Preconception dietary glycemic index and risk for large-for-gestational age births

OBJECTIVES

Diets with a high glycemic index (GI) leading to elevated postprandial glucose levels and hyperinsulinemia during pregnancy have been inconsistently linked to an increased risk for large-for-gestational-age (LGA) births. The effects of prepregnancy dietary GI on LGA risk are, to our knowledge, unknown. We examined the association of prepregnancy dietary GI with LGA births and joint associations of GI and maternal overweight/obesity and infant sex with LGA births among 10 188 infants born without congenital anomalies from 1997 to 2011, using data from the National Birth Defects Prevention Study (NBDPS). The aim of this study was to investigate this association among infants without major congenital anomalies (controls) who participated in the NBDPS and to evaluate how prepregnancy BMI and infant sex may modify this association on the additive scale.

METHODS

Dietary intake was ascertained using a 58-item food frequency questionnaire. We dichotomized dietary GI into high and low categories using spline regression models. Infants with a birth weight at or above the 90th percentile for gestational age and sex, according to a U.S. population reference, were considered LGA. We used logistic regression to obtain odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of the infants, 859 (9%) had a high dietary GI (cut-point: 59), and 1244 infants (12%) were born LGA. Unadjusted analysis suggested an inverse association between high dietary GI and LGA (OR, 0.79; 95% CI, 0.62-0.99). No association was observed in multivariable models when comparing high dietary GI intake between LGA births and all other births (OR, 0.94; 95% CI, 0.74-1.20) or when excluding small-for-gestational-age (SGA) births (OR, 0.94; 95% CI, 0.73-1.19). No joint associations with maternal overweight/obesity or infant sex were observed.

CONCLUSION

High prepregnancy maternal GI was not associated with LGA births independently of or jointly with other factors.

Validity of Birth Certificate Data Compared With Hospital Discharge Data in Reporting Maternal Morbidity and Disparities

A growing number of studies are using birth certificate data, despite data-quality concerns, to study maternal morbidity and associated disparities. We examined whether conclusions about the incidence of maternal morbidity, including Black-White disparities, differ between birth certificate data and hospitalization data. Using linked birth certificate and hospitalization data from California and Michigan for 2018 (N=543,469), we found that maternal morbidity measures using birth certificate data alone are substantially underreported and have poor validity. Furthermore, the degree of underreporting in birth certificate data differs between Black and White individuals and results in erroneous inferences about disparities. Overall, Black-White disparities were more modest in the birth certificate data compared with the hospitalization data. Birth certificate data alone are inadequate for studies of maternal morbidity and associated racial disparities.

Trends and Disparities in Severe Maternal Morbidity Indicator Categories during Childbirth Hospitalization in California from 1997 to 2017

OBJECTIVE

 Severe maternal morbidity (SMM) is increasing and characterized by substantial racial and ethnic disparities. Analyzing trends and disparities across time by etiologic or organ system groups instead of an aggregated index may inform specific, actionable pathways to equitable care. We explored trends and racial and ethnic disparities in seven SMM categories at childbirth hospitalization.

STUDY DESIGN

 We analyzed California birth cohort data on all live and stillbirths ≥ 20 weeks' gestation from 1997 to 2017 (n = 10,580,096) using the Centers for Disease Control and Prevention's SMM index. Cases were categorized into seven nonmutually exclusive indicator categories (cardiac, renal, respiratory, hemorrhage, sepsis, other obstetric, and other medical SMM). We compared prevalence and trends in SMM indicator categories overall and by racial and ethnic group using logistic and linear regression.

RESULTS

 SMM occurred in 1.16% of births and nontransfusion SMM in 0.54%. Hemorrhage SMM occurred most frequently (27 per 10,000 births), followed by other obstetric (11), respiratory (7), and sepsis, cardiac, and renal SMM (5). Hemorrhage, renal, respiratory, and sepsis SMM increased over time for all racial and ethnic groups. The largest disparities were for Black individuals, including over 3-fold increased odds of other medical SMM. Renal and sepsis morbidity had the largest relative increases over time (717 and 544%). Sepsis and hemorrhage SMM had the largest absolute changes over time (17 per 10,000 increase). Disparities increased over time for respiratory SMM among Black, U.S.-born Hispanic, and non-U.S.-born Hispanic individuals and for sepsis SMM among Asian or Pacific Islander individuals. Disparities decreased over time for sepsis SMM among Black individuals yet remained substantial.

CONCLUSION

 Our research further supports the critical need to address SMM and disparities as a significant public health priority in the United States and suggests that examining SMM subgroups may reveal helpful nuance for understanding trends, disparities, and potential needs for intervention.

KEY POINTS

· By SMM subgroup, trends and racial and ethnic disparities varied yet Black individuals consistently had highest rates.. · Hemorrhage, renal, respiratory, and sepsis SMM significantly increased over time.. · Disparities increased for respiratory SMM among Black, U.S.-born Hispanic and non-U.S.-born Hispanic individuals and for sepsis SMM among Asian or Pacific Islander individuals..

Structural Racism, Mass Incarceration, and Racial and Ethnic Disparities in Severe Maternal Morbidity

Importance

Racial and ethnic inequities in the criminal-legal system are an important manifestation of structural racism. However, how these inequities may influence the risk of severe maternal morbidity (SMM) and its persistent racial and ethnic disparities remains underinvestigated.

Objective

To examine the association between county-level inequity in jail incarceration rates comparing Black and White individuals and SMM risk in California.

Design, Setting, and Participants

This population-based cross-sectional study used state-wide data from California on all live hospital births at 20 weeks of gestation or later from January 1, 1997, to December 31, 2018. Data were obtained from hospital discharge and vital statistics records, which were linked with publicly available county-level data. Data analysis was performed from January 2022 to February 2023.

Exposure

Jail incarceration inequity was determined from the ratio of jail incarceration rates of Black individuals to those of White individuals and was categorized as tertile 1 (low), tertile 2 (moderate), tertile 3 (high), with mean cutoffs across all years of 0 to 2.99, 3.00 to 5.22, and greater than 5.22, respectively.

Main Outcome and Measures

This study used race- and ethnicity-stratified mixed-effects logistic regression models with birthing people nested within counties and adjusted for individual- and county-level characteristics to estimate the odds of non-blood transfusion SMM (NT SMM) and SMM including blood transfusion-only cases (SMM; as defined by the Centers for Disease Control and Prevention SMM index) associated with tertiles of incarceration inequity.

Results

This study included 10 200 692 births (0.4% American Indian or Alaska Native, 13.4% Asian or Pacific Islander, 5.8% Black, 50.8% Hispanic or Latinx, 29.6% White, and 0.1% multiracial or other [individuals who self-identified with ≥2 racial groups and those who self-identified as "other" race or ethnicity]). In fully adjusted models, residing in counties with high jail incarceration inequity (tertile 3) was associated with higher odds of SMM for Black (odds ratio [OR], 1.14; 95% CI, 1.01-1.29 for NT SMM; OR, 1.20, 95% CI, 1.01-1.42 for SMM), Hispanic or Latinx (OR, 1.24; 95% CI, 1.14-1.34 for NT SMM; OR, 1.20; 95% CI, 1.14-1.27 for SMM), and White (OR, 1.02; 95% CI, 0.93-1.12 for NT SMM; OR, 1.09; 95% CI, 1.02-1.17 for SMM) birthing people, compared with residing in counties with low inequity (tertile 1).

Conclusions and Relevance

The findings of this study highlight the adverse maternal health consequences of structural racism manifesting via the criminal-legal system and underscore the need for community-based alternatives to inequitable punitive practices.

Assessing the relationship between census tract rurality and severe maternal morbidity in California (1997-2018)

PURPOSE

Recent studies have demonstrated an increased risk of severe maternal morbidity (SMM) for people living in rural versus urban counties. Studies have not considered rurality at the more nuanced subcounty census-tract level. This study assessed the relationship between census-tract-level rurality and SMM for birthing people in California.

METHODS

We used linked vital statistics and hospital discharge records for births between 1997 and 2018 in California. SMM was defined by at least 1 of 21 potentially fatal conditions and lifesaving procedures. Rural-Urban Commuting Area codes were used to characterize census tract rurality dichotomously (2-category) and at 4 levels (4-category). Covariates included sociocultural-demographic, pregnancy-related, and neighborhood-level factors. We ran a series of mixed-effects logistic regression models with tract-level clustering, reporting risk ratios and 95% confidence intervals (CIs). We used the STROBE reporting guidelines.

FINDINGS

Of 10,091,415 births, 1.1% had SMM. Overall, 94.3% of participants resided in urban/metropolitan and 5.7% in rural tracts (3.9% micropolitan, 0.9% small town, 0.8% rural). In 2-category models, the risk of SMM was 10% higher for birthing people in rural versus urban tracts (95% CI: 6%, 13%). In 4-category models, the risk of SMM was 16% higher in micropolitan versus metropolitan tracts (95% CI: 12%, 21%).

CONCLUSION

The observed rurality and SMM relationship was driven by living in a micropolitan versus metropolitan tract. Increased risk may result from resource access inequities within suburban areas. Our findings demonstrate the importance of considering rurality at a subcounty level to understand locality-related inequities in the risk of SMM.

