Relative Risk Of Preterm Birth Research Articles

Investigating the Black Birth Experience: A Race-Stratified Analysis of Preterm Birth Risk and Exposure to Metropolitan Statistical Area-Level Police-Related Deaths, US 2018–2019

Police-related violence may be a source of chronic stress underlying entrenched racial inequities in reproductive health in the USA. Using publicly available data on police-related fatalities, we estimated total and victim race-specific rates of police-related fatalities (deaths per 100,000 population) in 2018–2019 for Metropolitan Statistical Areas (MSA) and counties within MSAs in the USA. Rates were linked to data on live births by maternal MSA and county of residence. We fit adjusted log-Poisson models with generalized estimating equations and cluster-robust standard errors to estimate the relative risk of preterm birth associated with the middle and highest tertiles of police-related fatalities compared to the lowest tertile. We included a test for heterogeneity by maternal race/ethnicity and additionally fit race/ethnicity-stratified models for associations with victim race/ethnicity-specific police-related fatality rates. Fully adjusted models indicated significant adverse associations between police-related fatality rates and relative risk of preterm birth for the total population, non-Hispanic Black, and non-Hispanic White groups separately. Results confirm the role of fatal police violence as a social determinant of population health outcomes and inequities, including preterm birth.

The impact of household fuel usage on adverse pregnancy outcomes in rural Ma'anshan City, Anhui Province: a birth cohort study.

The combustion of cooking fuels generates detrimental gases significantly impacting human health, particularly for vulnerable populations like expectant mothers. Prenatal exposure of such hazardous emissions raises the probability of adverse pregnancy outcomes, including preterm birth (PTB) and low birth weight (LBW). Our research aims to explore the association between cooking fuel utilization and adverse birth outcomes in rural Ma'anshan, Anhui Province. A prospective cohort study was executed, employing the Maternal and Infant Health Assessment questionnaire to classify fuels into clean (natural gas, electricity) and polluting energy sources (coal, coal gas, firewood). Multivariate logistic regression models were conducted to evaluate the association between fuel consumption and postpartum maternal and infant outcomes. Among the 442 surveyed pregnant women, 38.2% (N=169) utilized polluting fuels. After adjusting for covariates such as age and BMI, the relative risks of preterm birth, low birth weight, and postpartum hemorrhage in the polluting fuel group compared to the clean fuel group were OR: 3.27, 95% CI: 1.34, 8.00; OR: 3.50, 95% CI: 1.12, 10.90; and OR: 3.18, 95% CI: 1.06, 9.46, respectively. These results indicate that the usage of polluting fuels during pregnancy may heighten the risk of adverse birth outcomes. Consequently, additional research is advised to mitigate the harmful emissions generated by cooking fuels and advocate for clean energy adoption, enhancing maternal and infant well-being.

Sequential disruptions to inflammatory and angiogenic pathways and risk of spontaneous preterm birth in Malawian women

Preterm birth is a leading cause of death in children under five years of age. We hypothesized that sequential disruptions to inflammatory and angiogenic pathways during pregnancy increase the risk of placental insufficiency and spontaneous preterm labor and delivery. We conducted a secondary analysis of inflammatory and angiogenic analytes measured in plasma samples collected across pregnancy from 1462 Malawian women. Women with concentrations of the inflammatory markers sTNFR2, CHI3L1, and IL18BP in the highest quartile before 24weeks gestation and women with anti-angiogenic factors sEndoglin and sFlt-1/PlGF ratio in the highest quartile at 28-33weeks gestation had an increased relative risk of preterm birth. Mediation analysis further supported a potential causal link between early inflammation, subsequent angiogenic dysregulation detrimental to placental vascular development, and earlier gestational age at delivery. Interventions designed to reduce the burden of preterm birth may need to be implemented before 24weeks of gestation.

Racial/ethnic disparities in the risk of preterm birth among women with systemic lupus erythematosus or rheumatoid arthritis.

