The relationship of fetal sex and maternal race and ethnicity with early and late pregnancy C-reactive protein and interleukin-8

PROBLEM

Promotion of a healthy pregnancy is dependent on a coordinated immune response that minimizes inflammation at the maternal-fetal interface. Few studies investigated the effect of fetal sex on proinflammatory biomarkers during pregnancy and whether maternal race could impact this association. We aimed to examine whether fetal sex could, independently of maternal race/ethnicity and the condition of pregnancy (normal vs. complicated), impact inflammatory markers (C-reactive protein [CRP] and interleukin-8 [IL-8] levels) in early and late pregnancy.

METHODS OF STUDY

This study was a cohort analysis using prospectively collected data from pregnant women who participated in the Vitamin Antenatal Asthma Reduction Trial (VDAART, N = 816). Maternal serum CRP and IL-8 levels were measured in early and late pregnancy (10-18 and 32-38 weeks of gestation, respectively). Five hundred and twenty-eight out of 816 pregnant women who participated in the trial had available CRP and IL-8 measurements at both study time points. We examined the association of fetal sex with early and late CRP and IL-8 levels and their paired sample difference. We further investigated whether maternal race/ethnicity, pregnancy complications (i.e., preeclampsia and gestational diabetes), and early pregnancy body mass index (BMI) could affect the association between these two biomarkers and fetal sex adjusting for potential confounders. For this purpose, we used generalized linear and logistic regression models on log-normalized early and late CRP and IL-8 levels as well as their split at median to form high and low groups.

RESULTS

Women pregnant with male fetuses (266/528 = 56.5%) had higher CRP levels in early to mid-pregnancy (β = .18: 95% confidence interval [CI]: CI = 0.03-0.32; p = .02). Twenty-seven percent (143/528) of the study subjects were Hispanic. Hispanic African American [AA] women and women of races other than White and AA had higher levels of CRP at early to mid-pregnancy compared with White women (β = .57; 95% CI: 0.17-0.97; p < .01 and β = .27; 95% CI: 0.05-0.48; p = .02, respectively). IL-8 levels were not associated with fetal sex in early and late pregnancy (p's > .05). Other factors such as gestational diabetes and early pregnancy BMI were associated with higher CRP levels and higher CRP and IL-8 levels, respectively. Dichotomizing log-normalized cytokine levels at the median in a sensitivity analysis, women with male fetuses had lower odds of high (above-median) IL-8 levels at early pregnancy. Also, women with races other than AA and White carrying male fetuses had higher odds of having high (above-median) late-pregnancy CRP and early-pregnancy IL-8 levels (adjusted odds ratio [aOR] = 3.80, 95% CI: 0.24-1.23; p = .02 and aOR = 3.57; 95% CI: 0.23-1.03; p = .02, respectively). Of the pregnancy complications, women with gestational diabetes mellitus had a higher paired difference of early and late pregnancy CRP levels (β = .38; 95% CI: 0.09-0.68; p = .01), but no difference in IL-8 levels (p's > .05). No associations between the inflammatory markers and preeclampsia were found.

CONCLUSION

Fetal sex is associated with CRP in early pregnancy and an association with IL-8 in early pregnancy is implied. Our study further indicates that maternal race/ethnicity could be a contributing factor in the relationship between fetal sex and inflammatory responses during pregnancy. However, the specificity and level of the contribution might vary by type of cytokine, pregnancy stage, and other confounding factors such as BMI that may impact these associations.

Fetal sex and risk of preeclampsia: Dose maternal race matter?

OBJECTIVE

To examine whether maternal race could affect the relationship between fetal sex and preeclampsia.

MATERIAL AND METHODS

This study was a cohort analysis using prospectively collected data from pregnant women who participated in the Vitamin Antenatal Asthma Reduction Trial (VDAART). Preeclampsia was the secondary outcome of VDAART. We examined the association of fetal sex with preeclampsia and its potential interaction with maternal race in 813 pregnant women (8% with preeclampsia) in logistic regression models with adjustment for preterm birth (<37 weeks of gestation), maternal age, education, and body mass index at enrollment and clinical center. We further conducted a race stratified analysis and also examined whether any observed association was dependent on the gestational age at delivery and prematurity.

