Maternal ethnic ancestry and adverse perinatal outcomes in New York City

Adverse Birth Outcomes and Maternal Morbidity Among Afro-Latinas and Their Infants: A Systematic Literature Review

OBJECTIVES

To evaluate and synthesize research findings on adverse birth outcomes and maternal morbidity among Afro-Latinas and their infants.

METHODS

A systematic review was conducted within PubMed, Web of Science, and SCOPUS databases. Four thousand five hundred twenty-six published peer-reviewed articles from 1970 to 2023 that reported outcomes related to maternal morbidity and/or birth outcomes were screened. After screening, we assessed 22 for eligibility, and ultimately, seven studies were included for data extraction and analysis.

RESULTS

Although limited, the existing studies revealed disparities in abnormal birth weight (LBW & SGA) and higher preterm birth prevalence among Afro-Latinas compared to other racial and ethnic peers. These disparities are also prevalent among U.S.-born Afro-Latinas compared to foreign-born Afro-Latinas.

CONCLUSIONS

By critically examining the current empirical evidence, we can gain a deeper understanding of how intersectionality impacts perinatal health outcomes among Afro-Latinas. Understanding the root causes of these outcomes through increased research is critical to preventing and reducing poor maternal and child health among Afro-Latinas, particularly those who are U.S.-born.

Preterm Birth Risk and Maternal Nativity, Ethnicity, and Race

Importance

Immigrant birthing people have lower rates of preterm birth compared with their US-born counterparts. This advantage and associated racial and ethnic disparities across the gestational age spectrum have not been examined nationally.

Objective

To examine associations of maternal nativity, ethnicity, and race with preterm birth.

Design, Setting, and Participants

This cohort study used birth certificates from the National Vital Statistics System to analyze in-hospital liveborn singleton births in the US between January 1, 2009, and December 31, 2018. Data were analyzed from January to June 2023.

Exposure

Mutually exclusive nativity, ethnicity, and race subgroups were constructed using nativity (defined as US-born or non-US-born), ethnicity (defined as Hispanic or non-Hispanic), and race (defined as American Indian or Alaska Native, Asian, Black, Native Hawaiian or Other Pacific Islander, White, or other [individuals who selected other race or more than 1 race]).

Main Outcomes and Measures

The primary outcome of interest was preterm birth. Modified Poisson and multinomial logistic regression models quantified relative risk (RR) of preterm birth overall (<37 weeks' gestation) and by gestational category (late preterm: 34-36 weeks' gestation; moderately preterm: 29-33 weeks' gestation; and extremely preterm: <29 weeks' gestation) for each maternal nativity, ethnicity, and race subgroup compared with the largest group, US-born non-Hispanic White (hereafter, White) birthing people. The RR of preterm birth overall and by category was also measured within each racial and ethnic group by nativity. Models were adjusted for maternal demographic and medical covariates, birth year, and birth state.

Results

A total of 34 468 901 singleton live births of birthing people were analyzed, with a mean (SD) age at delivery of 28 (6) years. All nativity, ethnicity, and race subgroups had an increased adjusted risk of preterm birth compared with US-born White birthing people except for non-US-born White (adjusted RR, 0.85; 95% CI, 0.84-0.86) and Hispanic (adjusted RR, 0.98; 95% CI, 0.97-0.98) birthing people. All racially and ethnically minoritized groups had increased adjusted risks of extremely preterm birth compared with US-born White birthing people. Non-US-born individuals had a decreased risk of preterm birth within each subgroup except non-Hispanic Native Hawaiian or Other Pacific Islander individuals, in which immigrants had significantly increased risk of overall (adjusted RR, 1.07; 95% CI, 1.01-1.14), moderately (adjusted RR, 1.10; 95% CI, 0.92-1.30), and late (adjusted RR, 1.11; 95% CI, 1.02-1.22) preterm birth than their US-born counterparts.

Conclusions and Relevance

Results of this cohort study suggest heterogeneity of preterm birth across maternal nativity, ethnicity, and race and gestational age categories. Understanding these patterns could aid the design of targeted preterm birth interventions and policies, especially for birthing people typically underrepresented in research.

Adverse birth outcomes in New York City women: Revisiting the Hispanic Paradox

In the United States, African American or non-Hispanic Black infants experienced worst birth outcomes whereas Hispanic and Asian infants have intermediate or similar outcomes compared with non-Hispanic white infants. The findings of better birth outcomes for Hispanic women have been coined the "Hispanic Paradox" given their low education, income, and access to care. New York City (NYC) has a great racial/ethnic diversity with implications for neighborhood racial/ethnic composition on birth outcomes by protecting women from psychosocial stress via social support that may buffer against racial/ethnic discrimination and/or racism. Data from 2012 to 2018 were used to examine the association of NYC women's race/ethnicity and neighborhood racial/ethnic minority composition with adverse birth outcomes (low birthweight [LBW], small for gestational age [SGA], preterm birth and infant mortality); and whether the association between mother's race/ethnicity and each birth outcome differed by neighborhood racial/ethnic composition. Multilevel logistic regression was used to control for the clustering of outcomes within neighborhoods. Black, Asian, and American Indian women have poorer birth outcomes than white women. Infants of Mexican American, Central American, and South American women were less likely to be of LBW whereas the opposite was true for infants of Cuban and other Hispanic women compared with infants of white women. When compared with white women, Mexican American, and South American women were less likely to have an SGA infant whereas Puerto Rican and other Hispanic women were more likely to have an SGA infant. All Hispanic women were more likely to have a preterm birth than white women whereas for infant mortality, greater odds of dying were observed for infants of Puerto Rican, Dominican, and other Hispanic women. Higher neighborhood racial/ethnic minority composition was associated with greater odds of having an adverse outcome. Finally, we observed heterogeneity of the associations between mother's race/ethnicity and birth outcomes by neighborhood racial/ethnic minority composition.

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

OBJECTIVES

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.

STUDY DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

Maternal nativity and risk of adverse perinatal outcomes among Black women residing in California, 2011-2017

OBJECTIVE

Examine the risk of adverse perinatal outcomes among the United States (US)-born and foreign-born Black women in California.

STUDY DESIGN

The study comprised all singleton live births to Black women in California between 2011 and 2017. We defined maternal nativity as US-born or foreign-born. Using Poisson regression, we computed risk ratios (RR) and 95% confidence intervals (CI) for three adverse perinatal outcomes: preterm birth, small for gestational age deliveries, and infant mortality.

