Maternal life course socio-economic position and offspring body composition at birth in a multi-ethnic population

Placental weight, surface area, shape and thickness - Relations with maternal ethnicity and cardio-metabolic factors during pregnancy

INTRODUCTION

A better understanding of the determinants of placental growth is needed. Our primary aim was to explore associations between maternal ethnic origin and cardio-metabolic factors during pregnancy, and placental weight, surface area, shape and thickness.

METHODS

A multi-ethnic population-based cohort study of 474 pregnant women examined at mean 15 and 28 weeks' gestation. Placentas were inspected after birth by a placental pathologist. Outcome measures were trimmed placental weight and three uncorrelated placental components; surface area, shape (oval vs round) and thickness, created through a principal components analysis. Multivariate linear regression models were used to explore the associations with maternal factors.

RESULTS

Compared with ethnic European women, mothers with South- and East Asian ethnicity had placentas with lower weight (-51 g (95% CI: 75, -27) and -55 g (-95, -14) respectively), primarily due to a smaller surface area. The association between South Asian ethnicity and placental surface area was still significant after adjusting for maternal characteristics and cardio-metabolic factors. Fat mass index in early pregnancy was associated with higher placental weight and thickness. Placental surface area was positively associated with mid-gestational increases in fat mass, fasting glucose and triglycerides and with the 2-h glucose value at the 28 week oral glucose tolerance test, and inversely with a mid-gestational increase in HDL-cholesterol.

DISCUSSION

Mid-gestational changes in fat mass, glucose, triglycerides and cholesterol were associated with, but only partly explained ethnic differences in placental surface area, while maternal fat mass in early pregnancy was associated with placental thickness.

Cohort profile update: the Norwegian STORK Groruddalen (STORK G) pregnancy and birth cohort-the role of ethnicity and causal pathways for obesity, type 2 diabetes, cardiovascular disease and other health issues

PURPOSE

The STORK Groruddalen cohort was set up in 2008 to explore ethnic differences in: (1) maternal health, primarily gestational diabetes (GDM) and related health issues during pregnancy and post partum, and effects of exposures on risk for type 2 diabetes, cardiovascular disease and other health issues, and (2) offspring's growth and body composition, overweight/obesity and effects of early life exposures.

PARTICIPANTS

823 women (74% of invited) were followed from gestational week (GW) 15. Data were collected from 618 fathers. In total, 59% of women and 53% of fathers had origin from non-Western countries. Maternal mean age was 29.9 years (SD 4.9), and body mass index (BMI) 25.3 kg/m2 (4.9). Data were obtained from 772 women (94%) at GW 28, and 662 women (80%) 14 weeks post partum. Eleven years post partum, 385 women (53% of eligible/47% of original cohort) attended, age was 42.0 years (4.8) and BMI 27.1 kg/m2 (5.1). We have data for 783 children at birth, and for 586 at last time point, mean age 8.6 (0.5) years, weight 30.7 (6.8) kg and length 133.9 (6.3) cm.

FINDINGS TO DATE

We collected questionnaire data from parents, clinical measurements and blood samples from mothers, and data on children's growth (mid-pregnancy to 8 years). Our biobank includes maternal blood and urine samples, biopsy material from placentas and umbilical venous cord blood. We found several clinically important differences in maternal health, with higher risk in ethnic minority groups for GDM, insulin resistance, vitamin D and iron deficiency, depressive symptoms and physical inactivity. Contrasting patterns of fetal growth and risk of overweight/thinness at preschool age were observed across ethnic groups. Maternal GDM, obesity and high gestational weight gain were associated with children's BMI trajectories.

FUTURE PLANS

We will examine the impact of maternal and fetal health and development during pregnancy on long-term outcomes for mothers and offspring.

TRIAL REGISTRATION NUMBER

Project title STORK G-2: Women and Risk of Type 2 Diabetes NCT03870724 (ClinicalTrials.gov).