Is gastroschisis associated with county-level socio-environmental quality during pregnancy?

BACKGROUND

Gastroschisis prevalence more than doubled between 1995 and 2012. While there are individual-level risk factors (e.g., young maternal age, low body mass index), the impact of environmental exposures is not well understood.

METHODS

We used the U.S. Environmental Protection Agency's Environmental Quality Index (EQI) as a county-level estimate of cumulative environmental exposures for five domains (air, water, land, sociodemographic, and built) and overall from 2006 to 2010. Adjusted odds ratios (aOR) and 95% confidence interval (CI) were estimated from logistic regression models between EQI tertiles (better environmental quality (reference); mid; poorer) and gastroschisis in the National Birth Defects Prevention Study from births delivered between 2006 and 2011. Our analysis included 594 cases with gastroschisis and 4105 infants without a birth defect (controls).

RESULTS

Overall EQI was modestly associated with gastroschisis (aOR [95% CI]: 1.29 [0.98, 1.71]) for maternal residence in counties with poorer environmental quality, compared to the reference (better environmental quality). Within domain-specific indices, only the sociodemographic domain (aOR: 1.51 [0.99, 2.29]) was modestly associated with gastroschisis, when comparing poorer to better environmental quality.

CONCLUSIONS

Future work could elucidate pathway(s) by which components of the sociodemographic domain or possibly related psychosocial factors like chronic stress potentially contribute to risk of gastroschisis.

Neighborhood Deprivation and Neural Tube Defects

BACKGROUND

Individual measures of socioeconomic status (SES) have been associated with an increased risk of neural tube defects (NTDs); however, the association between neighborhood SES and NTD risk is unknown. Using data from the National Birth Defects Prevention Study (NBDPS) from 1997 to 2011, we investigated the association between measures of census tract SES and NTD risk.

METHODS

The study population included 10,028 controls and 1829 NTD cases. We linked maternal addresses to census tract SES measures and used these measures to calculate the neighborhood deprivation index. We used generalized estimating equations to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) estimating the impact of quartiles of census tract deprivation on NTDs adjusting for maternal race-ethnicity, maternal education, and maternal age at delivery.

RESULTS

Quartiles of higher neighborhood deprivation were associated with NTDs when compared with the least deprived quartile (Q2: aOR = 1.2; 95% CI = 1.0, 1.4; Q3: aOR = 1.3, 95% CI = 1.1, 1.5; Q4 (highest): aOR = 1.2; 95% CI = 1.0, 1.4). Results for spina bifida were similar; however, estimates for anencephaly and encephalocele were attenuated. Associations differed by maternal race-ethnicity.

CONCLUSIONS

Our findings suggest that residing in a census tract with more socioeconomic deprivation is associated with an increased risk for NTDs, specifically spina bifida.

Racial and Ethnic Disparities in Anemia and Severe Maternal Morbidity

OBJECTIVE

To evaluate antepartum anemia prevalence by race and ethnicity, to assess whether such differences contribute to severe maternal morbidity (SMM), and to estimate the contribution of antepartum anemia to SMM and nontransfusion SMM by race and ethnicity.

METHODS

We conducted a population-based cohort study using linked vital record and birth hospitalization data for singleton births at or after 20 weeks of gestation in California from 2011 through 2020. Pregnant patients with hereditary anemias, out-of-hospital births, unlinked records, and missing variables of interest were excluded. Antepartum anemia prevalence and trends were estimated by race and ethnicity. Centers for Disease Control and Prevention criteria were used for SMM and nontransfusion SMM indicators. Multivariable logistic regression modeling was used to estimate risk ratios (RRs) for SMM and nontransfusion SMM by race and ethnicity after sequential adjustment for social determinants, parity, obstetric comorbidities, delivery, and antepartum anemia. Population attributable risk percentages were calculated to assess the contribution of antepartum anemia to SMM and nontransfusion SMM by race and ethnicity.

RESULTS

In total, 3,863,594 births in California were included. In 2020, Black pregnant patients had the highest incidence of antepartum anemia (21.5%), followed by Pacific Islander (18.2%), American Indian-Alaska Native (14.1%), multiracial (14.0%), Hispanic (12.6%), Asian (10.6%), and White pregnant patients (9.6%). From 2011 to 2020, the prevalence of anemia increased more than100% among Black patients, and there was a persistent gap in prevalence among Black compared with White patients. Compared with White patients, the adjusted risk for SMM was high among most racial and ethnic groups; adjustment for anemia after sequential modeling for known confounders decreased SMM risk most for Black pregnant patients (approximated RR 1.47, 95% CI 1.42-1.53 to approximated RR 1.27, 95% CI 1.22-1.37). Compared with White patients, the full adjusted nontransfusion SMM risk remained high for most groups except Hispanic and multiracial patients. Within each racial and ethnic group, the population attributable risk percentage for antepartum anemia and SMM was highest for multiracial patients (21.4%, 95% CI 17.5-25.0%), followed by Black (20.9%, 95% CI 18.1-23.4%) and Hispanic (20.9%, 95% CI 19.9-22.1%) patients. The nontransfusion SMM population attributable risk percentages for Asian, Black, and White pregnant patients were less than 8%.

CONCLUSION

Antepartum anemia, most prevalent among Black pregnant patients, contributed to disparities in SMM by race and ethnicity. Nearly one in five to six SMM cases among Black, Hispanic, American Indian-Alaska Native, Pacific Islander, and multiracial pregnant patients is attributable in part to antepartum anemia.

Neighborhood gentrification, displacement, and severe maternal morbidity in California

Gentrification, a racialized and profit-driven process in which historically disinvested neighborhoods experience an influx of development that contributes to the improvement of physical amenities, increasing housing costs, and the dispossession and displacement of existing communities, may influence the risk of severe maternal morbidity (SMM). Leveraging a racially diverse population-based sample of all live hospital births in California between 2006 and 2017, we examined associations between neighborhood-level gentrification and SMM. SMM was defined as having one of 21 procedures and diagnoses, as described in the SMM index developed by Centers for Disease Control and Prevention. We compared three gentrification measures to determine which operationalization best captures aspects of gentrification most salient to SMM: Freeman, Landis 3-D, and Urban Displacement Project Gentrification and Displacement Typology. Descriptive analysis assessed bivariate associations between gentrification and birthing people's characteristics. Overall and race and ethnicity-stratified mixed-effects logistic models assessed associations between gentrification and SMM, adjusting for individual sociodemographic and pregnancy factors while accounting for clustering by census tract. The study sample included 5,256,905 births, with 72,718 cases of SMM (1.4%). The percentage of individuals living in a gentrifying neighborhood ranged from 5.7% to 11.7% across exposure assessment methods. Net of individual and pregnancy-related factors, neighborhood-level gentrification, as measured by the Freeman method, was protective against SMM (OR = 0.89, 95% CI: 0.86-0.93); in comparison, gentrification, as measured by the Gentrification and Displacement Typology, was associated with greater risk of SMM (OR = 1.18, 95% CI: 1.14-1.23). These associations were significant among non-Hispanic White, non-Hispanic Black, and Hispanic individuals. Findings demonstrate that gentrification plays a role in shaping the risk of SMM among birthing people in California. Differences in how gentrification is conceptualized and measured, such as an emphasis on housing affordability compared to a broader characterization of gentrification's multiple aspects, may explain the heterogeneity in the directions of observed associations.

Are individual-level risk factors for gastroschisis modified by neighborhood-level socioeconomic factors?

BACKGROUND

Two strong risk factors for gastroschisis are young maternal age (<20 years) and low/normal pre-pregnancy body mass index (BMI), yet the reasons remain unknown. We explored whether neighborhood-level socioeconomic position (nSEP) during pregnancy modified these associations.

METHODS

We analyzed data from 1269 gastroschisis cases and 10,217 controls in the National Birth Defects Prevention Study (1997-2011). To characterize nSEP, we applied the neighborhood deprivation index and used generalized estimating equations to calculate odds ratios and relative excess risk due to interaction.

RESULTS

Elevated odds of gastroschisis were consistently associated with young maternal age and low/normal BMI, regardless of nSEP. High-deprivation neighborhoods modified the association with young maternal age. Infants of young mothers in high-deprivation areas had lower odds of gastroschisis (adjusted odds ratio [aOR]: 3.1, 95% confidence interval [CI]: 2.6, 3.8) than young mothers in low-deprivation areas (aOR: 6.6; 95% CI: 4.6, 9.4). Mothers of low/normal BMI had approximately twice the odds of having an infant with gastroschisis compared to mothers with overweight/obese BMI, regardless of nSEP (aOR range: 1.5-2.3).

CONCLUSION

Our findings suggest nSEP modified the association between gastroschisis and maternal age, but not BMI. Further research could clarify whether the modification is due to unidentified biologic and/or non-biologic factors.