RESULTS

Rates of adverse perinatal outcomes were significantly higher among US-born Black women. In adjusted models, US-born Black women experienced an increased risk of preterm birth (RR 1.51, 95% CI 1.39, 1.65) and small for gestational age deliveries (RR 1.52, 95% CI 1.41, 1.64), compared to foreign-born Black women.

CONCLUSIONS

Future studies should consider experiences of racism across the life course when exploring heterogeneity in the risk of adverse perinatal outcomes by nativity among Black women in the US.

Resilience During Pregnancy by Race, Ethnicity and Nativity: Evidence of a Hispanic Immigrant Advantage

The similar socioeconomic position of black and Hispanic women coupled with better birth outcomes among Hispanic women is termed the "Hispanic Paradox." However, birth outcome disparities among Hispanic women exist by maternal nativity. Persistent unequal exposure over time to stressors contributes to these disparities. We hypothesized that variation in maternal resilience to stressors also exists by race, ethnicity, and nativity. We utilized data from the Spontaneous Prematurity and Epigenetics of the Cervix study in Boston, MA (n = 771) where resilience was measured mid-pregnancy using the Connor Davidson Resilience Scale 25. We assessed resilience differences by race/ethnicity, by nativity then by race, ethnicity, and nativity together. We also assessed the risk of low resilience among foreign-born women by region of origin. We used Poisson regression to calculate risk ratios for low resilience, adjusting for maternal age, education, and insurance. Resilience did not differ significantly across race/ethnicity or by foreign-born status in the overall cohort. US-born Hispanic women were more likely to be in the low resilience tertile compared with their foreign-born Hispanic counterparts (adjusted RR 3.52, 95% CI 1.18-10.49). Foreign-born Hispanic women also had the lowest risk of being in the low resilience tertile compared with US-born non-Hispanic white women (aRR 0.33, 95% CI 0.11-0.98). Resilience did not differ significantly among immigrant women by continent of birth. Overall, foreign-born Hispanic women appear to possess a resilience advantage. Given that this group often exhibits the lowest rates of adverse birth outcomes, our findings suggest a deeper exploration of resilience among immigrant Hispanic women.

Maternal Zika Virus Infection: Association With Small-for-Gestational-Age Neonates and Preterm Birth

OBJECTIVE

To evaluate whether antenatal Zika virus infection is associated with risk of having a small-for-gestational-age (SGA) neonate, risk of preterm birth, and lower mean birth weight of term neonates.

METHODS

For this retrospective observational study, we linked birth record data for women who delivered liveborn singleton neonates in New York City in 2016 to data for pregnant women with Zika virus infection reported to the New York City Health Department. We restricted the analysis to nonsmoking, nonwhite women and adjusted for maternal characteristics. Among women with antenatal Zika virus infection, we used modified Poisson regression to assess risks of having an SGA neonate and of delivering preterm, and linear regression to assess the association of infection with mean birth weight of term neonates.

RESULTS

Of 116,034 deliveries of singleton neonates in New York City in 2016, 251 (0.2%) were to women with antenatal Zika virus infection. A higher percentage of women with Zika virus infection delivered an SGA neonate compared with those without (11.2% vs 5.8%; adjusted relative risk [RR] 1.8; 95% CI 1.3-2.6). There was no difference in preterm birth prevalence for women with and without Zika virus infection (adjusted RR 1.0; 95% CI 0.69-1.6). Mean birth weight of term neonates born to women with Zika virus infection was 47 g less (95% CI -105 to 11 g); this difference was not statistically significant in crude or adjusted analyses.

CONCLUSION

For a cohort of New York City women, antenatal Zika virus infection was associated with an increased risk of having an SGA neonate, but not preterm birth or lower mean birth weight of term neonates. This supports a putative association between Zika virus infection during pregnancy and SGA.

An Examination of Preterm Birth and Residential Social Context among Black Immigrant Women in California, 2007-2010

The foreign-born black population contributes a considerable amount of heterogeneity to the US black population. In 2005, black immigrants accounted for 20% of the US black population. Compared to native-born black women, black immigrant women are at lower risk for adverse birth outcomes, including preterm birth. Some scholars posit that differential exposures to socioeconomic disadvantage and structural racism in the residential context may account for this advantage. However, to date, few studies offer comprehensive examinations of the black immigrant residential social context, particularly in settlement regions beyond predominantly black and historically segregated regions. Further, studies examining the black immigrant residential context typically use a single indicator, which limits discussion of the intersecting domains that simultaneously increase or decrease risk among black immigrants. We addressed these gaps by examining black immigrant neighborhoods in the state of California, where racial residential segregation of the black population is low. We operationalized the residential context of black immigrant women using three distinct attributes: immigrant co-ethnic density, black racial concentration, and neighborhood deprivation. We linked 2007-2010 California birth records of black immigrant women and 2010 census data on tract-level social attributes (N = 6930). OLS regression analyses showed that immigrant co-ethnic density, black racial concentration and neighborhood deprivation were not associated with preterm birth among black immigrants. Our findings indicate that in California, residential social context has little relation to black immigrant preterm birth-a finding that is unique compared to residential settings of other settlement contexts.

Do social factors and country of origin contribute towards explaining a "Latina paradox" among immigrant women giving birth in Germany?

Background

The “Latina paradox” describes the unexpected association between immigrant status, which is often correlated to low socioeconomic status, and low prevalence of unfavourable birth outcomes. Social (e.g. culture, religion) and/or non-social factors related to country of origin are potentially responsible for this paradox.

Methods

Questionnaire survey of 6413 women delivering in three large obstetric hospitals in Berlin (Germany) covering socioeconomic and migration status, country of origin (Turkey, Lebanon), and acculturation. Data was linked with routine obstetric data. Logistic regressions were performed to assess the effect of acculturation, affinity to religion and country of origin on preterm birth and small-for-gestational-age (SGA).

Results

Immigrant women with a low level of acculturation (reference) were less likely to have a preterm birth than those who were highly acculturated (aOR: 1.62, 95%CI: 1.01–2.59), as were women from Turkey compared to non-immigrants (aOR: 0.49, 95%CI: 0.33–0.73). For SGA, we found no epidemiologic paradox; conversely, women from Lebanon had a higher chance (aOR: 1.72, 95%CI: 1.27–2.34) of SGA. Affinity to religion had no influence on birth outcomes.