In a large multi-racial/ethnic cohort of women, we examined racial/ethnic disparities in preterm birth (PTB) risk stratified by autoimmune rheumatic disease (ARD) type, which included systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Birth records linked to hospital discharge data of singleton births in California from 2007 to 2012 were leveraged for a retrospective cohort study including women with SLE or RA. The relative risk of PTB (< 37 versus ≥ 37 weeks' gestation) was compared among different racial/ethnic groups (Asian, Hispanic, Non-Hispanic (NH) Black, and NH White) and stratified by ARD type. Results were adjusted for relevant covariates using Poisson regression. We identified 2874 women with SLE and 2309 women with RA. NH Black, Hispanic, and Asian women with SLE were 1.3 to 1.5 times more likely to have PTB compared to NH White women. NH Black women with RA were 2.0 to 2.4 times more likely to have PTB compared to Asian, Hispanic, or NH White women. The NH Black-NH White and NH Black-Hispanic disparity in PTB risk was significantly higher in women with RA compared to SLE or the general population. Our findings highlight the racial/ethnic disparities for risk of PTB among women with SLE or RA and highlight that several of the disparities are higher for women with RA compared to those with SLE or the general population. These data may provide important public health information for addressing racial/ethnic disparities in the risk of preterm birth, particularly among women with RA. Key Points • There is an unmet need for studies that evaluate racial/ethnic disparities in birth outcomes specifically in women with RA or SLE. • This is one of the first studies describing racial/ethnic disparities in PTB risk for women with RA, and to draw conclusions regarding Asian women in the USA with rheumatic diseases and PTB. • These data provide important public health information for addressing racial/ethnic disparities in the risk of preterm birth among women with autoimmune rheumatic diseases.

Maternal educational level and preterm birth: Exploring inequalities in a hospital-based cohort study.

Preterm birth has been related to inequalities in maternal educational level, but the causal mechanism is not entirely known. Some factors associated with preterm birth and low educational level such as chronic medical conditions, pregnancy complications and related-health behaviours could have a mediation role in the pathway. This study aimed to evaluate the association between maternal educational level and preterm birth, analysing the mediation role of these factors. We performed a retrospective cohort study based on hospital electronic records of 10467 deliveries that took place in the Hospital Clínic of Barcelona between 2011 and 2017. Poisson regression was used to obtain crude and adjusted relative risk of preterm birth in women with different educational level and the percentage of change in relative risk was calculated when mediation variables were included in the model. Women with a lower educational level had a higher risk of preterm birth (RR 1.57, 95% CI 1.21, 2.03). The loss of association after the inclusion of body mass index in the model suggests an important mediation role of maternal overweight. Other variables such as smoking, drug use, preeclampsia and genitourinary infections also appear to play a role in the observed inequality between women with different levels of education. Efforts to promote health literacy and to improve preventive interventions, before and during pregnancy, could decrease preterm birth rates and perinatal health inequalities.

Association of maternal nationality with preterm birth and low birth weight rates: analysis of nationwide data in Japan from 2016 to 2020

BackgroundThe rate of low birth weight or preterm birth is known to vary according to the birth place of mothers. However, in Japan, studies that investigated the association between maternal nationalities and adverse birth outcomes are few. In this study, we investigated the association between maternal nationalities and adverse birth outcomes.MethodsWe obtained live birth data from the Vital Statistics 2016–2020 of the Ministry of Health, Labour, and Welfare. We used data on maternal age, sex, parity, gestational age, birth weight, number of fetuses, household occupation, paternal nationality, and maternal nationality for each infant. We compared the rates of preterm birth and low birth weight at term among mothers whose nationalities were Japan, Korea, China, Philippines, Brazil, and other countries. Log binomial regression model was used to investigate the association between maternal nationality and the two birth outcomes using the other infants’ characteristics as covariates.ResultsIn the analysis, data on 4,290,917 singleton births were used. Mothers from Japan, Korea, China, the Philippines, Brazil, and other nations had preterm birth rates of 4.61%, 4.16%, 3.97%, 7.43%, 7.69%, and 5.61%, respectively. The low birth weight rate among Japanese mothers was 5.36% and was the highest among the maternal nationalities. Regression analysis showed that the relative risk for preterm birth among Filipino, Brazilian, and mothers from other countries (1.520, 1.329, and 1.222, respectively) was statistically significantly higher compared with Japanese mothers. In contrast, the relative risk for Korean and Chinese mothers (0.870 and 0.899, respectively) was statistically significantly lower compared with Japanese mothers. Mothers from Korea, China, the Philippines, Brazil, and other nations had a relative risk for low birth weight that was statistically significantly lower than that of Japanese mothers (0.664, 0.447, 0.867, 0.692, and 0.887, respectively).ConclusionsSupport for mothers from the Philippines, Brazil, and other countries are necessary to prevent preterm birth. A future study is necessary to investigate the differences in characteristics among mothers of different nationalities in order to uncover the reason for the high risk for low birth weight among Japanese mothers.