Periconceptional intakes of methyl donors and other micronutrients involved in one-carbon metabolism may further reduce the risk of neural tube defects in offspring: a United States population-based case-control study of women meeting the folic acid recommendations

BACKGROUND

Neural tube defects (NTDs) still occur among some women who consume 400 μg of folic acid for prevention. It has been hypothesized that intakes of methyl donors and other micronutrients involved in one-carbon metabolism may further protect against NTDs.

OBJECTIVES

To investigate whether intakes of vitamin B6, vitamin B12, choline, betaine, methionine, thiamine, riboflavin, and zinc, individually or in combination, were associated with NTD risk reduction in offspring of women meeting the folic acid recommendations.

METHODS

Data were from the National Birth Defects Prevention Study (United States population-based, case-control). We restricted deliveries between 1999 and 2011 with daily periconceptional folic acid supplementation or estimated dietary folate equivalents ≥400 μg. NTD cases were live births, stillbirths, or terminations affected by spina bifida, anencephaly, or encephalocele (n = 1227). Controls were live births without a major birth defect (n = 7095). We categorized intake of each micronutrient as higher or lower based on a combination of diet (estimated from a food frequency questionnaire) and periconceptional vitamin supplementation. We estimated NTD associations for higher compared with lower intake of each micronutrient, individually and in combination, expressed as odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for age, race/ethnicity, education, and study center.

RESULTS

NTD associations with each micronutrient were weak to modest. Greater NTD reductions were observed with concurrent higher-amount intakes of multiple micronutrients. For instance, NTD odds were ∼50% lower among participants with ≥4 micronutrients with higher-amount intakes than among participants with ≤1 micronutrient with higher-amount intake (adjusted OR: 0.53; 95% CI: 0.33, 0.86). The strongest reduction occurred with concurrent higher-amount intakes of vitamin B6, vitamin B12, choline, betaine, and methionine (adjusted OR: 0.26; 95% CI: 0.09, 0.77) compared with ≤1 micronutrient with higher-amount intake.

CONCLUSIONS

Our findings support that NTD prevention, in the context of folic acid fortification, could be augmented with intakes of methyl donors and other micronutrients involved in folate metabolism.

Remapping racial and ethnic inequities in severe maternal morbidity: The legacy of redlining in California

BACKGROUND

Historical mortgage redlining, a racially discriminatory policy designed to uphold structural racism, may have played a role in producing the persistently elevated rate of severe maternal morbidity (SMM) among racialised birthing people.

OBJECTIVE

This study examined associations between Home-Owner Loan Corporation (HOLC) redlining grades and SMM in a racially and ethnically diverse birth cohort in California.

METHODS

We leveraged a population-based cohort of all live hospital births at ≥20 weeks of gestation between 1997 and 2017 in California. SMM was defined as having one of 21 procedures and diagnoses, per an index developed by Centers for Disease Control and Prevention. We characterised census tract-level redlining using HOLC's security maps for eight California cities. We assessed bivariate associations between HOLC grades and participant characteristics. Race and ethnicity-stratified mixed effects logistic regression models assessed the risk of SMM associated with HOLC grades within non-Hispanic Black, Asian/Pacific Islander, American Indian/Alaskan Native and Hispanic groups, adjusting for sociodemographic information, pregnancy-related factors, co-morbidities and neighbourhood deprivation index.

RESULTS

The study sample included 2,020,194 births, with 24,579 cases of SMM (1.2%). Living in a census tract that was graded as "Hazardous," compared to census tracts graded "Best" and "Still Desirable," was associated with 1.15 (95% confidence interval [CI] 1.03, 1.29) and 1.17 (95% CI 1.09, 1.25) times the risk of SMM among Black and Hispanic birthing people, respectively, independent of sociodemographic factors. These associations persisted after adjusting for pregnancy-related factors and neighbourhood deprivation index.

CONCLUSIONS

Historical redlining, a tool of structural racism that influenced the trajectory of neighbourhood social and material conditions, is associated with increased risk of experiencing SMM among Black and Hispanic birthing people in California. These findings demonstrate that addressing the enduring impact of macro-level and systemic mechanisms that uphold structural racism is a vital step in achieving racial and ethnic equity in birthing people's health.

Neighborhood-level Socioeconomic Position During Early Pregnancy and Risk of Gastroschisis

BACKGROUND

Neighborhood-level socioeconomic position has been shown to influence birth outcomes, including selected birth defects. This study examines the un derstudied association between neighborhood-level socioeconomic position during early pregnancy and the risk of gastroschisis, an abdominal birth defect of increasing prevalence.

METHODS

We conducted a case-control study of 1,269 gastroschisis cases and 10,217 controls using data from the National Birth Defects Prevention Study (1997-2011). To characterize neighborhood-level socioeconomic position, we conducted a principal component analysis to construct two indices-Neighborhood Deprivation Index (NDI) and Neighborhood Socioeconomic Position Index (nSEPI). We created neighborhood-level indices using census socioeconomic indicators corresponding to census tracts associated with addresses where mothers lived the longest during the periconceptional period. We used generalized estimating equations to estimate odds ratios (ORs) and 95% confidence intervals (CIs), with multiple imputations for missing data and adjustment for maternal race-ethnicity, household income, education, birth year, and duration of residence.

RESULTS

Mothers residing in moderate (NDI Tertile 2 aOR = 1.23; 95% CI = 1.03, 1.48 and nSEPI Tertile 2 aOR = 1.24; 95% CI = 1.04, 1.49) or low socioeconomic neighborhoods (NDI Tertile 3 aOR = 1.28; 95% CI = 1.05, 1.55 and nSEPI Tertile 3 aOR = 1.32, 95% CI = 1.09, 1.61) were more likely to deliver an infant with gastroschisis compared with mothers residing in high socioeconomic neighborhoods.

CONCLUSIONS

Our findings suggest that lower neighborhood-level socioeconomic position during early pregnancy is associated with elevated odds of gastroschisis. Additional epidemiologic studies may aid in confirming this finding and evaluating potential mechanisms linking neighborhood-level socioeconomic factors and gastroschisis.

Oxidative balance scores and neural crest cell-related congenital anomalies

Oxidative stress and redox imbalance adversely affect embryonic development. We developed two oxidative balance scores (OBS) that include dietary and nondietary exposures. We hypothesized that higher scores (i.e., lower oxidative stress) would be associated with lower risk of neural tube defects, orofacial clefts, conotruncal heart defects, and limb deficiencies. We used data from the National Birth Defects Prevention Study to create a dietary OBS based on intake of 13 nutrients and an overall OBS that included the 13 nutrients and eight additional nondietary factors related to oxidative balance (e.g., smoking). We used logistic regression to examine odds ratios associated with having low or high scores (i.e., <10th or >90th percentiles). Continuous models indicated reduced odds associated with high versus low scores (i.e., comparing odds at the 90th versus 10th percentile values of the distribution) on the overall OBS for cleft lip with or without cleft palate [adjusted odds ratio (aOR) 0.72, 95% confidence interval (CI) 0.63-0.82], longitudinal limb deficiency (aOR 0.73, CI 0.54-0.99), and transverse limb deficiency (aOR 0.74, CI 0.58-0.95); increased odds for anencephaly (aOR 1.40, CI 1.07-1.84); and primarily nonsignificant associations with conotruncal heart defects. Results for the dietary OBS were similar. This study provides some evidence that oxidative stress contributes to congenital anomalies related to neural crest cell development.

Exome-wide assessment of isolated biliary atresia: A report from the National Birth Defects Prevention Study using child-parent trios and a case-control design to identify novel rare variants

The etiology of biliary atresia (BA) is unknown, but recent studies suggest a role for rare protein-altering variants (PAVs). Exome sequencing data from the National Birth Defects Prevention Study on 54 child-parent trios, one child-mother duo, and 1513 parents of children with other birth defects were analyzed. Most (91%) cases were isolated BA. We performed (1) a trio-based analysis to identify rare de novo, homozygous, and compound heterozygous PAVs and (2) a case-control analysis using a sequence kernel-based association test to identify genes enriched with rare PAVs. While we replicated previous findings on PKD1L1, our results do not suggest that recurrent de novo PAVs play important roles in BA susceptibility. In fact, our finding in NOTCH2, a disease gene associated with Alagille syndrome, highlights the difficulty in BA diagnosis. Notably, IFRD2 has been implicated in other gastrointestinal conditions and warrants additional study. Overall, our findings strengthen the hypothesis that the etiology of BA is complex.

Neighborhood disinvestment and severe maternal morbidity in the state of California

BACKGROUND

Social determinants of health, including neighborhood context, may be a key driver of severe maternal morbidity and its related racial and ethnic inequities; however, investigations remain limited.

OBJECTIVE

This study aimed to examine the associations between neighborhood socioeconomic characteristics and severe maternal morbidity, as well as whether the associations between neighborhood socioeconomic characteristics and severe maternal morbidity were modified by race and ethnicity.