Conclusions

There is evidence that low acculturation (but not affinity to religion) contributes towards explaining the epidemiologic paradox with regard to preterm birth, emphasising the influence of socioeconomic characteristics on birth outcomes. The influence of Turkish origin on preterm birth and Lebanese origin on SGA suggests that non-social factors relating to the country of origin are also at play in explaining birth outcome differences, and that the direction of the effect varies depending on the country of origin and the outcome.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-6523-9) contains supplementary material, which is available to authorized users.

Maternal Birthplace is Associated with Low Birth Weight Within Racial/Ethnic Groups

Introduction While disparities in low birth weight (LBW) incidence by racial/ethnic group are well known, differences in LBW incidence by maternal birthplace within racial/ethnic groups, and particularly, differences after adjustment for pregnancy complications, are less clear. Methods We conducted a population-based study of LBW using 113,760 singleton, live birth records from King County, Washington (2008-2012), a region in the Pacific Northwest with a large immigrant population. Study participants were Asian, non-Hispanic black, Hispanic, Native Hawaiian/Other Pacific Islander (NHOPI), and non-Hispanic white women. Using multivariable logistic regression models, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) to estimate relative risk of LBW (<2500 g) related to maternal race/ethnicity and birthplace (defined by the Millennium Development Goals Regional Groupings). Results Compared with non-Hispanic white women, non-Hispanic black, Asian Indian, Filipino, Japanese, and Vietnamese women had 1.57-2.23-fold higher, statistically significant, risk of having a LBW infant, and NHOPI and Mexican women had 1.30-1.33-fold, statistically significant, higher risk. LBW risk was lower for Asian women from Eastern Asia (OR 0.68, 95% CI 0.55-0.85), non-Hispanic black women from Sub-Saharan Africa (OR 0.58, 95% CI 0.47-0.73), and non-Hispanic white women from other developed countries (OR 0.83, 95% CI 0.69-1.00), as compared with their US-born racial/ethnic counterparts. Results were, in general, similar after adjustment for pregnancy complications. Conclusions Compared with most other racial/ethnic groups, non-Hispanic whites had lower risk of LBW. Foreign-born women had lower risk of LBW compared with their US-born counterparts in the majority of racial/ethnic groups. Pregnancy complications had minimal effect on the associations.

Determining optimal gestational weight gain in the Korean population: a retrospective cohort study

BACKGROUND

The World Health Organization (WHO) international body mass index (BMI) cut-off points defining pre-pregnancy BMI categories in the Institute of Medicine (IOM) guidelines are not directly applicable to Asians. We aimed to define the optimal gestational weight gain (GWG) for the Korean population based on Asia-specific BMI categories.

METHODS

Data from 2702 live singleton deliveries in three tertiary centers between 2010 and 2011 were analyzed retrospectively. A multivariable logistic regression analysis was conducted to determine the lowest aggregated risk of composite perinatal outcomes based on Asia-specific BMI categories. The perinatal outcomes included gestational hypertensive disorder, emergency cesarean section, and fetal size for gestational age. In each BMI category, the GWG value corresponding to the lowest aggregated risk was defined as the optimal GWG.

RESULTS

Among the study population, 440 (16.3%) were underweight (BMI < 18.5), 1459 (54.0%) were normal weight (18.5 ≤ BMI < 23), 392 (14.5%) were overweight (23 ≤ BMI < 25) and 411 (15.2%) were obese (BMI ≥ 25). The optimal GWG by Asia-specific BMI category was 20.8 kg (range, 16.7 to 24.7) for underweight, 16.6 kg (11.5 to 21.5) for normal weight, 13.1 kg (8.0 to 17.7) for overweight, and 14.4 kg (7.5 to 21.9) for obese.

CONCLUSION

Considerably higher and wider optimal GWG ranges than recommended by IOM are found in our study in order to avoid adverse perinatal outcomes. Revised IOM recommendations for GWG could be considered for Korean women according to Asian BMI categories. Further prospective studies are needed in order to determine the optimal GWG for the Korean population.

The impact of high apparent temperature on spontaneous preterm delivery: a case-crossover study

BACKGROUND

Despite the prediction that temperatures are expected to increase in the future, little is known about the health effects of increasing temperatures on pregnant women. The objective of this study was to investigate the impact of apparent temperature on spontaneous preterm delivery (PTD).

METHODS

A case-crossover study of 14,466 singleton spontaneous preterm deliveries occurring between January 1, 1995 and December 31, 2009 among Kaiser Permanente Northern California (KPNC) members was conducted. Preterm deliveries were identified through KPNC's Electronic Health Records (EHR) data. Data on gestational age at delivery, infant sex, and maternal address were also extracted from KPNC's EHR and linked to meteorologic and air pollution monitoring data based on residential zip code.

RESULTS

An 11.6% (95% CI: 4.1, 19.7) increase in spontaneous PTD was associated with a 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature, during the warm season. During the cold season, increases in apparent temperature did not significantly impact the overall effect of spontaneous PTD (6.2%, (95% CI: -3.0, 16.2) per 10 °F (5.6 °C) increase in weekly average (lag06) apparent temperature). Significant differences in the relationship between apparent temperature and spontaneous PTD emerged for region, gestational age and infant sex, during the cold season. No significant differences emerged for air pollutants.

CONCLUSIONS

Our findings provide evidence for an increase in the odds of spontaneous PTD associated with increases in apparent temperature, especially during the warm season.

Adverse Outcomes Among Asian Indian Singleton Births in New Jersey, 2008-2011

The study determined the incidence of low birth weight (LBW), small for gestational age (SGA), preterm birth, and perinatal morbidity among Asian Indians (AI) in New Jersey (NJ), as well as identified predictors of SGA. We analyzed birth records for singletons born to mothers identified as AI and non-Hispanic white from 2008 to 2011, obtained from the NJ Department of Health. For AI, rates of LBW and SGA were elevated, rates of preterm birth were similar, and neonatal intensive care unit admission was lower, compared to whites. Factors associated with SGA in AI included nulliparity, anemia, hypertension, placental abruption, and lack of prenatal care. Maternal education, marital status, substance abuse, and timing of prenatal care were associated with SGA in whites, but not in AI. SGA incidence was higher among AI despite preterm rates similar to whites. Anemia was associated with SGA uniquely among AI.