The impact of recommending iron supplements to women with depleted iron stores in early pregnancy on use of supplements, and factors associated with changes in iron status from early pregnancy to postpartum in a multi-ethnic population-based cohort

BACKGROUND

We aimed to evaluate the impact of recommending supplementation to pregnant women with serum ferritin (SF) < 20 µg/L in early pregnancy on use of supplements, and to explore which factors were associated with changes in iron status by different iron indicators to 14 weeks postpartum.

METHODS

A multi-ethnic population-based cohort study of 573 pregnant women examined at mean gestational week (GW) 15 (enrolment), at mean GW 28 and at the postpartum visit (mean 14 weeks after delivery). Women with SF < 20 µg/L at enrolment were recommended 30-50 mg iron supplementation and supplement use was assessed at all visits. Change of SF, soluble transferrin receptor and total body iron from enrolment to postpartum were calculated by subtracting the concentrations at the postpartum visit from that at enrolment. Linear and logistic regression analyses were performed to assess associations between use of supplements in GW 28 and changes in iron status and postpartum iron deficiency/anaemia. Change of iron status was categorized into 'steady low', 'improvement', 'deterioration', and 'steady high' based on SF status at enrolment and postpartum. Multinomial logistic regression analyses were performed to identify factors associated with change of iron status.

RESULTS

At enrolment, 44% had SF < 20 µg/L. Among these women (78% non-Western European origin), use of supplements increased from 25% (enrolment) to 65% (GW 28). Use of supplements in GW 28 was associated with improved iron levels by all three indicators (p < 0.05) and with haemoglobin concentration (p < 0.001) from enrolment to postpartum, and with lower odds of postpartum iron deficiency by SF and TBI (p < 0.05). Factors positively associated with 'steady low' were: use of supplements, postpartum haemorrhage, an unhealthy dietary pattern and South Asian ethnicity (p ≤ 0.01 for all); with 'deterioration': postpartum haemorrhage, an unhealthy dietary pattern, primiparity and no use of supplements (p < 0.01 for all), and with 'improvement': use of supplements, multiparity and South Asian ethnicity (p < 0.03 for all).

CONCLUSIONS

Both supplement use and iron status improved from enrolment to the postpartum visit among women recommended supplementation. Dietary pattern, use of supplements, ethnicity, parity and postpartum haemorrhage were identified as factors associated with change in iron status.

Prevalence of postpartum anaemia and iron deficiency by serum ferritin, soluble transferrin receptor and total body iron, and associations with ethnicity and clinical factors: a Norwegian population-based cohort study

Worldwide, there are limited data on the prevalence of postpartum anaemia and iron status. The aims of the present study were to assess the prevalence of anaemia and iron deficiency (ID) by three iron indicators 14 weeks postpartum, their relations to haemoglobin (Hb) and associations with ethnicity and clinical factors in a multi-ethnic population. We conducted a population-based cohort study of 573 women followed from early pregnancy. The prevalence of postpartum anaemia (Hb <12·0 g/dl) was 25 %. ID prevalence varied from 39 % by serum ferritin (SF <15 μg/l), to 19 % by soluble transferrin receptor (sTfR >4·4 mg/l) and 22 % by total body iron (TBI < 0 mg/kg). The mean Hb concentration was 12·8 g/dl in women with no ID, 12·6 g/dl in those with ID by SF only and 11·6 g/dl in those with ID by SF, sTfR and TBI. ID by sTfR and TBI defined by the current threshold values probably identified a more severe iron-deficient population compared with ID assessed by SF. Compared with Western Europeans, the prevalence of anaemia was at least the double in ethnic minorities (26–40 % v. 14 %; P < 0·01–0·05), and the prevalence of ID by sTfR and TBI, but not of ID by SF < 15 μg/l, was significantly higher in some minority groups. After adjustment for covariates, only South Asians had lower Hb and higher sTfR concentration. Insufficient iron intake, gestational anaemia or ID, and postpartum haemorrhage were associated with lower postpartum Hb concentration and poorer iron status.

Lipid and lipoprotein concentrations during pregnancy and associations with ethnicity

Background

To describe ethnic differences in concentrations of lipids and lipoproteins, and their changes, during pregnancy to postpartum.