STUDY DESIGN

This study leveraged a California statewide data resource on all hospital births at ≥20 weeks of gestation (1997-2018). Severe maternal morbidity was defined as having at least 1 of 21 diagnoses and procedures (eg, blood transfusion or hysterectomy) as outlined by the Centers for Disease Control and Prevention. Neighborhoods were defined as residential census tracts (n=8022; an average of 1295 births per neighborhood), and the neighborhood deprivation index was a summary measure of 8 census indicators (eg, percentage of poverty, unemployment, and public assistance). Mixed-effects logistic regression models (individuals nested within neighborhoods) were used to compare odds of severe maternal morbidity across quartiles (quartile 1 [the least deprived] to quartile 4 [the most deprived]) of the neighborhood deprivation index before and after adjustments for maternal sociodemographic and pregnancy-related factors and comorbidities. Moreover, cross-product terms were created to determine whether associations were modified by race and ethnicity.

RESULTS

Of 10,384,976 births, the prevalence of severe maternal morbidity was 1.2% (N=120,487). In fully adjusted mixed-effects models, the odds of severe maternal morbidity increased with increasing neighborhood deprivation index (odds ratios: quartile 1, reference; quartile 4, 1.23 [95% confidence interval, 1.20-1.26]; quartile 3, 1.13 [95% confidence interval, 1.10-1.16]; quartile 2, 1.06 [95% confidence interval, 1.03-1.08]). The associations were modified by race and ethnicity such that associations (quartile 4 vs quartile 1) were the strongest among individuals in the "other" racial and ethnic category (1.39; 95% confidence interval, 1.03-1.86) and the weakest among Black individuals (1.07; 95% confidence interval, 0.98-1.16).

CONCLUSION

Study findings suggest that neighborhood deprivation contributes to an increased risk of severe maternal morbidity. Future research should examine which aspects of neighborhood environments matter most across racial and ethnic groups.

Early postpartum hospital encounters among patients with genitourinary and wound infections during hospitalization for birth

OBJECTIVES

To assess the associations between genitourinary and wound infections during the birth hospitalization and early postpartum hospital encounters, and to evaluate clinical risk factors for early postpartum hospital encounters among patients with a genitourinary or wound infection during the birth hospitalization.

STUDY DESIGN

We conducted a population-based cohort study of births in California during 2016-2018 and postpartum hospital encounters. We identified genitourinary and wound infections using diagnosis codes. Our main outcome was early postpartum hospital encounter, defined as a readmission or ED visit within 3 days after discharge from the birth hospitalization. We evaluated the association of genitourinary and wound infections (overall and subtypes) with early postpartum hospital encounter using logistic regression, adjusting for sociodemographic factors and comorbidities and stratified by mode of birth. We then evaluated factors associated with early postpartum hospital encounter among patients with genitourinary and wound infections.

RESULTS

Among 1,217,803 birth hospitalizations, 5.5% were complicated by genitourinary and wound infections and 1.8% resulted in an early postpartum hospital encounter. Genitourinary or wound infection was associated with an early postpartum hospital encounter among patients with both vaginal births (aRR 1.26, 95% CI 1.17, 1.36) and cesarean births (aRR 1.23, 95% CI 1.15, 1.32). Major puerperal infection, followed by wound infection, among patients with a cesarean birth conferred the highest risk of an early postpartum hospital encounter (6.4% and 4.3%, respectively). Among patients with genitourinary and wound infections at birth hospitalization, factors associated with an early postpartum hospital encounter included severe maternal morbidity, major mental health condition, prolonged postpartum hospital stay, and, among cesarean births, postpartum hemorrhage (P-value < 0.05).

CONCLUSIONS

Genitourinary and wound infections during hospitalization for birth may increase risk of a readmission or ED visit within the first few days after discharge, particularly among patients who have a major puerperal infection or wound infection.

Linked birth cohort files for perinatal health research: California as a model for methodology and implementation

PURPOSE

Rigorous perinatal epidemiologic research depends on population-based parental and neonatal sociodemographic and clinical data. Here we describe the creation of linked birth cohort files, an enriched data source that combines information from vital records with maternal delivery and infant hospital encounter records.

METHODS

Probabilistic linkage techniques were used to link vital records (i.e., birth and fetal death certificates) from the California Department of Public Health with hospital inpatient, ambulatory surgery and emergency department encounter data for mothers and infants from the California Department of Health Care Access and Information.

RESULTS

From 2012 to 2018, 95% of live birth records were successfully linked to maternal and newborn hospital records while 85% of fetal death records were linked to a maternal delivery record. Overall, 93% of postnatal hospital encounters of infants (i.e., <1 year old) were matched to a linked record.

CONCLUSIONS

The linked birth cohort files is a rich resource opening many possibilities for understanding perinatal health outcomes and opportunities for linkage to longitudinal, social determinant, and environmental data. To optimally use this file for research, analysts should evaluate possible shortcomings or biases of the data sources being linked.

Postpartum Hospital Readmissions With and Without Severe Maternal Morbidity Within 1 Year of Birth, Oregon, 2012-2017

Postpartum readmissions (PPRs) represent a critical marker of maternal morbidity after hospital childbirth. Most severe maternal morbidity (SMM) events result in a hospital admission, but most PPRs do not have evidence of SMM. Little is known about PPR and SMM beyond the first 6 weeks postpartum. We examined the associations of maternal demographic and clinical factors with PPR within 12 months postpartum. We categorized PPR as being with or without evidence of SMM to assess whether risk factors and timing differed. Using the Oregon All Payer All Claims database, we analyzed hospital births from 2012-2017. We used log-binomial regression to estimate associations between maternal factors and PPR. Our final analytical sample included 158,653 births. Overall, 2.6% (n = 4,141) of births involved at least 1 readmission within 12 months postpartum (808 (19.5% of PPRs) with SMM). SMM at delivery was the strongest risk factor for PPR with SMM (risk ratio (RR) = 5.55, 95% confidence interval (CI): 4.14, 7.44). PPR without SMM had numerous risk factors, including any mental health diagnosis (RR = 2.10, 95% CI: 1.91, 2.30), chronic hypertension (RR = 2.17, 95% CI: 1.85, 2.55), and prepregnancy diabetes (RR = 2.85, 95% CI: 2.47, 3.30), all which were on par with SMM at delivery (RR = 1.89, 95% CI: 1.49, 2.40).

Early pregnancy vitamin D status and risk of select congenital anomalies in the National Birth Defects Prevention Study

INTRODUCTION

Vitamin D deficiency is associated with adverse pregnancy events. However, its role in the etiology of congenital anomalies remains unclear. We examined the association between vitamin D status, measured through prepregnancy diet, UV exposure, season of conception, and congenital anomalies.

METHODS

We used data from the National Birth Defects Prevention Study, a U.S. population-based case-control study (1997-2011). Prepregnancy dietary vitamin D was calculated from food frequency questionnaires and evaluated using tertiles, based on the distribution in controls. We used the National Oceanic and Atmospheric Administration Weather Service to assign UV indices based on location and estimated date of conception, then dichotomized UV exposure (low vs. high). Seasons of conception was categorized as fall/winter spring/summer. We used logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI).

RESULTS

Lower prepregnancy dietary vitamin D intake (<65.21 IU/d vs. >107.55 IU/d) was associated with increased odds of anencephaly (aOR = 1.28, 95% CI 1.01, 1.63), hypospadias (aOR = 1.21, 95% CI 1.04, 1.40), septal defects (aOR = 1.16, 95% CI 1.05, 1.30), diaphragmatic hernia (aOR = 1.42, 95% CI 1.13, 1.79), and gastroschisis (aOR = 1.27, 95% CI 1.07, 1.52). Findings were consistent when we stratified by UV exposure and season of conception.

CONCLUSIONS

Our findings suggest lower dietary intake of vitamin D may be associated with increased risk of select congenital anomalies. Further investigations are warranted to evaluate the effects of other nutrients and appropriate thresholds and sources of vitamin D using serum.

Factors Associated with Transfer Distance from Birth Hospital to Repair Hospital for First Surgical Repair among Infants with Myelomeningocele in California

OBJECTIVE

 The objective of our study was to examine factors associated with distance to care for first surgical repair among infants with myelomeningocele in California.

STUDY DESIGN

 A total of 677 eligible cases with complete geocoded data were identified for birth years 2006 to 2012 using data from the California Perinatal Quality Care Collaborative linked to hospital and vital records. The median distance from home to birth hospital among eligible infants was 9 miles, and from birth hospital to repair hospital was 15 miles. We limited our analysis to infants who lived close to the birth hospital, creating two study groups to examine transfer distance patterns: "lived close and had a short transfer" (i.e., lived <9 miles from birth hospital and traveled <15 miles from birth hospital to repair hospital; n = 92), and "lived close and had a long transfer" (i.e., lived <9 miles from birth hospital and traveled ≥15 miles from birth hospital to repair hospital; n = 96). Log-binomial regression was used to estimate crude and adjusted risk ratios (aRRs and 95% confidence intervals (CIs). Selected maternal, infant, and birth hospital characteristics were compared between the two groups.

RESULTS

 We found that low birth weight (aRR = 1.44; 95% CI = 1.04, 1.99) and preterm birth (aRR = 1.41; 95% CI = 1.01, 1.97) were positively associated, whereas initiating prenatal care early in the first trimester was inversely associated (aRR = 0.64; 95% CI = 0.46, 0.89) with transferring a longer distance (≥15 miles) from birth hospital to repair hospital. No significant associations were noted by maternal race-ethnicity, socioeconomic indicators, or the level of hospital care at the birth hospital.