Predictors of Gestational Weight Gain among White and Latina Women and Associations with Birth Weight

This study examined racial/ethnic differences in gestational weight gain (GWG) predictors and association of first-trimester GWG to overall GWG among 271 White women and 300 Latina women. Rates of within-guideline GWG were higher among Latinas than among Whites (28.7% versus 24.4%, p < 0.016). Adjusted odds of above-guideline GWG were higher among prepregnancy overweight (OR = 3.4, CI = 1.8-6.5) and obese (OR = 4.5, CI = 2.3-9.0) women than among healthy weight women and among women with above-guideline first-trimester GWG than among those with within-guideline first-trimester GWG (OR = 4.9, CI = 2.8-8.8). GWG was positively associated with neonate birth size (p < 0.001). Interventions targeting prepregnancy overweight or obese women and those with excessive first-trimester GWG are needed.

Parental Race/Ethnicity and Adverse Birth Outcomes in New York City: 2000-2010

OBJECTIVES

To examine the association of maternal race/ethnicity only and parental race/ethnicity jointly with adverse birth outcomes (low birth weight, small for gestational age, preterm birth, and infant mortality) among New York City women.

METHODS

We used Bureau of Vital Statistics, New York City Department of Health and Mental Hygiene birth- and death-linked data from 2000 to 2010 (n = 984 807) to quantify the association of maternal race/ethnicity and parental race/ethnicity concordance or discordance with each outcome.

RESULTS

By maternal race/ethnicity, infants of non-Hispanic Black, Hispanic, and Asian women had risks of adverse birth outcomes between 10% and 210% greater than infants of non-Hispanic White women. Infants of non-Hispanic Black, Asian, and Hispanic couples exhibited higher risk of adverse birth outcomes than infants of non-Hispanic White couples. Moreover, parental racial/ethnic discordance was associated with an increased risk of adverse birth outcomes, with highest risks for pairings of Asian men with non-Hispanic White, non-Hispanic Black, and Hispanic women, and of Asian women with non-Hispanic Black and Hispanic men.

CONCLUSIONS

Parental race/ethnicity discordance may add stress to women during pregnancy, affecting birth outcomes. Thus, parental race/ethnicity should be considered when examining such outcomes.

A Comparison of Birth Outcomes Among Black, Hispanic, and Black Hispanic Women

BACKGROUND

While non-Hispanic Black populations tend to be disproportionately affected by adverse reproductive outcomes, Hispanic populations tend to demonstrate healthier birth outcomes, regardless of socioeconomic background. Little is known about birth outcomes for women who are both Black and Hispanic. We examined whether birth outcomes and risk factors for women who are both Black and Hispanic most closely resemble those of women who are only Black or Hispanic and also compared these outcomes to those for Whites.

METHODS

Using the 2013 US natality files, we examined 2,970,315 singleton births to Black Hispanic, Hispanic, Black, and White mothers. We used logistic regression to calculate predicted probabilities of low birth weight (LBW), preterm birth (PTB), or small for gestational age (SGA). Race-stratified regression analysis was used to identify the factors that significantly predicted risk for each outcome for each racial/ethnic group.

RESULTS

Black mothers had the highest prevalence and predicted probabilities of experiencing all three outcomes. Black Hispanic mothers were less likely than Black mothers and more likely than Hispanic mothers to experience each of the adverse outcomes. We also found support for racial variation in risk and protective factors for mothers in the different groups. Factors like age and education inconsistently predicted risk of experiencing the birth outcomes for all groups. Overall, Black Hispanic mothers had birth outcomes and risk factor profiles like Hispanic mothers, although they had sociodemographic characteristics and health behaviors like Black mothers.

CONCLUSIONS

Patterning of birth outcomes among Black Hispanic women suggest an intersection of risk and protective factors associated with their respective racial and ethnic identities. Additional information about sociodemographic context is needed to develop a more complete picture of how factors related to race and ethnic group membership influence Black Hispanic women's birth outcomes.

Maternal characteristics and mid-pregnancy serum biomarkers as risk factors for subtypes of preterm birth

OBJECTIVE

To examine the relationship between maternal characteristics, serum biomarkers and preterm birth (PTB) by spontaneous and medically indicated subtypes.

DESIGN

Population-based cohort.

SETTING

California, United States of America.

POPULATION

From a total population of 1 004 039 live singleton births in 2009 and 2010, 841 665 pregnancies with linked birth certificate and hospital discharge records were included.

METHODS

Characteristics were compared for term and preterm deliveries by PTB subtype using logistic regression and odds ratios adjusted for maternal characteristics and obstetric factors present in final stepwise models and 95% confidence intervals. First-trimester and second-trimester serum marker levels were analysed in a subset of 125 202 pregnancies with available first-trimester and second-trimester serum biomarker results.

MAIN OUTCOME MEASURE

PTB by subtype.

RESULTS

In fully adjusted models, ten characteristics and three serum biomarkers were associated with increased risk in each PTB subtype (Black race/ethnicity, pre-existing hypertension with and without pre-eclampsia, gestational hypertension with pre-eclampsia, pre-existing diabetes, anaemia, previous PTB, one or two or more previous caesarean section(s), interpregnancy interval ≥ 60 months, low first-trimester pregnancy-associated plasma protein A, high second-trimester α-fetoprotein, and high second-trimester dimeric inhibin A). These risks occurred in 51.6-86.2% of all pregnancies ending in PTB depending on subtype. The highest risk observed was for medically indicated PTB <32 weeks in women with pre-existing hypertension and pre-eclampsia (adjusted odds ratio 89.7, 95% CI 27.3-111.2).

CONCLUSIONS

Our findings suggest a shared aetiology across PTB subtypes. These commonalities point to targets for further study and exploration of risk reduction strategies.

TWEETABLE ABSTRACT

Findings suggest a shared aetiology across preterm birth subtypes. Patterns may inform risk reduction efforts.