Methods

This was a population-based cohort study conducted in primary antenatal care in Norway. The participants (n = 806) were healthy, pregnant women, 59% were ethnic minorities. Outcomes were triglycerides, total cholesterol, HDL- and LDL-cholesterol, analysed from fasting blood samples drawn at gestational age (weeks) 15, 28 and 14 weeks postpartum. We performed linear regression models and linear mixed models to explore the total effect of ethnicity on the outcomes, adjusting for gestational age /week postpartum, maternal age and education. The analyses are corrected for multiple testing using the Bonferroni correction.

Results

At gestational age 15, triglyceride concentrations were lower in women of African origin (1.03 mmol/mol (95% CI: 0.90, 1.16)) and higher in women of South Asian (primarily Pakistan and Sri Lanka) origin (1.42 mmol/mol (1.35, 1.49)) and East Asian (primarily Vietnam, Philippines and Thailand) origin (1.58 mmol/mol (1.43, 1.73)) compared with Western Europeans (1.26 mmol/mol (1.20, 1.32)). Women of Asian and African origin had a smaller increase in triglycerides, LDL- and total cholesterol from gestational age 15 to 28. At gestational age 28, LDL-cholesterol levels were lowest among East Asians (3.03 mmol/mol (2.72, 3.34)) compared with Western Europeans (3.62 mmol/mol (3.50, 3.74)). Triglycerides and HDL-cholesterol were lower postpartum than at gestational age 15 in all groups, but the concentration of LDL-cholesterol was higher, except in Africans. South and East Asian women had lower HDL-cholesterol and higher triglycerides postpartum, while African women had lower triglycerides than Western Europeans.

Conclusion

We found significant differences in the concentrations of lipids and lipoproteins and their changes during pregnancy and the early postpartum period related to ethnic origin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04524-2.

Body mass index trajectories up to preschool age in a multi-ethnic population; relations with maternal gestational diabetes, BMI and gestational weight gain

AIM

Independent effects of gestational diabetes (GDM), maternal prepregnant obesity and gestational weight gain on offspring BMI and obesity are scarcely documented. We examined associations between GDM and children's BMI trajectories from birth to 4-5 years age, and effects of prepregnant obesity and gestational weight gain not mediated through GDM.

METHODS

We included 734 children from a population-based, multi-ethnic cohort of women and their offspring followed from early pregnancy. All women were screened for GDM. Using linear mixed models, we explored associations between maternal factors and children's BMI development through seven serial measurements.

RESULTS

At birth and age 4-5 years, BMI of children exposed to GDM was similar to those not exposed. However, they had slower BMI growth (B = -0.1 BMI units/month (95% CI: -0.17, -0.04)) during first 6 months, and faster BMI growth from 6 months to 4-5 years. Maternal prepregnant obesity was associated with higher child BMI at birth, and thereafter persistently higher BMI. High gestational weight gain was associated with faster BMI growth from 6 months to 4-5 years.

CONCLUSION

Effects of maternal GDM, prepregnant obesity, and gestational weight gain on children's BMI and BMI trajectories from birth to preschool age differed in relation to effect size, timing and direction.

Maternal Glucose and LDL-Cholesterol Levels Are Related to Placental Leptin Gene Methylation, and, Together With Nutritional Factors, Largely Explain a Higher Methylation Level Among Ethnic South Asians

BACKGROUND

Leptin, mainly secreted by fat cells, plays a core role in the regulation of appetite and body weight, and has been proposed as a mediator of metabolic programming. During pregnancy leptin is also secreted by the placenta, as well as being a key regulatory cytokine for the development, homeostatic regulation and nutrient transport within the placenta. South Asians have a high burden of type 2 diabetes, partly attributed to a "thin-fat-phenotype".

OBJECTIVE

Our aim was to investigate how maternal ethnicity, adiposity and glucose- and lipid/cholesterol levels in pregnancy are related to placental leptin gene (LEP) DNA methylation.

METHODS

We performed DNA methylation analyses of 13 placental LEP CpG sites in 40 ethnic Europeans and 40 ethnic South Asians participating in the STORK-Groruddalen cohort.