CONCLUSION

 Our study identified selected infant factors associated with the distance to access surgical care for infants with myelomeningocele who had to transfer from birth hospital to repair hospital. Distance-based barriers to care should be identified and optimized when planning deliveries of at-risk infants in other populations.

KEY POINTS

· Low birth weight predicted long hospital transfer distance.. · Preterm birth was associated with transfer distance.. · Prenatal care was associated with transfer distance..

Assessing associations between residential proximity to greenspace and birth defects in the National Birth Defects Prevention Study

BACKGROUND

Residential proximity to greenspace is associated with various health outcomes.

OBJECTIVES

We estimated associations between maternal residential proximity to greenspace (based on an index of vegetation) and selected structural birth defects, including effect modification by neighborhood-level factors.

METHODS

Data were from the National Birth Defects Prevention Study (1997-2011) and included 19,065 infants with at least one eligible birth defect (cases) and 8925 without birth defects (controls) from eight Centers throughout the United States. Maternal participants reported their addresses throughout pregnancy. Each address was systematically geocoded and residences around conception were linked to greenspace, US Census, and US Department of Agriculture data. Greenspace was estimated using the normalized difference vegetation index (NDVI); average maximum NDVI was estimated within 100 m and 500 m concentric buffers surrounding geocoded addresses to estimate residential NDVI. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals comparing those in the highest and lowest quartiles of residential NDVI and stratifying by rural/urban residence and neighborhood median income.

RESULTS

After multivariable adjustment, for the 500 m buffer, inverse associations were observed for tetralogy of Fallot, secundum atrial septal defects, anencephaly, anotia/microtia, cleft lip ± cleft palate, transverse limb deficiency, and omphalocele, (aORs: 0.54-0.86). Results were similar for 100 m buffer analyses and similar patterns were observed for other defects, though results were not significant. Significant heterogeneity was observed after stratification by rural/urban for hypoplastic left heart, coarctation of the aorta, and cleft palate, with inverse associations only among participants residing in rural areas. Stratification by median income showed heterogeneity for atrioventricular and secundum atrial septal defects, anencephaly, and anorectal atresia, with inverse associations only among participants residing in a high-income neighborhood (aORs: 0.45-0.81).

DISCUSSION

Our results suggest that perinatal residential proximity to more greenspace may contribute to a reduced risk of certain birth defects, especially among those living in rural or high-income neighborhoods.

Prepregnancy body mass index and gestational diabetes mellitus across Asian and Pacific Islander subgroups in California

BACKGROUND

The American College of Obstetricians and Gynecologists recommends early screening for gestational diabetes mellitus among pregnant Asian people with a prepregnancy body mass index ≥23.0 kg/m², in contrast with the recommended screening at a body mass index ≥25 kg/m² for other races and ethnicities. However, there is significant heterogeneity within Asian and Pacific Islander populations, and gestational diabetes mellitus and its association with body mass index among Asian and Pacific Islander subgroups may not be uniform across all groups.

OBJECTIVE

This study aimed to analyze the association between body mass index and gestational diabetes mellitus among Asian and Pacific Islander subgroups in California, specifically gestational diabetes mellitus rates among those with a body mass index above vs below 23 kg/m², which is the cutoff point for the designation of being overweight among Asians populations.

STUDY DESIGN

Using a linked delivery hospitalization discharge and vital records database, we identified patients who gave birth in California between 2007 and 2017 and who self-reported to be 1 of 13 Asian and Pacific Islander subgroups, which was collected from birth and fetal death certificates. In each subgroup, we evaluated the association between body mass index and gestational diabetes mellitus using multivariable logistic regression models adjusted for age, education, parity, payment method, the trimester in which prenatal care was initiated, and nativity. We fit body mass index nonlinearly with splines and categorized body mass index as being above or below 23 kg/m². Predicted probabilities of gestational diabetes mellitus with 95% confidence intervals were calculated across body mass index values using the nonlinear regression models.

RESULTS

The overall prevalence of gestational diabetes mellitus was 14.3% (83,400/584,032), ranging between 8.4% and 17.1% across subgroups. The highest prevalence was among Indian (17.1%), Filipino (16.7%), and Vietnamese (15.5%) subgroups. In these subgroups, gestational diabetes mellitus was diagnosed in 10% to 13% of those with a body mass index <23.0 kg/m² and in 22% of those with a body mass index ≥23 kg/m². Gestational diabetes mellitus was least common among Korean (8.4%), Japanese (9.0%), and Samoan (9.8%) subgroups with a gestational diabetes mellitus rate of 5% to 7% among those with a body mass index <23.0 kg/m² and in 10% to 15% among those with a body mass index ≥23 kg/m². Although Samoan patients had the highest rate of obesity, defined as body mass index ≥30 kg/m² (57.4%), they had the third lowest prevalence of gestational diabetes mellitus. Conversely, Vietnamese patients had the second lowest rate of obesity (2.4%) but the highest rate of gestational diabetes mellitus at a body mass index of ≥23 kg/m² (22.3%).

CONCLUSION

Gestational diabetes mellitus and its association with body mass index varied among Asian subgroups but increased as body mass index increased. Subgroups with the lowest prevalence of obesity trended toward a higher prevalence of gestational diabetes mellitus and those with a higher prevalence of obesity trended toward a lower prevalence of gestational diabetes mellitus.

Racial/ethnic disparities in severe maternal morbidity: An intersectional lifecourse approach

Despite long-existing calls to address alarming racial/ethnic gaps in severe maternal morbidity (SMM), research that considers the impact of intersecting social inequities on SMM risk remains scarce. Invoking intersectionality theory, we sought to assess SMM risk at the nexus of racial/ethnic marginalization, weathering, and neighborhood/individual socioeconomic disadvantage. We used birth hospitalization records from California across 20 years (1997-2017, N = 9,806,406) on all live births ≥20 weeks gestation. We estimated adjusted average predicted probabilities of SMM at the combination of levels of race/ethnicity, age, and neighborhood deprivation or individual socioeconomic status (SES). The highest risk of SMM was observed among Black birthing people aged ≥35 years who either resided in the most deprived neighborhoods or had the lowest SES. Black birthing people conceptualized to be better off due to their social standing (aged 20-34 years and living in the least deprived neighborhoods or college graduates) had comparable and at times worse risk than White birthing people conceptualized to be worse off (aged ≥35 years and living in the most deprived neighborhoods or had a high-school degree or less). Our findings highlight the need to explicitly address structural racism as the driver of racial/ethnic health inequities and the imperative to incorporate intersectional approaches.

Subsequent risk of stillbirth, preterm birth, and small for gestational age: A cross-outcome analysis of adverse birth outcomes

BACKGROUND

Stillbirth, preterm birth, and small for gestational age (SGA) birth have an increased recurrence risk. The occurrence of one of these biologically related outcomes could also increase the risk for another one of these outcomes in a subsequent pregnancy.

OBJECTIVES

We assessed cross-outcome risks for subsequent stillbirth, preterm birth, and SGA.

METHODS

We used live birth and fetal death records to identify singleton, sequential birth pairs in California (1997-2017). Stillbirth was defined as delivery at ≥20 weeks of gestation of a foetus that died in utero; preterm birth as live birth at 20-36 weeks; and small for gestational age as sex-specific birthweight <10th percentile for gestational age. Risk ratios (RR) were computed using modified Poisson regression and adjusted for potential confounders. Sensitivity analyses included analysing a cohort restricted to primiparous index births and using inverse-probability censoring weights.

RESULTS

Of 3,108,532 birth pairs, 16,668 (0.5%), 260,596 (8.4%) and 331,109 (10.7%) of index births were stillborn, preterm and SGA, respectively. Among individuals with an index stillbirth, the adjusted RRs were 1.90 (95% confidence interval [CI] 1.83, 1.98) for subsequent preterm and 1.35 (95% CI 1.28, 1.41) for subsequent SGA. Among those with index preterm birth, the adjusted RRs were 2.02 (95% CI 1.92, 2.13) for stillbirth and 1.42 (95% CI 1.41, 1.44) for SGA. Among those with index SGA, the adjusted RRs were 1.54 (95% CI 1.46, 1.63) for stillbirth and 1.45 (95% CI 1.44, 1.47) for preterm birth. Similar results were reported for sensitivity analyses.

CONCLUSIONS

Individuals experiencing stillbirth, preterm birth, or SGA in one pregnancy had an increased risk of one of these biologically related outcomes in a subsequent pregnancy. These findings could encourage enhanced surveillance for individuals who experience stillbirth, preterm birth, or SGA and desire a subsequent pregnancy.