Disparities in cesarean delivery by ethnicity and nativity in New York city

Our objective was to examine differences in risk of cesarean delivery among diverse ethnic groups in New York City. Using cross-sectional New York City birth and hospitalization data from 1995 to 2003 (n = 961,381) we estimated risk ratios for ethnic groups relative to non-Hispanic whites and immigrant women relative to US-born women. Adjusting for insurance, pre-pregnancy weight, maternal age, education, parity, birthweight, gestational age, year, medical complications, and pregnancy complications, all ethnic groups except East Asian women were at an increased risk of cesarean delivery, with the highest risk among Hispanic Caribbean women [adjusted risk ratio (aRR) = 1.27, 95 % CI (confidence interval) = 1.24, 1.30] and African American women (aRR = 1.20, 95 % CI = 1.17, 1.23). Among Hispanic groups, immigrant status further increased adjusted risk of cesarean delivery; adjusted risk ratios for foreign-born women compared to US-born women of the same ethnic group were 1.27 for Mexican women (95 % CI = 1.05, 1.53), 1.23 for Hispanic Caribbean women (95 % CI = 1.20, 1.27), and 1.12 for Central/South American women (95 % CI = 1.04, 1.21). Similar patterns were found in subgroup analyses of low-risk women (term delivery and no pregnancy or medical complications) and primiparous women. We found evidence of disparities by ethnicity and nativity in cesarean delivery rates after adjusting for multiple risk factors. Efforts to reduce rates of cesarean delivery should address these disparities. Future research should explore potential explanations including hospital environment, provider bias, and patient preference.

Maternal mercury exposure, season of conception and adverse birth outcomes in an urban immigrant community in Brooklyn, New York, U.S.A

Adverse birth outcomes including preterm birth (PTB: <37 weeks gestation) and low birth weight (LBW: <2500 g) can result in severe infant morbidity and mortality. In the United States, there are racial and ethnic differences in the prevalence of PTB and LBW. We investigated the association between PTB and LBW with prenatal mercury (Hg) exposure and season of conception in an urban immigrant community in Brooklyn, New York. We recruited 191 pregnant women aged 18-45 in a Brooklyn Prenatal Clinic and followed them until delivery. Urine specimens were collected from the participants during the 6th to 9th month of pregnancy. Cord blood specimens and neonate anthropometric data were collected at birth. We used multivariate logistic regression models to investigate the odds of LBW or PTB with either maternal urinary mercury or neonate cord blood mercury. We used linear regression models to investigate the association between continuous anthropometric outcomes and maternal urinary mercury or neonate cord blood mercury. We also examined the association between LBW and PTB and the season that pregnancy began. Results showed higher rates of PTB and LBW in this cohort of women compared to other studies. Pregnancies beginning in winter (December, January, February) were at increased odds of LBW births compared with births from pregnancies that began in all other months (OR7.52 [95% CI 1.65, 34.29]). We observed no association between maternal exposure to Hg, and either LBW or PTB. The apparent lack of association is consistent with other studies. Further examination of seasonal association with LBW is warranted.

Race/ethnicity, educational attainment, and pregnancy complications in New York City women with pre-existing diabetes

BACKGROUND

More women are entering pregnancy with pre-existing diabetes. Disease severity, glycaemic control, and predictors of pregnancy complications may differ by race/ethnicity or educational attainment, leading to differences in adverse pregnancy outcomes.

METHODS

We used linked New York City hospital record and birth certificate data for 6291 singleton births among women with pre-existing diabetes between 1995 and 2003. We defined maternal race/ethnicity as non-Hispanic white, non-Hispanic black, Hispanic, South Asian, and East Asian, and education level as <12, 12, and >12 years. Our outcomes were pre-eclampsia, preterm birth (PTB) (<37 weeks gestation and categorised as spontaneous or medically indicated), as well as small-for-gestational age (SGA) and large-for-gestational age (LGA). Using multivariable binomial regression, we estimated the risk ratios for pre-eclampsia, SGA, and LGA. We used multivariable multinomial regression to estimate odds ratios (OR) for PTB.

RESULTS

Compared with non-Hispanic white women with pre-existing diabetes, non-Hispanic black and Hispanic women with pre-existing diabetes had a 1.50-fold increased risk of pre-eclampsia compared with non-Hispanic whites with pre-existing diabetes, after full adjustment. Non-Hispanic black and Hispanic women with pre-existing diabetes had adjusted ORs of 1.72 [adj. 95% confidence interval (CI) 1.38, 2.15] and 1.65 [adj.95% CI 1.32, 2.05], respectively, for medically indicated PTB. South Asian women with pre-existing diabetes had the highest risk for having an SGA infant [adj. OR: 2.29; adj. 95% CI 1.73, 3.03]. East Asian ethnicity was not associated with these pregnancy complications.

CONCLUSIONS

Non-Hispanic black, Hispanic, and South Asian women with pre-existing diabetes may benefit from targeted interventions to improve pregnancy outcomes.

Obesity and pregnancy, an epidemiological and intervention study from a psychosocial perspective

BACKGROUND

Maternal obesity is a growing public health concern in Belgium as well as in other European countries and is now becoming the most common risk factor associated with pregnancy complications with impact on the health of the women and her offspring. At this moment, there is no specific management strategy for obese pregnant women and mothers, focusing on physical health and psychological well-being.

OBJECTIVES

We aimed (1) to study the influence of socio-demographic and obstetrical correlates on pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) in different regions of Flanders, Belgium, (2) to review the literature on the onset and progression of labour in normal weight and obese pregnant women, (3) to compare levels and evolution of anxiety and depressed mood during pregnancy between obese women and normal-weight women, (4) to examine whether a prenatal lifestyle intervention programme, based on principles of motivational interviewing, in obese pregnant women reduces GWG and lowers levels of anxiety and depressed mood during pregnancy, (5) to examine associations between inter-pregnancy weight change from the first to the second pregnancy and the risk for adverse perinatal outcomes during the second pregnancy and finally (6) to study predictors of postpartum weight retention (PPWR) in obese mothers at six months after delivery in order to provide clues for the design of interventions aimed at preventing weight retention related to childbearing.

METHODS

We performed an epidemiological study, an intervention study during pregnancy with postpartum follow up and a literature review.