Gestational age, birth weight, and perinatal complications in mothers with diabetes and impaired glucose tolerance: Japan Environment and Children's Study cohort.

We aimed to determine the risk of perinatal complications during delivery in mothers with non-normal glucose tolerance in a large Japanese birth cohort. We analysed data of 24,295 neonate-mother pairs in the Japan Environment and Children's Study cohort between 2011 and 2014. We included 67 mothers with type 1 diabetes, 102 with type 2 diabetes (determined by questionnaire), 2,045 with gestational diabetes (determined by diagnosis), and 2,949 with plasma glucose levels ≥140 mg/dL (shown by a screening test for gestational diabetes). Gestational age, birth weight, placental weight, and proportions of preterm birth, and labour and neonatal complications at delivery in mothers with diabetes were compared with those in mothers with normal glucose tolerance. Mean gestational age was shorter in mothers with any type of diabetes than in mothers without diabetes. Birth weight tended to be heavier in mothers with type 1 diabetes, and placental weight was significantly heavier in mothers with type 1 and gestational diabetes and elevated plasma glucose levels (all p<0.05). The relative risks of any labour complication and any neonatal complication were 1.49 and 2.28 in type 2 diabetes, 1.59 and 1.95 in gestational diabetes, and 1.22 and 1.30 in a positive screening test result (all p<0.05). The relative risks of preterm birth, gestational hypertension, and neonatal jaundice were significantly higher in mothers with types 1 (2.77; 4.07; 2.04) and 2 diabetes (2.65; 5.84; 1.99) and a positive screening test result (1.29; 1.63; 1.12) than in those without diabetes (all p<0.05). In conclusion, placental weight is heavier in mothers with non-normal glucose tolerance. Preterm birth, gestational hypertension, and jaundice are more frequent in mothers with types 1 and 2 diabetes. A positive result in a screening test for gestational diabetes suggests not only a non-normal glucose tolerance, but also a medium (middle-level) risk of perinatal complications.

The risk of preterm birth in combinations of socioeconomic position and mental health conditions in different age groups: a Danish nationwide register-based cohort study

BackgroundInequality in preterm birth is a world-wide challenge that has proved difficult for maternity care services to meet. Reducing the inequality requires identification of pregnant women at particularly high risk of preterm birth in order to target interventions. Therefore, the aim was to estimate the risk of preterm birth in women with different combinations of socioeconomic position, mental health conditions, and age.MethodsIn this nationwide register-based cohort study, we included all first-time mothers that gave birth to a singleton liveborn infant in Denmark between 2000 and 2016. The absolute and relative risk of preterm birth (< 37 weeks of gestation) was examined in different combinations of educational level (high, intermediate, and low) and mental health conditions (no, minor, and moderate/severe) in three age strata (≤23, 24–30, and ≥ 31 years). We estimated the relative risk using Poisson regression with a robust error variance. As additive interaction can help identify subgroups where limited resources can be of best use, we measured the attributable proportion to assess the risk that is due to interaction of the different exposures.ResultsOf the 415,523 included first-time mothers, 6.3% gave birth prematurely. The risk of preterm birth increased with decreasing educational level and increasing severity of mental health conditions in all age strata, but most in women aged ≥31 years. The highest absolute risk was 12.9% [95% CI: 11.2;14.8%] in women aged ≥31 years with low education and moderate/severe mental health conditions resulting in a relative risk of 2.23 [95% CI: 1.93–2.58] compared to the unexposed reference group in that age strata. We found positive additive interaction between low education and mental health conditions in women aged 24–30 and ≥ 31 years and between age ≥ 31 years and combinations of mental health conditions and educational levels.ConclusionThe inequality in preterm birth increased with increasing age. To reduce inequality in preterm birth focused attention on women with higher age further combined with lower educational levels and mental health conditions is essential.