RESULTS

In an analysis of all races combined, preeclampsia was not more common among pregnant women with a male fetus compared to those with a female fetus (odds ratio [OR] = 1.3, 95% CI = 0.81, 2.24). There was an interaction between African American race and fetal sex in association with preeclampsia after adjustment for preterm delivery and other potential confounders (p = .014). In race stratified analyses, we observed higher odds of preeclampsia among African American pregnant women who carried male fetuses after adjustment for preterm delivery and other potential confounders (adjusted OR = 2.4, 95% CI = 1.12, 5.60).

CONCLUSION

We observed fetal sexual dimorphic differences in the occurrence of preeclampsia in African American women, but not in Whites. Information on fetal sex may ultimately improve the prediction of pre-eclampsia in African American mothers, who might be at higher risk for this adverse condition in pregnancy.

The Association of Paternal Race and Ethnicity with Adverse Pregnancy Outcomes in a Contemporary U.S. Cohort

OBJECTIVE

Maternal racial and ethnic disparities exist in obstetric outcomes. The contribution of paternal race and ethnicity toward obstetric outcomes has been less well documented. The objective of this study was to investigate the association between paternal race and ethnicity and several adverse pregnancy outcomes.

STUDY DESIGN

This was a retrospective cohort of birth data from the CDC National Vital Statistics, years 2013-2017. All singleton live births were included in the analysis. Records with missing paternal race and ethnicity were excluded. The primary dependent variables were the following adverse maternal and perinatal outcomes: gestational diabetes, hypertensive disorder of pregnancy, preterm birth <37 weeks, cesarean delivery, low birth weight <2,500 g, 5-minute Apgar's score <7, admission to neonatal intensive care unit (NICU), and assisted ventilation at > 6 hours of life. The main exposure was paternal race and ethnicity, which was grouped into non-Hispanic white, non-Hispanic black, Hispanic, and other. Other race and ethnicity category included: American Indian, Alaskan Native, Asian, Native Hawaiian, or other Pacific Islander. Univariable and multivariable analyses were done to determine whether paternal race and ethnicity was independently associated with adverse pregnancy outcomes.

RESULTS

A total of 16,482,745 births were included. In univariable analysis, all adverse obstetric outcomes were significantly associated with paternal race and ethnicity. In multivariable analysis, controlling for maternal and paternal demographic characteristics and maternal clinical factors, paternal race and ethnicity remained significantly associated with the majority of the adverse pregnancy outcomes. The strongest association was seen with: (1) paternal non-Hispanic black race and ethnicity, and higher rates of LBW and preterm birth (Odds ratio [OR] = 1.25, 95% CI: 1.24-1.27 and OR = 1.14, 95% CI: 1.13-1.15, respectively); (2) paternal Hispanic race and ethnicity and lower rates of 5-minute Apgar's score <7, and assisted ventilation at >6 hours of life (OR = 0.78, 95% CI: 0.77-0.79, and OR = 0.77, 95% CI: 0.75-0.78, respectively); and (3) other paternal race and ethnicity and higher rates of gestational diabetes, but lower rates of hypertensive disorder of pregnancy and assisted ventilation >6 hours of life (OR = 1.26, 95% CI: 1.25-1.27; OR = 0.79, 95% CI: 0.78-0.80; and OR = 0.80, 95% CI: 0.78-0.82, respectively). All associations were in comparison to paternal non-Hispanic white race and ethnicity.

CONCLUSION

Paternal race and ethnicity has an independent association with adverse obstetric outcomes. The pathway and the extent of the paternal racial influence are not fully understood and deserve additional research.

Assessing the role of maternal race on the prediction of NICU admission by three growth charts: a cross-sectional study

BACKGROUND

The National Institutes of Health (NIH) race-specific and Intergrowth 21st race-independent fetal growth standards have recently been developed to assess fetal growth although the Alexander reference has been commonly used for over two decades. Societies are becoming increasingly stratified by race, and thus fetal growth effects are increasingly socially-derived. Relatedly, there is discussion surrounding the utility of classifying fetal growth on the basis of ideal growth versus typical growth. Therefore, we aimed to evaluate the classification discrepancies for small for gestational age (SGA) or large for gestational age (LGA) infants between growth charts, stratified by maternal race; and to determine which chart most accurately identifies vulnerable infants requiring NICU (Neonatal Intensive Care Unit) admission.