Structural racism and adverse maternal health outcomes: A systematic review

In the United States, racial disparities in adverse maternal health outcomes remain a pressing issue, with Black women experiencing a 3-4 times higher risk of maternal mortality and a 2-3 times higher risk of severe maternal morbidity. Despite recent encouraging efforts, fundamental determinants of these alarming inequities (e.g. structural racism) remain understudied. Approaches that address these structural drivers are needed to then intervene upon root causes of adverse maternal outcomes and their disparities and to ultimately improve maternal health across the U.S. In this paper, we offer a conceptual framework for studies of structural racism and maternal health disparities and systematically synthesize the current empirical epidemiologic literature on the links between structural racism measures and adverse maternal health outcomes. For the systematic review, we searched electronic databases (Pubmed, Web of Science, and EMBASE) to identify peer-reviewed U.S. based quantitative articles published between 1990 and 2021 that assessed the link between measures of structural racism and indicators of maternal morbidity/mortality. Our search yielded 2394 studies and after removing duplicates, 1408 were included in the title and abstract screening, of which 18 were included in the full text screening. Only 6 studies met all the specified inclusion criteria for this review. Results revealed that depending on population sub-group analyzed, measures used, and covariates considered, there was evidence that structural racism may increase the risk of adverse maternal health outcomes. This review also highlighted several areas for methodological and theoretical development in this body of work. Future work should more comprehensively assess structural racism in a way that informs policy and interventions, which can ameliorate its negative consequences on racial/ethnic disparities in maternal morbidity/mortality.

Antihypertensive Medication Use before and during Pregnancy and the Risk of Severe Maternal Morbidity in Individuals with Prepregnancy Hypertension

OBJECTIVE

 Our objective is to examine severe maternal morbidity (SMM) and patterns of antihypertensive medication use before and during pregnancy among individuals with chronic hypertension.

STUDY DESIGN

 We examined 11,759 pregnancies resulting in a live birth or stillbirth to individuals with chronic hypertension and one or more antihypertensive prescription 6 months before pregnancy (Optum, 2007-17). We examined whether study outcomes were associated with the use of medication as compared to no use during pregnancy. In addition, patterns of medication use based on the Food and Drug Administration guidance and literature were evaluated. Medication use was divided into prepregnancy and during pregnancy use and classified as pregnancy recommended (PR) or not pregnancy recommended (nPR) or no medication use. SMM was defined per the Centers for Disease Control and Prevention definition of 21 indicators. Risk ratios (RR) reflecting the association of SMM with the use of antihypertensive medications were computed using modified Poisson regression with robust standard errors and adjusted for maternal age, education, and birth year.

RESULTS

 Overall, 83% of individuals filled an antihypertensive prescription during pregnancy and 6.3% experienced SMM. The majority of individuals with a prescription prior to pregnancy had a prescription for the same medication in pregnancy. Individuals with any versus no medication use in pregnancy had increased adjusted RR (aRR) of SMM (1.18, 95% confidence interval [CI]: 0.96-1.44). Compared to the use of PR medications before and during pregnancy, aRRs were 1.42 (95% CI: 1.18-1.69, 12.4% of sample) for nPR use before and during pregnancy, 1.52 (1.23-1.86; 12.4%) for nPR (before) and PR (during) use, and 2.67 (1.73-4.15) for PR and nPR use. Patterns with no medication use during pregnancy were not statistically significant.

CONCLUSION

 Pattern of antihypertensive medication use before and during pregnancy may be associated with an elevated risk of SMM. Further research is required to elucidate whether this association is related to the severity of hypertension, medication effectiveness, or suboptimal quality of care.

KEY POINTS

· Individuals with any medication use compared to no medication use in pregnancy had an increased risk of SMM.. · Specific medication use patterns were associated with an elevated risk of SMM.. · Pattern of antihypertensive medication use before and during pregnancy may be associated with an increased risk of SMM..

Differential newborn DNA methylation among individuals with complex congenital heart defects and childhood lymphoma

BACKGROUND

There is emerging evidence that children with complex congenital heart defects (CHDs) are at increased risk for childhood lymphoma, but the mechanisms underlying this association are unclear. Thus, we sought to evaluate the role of DNA methylation patterns on "CHD-lymphoma" associations.

METHODS

From >3 million live births (1988-2004) in California registry linkages, we obtained newborn dried bloodspots from eight children with CHD-lymphoma through the California BioBank. We performed case-control epigenome-wide association analyses (EWAS) using two comparison groups with reciprocal discovery and validation to identify differential methylation associated with CHD-lymphoma.

RESULTS

After correction for multiple testing at the discovery and validation stages, individuals with CHD-lymphoma had differential newborn methylation at six sites relative to two comparison groups. Our top finding was significant in both EWAS and indicates PPFIA1 cg25574765 was hypomethylated among individuals with CHD-lymphoma (mean beta = 0.04) relative to both unaffected individuals (mean beta = 0.93, p = 1.5 × 10^-12 ) and individuals with complex CHD (mean beta = 0.95, p = 3.8 × 10^-8 ). PPFIA1 encodes a ubiquitously expressed liprin protein in one of the most commonly amplified regions in many cancers (11q13). Further, cg25574765 is a proposed marker of pre-eclampsia, a maternal CHD risk factor that has not been fully evaluated for lymphoma risk in offspring, and the tumor microenvironment that may drive immune cell malignancies.

CONCLUSIONS

We identified associations between molecular changes present in the genome at birth and risk of childhood lymphoma among those with CHD. Our findings also highlight novel perinatal exposures that may underlie methylation changes in CHD predisposing to lymphoma.

Risk factors and pregnancy outcomes vary among Asian American, Native Hawaiian, and Pacific Islander individuals giving birth in California

OBJECTIVE

To compare frequencies of risk factors and pregnancy outcomes in ethnic groups versus the combined total of Asian American, Native Hawaiian, and Pacific Islander (AANHPI) populations.

METHODS

Using linked birth and fetal death certificate and maternal hospital discharge data (California 2007-2018), we estimated frequencies of 15 clinical and sociodemographic exposures and 11 pregnancy outcomes. Variability across 15 AANHPI groups was compared using a heat map and compared to frequencies for the total group (n=904,232).

RESULTS

AANHPI groups varied significantly from each other and the combined total regarding indicators of social disadvantage (e.g., range for high school-level educational or less: 6.4% Korean-55.8% Samoan) and sociodemographic factors (e.g., maternal age <20 years: 0.2% Chinese-8.8% Guamanian) that are related to adverse pregnancy outcomes. Perinatal outcomes varied significantly (e.g., severe maternal morbidity: 1.2% Korean-1.9% Filipino). No single group consistently had risk factors or outcome prevalence at the extremes, i.e., no group was consistently better or worse off across examined factors.

CONCLUSIONS

Substantial variability in perinatal risk factors and outcomes exists across AANHPI groups. Aggregation into "AANHPI" is not appropriate for outcome reporting.

Using Longitudinally Linked Data to Measure Severe Maternal Morbidity Beyond the Birth Hospitalization in California

Most studies of severe maternal morbidity (SMM) include only cases that occur during birth hospitalizations. We examined the increase in cases when including SMM during antenatal and postpartum (within 42 days of discharge) hospitalizations, using longitudinally linked data from 1,010,250 births in California from September 1, 2016, to December 31, 2018. For total SMM, expanding the definition resulted in 22.8% more cases; for nontransfusion SMM, 45.1% more cases were added. Sepsis accounted for 55.5% of the additional cases. The increase varied for specific indicators, for example, less than 2% for amniotic fluid embolism, 7.0% for transfusion, 112.9% for sepsis, and 155.6% for acute myocardial infarction. These findings reiterate the importance of considering SMM beyond just the birth hospitalization and facilitating access to longitudinally linked data to facilitate a more complete understanding of SMM.

Interpregnancy weight change: associations with severe maternal morbidity and neonatal outcomes

BACKGROUND

Prepregnancy body mass index and gestational weight gain have been linked with severe maternal morbidity, suggesting that weight change between pregnancies may also play a role, as it does for neonatal outcomes.

OBJECTIVE

This study assessed the association of changes in prepregnancy body mass index between 2 consecutive singleton pregnancies with the outcomes of severe maternal morbidity, stillbirth, and small- and large-for-gestational-age infants in the subsequent pregnancy.

STUDY DESIGN

This observational study was based on birth records from 1,111,032 consecutive pregnancies linked to hospital discharge records in California (2007-2017). Interpregnancy body mass index change between the beginning of an index pregnancy and the beginning of the subsequent pregnancy was calculated from self-reported weight and height. Severe maternal morbidity was defined based on the Centers for Disease Control and Prevention index, including and excluding transfusion-only cases. We used multivariable log-binomial regression models to estimate adjusted risks, overall and stratified by prepregnancy body mass index at index birth.

RESULTS

Substantial interpregnancy body mass index gain (≥4 kg/m2) was associated with severe maternal morbidity in crude but not adjusted analyses. Substantial interpregnancy body mass index loss (>2 kg/m2) was associated with increased risk of severe maternal morbidity (adjusted relative risk, 1.13; 95% confidence interval (1.07-1.19), and both substantial loss (adjusted relative risk, 1.11 [1.02-1.19]) and gain (≥4 kg/m2; adjusted relative risk, 1.09 [1.02-1.17]) were associated with nontransfusion severe maternal morbidity. Substantial loss (adjusted relative risk, 1.17 [1.05-1.31]) and gain (1.26 [1.14-1.40]) were associated with stillbirth. Body mass index gain was positively associated with large-for-gestational-age infants and inversely associated with small-for-gestational-age infants.