RESULTS

One in three Flemish women start pregnancy being overweight or obese and this prevalence has slowly been rising since 2009 in the Flanders. We identified women at risk for a high pre-pregnancy BMI and excessive GWG, both being important predictors for increased pregnancy and birth related complications. In a literature review, we showed that the combination of a higher incidence of post-term deliveries and increased inadequate contraction pattern during the first stage of labour in obese women suggests an influence of obesity on myometrial activity. Given the low compliance for adequate GWG in obese women in the general Flemish population and their increased psycho-social vulnerability compar-ed to the normal weight pregnant women, counselling obese pregnant women can lead to a reduced GWG and increased psychological comfort. Stabilizing inter-pregnancy maternal weight for all women is an important target for reducing adverse perinatal outcomes in the subsequent pregnancy. Psychological discomfort during pregnancy does impact on PPWR in obese mothers six months after delivery.

DISCUSSION AND CONCLUSION

Focusing on weight management in obese women before, during and after a pregnancy has advantages for both the mother and her infant. Theoretical and practice based training modules should be developed and focus on: (1) awareness of techniques for identifying the clearly identified risk groups with a high pre-pregnancy BMI and excessive GWG, (2) the increased perinatal risks, (3) an adapted perinatal management and (4) counselling techniques for an adequate weight management and psychological wellbeing in obese pregnant women. To achieve better care for the future, we must focus on tackling maternal obesity. This means that obese women should be reached before they get pregnant for the first time. Targeting primary and community based care, promotion and education are challenging, but the psychosocial context should be acknowledged.

Ethnic differences in neonatal body composition in a multi-ethnic population and the impact of parental factors: a population-based cohort study

BACKGROUND

Neonates from low and middle income countries (LAMIC) tend to have lower birth weight compared with Western European (WE) neonates. Parental height, BMI and maternal parity, age and educational level often differ according to ethnic background, and are associated with offspring birth weight. Less is known about how these factors affect ethnic differences in neonatal body composition.

OBJECTIVES

To explore differences in neonatal body composition in a multi-ethnic population, and the impact of key parental factors on these differences.

METHODS

A population-based cohort study of pregnant mothers, fathers and their offspring, living in Oslo, Norway. Gender- and gestational-specific z-scores were calculated for several anthropometric measurements, with the neonates of WE ethnic origin as reference. Mean z-scores for neonates with LAMIC origin, and their parents, are presented as outcome variables.

RESULTS

537 singleton, term neonates and their parents were included. All anthropometric measurements were smaller in neonates with LAMIC origin. Abdominal circumference and ponderal index differed the most from WE (mean z-score: -0.57 (95% CI:-0.69 to -0.44) and -0.54 (-0.66 to -0.44), and remained so after adjusting for parental size. Head circumference and skin folds differed less, and length the least (-0.21 (-0.35 to -0.07)). These measures became comparable to WEs when adjusted for parental factors.

CONCLUSIONS

LAMIC origin neonates were relatively "thin-fat", as indicated by reduced AC and ponderal index and relatively preserved length and skin folds, compared with neonates with WE origin. This phenotype may predispose to type 2 diabetes.

Exploring factors related to oral feeding progression in premature infants

PURPOSE

To identify infant and maternal characteristics associated with the pace of progression from the first oral feeding to complete oral feeding.

SUBJECTS

One hundred forty-two stable premature infants who were fully or partially gavage feeding immediately after birth (29 to 34 weeks gestational age at birth).

DESIGN

Exploratory secondary analysis.

METHODS

Data are from an ongoing randomized clinical trial of a developmental maternally administered intervention (Hospital to Home Transition-Optimizing Premature Infant's Environment) for mother-infant dyads at high social-environmental risk.

MAIN OUTCOME MEASURES

Oral feeding progression (transition time from the first attempt to complete oral feeding).

SAMPLE CHARACTERISTICS

The convenience sample of preterm infants consisted of 48.6% male infants; the mean gestational age at birth was 32.4 weeks and mean birth weight 1787 g; and African American mothers (47.9%; n = 80) and Latina mothers (52.1%; n = 83).

PRINCIPLE RESULTS

Multivariable linear regression results showed that, on average, the number of days for infants of Latina mothers to achieve complete oral feeding was 2.43 days more than for infants of African American mothers. In addition, lower birth weight and lower postmenstrual age at first oral feeding were associated with longer feeding progression. Higher infant morbidity was correlated with longer feeding progression.

CONCLUSION

Infants with Latina mothers, lower birth weight, lower postmenstrual age at first oral feeding, and higher morbidity scores had a longer transition from first to complete oral feeding. Identification of infants at risk for delayed transition from first to complete oral feeding may allow for the development and testing of appropriate interventions that support the transition from gavage to complete oral feeding.

Perinatal outcomes of Southeast Asians with pregnancies complicated by gestational diabetes mellitus or preeclampsia

To examine risks for adverse perinatal outcomes among Southeast Asian women with pregnancies complicated by gestational diabetes mellitus (GDM) or preeclampsia. Perinatal outcomes of singleton births of Cambodian (3,489), Laotian (2,038), Vietnamese (11,605), Japanese (3,083) and non-Hispanic White women (33,088) were analyzed using Washington state linked birth certificate and hospitalization discharge records (1993-2006). Both Cambodian (aOR = 1.68) and Laotian (aOR = 1.71) women with GDM had increased odds of macrosomia when compared with Japanese women with GDM. Southeast Asian women with GDM had reduced odds of macrosomia when compared with White women. Southeast Asian women with preeclampsia had increased odds for preterm delivery when compared with Japanese and White women with preeclampsia. Research is needed to understand why Southeast Asian women with GDM are more likely to have better perinatal outcomes when compared with White women. Vigilant monitoring and culturally sensitive care for Southeast Asian women with preeclampsia is needed.

Socio-demographic and obstetrical correlates of pre-pregnancy body mass index and gestational weight gain

Both pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) are important determinants of a healthy pregnancy outcome and may show important variation. To study the influence of socio-demographic and obstetrical correlates on pre-pregnancy BMI and GWG, data of 54 022 singleton term pregnancies were analysed using adjusted regression models. In 2009, in the Northern region of Belgium, one-third of women were overweight (21.6%) or obese (10.1%) and GWG as recommended by the Institute of Medicine occurred in only 28% of obese women. A high pre-pregnancy BMI was significantly associated with low maternal education, high maternal age and multiparity, belonging to ethnic minority groups and a lower professional state. Compared to adequate GWG, excessive GWG was more common in younger (<20 years) women, with higher pre-pregnancy BMI and pregnancy-induced hypertension. Moreover, younger (20-24 years), single women, belonging to ethnic minority groups showed higher odds for excessive as well as insufficient GWG, while those with high/highest educational level had lower odds for excessive (odds ratio [OR] 0.76; confidence interval [CI] 0.72-0.80) and insufficient (OR 0.93; CI 0.89-0.98) GWG. The results of this study highlight the scale of the problem of maternal obesity and excessive GWG for this region and offer opportunities to target educational campaigns and intervention programmes in the clinical setting.