RESULTS

South Asian ethnicity and gestational diabetes (GDM) were associated with higher placental LEP methylation. The largest ethnic difference was found for CpG11 [5.8% (95% CI: 2.4, 9.2), p<0.001], and the strongest associations with GDM was seen for CpG5 [5.2% (1.4, 9.0), p=0.008]. Higher maternal LDL-cholesterol was associated with lower placental LEP methylation, in particular for CpG11 [-3.6% (-5.5, -1.4) per one mmol/L increase in LDL, p<0.001]. After adjustments, including for nutritional factors involved in the one-carbon-metabolism cycle (vitamin D, B12 and folate levels), ethnic differences in placental LEP methylation were strongly attenuated, while associations with glucose and LDL-cholesterol persisted.

CONCLUSIONS

Maternal glucose and lipid metabolism is related to placental LEP methylation, whilst metabolic and nutritional factors largely explain a higher methylation level among ethnic South Asians.

Maternal Socioeconomic Factors and Racial/Ethnic Differences in Neonatal Anthropometry

Disparities in birthweight by maternal race/ethnicity are commonly observed. It is unclear to what extent these disparities are correlates of individual socioeconomic factors. In a prospective cohort of 1645 low-risk singleton pregnancies included in the NICHD Fetal Growth Study (2009-2013), neonatal anthropometry was measured by trained personnel using a standard protocol. Socioeconomic characteristics included employment status, marital status, health insurance, annual income, and education. Separate adjusted generalized linear models were fit to both test the effect of race/ethnicity and the interaction of race/ethnicity and socioeconomic characteristics on neonatal anthropometry. Mean infant birthweight, length, head circumference, and abdominal circumference all differed by race/ethnicity (p < 0.001). We observed no statistically significant interactions between race/ethnicity and full-time employment/student status, marital status, insurance, or education in association with birthweight, neonatal exam weight, length, or head or abdominal circumference at examination. The interaction between income and race/ethnicity was significant only for abdominal circumference (p = 0.027), with no other significant interactions for other growth parameters, suggesting that racial/ethnic differences in neonatal anthropometry did not vary by individual socioeconomic factors in low-risk women. Our results do not preclude structural factors, such as lifetime exposure to poverty, as an explanation for racial/ethnic disparities.

The association between birthweight and grandparental type 2 diabetes and cardiovascular disease in a multiethnic population

Intergenerational links of chronic disease have been suggested, as birthweight (BW) is associated with cardiovascular disease (CVD) and type 2 diabetes (T2D) in both parents and grandparents. However, most studies investigating these relationships have used relatively homogenous, white, majority populations. This study aimed to investigate the association between BW and CVD and T2D in a multiethnic population, that is, where the parents and grandparents often developed in a different environment from that where the child was born. Participants were women from a population-based cohort study of pregnant women (STORK Groruddalen), attending Child Health Clinics for antenatal care in three administrative city districts in Oslo, Norway, 2008-2010. Information about socioeconomic and lifestyle factors were collected among mothers and fathers. Parents reported history of CVD or T2D among grandparents. In logistic regressions, higher BW z-scores were associated with lower odds of T2D among maternal (OR 0.71 (95% CI 0.53, 0.97) and paternal (0.68 (0.49, 0.94) grandmothers after adjustments for parental and grandmothers' characteristics. BW was not associated with CVD, but the association in maternal grandfathers was borderline significant. Our results indicate intergenerational transmission of chronic diseases like T2D in a multiethnic population.

Parental socioeconomic position and risk of ADHD in offspring: a cohort study of 9648 individuals in Denmark 1976-2013