Risk of Extreme, Moderate, and Late Preterm Birth by Maternal Race, Ethnicity, and Nativity

To explore the relative risks of preterm birth-both overall and stratified into 3 groups (late, moderate, and extreme prematurity)-associated with maternal race, ethnicity, and nativity (ie, birthplace) combined. This was a retrospective cross-sectional cohort study of women delivering a live birth in Pennsylvania from 2011 to 2014 (n=4 499 259). Log binomial and multinomial regression analyses determined the relative risks of each strata of preterm birth by racial/ethnic/native category, after adjusting for maternal sociodemographic, medical comorbidities, and birth year. Foreign-born women overall had lower relative risks of both overall preterm birth and each strata of prematurity when examined en bloc. However, when considering maternal race, ethnicity, and nativity together, the relative risk of preterm birth for women in different racial/ethnic/nativity groups varied by preterm strata and by race. Being foreign-born appeared protective for late prematurity. However, only foreign-born White women had lower adjusted relative risks of moderate and extreme preterm birth compared with reference groups. All ethnic/native sub-groups of Black women had a significantly increased risk of extreme preterm births compared with US born non-Hispanic White women. Race, ethnicity, and nativity contribute differently to varying levels of prematurity. Future research involving birth outcome disparities may benefit by taking a more granular approach to the outcome of preterm birth and considering how nativity interacts with race and ethnicity.

Smoking Cessation and Preterm Birth in Second Pregnancy Among Women who Smoked in Their First.

The benefit of smoking cessation in reducing the risk of preterm birth is well established. Relatively less well understood is the prevalence of smoking cessation maintenance at the next pregnancy and the associated preterm risk reduction. The aim of this study was to estimate the prevalence of maintenance of smoking cessation at second pregnancy and the associated relative risk of preterm birth. This was a longitudinal study with retrospectively obtained records of births to multiparous women who smoked in the pregnancy of their first birth in New South Wales, 1994-2016 (N = 63 195 mothers). Relative risks (RR) of preterm birth of the second child were estimated for smoking cessation with adjustment for final gestational age of the first birth, maternal age at the first birth, change in socioeconomic disadvantage between the first and second pregnancy, interpregnancy interval, and calendar time. Approximately 34% (N = 21 540) of women who smoked during their first pregnancy did not smoke in the second pregnancy. Smoking cessation among women who smoked at first pregnancy was associated with a 26% (95% CI: 21%, 31%) decrease in risk of preterm birth at a second pregnancy. Despite smoking during the first pregnancy, smoking cessation was achieved and maintained by more than one-third of women in their second pregnancy with encouraging levels of preterm risk reduction. It is well-established that the period after birth provides an opportunity to reduce smoking-related morbidity for both the mother and neonate. Our results indicate that this period also offers an opportunity to prevent morbidity of future pregnancy. A considerable amount of research has been undertaken on the effects of smoking during pregnancy on birth outcomes, the influence of postpartum smoking on the health of the mother and newborn child, and postpartum smoking cessation. However, follow-up of women after giving birth does not tend to be long enough to observe smoking and outcomes of subsequent pregnancies. We show that smoking cessation in the subsequent pregnancy is achievable by a large proportion of women despite smoking in their first pregnancy, which translates to clear reductions in risk of preterm birth in the subsequent pregnancy.

Term Complications and Subsequent Risk of Preterm Birth: Registry-Based Study

Abstract Objective To explore conditions and outcomes of a first delivery at term that might predict later preterm birth. Design Population based, prospective register based study. Setting Medical Birth Registry of Norway, 1999-2015. Participants 302 192 women giving birth (live or stillbirth) to a second singleton child between 1999 and 2015. Main outcome measures Main outcome was the relative risk of preterm delivery ( Results Women with any of the five complications at term showed a substantially increased risk of preterm delivery in the next pregnancy. The absolute risks for preterm delivery in a second pregnancy were 3.1% with none of the five term complications (8202/265 043), 6.1% after term pre-eclampsia (688/11 225), 7.3% after term placental abruption (41/562), 13.1% after term stillbirth (72/551), 10.0% after term neonatal death (22/219), and 6.7% after term small for gestational age (463/6939). The unadjusted relative risk for preterm birth after term pre-eclampsia was 2.0 (95% confidence interval 1.8 to 2.1), after term placental abruption was 2.3 (1.7 to 3.1), after term stillbirth was 4.2 (3.4 to 5.2), after term neonatal death was 3.2 (2.2 to 4.8), and after term small for gestational age was 2.2 (2.0 to 2.4). On average, the risk of preterm birth was increased 2.0-fold (1.9-fold to 2.1-fold) with one term complication in the first pregnancy, and 3.5-fold (2.9-fold to 4.2-fold) with two or more complications. The associations persisted after excluding recurrence of the specific complication in the second pregnancy. These links between term complications and preterm delivery were also seen in the reverse direction: preterm birth in the first pregnancy predicted complications in second pregnancies delivered at term. Conclusions Pre-eclampsia, placental abruption, stillbirth, neonatal death, or small for gestational age experienced in a first term pregnancy are associated with a substantially increased risk of subsequent preterm delivery. Term complications seem to share important underlying causes with preterm delivery that persist from pregnancy to pregnancy, perhaps related to a mother’s predisposition to disorders of placental function.