METHODS

This cross-sectional study examined singleton liveborn infants born between 33 and 42 weeks of gestation with a self-identified White, Black, Hispanic, or Asian mother. Data were obtained from the 2014 National Centre of Health Statistics' Vital Statistics Natality files. SGA infants were considered those <10th percentile and LGA were those >90th percentile, for each growth chart. SGA and LGA classification by maternal race was evaluated using stratified analysis and logistic regression. Odds ratios and goodness of fit characteristics were assessed to determine which chart best predicted NICU admission.

RESULTS

In our sample of 3,782,660 singleton infants, significantly different proportions of infants were classified SGA/LGA using the Alexander (SGA: 4.6%, LGA:19.4%), Intergrowth 21st (SGA: 4.0%, LGA:19.6%), and NIH (SGA: 9.8%, LGA: 8.5%) charts. Race-specific classification of SGA differed by race and chart; there was an 8.4% difference in white infants considered SGA by Intergrowth (3.3; 95% CI, 3.2-3.3) compared to NIH (11.7%; 95% CI, 11.6-11.7). The NIH and Intergrowth 21st charts were typically in agreement for both SGA and LGA, differing substantially from the Alexander reference; however, there were significant differences between Intergrowth and NIH for proportions of SGA (NIH: 10.2%, CI 95%, 10.1-10.2; Intergrowth: 4.0%, CI 95%, 3.9-4.0) and LGA (NIH: 6.3%, CI 95%, 6.3-6.4; Intergrowth: 19.6%, CI 95%, 19.5-19.6) infants. Overall, 11.1% of Black infants were considered SGA by NIH and 6.8% by Intergrowth-more often than other races. Intergrowth classified the fewest infants as SGA and Alexander classified the most as SGA for all races. While NIH was better at discriminating LGA (OR: 2.72) and SGA-associated (OR: 1.71) NICU admissions compared to other charts, no standard was a significantly better predictor of NICU admission.

CONCLUSION

Since the NIH standard identified the fewest LGA infants and the Intergrowth 21st standard identified the fewest SGA infants, these charts may have been better identifiers of infants on either extreme of growth. The agreement between NIH and Intergrowth 21st charts suggest their interchangeable use for healthy populations, but the NIH may be more applicable given its racial stratification. However, the differences in proportions of SGA/LGA infants among the three charts according to maternal race introduce significant clinical ambiguity when identifying vulnerable infants. Additionally, no chart was able to accurately identify vulnerable infants and the dataset did not permit differentiation between growth-restricted and constitutionally small infants. Further work is necessary before selecting a true gold standard for use in routine clinical practice.

The association between maternal race and adverse outcomes in twin pregnancies with similar healthcare access

OBJECTIVE

To compare twin pregnancy outcomes between white and nonwhite women with similar access to health care.

METHODS

Retrospective cohort study of all twin pregnancies delivered by a single maternal-fetal medicine practice from 2005-2016. All patients had private health insurance and equal access to physician care. Outcomes were compared between white and nonwhite women using logistic regression to adjust for differences at baseline.

RESULTS

Of the 858 women included, 730 (85.1%) were white and 128 (14.9%) were nonwhite. Univariate analysis demonstrated that nonwhite women had higher rates of preterm birth <32 weeks (12.5 versus 6.7%, p = .022), cesarean delivery (78.1% versus 61.4% of all women, p < .001 and 43.5% versus 16.1% of women who attempted labor, p < .001), preeclampsia (22.4% versus 14.5%, p = .029) and gestational diabetes (23.2% versus 7.3%, p < .001). On adjusted analysis, nonwhite race remained significantly associated with cesarean delivery in women who attempted labor (aOR 2.27, 95% CI: 1.09, 4.71) and gestational diabetes (aOR 2.61, 95% CI: 1.53, 4.45).

CONCLUSIONS

Nonwhite women with twin pregnancies have an increased risk of adverse outcomes that cannot be explained by access to care. Although improving access to care is an important goal for health care systems, our data suggest that this alone will not eliminate all disparities in health care outcomes between women of different races.