The strength of the association between parental socioeconomic position (SEP) and risk of attention-deficit/hyperactivity disorder (ADHD) in offspring is found to vary substantially, perhaps due to the negligence of possible changes in parental life course SEP. The present study investigated the association between parental SEP in adulthood and risk of ADHD diagnosis in offspring and whether parental childhood SEP modified this association. The study population included 9648 live-born singletons followed in the Psychiatric Central Register from birth in 1976-1996 until 2013. Cox regression was used to estimate hazard ratios for ADHD diagnosis according to parental SEP in adulthood. The results showed that low parental SEP in adulthood was associated with higher risk of ADHD diagnosis in offspring, also after adjustment for possible confounders. Thus, offspring of parents with low SEP in adulthood had 4.52 (95% CI 2.81-7.26) times higher hazard of ADHD diagnosis compared with offspring of parents with high SEP in adulthood. Further, parental childhood SEP was found to modify the observed association. Thus, offspring of parents with downward social mobility from childhood to adulthood and offspring of parents with stable low SEP experienced the highest risk of ADHD diagnosis, followed by offspring of parents with upward social mobility, compared with offspring of parents with stable high SEP. The results suggest that it is important to take into account the possibility of social mobility as changes in parental life course SEP from childhood to adulthood seem to influence the risk of ADHD diagnosis in offspring.

Ethnic differences in body mass index trajectories from 18 years to postpartum in a population-based cohort of pregnant women in Norway

OBJECTIVES

To explore ethnic differences in changes in body mass index (BMI) from the age of 18 years to 3 months postpartum.

DESIGN

A population-based cohort study.

SETTING

Child Health Clinics in Oslo, Norway.

PARTICIPANTS

Participants were 811 pregnant women (mean age 30 years). Ethnicity was categorised into six groups.

PRIMARY OUTCOME MEASURES

The outcome variable was BMI (kg/m²) measured at the age of 18 and 25 years, at prepregnancy and at 3 months postpartum. Body weight at 18 years, 25 years and prepregnancy were self-reported in early pregnancy, while body height and weight at 3 months postpartum were measured. The main statistical method was generalised estimating equations, adjusted for age. The analyses were stratified by parity due to ethnicity×time×parity interaction (p<0.001).

RESULTS

Primiparous South Asian women had a 1.45 (95% CI 0.39 to 2.52) kg/m² higher and Middle Eastern women had 1.43 (0.16 to 2.70) kg/m² higher mean BMI increase from 18 years to postpartum than Western European women. Among multiparous women, the mean BMI increased 1.99 (1.02 to 2.95) kg/m² more in South Asian women, 1.48 (0.31 to 2.64) kg/m² more in Middle Eastern women and 2.49 (0.55 to 4.42) kg/m² more in African women than in Western European women from 18 years to prepregnancy. From 18 years to postpartum, the mean increase was 4.40 (2.38 to 6.42) kg/m² higher in African women and 1.94 to 2.78 kg/m² higher in the other groups than in Western European women.

CONCLUSIONS

Multiparous women of ethnic minority origin seem substantially more prone to long-term weight gain than multiparous Western European women in Norway.

Prevalence of postpartum depressive symptoms in a multiethnic population and the role of ethnicity and integration

BACKGROUND

Postpartum depression (PPD) may have adverse effects on both mother and child. The aims were to determine the prevalence of postpartum depressive symptoms, PPDS, identify associations with ethnicity and with the level of social integration.

METHOD

Population-based, prospective cohort study of 643 pregnant women (58% ethnic minorities) attending primary antenatal care in Oslo. Questionnaires regarding demographics and health issues were collected through interviews. PPDS was defined as a sum score ≥ 10 by the Edinburgh Postnatal Depression Scale, used as the main outcome in logistic regression analyses, first with ethnicity, second with level of integration as main explanatory factors.

RESULTS

The prevalence of PPDS was higher in ethnic minorities 12.7% (95% CI: 9.31-16.09) than in Western Europeans 4.8% (2.26-7.34). Adverse life events, lack of social support and depressive symptoms during the index pregnancy were other significant risk factors. Western European with PPDS were more likely to have had depressive symptoms also during pregnancy than women from ethnic minorities (72.2% versus 33.3%, p = 0.041). When replacing ethnicity with integration, a low level of integration was independently associated with PPDS (2.1 (1.11-3.95)).

LIMITATIONS

Cases with PPDS were limited. Heterogeneity in the ethnic groups is a concern.

CONCLUSION

Both point prevalence and new onset of PPDS was higher among ethnic minorities than among Western Europeans. Low level of integration was associated with PPDS. Our findings suggest that clinicians should be aware of the increased risk of new cases of PPDS among ethnic minorities compared to Western European women and offer evidence-based care accordingly.