Prenatal PM2.5 exposure and the risk of adverse births outcomes: Results from Project ELEFANT

BackgroundStudies investigating the impact of fine particulate matter (PM2.5) exposure during pregnancy upon adverse birth outcomes have primarily been performed in Western nations with low ambient PM2.5 levels. We examined associations between high levels of PM2.5 exposure during pregnancy and risk of adverse birth outcomes by timing and level of exposure in a Chinese population. MethodsWe analysed data from 10,738 live births within the Project ELEFANT study based in Tianjin, China. Personal mean daily PM2.5 exposures were estimated using data from 25 local monitoring sites across the city, used to compute the days exceeding 50, 100, 150, 200 and 250 μg/m3. Relative risk of pre-term birth (<37 weeks) and low birthweight (<2500 g) were estimated by generalized additive distributed lag models, adjusted for maternal age, sex, region, paternal smoking, parity, maternal occupation, season, temperature and dew point. ResultsA dose-response was exhibited for PM2.5 exposure and relative risk (RR) of adverse birth outcomes, with exposure in the second and third trimesters of pregnancy associated with greatest risk of adverse birth outcomes. The RRs of pre-term birth with exposures of >50, >150 and > 250 μg/m3 PM2.5 in the third trimester were 1.09 (95%CI: 1.03–1.16), 1.30 (1.09–1.54) and 2.73 (2.03–3.66) respectively. For low birthweight, exposures of >50, >150 and > 250 μg/m3 PM2.5 in the third trimester were associated with RRs of 0.99 (0.88–1.11), 1.37 (1.04–1.81) and 3.03 (1.75–5.23) respectively. ConclusionsExposure to high levels of PM2.5 from the second trimester onwards was most strongly associated with increased risk of pre-term birth and low birthweight, with a dose-response relationship. Our data demonstrates the need to account for both level and timing of exposure in analysis of PM2.5-associated birth outcomes.

The risk of preterm birth in combinations of mental disorder and socioeconomic position among Danish women

Abstract Background Inequality in preterm birth is a public health challenge requiring identification of pregnant women at particularly high risk of preterm birth. Therefore, the aim was to estimate the risk of preterm birth in women with different combinations of mental health conditions and socioeconomic position. Methods Based on Danish registries, we conducted a nationwide cohort study including all first-time mothers giving birth to a singleton liveborn infant in Denmark between 2000 through 2016. We examined the risk of preterm birth (&amp;lt;37 weeks of gestation) in different combinations of mental health conditions (no, minor, and moderate/severe) and educational level (high, intermediate, and low) in three age strata (&amp;lt;25, 25-30, and &amp;gt;30 years). The relative risk of preterm birth was estimated using Poisson regression with a robust error variance. We measured the attributable proportion to assess additive interaction between the effects of exposures. Results Of the 415,523 included first time mothers, 29,069 (7,0%) gave birth preterm. The risk of preterm birth increased in combinations of higher degree of mental health conditions, lower degree of educational level, and increasing age. Women aged&amp;gt;30 years with moderate/severe mental health conditions and low educational level had the highest risk of preterm birth (13.7%). The analysis of additive interaction revealed only a limited additional effect of being exposed to mental health conditions and lower educational levels in each age strata. However, positive additive interaction was found between age&amp;gt;30 year and combinations of mental health conditions and educational level. Conclusions Substantial inequality in preterm birth remains with increasing risk in women with combinations of higher degree of mental health conditions and lower degree of educational level. In the prevention of inequality in preterm birth special attention on women aged&amp;gt;30 years exposed to mental health conditions and lower educational levels is essential

Term complications and subsequent risk of preterm birth: registry based study

ObjectiveTo explore conditions and outcomes of a first delivery at term that might predict later preterm birth.DesignPopulation based, prospective register based study.SettingMedical Birth Registry of Norway, 1999-2015.Participants302 192 women giving...