CONCLUSION

Substantial interpregnancy body mass index changes were associated with modestly increased risk of severe maternal morbidity, stillbirth, and small- and large-for-gestational-age infants.

Distance from home to birth hospital, transfer, and mortality in neonates with hypoplastic left heart syndrome in California

BACKGROUND

Prior studies report a lower risk of mortality among neonates with hypoplastic left heart syndrome (HLHS) who are born at a cardiac surgical center, but many neonates with HLHS are born elsewhere and transferred for repair. We investigated the associations between the distance from maternal home to birth hospital, the need for transfer after birth, sociodemographic factors, and mortality in infants with HLHS in California from 2006 to 2011.

METHODS

We used linked data from two statewide databases to identify neonates for this study. Three groups were included in the analysis: "lived close/not transferred," "lived close/transferred," and "lived far/not transferred." We defined "lived close" versus "lived far" as 11 miles, the median distance from maternal residence to birth hospital. Log-binomial regression models were used to identify the association between sociodemographic variables, distance to birth hospital and transfer. Cox proportional hazards models were used to identify the association between mortality and distance to birth hospital and transfer. Models were adjusted for sociodemographic variables.

RESULTS

Infants in the lived close/not transferred and the lived close/transferred groups (vs. the lived far/not transferred group) were more likely to live in census tracts above the 75th percentile for poverty with relative risks 1.94 (95% confidence interval [CI] 1.41-2.68) and 1.21 (95% CI 1.05-1.40), respectively. Neonatal mortality was higher among the lived close/not transferred group compared with the lived far/not transferred group (hazard ratio 1.77, 95% CI 1.17-2.67).

CONCLUSIONS

Infants born to mothers experiencing poverty were more likely to be born close to home. Infants with HLHS who were born close to home and not transferred to a cardiac center had a higher risk of neonatal mortality than infants who were delivered far from home and not transferred. Future studies should identify the barriers to delivery at a cardiac center for mothers experiencing poverty.

Obstetric comorbidity scores and disparities in severe maternal morbidity across marginalized groups

BACKGROUND

A recently developed obstetrical comorbidity scoring system enables the comparison of severe maternal morbidity rates independent of health status at the time of birth hospitalization. However, the scoring system has not been evaluated in racial-ethnic and socioeconomic groups or used to assess disparities in severe maternal morbidity.

OBJECTIVE

This study aimed to evaluate the performance of an obstetrical comorbidity scoring system when applied across racial-ethnic and socioeconomic groups and to determine the effect of comorbidity score risk adjustment on disparities in severe maternal morbidity.

STUDY DESIGN

We analyzed a population-based cohort of live births that occurred in California during 2011 through 2017 with linked birth certificates and birth hospitalization discharge data (n=3,308,554). We updated a previously developed comorbidity scoring system to include the International Classification of Diseases, Ninth and Tenth Revisions, Clinical Modifications diagnosis codes and applied the scoring system to subpopulations (groups) defined by race-ethnicity, nativity, payment method, and educational attainment. We then calculated the risk-adjusted rates of severe maternal morbidity (including and excluding blood transfusion-only cases) for each group and estimated the disparities for these outcomes before and after adjustment for the comorbidity score using logistic regression.

RESULTS

The obstetric comorbidity scores performed consistently across groups (C-statistics ranged from 0.68 to 0.76; calibration curves demonstrated overall excellent prediction of absolute risk). All non-White groups had significantly elevated rates of severe maternal morbidity before and after risk adjustment for comorbidities when compared with the White group (1.3% before, 1.3% after) (American Indian-Alaska Native: 2.1% before, 1.8% after; Asian: 1.5% before, 1.7% after; Black: 2.5% before, 2.0% after; Latinx: 1.6% before, 1.7% after; Pacific Islander: 2.2% before, 1.9% after; and multi-race groups: 1.7% before, 1.6% after). Risk adjustment also modestly increased disparities for the foreign-born group and government insurance groups. Higher educational attainment was associated with decreased severe maternal morbidity rates, which was largely unaffected by comorbidity risk adjustment. The pattern of results was the same whether or not transfusion-only cases were included as severe maternal morbidity.

CONCLUSION

These results support the use of an updated comorbidity scoring system to assess disparities in severe maternal morbidity. Disparities in severe maternal morbidity decreased in magnitude for some racial-ethnic and socioeconomic groups and increased in magnitude for other groups after adjustment for the comorbidity score.

Association of infertility with atherosclerotic cardiovascular disease among postmenopausal participants in the Women’s Health Initiative

OBJECTIVE

To investigate the association of infertility with atherosclerotic cardiovascular disease (ASCVD) among postmenopausal participants in the Women's Health Initiative (WHI). We hypothesized that nulliparity and pregnancy loss may reveal more extreme phenotypes of infertility, enabling further understanding of the association of infertility with ASCVD.

DESIGN

Prospective cohort study.

SETTING

Forty clinical centers in the United States.

PATIENT(S)

A total of 158,787 postmenopausal participants in the Women's Health Initiative cohort.

INTERVENTION(S)

Infertility, parity, and pregnancy loss.

MAIN OUTCOME MEASURE(S)

The primary outcome was risk of ASCVD among women with and without a history of infertility, stratified by history of live birth and pregnancy loss. Cox proportional-hazards models were adjusted for demographics and risk factors for ASCVD.

RESULT(S)

Among 158,787 women, 25,933 (16.3%) reported a history of infertility; 20,427 (80%) had at least 1 live birth; and 9,062 (35%) had at least 1 pregnancy loss. There was a moderate overall association between infertility and ASCVD (adjusted hazard ratio, 1.02; 95% confidence interval [CI], 0.99-1.06) over 19 years of follow-up. Among nulliparous women, infertility was associated with a 13% higher risk of ASCVD (95% CI, 1.04-1.23). Among nulliparous women who had a pregnancy loss, infertility was associated with a 36% higher risk of ASCVD (95% CI, 1.09-1.71).

CONCLUSION(S)

Women with a history of infertility overall had a moderately higher risk of ASCVD compared with women without a history of infertility. Atherosclerotic cardiovascular disease risk was much higher among nulliparous infertile women and among nulliparous infertile women who also had a pregnancy loss, suggesting that in these more extreme phenotypes, infertility may be associated with ASCVD risk.

The impact of Severe Maternal Morbidity on probability of subsequent birth in a population-based study of women in California from 1997-2017

IMPORTANCE

Complications during pregnancy and birth can impact whether an individual has more children. Individuals experiencing SMM are at a higher risk of general and reproductive health issues after pregnancy, which could reduce the probability of a subsequent birth.

OBJECTIVE

To examine whether experiencing SMM during an individual's first birth affects their probability of having an additional birth, and whether this effect varies by maternal factors.

METHODS

This retrospective cohort study US linked vital records and maternal discharges from 1997 to 2017 to identify all California births. The exposure, Severe Maternal Morbidity (SMM) was identified using a Centers for Disease Control and Prevention index. Individuals whose first birth was a singleton live birth were followed until their second birth or December 31, 2017, whichever came first. Hazard ratios for having a subsequent birth were estimated using Cox proportional hazard regression models. This association was assessed overall and stratified by maternal factors of a priori interest: age, race/ethnicity, and payer.

RESULTS

Of the 3,916,413 individuals in our study, 51,872 (1.3%) experienced SMM at first birth. Compared to those who do not experience SMM, individuals who had SMM had a lower hazard, or instantaneous rate, of subsequent birth (adjusted HR 0.83, 95% CI: 0.82, 0.84); this association was observed in all levels of stratification (for example, adjusted HR range for known race/ethnicity: 0.78, 95% CI: 0.76, 0.80 for non-Hispanic White to 0.90, 95% CI: 0.88, 0.92 for Hispanic) and all indicators of SMM (0.24, 95% CI: 0.17, 0.35 for cardiac arrest/ventricular fibrillation to 0.84, 95% CI: 0.80, 0.87 for eclampsia).

CONCLUSION AND RELEVANCE

Our findings suggest that individuals who experience SMM at the time of their first birth are less likely to have a subsequent birth as compared to those who do not experience SMM at the time of their first birth. While the reasons for these findings are unclear, they could inform reproductive life planning discussions for individuals experiencing SMM. Future directions include studies exploring the reasons for not having a subsequent birth.

Association of Epilepsy and Severe Maternal Morbidity

OBJECTIVE

To evaluate severe maternal morbidity (SMM) among patients with epilepsy and patients without epilepsy.

METHODS

We retrospectively examined SMM using linked birth certificate and maternal hospital discharge records in California between 2007 and 2012. Epilepsy present at delivery admission was the exposure and was subtyped into generalized, focal and other less specified, or unspecified. The outcomes were SMM and nontransfusion SMM from delivery up to 42 days' postpartum, identified using Centers for Disease Control and Prevention indicators. Multivariable logistic regression models were used to adjust for confounders, which were selected a priori. We also estimated the association between epilepsy and SMM independent of comorbidities by using a validated obstetric comorbidity score. Severe maternal morbidity indicators were then compared using the same multivariable logistic regression models.