Maternal Socioeconomic Mobility and Preterm Delivery: A Latent Class Analysis

Objective Growing evidence suggests that maternal socioeconomic mobility (SM) is associated with pregnancy outcomes. Our study investigated the association between maternal SM from childhood to adulthood and the risk of preterm delivery (PTD), and examined heterogeneity of associations by race/ethnicity. Methods In this study, 3019 pregnant women enrolled from 5 Michigan communities at 16-27 weeks' gestation (1998-2004) provided their parents' socioeconomic position (SEP) indicators (education, occupation, receipt of public assistance) and their own and child's father's SEP indicators (education, occupation, Medicaid status, and household income) at the time of enrollment. Latent class analysis was used to identify latent classes of childhood SEP indicators, adulthood SEP indicators, and SM from childhood to adulthood, respectively. A model-based approach to latent class analysis with distal outcome assessed relations between latent class and PTD, overall and within race/ethnicity groups. Results Three latent classes (low, middle, high) were identified for childhood SEP indicators and adulthood SEP indicators, respectively; while four latent classes (static low, upward, downward, and static high) best described SM. Women with upward SM had decreased odds of PTD (Odds ratio = 0.60, 95% confidence interval: 0.42, 0.87), compared to those with static low SEP. This SM advantage was true for all women and most pronounced in white/others women. Conclusions Maternal experiences of upward SM may be important considerations when assessing PTD risk. Our results support the argument that policies and programs aimed at improving women's SEP could lower PTD rates.

Ethnic differences in blood pressure from early pregnancy to postpartum: a Norwegian cohort study

OBJECTIVE

To examine blood pressure (BP) differences and changes between and within ethnic Western European, South Asian, Middle Eastern, East Asian, African, and East European living in Norway, from early pregnancy to postpartum and to explore associations between BP and explanatory variables.

METHODS

This was a population-based cohort study of 811 healthy pregnant women, 59% had ethnic minority origin. Participants were from Western Europe, Eastern Europe, South Asia, East Asia, Middle East, and Africa. We performed ANOVA, generalized estimating equations linear regression and multiple linear regression analysis.

RESULTS

At 15 weeks' gestation, mean SBP were 4.9-7.0 mmHg lower and mean DBP 2.1-3.4 mmHg lower for the non-Europeans compared with Western Europeans. SBP increased in all non-European groups from 15 weeks' gestation to 14 weeks' postpartum (P < 0.01), but not in Europeans. Ethnic differences were further reduced postpartum, with only South Asians having lower mean SBP than Western Europeans (P < 0.01). The ethnic differences persisted after adjusting for age, family history of cardiovascular disease, prepregnancy BMI, and prepregnancy physical activity. Age, prepregnancy BMI, prepregnancy physical activity, postpartum weight retention, and breastfeeding were independently associated with postpartum BP (P < 0.05).

CONCLUSION

Pregnancy may have a more adverse effect on BP trajectories from early pregnancy to postpartum among non-European women compared with Western Europeans, despite their more favorable BP in early pregnancy.

Ethnic differences in folic acid supplement use in a population-based cohort of pregnant women in Norway

Background

Peri-conceptional use of folic acid supplements is recommended to prevent neural tube defects. Correct supplement use seems to be less common among ethnic minorities. We examined ethnic differences in folic acid supplement use before and during pregnancy and possible effect modification by education or planning of pregnancy.

Methods

The participants were 811 healthy pregnant women from a population-based cohort study in Oslo, Norway in 2008–2010. Ethnicity was categorized to five groups (European, Middle Eastern, South Asian, East Asian, African). Data on folic acid supplement use were obtained from hospital records and remaining data by a questionnaire. Logistic regression analyses were adjusted for age, parity, planning of pregnancy, education and Norwegian language skills.