Rising disparities in severe adverse birth outcomes among Haitians in Québec, Canada, 1981-2006

Perinatal health data for Haitians are scant. We evaluated adverse birth outcomes for Haitians in Québec, Canada. We analyzed 2,124,909 live births from 1981 to 2006. Haitian ethnicity was assessed using maternal birth country (Haiti, other Caribbean country, other foreign country, Canada) and home language (Creole, French/English but Creole mother tongue, French/English, other). Associations between ethnicity and preterm birth (PTB), low birth weight (LBW), and small-for-gestational-age (SGA) birth were calculated. Adverse birth outcomes were more common among mothers with Haitian ethnicity. Relative to Canadian-born mothers, odds for Haitian-born mothers were 4 times greater for extreme PTB (≤27 weeks), twice greater for very PTB (28-31 weeks), and 25% higher for moderate PTB (32-36 weeks). Patterns were similar for SGA birth and severe cases of LBW. Despite overall decreases LBW and SGA birth, relative and absolute inequalities increased over time. Perinatal health inequalities are increasing for Haitian-born mothers.

Francophone and Anglophone perinatal health: temporal and regional inequalities in a Canadian setting, 1981-2008

OBJECTIVES

We evaluated temporal and regional inequalities in adverse birth outcomes between Anglophones and Francophones of a Canadian province.

METHODS

Odds ratios and rate differences in preterm birth (PTB, <37 gestational weeks) and small-for-gestational-age (SGA) birth were computed for Anglophones relative to Francophones for singleton live births in Québec from 1981 to 2008 (N = 2,292,237), adjusting for maternal characteristics. Trends over time and residential region were evaluated.

RESULTS

Rates of PTB and SGA birth overall were lower for Anglophones relative to Francophones, but temporal and regional trends varied by outcome. Although PTB rates increased over time, inequalities between Francophones and Anglophones were relatively stable. In contrast, inequalities in SGA birth narrowed over time as Francophone rates declined more than Anglophones. Inequalities in SGA birth favored Anglophones overall, but the gap gradually reversed in Montréal (the largest metropolitan center) to currently favor Francophones.

CONCLUSIONS

PTB and SGA birth rates favored Anglophones over Francophones. The linguistic gap was generally stable over time for PTB, but narrowed or reversed for SGA birth. Language may be used to capture inequalities in perinatal health in countries where different linguistic groups predominate.

Risk factors for low birth weight in New York state counties

The rate of low birth weight (LBW) is a national concern. In New York counties in 2009, the LBW rate was 8.2%. Reducing LBW has significant humanitarian and economic implications. At an average cost of $51,600 per infant, care for infants weighing less than 2,500 grams at birth is substantial. The purpose of this study was to identify demographic, socioeconomic, and health service factors that contribute to LBW among counties in New York. Analyses of data indicated that the number of MOMs providers and teen pregnancy rate were the strongest predictors for LBW. These findings reinforce the fact that LBW is a correctable phenomenon that can be addressed through public policy. With increasing budget cuts, provision of health services and implementation of programs that address teen pregnancy have become challenging. Public policy decisions and stewardship that support programs that increase the number of providers for the uninsured, underinsured, and economic underclass and maintain programs for the pregnant adolescent will help New York counties in their fight against LBW.

Birth outcomes for African and Caribbean babies in England and Wales: retrospective analysis of routinely collected data

OBJECTIVES

To compare mean birth weights, gestational ages and odds of preterm birth and low birth weight of live singleton babies of black African or Caribbean ethnicity born in 2005 or 2006 by mother's country of birth.

DESIGN

Secondary analysis of data from linked birth registration and NHS Numbers for Babies data set.

SETTING

Births to women in England and Wales in 2005 and 2006.

PARTICIPANTS

Babies of African and Caribbean ethnicity born in England and Wales in 2005-2006, whose mothers were born in African and Caribbean countries or the UK. Birth outcomes for 51 599 singleton births were analysed.

MAIN OUTCOME MEASURES

Gestational age and birth weight.

RESULTS

Mothers born in Eastern or Northern Africa had babies at higher mean gestational ages (39.38 and 39.41 weeks, respectively) and lower odds of preterm birth (OR=0.80 and 0.65, respectively) compared with 39.00 weeks for babies with mothers born in the UK. Babies of African ethnicity whose mothers were born in Middle or Western Africa had mean birth weights of 3327 and 3311 g, respectively. These were significantly higher than the mean birth weight of 3257 g for babies of the UK-born mothers. Their odds of low birth weight (OR=0.75 and 0.72, respectively) were significantly lower. Babies of Caribbean ethnicity whose mothers were born in the Caribbean had higher mean birth weight and lower odds of low birth weight than those whose mothers were born in the UK.

CONCLUSIONS

The study shows that in babies of African and Caribbean ethnicity, rates of low birth weight and preterm birth varied by mothers' countries of birth. Ethnicity and country of birth are important factors associated with perinatal health, but assessing them singly can mask important heterogeneity in birth outcomes within categories particularly in relation to African ethnicity. These differences should be explored further.

Maternal ethnicity and pre-eclampsia in New York City, 1995-2003

Studies on ethnic differences in the risk of pre-eclampsia are limited. We linked birth records for 902,460 singleton births for the period 1995-2003 in New York City with hospital discharge data to evaluate the association between ethnicity and the risk of pre-eclampsia and compare risks between US-born and foreign-born women. Logistic regression models adjusted for maternal age, maternal education, parity, self-reported pre-pregnancy maternal weight, smoking during pregnancy and year of delivery were used to compare each ethnic group with non-Hispanic White women. The prevalence of pre-eclampsia in this study population was 3.2%. Among the major ethnic groups considered in our study, East Asian women had the lowest risk of pre-eclampsia (1.4%) and Mexican women had the highest risk (5.0%). Compared with non-Hispanic White women, there was a slightly decreased risk for East Asian women (adjusted OR = 0.8, [95% CI 0.7, 0.8]), similar risk for North African women (adjusted OR = 1.1, [95% CI 0.9, 1.3]), and increased risk for all other major ethnic groups (adjusted ORs: 1.3, 2.9), with the highest risk for Mexican women (adjusted OR = 2.9, [95% CI 2.7, 3.1]). No difference in risks was observed for US- vs. foreign-born women with the exception that foreign-born South-East Asian and Pacific Islanders had an increased risk of pre-eclampsia (adjusted OR = 1.8, [95% CI 1.0, 3.1]) relative to those born in the US. We concluded that there was ethnic heterogeneity in the development of pre-eclampsia among women in New York City and that Asian subgroups should be examined separately in future studies on ethnicity. Our results should contribute to screening for pre-eclampsia taking ethnic variation into account, and may help to suggest leads for the study of the aetiology of the condition.