RESULTS

Of 2,668,442 births, 8,145 (0.3%) were to patients with epilepsy; 637 (7.8%) had generalized, 6,250 (76.7%) had focal or other less specified, and 1,258 (15.4%) had unspecified subtypes. Compared with patients without epilepsy, patients with epilepsy had greater odds of SMM (4.3% vs 1.4%, adjusted odds ratio [aOR] 2.91, 95% CI 2.61-3.24) and nontransfusion SMM (2.9% vs 0.7%, aOR 4.16, 95% CI 3.65-4.75). Epilepsy remained significantly associated with increased SMM and nontransfusion SMM after additional adjustment for the obstetric comorbidity score, though the effects were attenuated. When grouped by organ system, all SMM indicators were significantly more common among patients with epilepsy-most notably those related to hemorrhage and transfusion.

CONCLUSION

Severe maternal morbidity was significantly increased in patients with epilepsy, and SMM indicators across all organ systems contributed to this.

Factors Associated with Early Neonatal and First-Year Mortality in Infants with Myelomeningocele in California from 2006 to 2011

OBJECTIVE

The aim of this study is to examine factors associated with early neonatal (death within first 7 days of birth) and infant (death during the first year of life) mortality among infants born with myelomeningocele.

STUDY DESIGN

We examined linked data from the California Perinatal Quality Care Collaborative, vital records, and hospital discharge records for infants born with myelomeningocele from 2006 to 2011. Survival probability was calculated using Kaplan-Meier Product Limit method and 95% confidence intervals (CI) using Greenwood's method; Cox proportional hazard models were used to estimate unadjusted and adjusted hazard ratios (HR) and 95% CI.

RESULTS

Early neonatal and first-year survival probabilities among infants born with myelomeningocele were 96.0% (95% CI: 94.1-97.3%) and 94.5% (95% CI: 92.4-96.1%), respectively. Low birthweight and having multiple co-occurring birth defects were associated with increased HRs ranging between 5 and 20, while having congenital hydrocephalus and receiving hospital transfer from the birth hospital to another hospital for myelomeningocele surgery were associated with HRs indicating a protective association with early neonatal and infant mortality.

CONCLUSION

Maternal race/ethnicity and social disadvantage did not predict early neonatal and infant mortality among infants with myelomeningocele; presence of congenital hydrocephalus and the role of hospital transfer for myelomeningocele repair should be further examined.

KEY POINTS

· Mortality in myelomeningocele is a concern. · Social disadvantage was not associated with death. · Hospital-based factors should be further examined.

Pre-pregnancy Obesity and the Risk of Peripartum Cardiomyopathy

OBJECTIVE

The aim of this study is to evaluate the contribution of pre-pregnancy obesity and overweight to peripartum cardiomyopathy.

STUDY DESIGN

This population-based study used linked birth record and maternal hospital discharge data from live births in California during 2007 to 2012 (n = 2,548,380). All women who had a diagnosis of peripartum cardiomyopathy during the childbirth hospitalization or who were diagnosed with peripartum cardiomyopathy during a postpartum hospital readmission within 5 months of birth were identified as cases. Pre-pregnancy body mass index (BMI, kg/m²) was classified as normal weight (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (≥40). Because of small numbers, we excluded women with underweight BMI, and in some analyses, we combined obesity classes into one group. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) expressing associations between BMI and peripartum cardiomyopathy, adjusted for maternal age, race/ethnicity, education, health care payer, parity, plurality, and comorbidities.

RESULTS

The overall prevalence of peripartum cardiomyopathy during hospital admissions was 1.3 per 10,000 live births (n = 320). Unadjusted ORs were 1.32 (95% CI: 1.01-1.74) for women with overweight BMI and 2.03 (95% CI: 1.57-2.62) for women with obesity, compared with women with normal pre-pregnancy BMI. Adjusted ORs were 1.26 (95% CI: 0.95-1.66) for overweight women and 1.38 (95% CI: 1.04-1.84) for women with obesity. The ORs suggested a dose-response relationship with increasing levels of obesity, but the 95% CIs for the specific classes of obesity included 1.00.

CONCLUSION

Pre-pregnancy obesity was associated with an increased risk of peripartum cardiomyopathy. These findings underscore the importance of BMI during pregnancy. There is a need to recognize the increased risk of peripartum cardiomyopathy in women with high BMI, especially in the late postpartum period.

KEY POINTS

· Pre-pregnancy obesity affects maternal health.. · Effects may extend to peripartum cardiomyopathy.. · The risk includes peripartum cardiomyopathy that emerges postpartum..

Severe Maternal Morbidity: A Comparison of Definitions and Data Sources

Severe maternal morbidity (SMM) is a composite outcome measure that indicates serious, potentially life-threatening maternal health problems. There is great interest in defining SMM using administrative data for surveillance and research. In the United States, one common way of defining SMM at the population level is an index developed by the Centers for Disease Control and Prevention. Modifications to this index (e.g., exclusion of maternal blood transfusion) have been proposed; some research defines SMM using an index introduced by Bateman et al. (Obstet Gynecol. 2013;122(5):957-965). Birth certificate data are also increasingly being used to define SMM. We compared commonly used US definitions of SMM among all California births (2007-2012) using the kappa (κ) statistic and other measures. We also evaluated agreement between maternal morbidity fields on the birth certificate as compared with health insurance claims data. Concordance between the 7 definitions of SMM analyzed was generally low (i.e., κ < 0.41 for 13 of 21 two-way comparisons). Low concordance was particularly driven by the presence/absence of transfusion and claims data versus birth certificate definitions. Low agreement between administrative data-based definitions of SMM highlights that results can be expected to differ between them. Further research on validity of SMM definitions, using more fine-grained data sources, is needed.

Maternal Health after Stillbirth: Postpartum Hospital Readmission in California

OBJECTIVE

The aim of this study is to assess whether the risk of postpartum readmission within 6 weeks of giving birth differs for women who had stillbirths compared with live births.

STUDY DESIGN

Using data from the Office of Statewide Health Planning and Development in California, we performed a population-based cohort study of 7,398,640 births between 1999 and 2011. We identified diagnoses and procedures associated with the first postpartum hospital readmission that occurred within 6 weeks after giving birth. We used log-binomial models to estimate relative risk (RR) of postpartum readmission for women who had stillbirth compared with live birth deliveries, adjusting for maternal demographic, prepregnancy, pregnancy, and delivery characteristics.

RESULTS

The rate of postpartum readmission was higher among women who had stillbirths compared with women who had live births (206 and 96 per 10,000 births, respectively). After adjusting for maternal demographic and medical characteristics, the risk of postpartum readmission for women who had stillbirths was nearly 1.5 times greater (adjusted RR = 1.47, 95% confidence interval: 1.35-1.60) compared with live births. Among women with stillbirths, the most common indications at readmission were uterine infection or pelvic inflammatory disease, psychiatric conditions, hypertensive disorder, and urinary tract infection.

CONCLUSION

Based on our findings, women who have stillbirths are at higher risk of postpartum readmissions within 6 weeks of giving birth than women who have live births. Women who have stillbirths may benefit from additional monitoring and counseling after hospital discharge for potential postpartum medical and psychiatric complications.

KEY POINTS

· Women who have stillbirths are at nearly 1.5 times greater risk of postpartum readmission than women who have live births.. · Uterine infections and pelvic inflammatory disease, and psychiatric conditions are the most common reasons for readmission among women who had a stillbirth.. · Women who have stillbirths may benefit from additional monitoring and counseling after hospital discharge for potential postpartum medical and psychiatric complications..

Maternal exposure to hydroxychloroquine and birth defects

Background

Hydroxychloroquine is a treatment for rheumatic disease and considered safe during pregnancy. Interest in hydroxychloroquine has increased as it is being examined as a potential treatment and prophylaxis for coronavirus disease 2019. Data on the risks of specific birth defects associated with hydroxychloroquine use are sparse.

Methods

Using data from two case–control studies (National Birth Defects Prevention Study and Slone Epidemiology Center Birth Defects Study), we described women who reported hydroxychloroquine use in pregnancy and the presence of specific major birth defects in their offspring. Cases had at least one major birth defect and controls were live‐born healthy infants. Women self‐reported medication use information in the few months before pregnancy through delivery.

Results

In total, 0.06% (19/31,468) of case and 0.04% (5/11,614) of control mothers in National Birth Defects Prevention Study, and 0.04% (11/29,838) of case and 0.05% (7/12,868) of control mothers in Birth Defects Study reported hydroxychloroquine use. Hydroxychloroquine users had complicated medical histories and frequent medication use for a variety of conditions. The observed birth defects among women taking hydroxychloroquine were varied and included nine oral cleft cases; the elevated observed:expected ratios for specific oral cleft phenotypes and for oral clefts overall had 95% confidence intervals that included 1.0.

Conclusion

While teratogens typically produce a specific pattern of birth defects, the observed birth defects among the hydroxychloroquine‐exposed women did not present a clear pattern, suggesting no meaningful evidence for the risk of specific birth defects. The number of exposed cases is small; results should be interpreted cautiously.