Results

Before pregnancy, 30.1% of European women and 7.1 to 13.6% of women in the other ethnic groups used folic acid supplements (p < 0.001). The adjusted odds ratio (OR) for supplement use was 0.55 (95% confidence interval 0.31; 0.96) for South Asian and 0.42 (95% confidence interval 0.19; 0.94) for Middle Eastern women compared with European women. During pregnancy, supplement use was most common in European women (65.7%) and least common in Middle Eastern (29.4%) and African women (29.0%) (p < 0.001). Compared with European women, all other ethnic groups had lower adjusted odds (OR 0.30 to 0.50, p < 0.05 for all) for supplement use among women with high school or less education, but not among more educated women. Planning of pregnancy did not modify the association between ethnicity and supplement use.

Conclusions

Few women used folic acid supplements before pregnancy. Educational level modified the association between ethnicity and supplement use during pregnancy. Public health campaigns should focus on increasing awareness especially in ethnic minority groups with low educational level.

Vitamin D levels during pregnancy and associations with birth weight and body composition of the newborn: a longitudinal multiethnic population-based study

We investigated associations between serum 25-hydroxyvitamin D (25(OH)D) in pregnancy and birth weight and other neonatal anthropometric measures. The present study was a population-based, multiethnic cohort study of 719 pregnant women (59 % ethnic minorities) in Oslo, Norway, delivering a singleton neonate at term and with birth weight measurements. In a representative sample, anthropometric measurements were taken. Maternal 25(OH)D was measured at gestational weeks 15 and 28. Women with 25(OH)D <37 nmol/l were recommended vitamin D3 supplementation. Separate linear regression analyses were performed to model the associations between 25(OH)D and each of the outcomes: birth weight, crown-heel length, head circumference, abdominal circumference, sum of skinfolds, mid-upper arm circumference and ponderal index. In early pregnancy, 51 % of the women were vitamin D deficient (25(OH)D<50 nmol/l). In univariate analyses and in models adjusting for maternal age, parity, education, prepregnancy BMI, season, gestational age and neonate sex, maternal 25(OH)D was significantly associated with birth weight, head circumference, abdominal circumference and ponderal index (P<0·05 for all), when used as a continuous variable and categorised (consistently low, consistently high, increasing and decreasing level). However, after adjusting for ethnicity, 25(OH)D was no longer associated with any of the outcomes. Sex-specific associations for abdominal circumference and sum of skinfolds were found (P for interaction<0·05). In conclusion, in a multiethnic cohort of pregnant women with high prevalence of vitamin D deficiency, we found no independent relation between maternal vitamin D levels and any of the neonatal anthropometric measures, and the strong association between ethnicity and neonatal outcomes was not affected by maternal vitamin D status.

Life-course Social Mobility and Reduced Risk of Adverse Birth Outcomes

INTRODUCTION

Higher adult socioeconomic position (SEP) is associated with better birth outcomes. However, few studies incorporate life-course or intergenerational SEP, which may inform etiology and targeted prevention efforts. This study tested whether life-course social mobility from childhood was associated with lower risk of adverse birth outcomes.

METHODS

Data were from the Life-course Influences of Fetal Environments (LIFE) retrospective cohort study among black women, 2009-2011, in metropolitan Detroit, MI. This study (analyzed in 2014-2016) examined whether social mobility was associated with two primary birth outcomes: small for gestational age (SGA) and preterm birth (PTB). Childhood and adulthood SEP were measured by survey in adulthood, for two constructs, measured ordinally: educational attainment and perceived financial sufficiency (subjective income/wealth). Social mobility was calculated as the difference of adulthood minus childhood SEP.

RESULTS

In covariate-adjusted Poisson regression models, 1-SD improved educational social mobility from childhood to adulthood was protective for SGA (adjusted risk ratio=0.76; 95% CI=0.64, 0.91); this association remained after adjusting for financial mobility. Upward financial social mobility from early childhood was marginally protective for SGA (adjusted risk ratio=0.85; 95% CI=0.72, 1.02), but became nonsignificant after controlling educational mobility. There were no overall associations of social mobility with PTB or low birth weight, although sensitivity analyses identified that improved financial mobility was associated with 16% marginally lower risk of spontaneous PTB and 28% marginally lower risk of low birth weight among upwardly mobile/stable women only.