Quality of periconceptional dietary intake and maternal and neonatal outcomes

Periconceptional diet quality is commonly suboptimal and sociodemographic disparities in diet quality exist. However, it is unknown whether individual periconceptional diet quality is associated with obstetric outcomes. Our objective was to assess differences in maternal and neonatal outcomes according to maternal periconceptional diet quality. This is a secondary analysis of a large, multicenter prospective cohort study of 10,038 nulliparous women receiving obstetrical care at 8 United States centers. Women underwent 3 antenatal study visits and had detailed maternal and neonatal data abstracted by trained research personnel. In the first trimester (between 6 and 13 weeks), women completed the modified Block 2005 Food Frequency Questionnaire, a semiquantitative assessment of usual dietary intake for the 3 months around conception. Responses were scored using the Healthy Eating Index-2010, which assesses adherence to the 2010 Dietary Guidelines for Americans. Higher scores on the Healthy Eating Index represent better adherence. Healthy Eating Index scores were analyzed by quartile; quartile 4 represents the highest dietary quality. Bivariable and multivariable analyses were performed to assess associations between diet quality and outcomes. A sensitivity analysis in which markers of socioeconomic status were included in the multivariable Poisson regression models was performed. In the cohort of 8259 women with Healthy Eating Index data, the mean Healthy Eating Index score was 63 (±13) of 100. Women with the lowest quartile Healthy Eating Index scores were more likely to be younger, non-Hispanic black and Hispanic, publicly insured, low income, and tobacco users. They were more likely to have comorbidities (obesity, chronic hypertension, pregestational diabetes, mental health disorders), a higher prepregnancy body mass index, and less education. Women with lowest quartile scores experienced less frequent major perineal lacerations and more frequent postpartum hemorrhage requiring transfusion and hypertensive disorders of pregnancy, which persisted on multivariable analyses (controlling for age, body mass index, tobacco use, chronic hypertension, pregestational diabetes mellitus, and mental health disorders) comparing women in each quartile with quartile 4. Additionally, women in quartiles 1 and 2 experienced greater adjusted relative risk of cesarean delivery compared with women in quartile 4. Neonatal outcomes also differed by dietary quartile, with women in the lowest Healthy Eating Index quartile experiencing greater adjusted relative risk of preterm birth, neonatal intensive care unit admission, small for gestational age infant, and low birthweight, and lower risk of macrosomia; all neonatal findings also persisted in multivariable analyses. The sensitivity analysis with inclusion of markers of socioeconomic status (race/ethnicity, insurance status, marital status) in the multivariable models supported these findings. Periconceptional diet quality among women in the United States is poor. Poorer periconceptional dietary quality is associated with adverse maternal and neonatal outcomes, even after controlling for potential comorbidities and body mass index, suggesting periconceptional diet may be an important social or biological determinant of health underlying existing health disparities.

Mass incarceration and public health: the association between black jail incarceration and adverse birth outcomes among black women in Louisiana

BackgroundA growing body of evidence is beginning to highlight how mass incarceration shapes inequalities in population health. Non-Hispanic blacks are disproportionately affected by incarceration and criminal law enforcement, an enduring legacy of a racially-biased criminal justice system with broad health implications for black families and communities. Louisiana has consistently maintained one of the highest rates of black incarceration in the nation. Concurrently, large racial disparities in population health persist.MethodsWe conducted a cross-sectional analysis of all births among non-Hispanic black women in Louisiana in 2014 to identify associations between parish-level (county equivalent) prevalence of jail incarceration within the black population and adverse birth outcomes (N = 23,954). We fit a log-Poisson model with generalized estimating equations to approximate the relative risk of preterm birth and low birth weight associated with an interquartile range increase in incarceration, controlling for confounders. In sensitivity analyses, we additionally adjusted for the parish-level index crime prevalence and analyzed regression models wherein white incarceration was used to predict the risk of adverse birth outcomes in order to quantify the degree to which mass incarceration may harm health above and beyond living in a high crime area.ResultsThere was a significant 3% higher risk of preterm birth among black women associated with an interquartile range increase in the parish-level incarceration prevalence of black individuals, independent of other factors. Adjusting for the prevalence of index crimes did not substantively change the results of the models.ConclusionDue to the positive significant associations between the prevalence of black individuals incarcerated in Louisiana jails and estimated risk of preterm birth, mass incarceration may be an underlying cause of the persistent inequities in reproductive health outcomes experienced by black women in Louisiana. Not only are there economic and social impacts stemming from mass incarceration, but there may also be implications for population health and health inequities, including the persistence of racial disparities in preterm birth and low birth weight.