Black preterm birth risk in nonblack neighborhoods: effects of Hispanic, Asian, and non-Hispanic white ethnic densities

PURPOSE

Studies of ethnic density and health in the United States have documented poorer health outcomes among black individuals living in black compared with nonblack neighborhoods, but few studies have considered the identities of the populations in nonblack neighborhoods.

METHODS

New York City birth records from 1995 through 2003 and a spatial measure of ethnic density were used to examine preterm birth risks among non-Hispanic black women associated with non-Hispanic white, Hispanic, Asian, and non-Hispanic black neighborhood densities. Logistic regression models were used to estimate the effect on black preterm birth risks of replacing white neighbors with Hispanic, Asian, and black neighbors. Risk differences were computed for changes from the 10th to the 90th percentiles of ethnic density.

RESULTS

Increasing Hispanic density was associated with reduced preterm birth risks among non-Hispanic black women, especially if the black women were foreign-born (RD = -19.1 per 1,000 births; 95% confidence interval. -28.6 to -9.5). Estimates for increasing Asian density were null. Increasing black density was associated with increasing black preterm birth risk, with a threshold at greater levels of black density.

CONCLUSIONS

The low risks of preterm birth among foreign-born non-Hispanic black women in majority-Hispanic neighborhoods may be related to protective psychosocial or lifestyle and warrant further investigation.

Ethnic density and preterm birth in African-, Caribbean-, and US-born non-Hispanic black populations in New York City

Segregation studies suggest that the health of blacks in the United States is poorer in majority-black compared with mixed-race neighborhoods. However, segregation studies have not examined black immigrants, who may benefit from social support and country-of-origin foods in black immigrant areas. The authors used 1995-2003 New York City birth records and a spatial measure of ethnic density to conduct a cross-sectional investigation of the risks of preterm birth for African-, Caribbean-, and US-born non-Hispanic black women associated with neighborhood-level African-, Caribbean-, and US-born non-Hispanic black density, respectively. Preterm birth risk differences were computed from logistic model coefficients, comparing neighborhoods in the 90th percentile of ethnic density with those in the 10th percentile. African black preterm birth risks increased with African density, especially in more deprived neighborhoods, where the risk difference was 6.1 per 1,000 (95% confidence interval: 1.9, 10.2). There was little evidence of an ethnic density effect among non-Hispanic black Caribbeans. Among US-born non-Hispanic blacks, an increase in preterm birth risk associated with US-born black density was observed in more deprived neighborhoods only (risk difference = 12.5, 95% confidence interval: 6.6, 18.4). Ethnic density seems to be more strongly associated with preterm birth for US-born non-Hispanic blacks than for non-Hispanic black immigrants.

Neighborhood deprivation and adverse birth outcomes among diverse ethnic groups

PURPOSE

Living in a socioeconomically deprived neighborhood has been associated with an increased risk of adverse birth outcomes. However, variation in the effect of neighborhood deprivation among diverse ethnic groups has not been studied.

METHODS

Using linked hospital discharge and birth data for 517,994 singleton live births in New York City from 1998 through 2002, we examined the association between neighborhood deprivation, preterm birth (PTB), and term low birthweight (TLBW) (>or=37 weeks and <2500g). Adjusted odds ratios (aORs) for PTB (<32 and 33-36 weeks) and TLBW were estimated using logistic regression.

RESULTS

The aOR for PTB of less than 32 weeks for the highest quartile of deprivation compared to the lowest was 1.24 (95% confidence limit [CL] = 1.13, 1.36), for PTB 33-36 weeks was 1.06 (95% CL = 1.01, 1.11), and for TLBW was 1.19 (95% CL = 1.11, 1.27). Measures of association varied by ethnicity; aORs of the greatest magnitude for PTB were found among Hispanic Caribbean women (PTB < 32 weeks: aOR = 1.63, 95% CL = 1.27, 2.10; PTB 33-36 weeks: aOR = 1.32, 95% CL = 1.02, 1.70), and for TLBW among African women (aOR = 1.47, 95% CL = 1.02, 2.13).

CONCLUSIONS

The mechanisms linking neighborhood deprivation to adverse birth outcomes may differ depending on individual ethnicity and/or cultural context and should be investigated in future research.

Gestational weight gain and birth outcome in relation to prepregnancy body mass index and ethnicity

PURPOSE

The obesity epidemic raises concerns about the impact of excessive and insufficient weight gain during pregnancy.

METHODS

We examined the association between gestational weight gain (GWG) and preterm birth, term small- and large-for-gestational-age (SGA and LGA), term birthweight, and term primary Cesarean delivery, considering prepregnancy body mass index (BMI) and ethnicity in a cohort of 33,872 New York City residents who gave birth between 1995 and 2003 and delivered in hospitals elsewhere in New York State.

RESULTS

Preterm birth (<37 weeks' gestation) showed a modest U-shaped relationship, with projected GWG of <10 kg and 20+ kg associated with odds ratios of 1.4 and 1.3, respectively, relative to 10 to 14 kg. The pattern was stronger for preterm birth <32 weeks' and for underweight women with low GWG and overweight/obese women with high GWG. Term SGA decreased and term LGA and birthweight increased monotonically with increasing GWG. Primary Cesarean delivery followed the same pattern as LGA, but less strongly.

CONCLUSIONS

Although the study is limited by potential selection bias and measurement error, our findings support the contention that GWG may be a modifiable predictor of pregnancy outcome that warrants further investigation, particularly randomized trials, to assess whether the relation is causal.