39 years (risk ratio 1.18, p < 0.01) and ≥40 years (risk ratio 1.22, p < 0.01), GDM risk was higher in NHBs than NHWs, but risk was higher in NHWs after adjustment for BMI. Associations between BMI and GDM risk did not vary by race/ethnicity or age group. NHBs have lower risk of GDM than NHWs at younger ages, regardless of BMI. NHBs had higher risk than NHWs at older ages, largely due to racial/ethnic disparities in overweight/obesity at older ages.

Ascertainment of medicaid payment for delivery on the iowa birth certificate: is accuracy sufficient for timely policy and program relevant analysis?

The Iowa Department of Public Health annually links Medicaid claims data to the birth certificate. Because the latest version of the birth certificate provides more timely and less costly information on delivery payment source, we were interested in assessing the validity and reliability of the birth certificate payment source compared to Medicaid paid claims. We linked Medicaid paid claims to birth certificates for calendar years 2007-2009 (n = 120,626). We measured reliability by Kappa statistic and validity by sensitivity, specificity, predictive value positive and negative. We examined reliability and validity overall and by maternal characteristics (e.g. age, race, ethnicity, education). The Kappa statistic for the birth certificate payment source indicated substantial agreement (0.78; 95 % CL 0.78-0.79). Sensitivity and specificity were also high, 86.3 % (95 % CL 86.0-86 6 %) and 91.9 % (95 % CL 91.7-92.1 %), respectively. The predictive value positive was 87.0 %. The predictive value negative was 91.4 %. Kappa and specificity were lower among women of racial and ethnic minorities, women younger than age 24, and women with less education. The overall Kappa, sensitivity and specificity generally suggest the birth certificate payment source is as valid and reliable as the linked data source. The birth certificate payment source is less valid and reliable for women of racial and ethnic minorities, women younger than age 24, and those with less education. Consequently caution should be exercised when using the birth certificate payment source for monitoring service use by the Medicaid population within specific population subgroups.