Systemic inflammation is associated with malaria and preterm birth in women living with HIV on antiretrovirals and co-trimoxazole

Women living with HIV (WLHIV) have an increased risk of malaria in pregnancy (MiP). It is unclear if MiP in WLHIV causes a systemic inflammatory response and increases the risk of adverse birth outcomes, especially for women receiving antiretroviral therapy (ART) and daily trimethoprim-sulfamethoxazole (TMP/SXT). We analyzed repeated plasma samples in a cohort of malaria-exposed Ugandan WLHIV receiving ART and daily TMP/SXT to examine changes in inflammatory markers across pregnancy and their association with birth outcomes. Concentrations of CHI3L1, CRP, IL-18BP, IL-6, sICAM-1, and sTNFR2 were quantified by ELISA in 1115 plasma samples collected over pregnancy from 326 women. MiP was associated with increased sTNFR2, sICAM-1 and IL-18BP concentrations across pregnancy. Women who delivered preterm had elevated concentrations of sTNFR2 and altered levels of IL-6 during pregnancy. Women with sTNFR2 concentrations in the highest quartile within 6 weeks of delivery had an increased relative risk of preterm birth. Our results indicate that despite daily TMP/SXT, MiP in WLHIV induced a systemic inflammatory response that was associated with an increased risk of preterm birth. These findings highlight the need for additional strategies to protect WLHIV from malaria infection in pregnancy to promote healthy outcomes for mother and child.

Beyond Cervical Length: Association between Postcerclage Transvaginal Ultrasound Parameters and Preterm Birth.

To assess the value of transvaginal ultrasound parameters after cerclage placement in estimating the risk of spontaneous preterm birth. This is a retrospective cohort at a single tertiary care center from 2013 to 2016. Women carrying a singleton, nonanomalous fetus with cerclage in situ and at least one postcerclage transvaginal ultrasound from 160/7 to 256/7 weeks' gestation were included. In addition to abstracting maternal demographic and obstetric characteristics, two study investigators separately reviewed each of the images from the first transvaginal ultrasound after cerclage placement, masked to pregnancy outcomes. We measured the angle between the anterior uterine wall and cervical canal at the internal os and external os, closed canal length above and below the stitch, width of the anterior and posterior cervix at the level of the cerclage, and stitch distance from the cervical canal. The presence of additional ultrasound findings such as sludge and cervical funneling was also noted. The main outcomes were preterm birth < 34 weeks and preterm birth < 37 weeks. Transvaginal ultrasound parameters were compared between women with preterm birth and those without preterm birth using chi-square, Fisher's exact, and Wilcoxon's rank-sum tests, as appropriate. Log binomial regression was used to estimate the relative risk of preterm birth for all significant obstetric and ultrasound characteristics. A total of 102 women met inclusion criteria: 58% had history-indicated, 20% ultrasound-indicated, and 23% exam-indicated cerclages. Of these, 28 (27.5%) women delivered at < 34 weeks' gestation, and 48 (47.0%) women delivered at < 37 weeks' gestation. Preterm birth did not vary by race, maternal age, insurance, smoking, or gestational age of the earliest prior preterm birth (for multiparous women), but women who had preterm birth were more likely to have exam-indicated cerclage. There were several transvaginal ultrasound parameters associated with preterm birth < 34 weeks and preterm birth < 37 weeks. Of these, cervical length below the stitch, stitch distance from the cervical canal, straight cervical canal, funneling to or past the stitch, and presence of sludge had the greatest effect sizes. Rates of preterm birth are high postcerclage. In addition to measuring cervical length, utilization of postcerclage transvaginal ultrasound to evaluate the location of the cerclage within the cervix, the curvature of the cervical canal, and the presence of funneling and sludge may help identify women who are at the highest risk for preterm birth.

Ambient temperature and preterm birth: A retrospective study of 32 million US singleton births

BackgroundDays of extreme temperature may be associated with transiently higher risk of preterm birth, but prior studies have been limited and results have been heterogeneous. ObjectivesTo evaluate the association between days of extreme heat and cold and risk of preterm birth among ~32 million live singleton births between 1989 and 2002 across 403 counties in the contiguous United States (US). MethodsWe used a distributed lag nonlinear model to estimate the association between population-weighted daily mean temperature and risk of preterm birth in each county and then pooled results across geographic regions and climate zones. We defined extreme heat and cold as the 95th and 5th percentile of the county-specific temperatures, respectively. ResultsPreterm birth accounted for 9.3% of deliveries. There was a monotonic association between ambient temperature and risk of preterm birth. Days of extreme heat and cold were associated with a relative risk of preterm birth of 1.025 (95% CI: 1.015, 1.036) and 0.985 (95% CI: 0.976, 0.993) over the subsequent four days, respectively, relative to the county-specific median temperature. If causal, the fraction of preterm births attributable to extreme heat was 0.17% (empirical 95% CI: 0.14%, 0.19%), corresponding to 154 (empirical 95% CI: 127, 173) preterm births per million births. Extreme heat was more strongly associated with preterm birth in regions with colder and drier climates, and among younger women. Days of extreme cold temperature were associated with lower rather than higher risk of preterm birth. ConclusionsDays of extreme heat, but not extreme cold, are associated with higher risk of preterm birth in the contiguous US. If causal, these results may have important implications for the management of pregnant women during forecasted periods of extreme heat.

76: Quality of periconceptional dietary intake and maternal and neonatal outcomes

Abstract Background Periconceptional diet quality is commonly suboptimal and sociodemographic disparities in diet quality exist. However, it is unknown whether individual periconceptional diet quality is associated with obstetric outcomes. Objective Our objective was to assess differences in maternal and neonatal outcomes according to maternal periconceptional diet quality. Study Design This is a secondary analysis of a large, multicenter prospective cohort study of 10,038 nulliparous women receiving obstetrical care at 8 United States centers. Women underwent three antenatal study visits and had detailed maternal and neonatal data abstracted by trained research personnel. In the first trimester (between 6 and 13 weeks), women completed the modified Block 2005 Food Frequency Questionnaire, a semiquantitative assessment of usual dietary intake for the 3 months around conception. Responses were scored using the Healthy Eating Index-2010, which assesses adherence to the 2010 Dietary Guidelines for Americans. Higher scores on the Healthy Eating Index represent better adherence. Healthy Eating Index scores were analyzed by quartile; quartile 4 represents the highest dietary quality. Bivariable and multivariable analyses were performed to assess associations between diet quality and outcomes. A sensitivity analysis in which markers of socioeconomic status were included in the multivariable Poisson regression models was performed. Results In the cohort of 8,259 women with Healthy Eating Index data, the mean Healthy Eating Index score was 63 (± 13) of 100. Women with the lowest quartile Healthy Eating Index scores were more likely to be younger, non-Hispanic black and Hispanic, publicly insured, low income, and tobacco users. They were more likely to have comorbidities (obesity, chronic hypertension, pregestational diabetes, mental health disorders), a higher pre-pregnancy body mass index, and less education. Women with lowest quartile scores experienced less frequent major perineal lacerations and more frequent postpartum hemorrhage requiring transfusion and hypertensive disorders of pregnancy, which persisted on multivariable analyses (controlling for age, body mass index, tobacco use, chronic hypertension, pregestational diabetes mellitus, and mental health disorders) comparing women in each quartile to quartile 4. Additionally, women in quartiles 1 and 2 experienced greater adjusted relative risk of cesarean delivery compared to women in quartile 4. Neonatal outcomes also differed by dietary quartile, with women in the lowest Healthy Eating Index quartile experiencing greater adjusted relative risk of preterm birth, neonatal intensive care unit admission, small for gestational age infant, and low birthweight, and lower risk of macrosomia; all neonatal findings also persisted in multivariable analyses. The sensitivity analysis with inclusion of markers of socioeconomic status (race/ethnicity, insurance status, marital status) in the multivariable models supported these findings. Conclusions Periconceptional diet quality among women in the United States is poor. Poorer periconceptional dietary quality is associated with adverse maternal and neonatal outcomes even after controlling for potential comorbidities and body mass index, suggesting periconceptional diet may be an important social or biological determinant of health underlying existing health disparities.