CONCLUSIONS

Improved life-course social mobility is associated with reduced risk for SGA and spontaneous PTB among black women.

Objectively recorded physical activity in pregnancy and postpartum in a multi-ethnic cohort: association with access to recreational areas in the neighbourhood

Background

Physical activity may reduce the risk of adverse pregnancy outcomes; however, compared to non-pregnant women, a lower proportion of pregnant women meet the physical activity guidelines. Our objectives were to explore overall changes and ethnic differences in objectively recorded moderate-to-vigorous intensity physical activity (MVPA) during pregnancy and postpartum and to investigate the associations with objective and perceived access to recreational areas.

Methods

We analysed 1,467 person-observations from 709 women in a multi-ethnic population-based cohort, with MVPA data recorded with the SenseWear™ Pro³ Armband in early pregnancy (mean gestational week (GW) 15), mid-pregnancy (mean GW 28) and postpartum (mean postpartum week 14). MVPA was limited to bouts ≥10 min. Women were nested within 56 neighbourhoods defined by postal code area. We derived neighbourhood-level objective access to recreational areas (good vs limited) by geographic information systems. We collected information about perceived access (high vs low perception) to recreational areas in early pregnancy. We treated ethnicity, objective and perceived access as explanatory variables in separate models based on linear mixed effects regression analyses.

Results

Overall, MVPA dropped between early and mid-pregnancy, followed by an increase postpartum. Western women performed more MVPA than women in other ethnic groups across time points, but the differences increased postpartum. Women residing in neighbourhoods with good objective access to recreational areas accumulated on average nine additional MVPA minutes/day (p < 0.01) compared with women in neighbourhoods with limited access. Women with perceptions of high access to recreational areas accumulated on average five additional MVPA minutes/day (p < 0.01) compared with women with perceptions of low access. After mutual adjustments, perceived and objective access to recreational areas remained significantly associated with MVPA. The association between MVPA and access to recreational areas did not differ by time point, ethnic group or socio-economic position.

Conclusions

In all ethnic groups, we observed a decline in MVPA between early and mid-pregnancy. However, at both time points during pregnancy, and especially three months postpartum, Western women were more physically active than ethnic minority women. In all ethnic groups, and at all three time points, both objective and perceived access to recreational areas were positively associated with MVPA levels.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-016-0401-y) contains supplementary material, which is available to authorized users.

Movin' on Up: Socioeconomic Mobility and the Risk of Delivering a Small-for-Gestational Age Infant

OBJECTIVE

Poor fetal growth is associated with increased rates of adverse health outcomes in children and adults. The social determinants of poor fetal growth are not well understood. Using multiple socioeconomic indicators measured at the individual level, this study examined changes in maternal socioeconomic position (SEP) from childhood to adulthood (socioeconomic mobility) in relation to poor fetal growth in offspring.

METHODS

Data were from the Pregnancy Outcomes and Community Health Study (September 1998-June 2004) that enrolled women in mid-pregnancy from 52 clinics in five Michigan communities (2463 women: 1824 non-Hispanic White, 639 non-Hispanic Black). Fetal growth was defined by birthweight-for-gestational age percentiles; infants with birthweight-for-gestational age <10th percentile were referred to as small-for-gestational age (SGA). In logistic regression models, mothers whose SEP changed from childhood to adulthood were compared to two reference groups, the socioeconomic group they left and the group they joined.

RESULTS

Approximately, 8.2 % of women (non-Hispanic White: 6.3 %, non-Hispanic Black: 13.9 %) delivered an SGA infant. Upward mobility was associated with decreased risk of delivering an SGA infant. Overall, the SGA adjusted-odds ratio was 0.34 [95 % confidence interval (CI) 0.17-0.69] for women who moved from lower to middle/upper versus static lower class, and 0.44 (CI 0.28-1.04) for women who moved from middle to upper versus static middle class. There were no significant differences in SGA risk when women were compared to the SEP group they joined.

CONCLUSIONS

Our findings support a link between mother's socioeconomic mobility and SGA offspring. Policies that allow for the redistribution or reinvestment of resources may reduce disparities in rates of SGA births.

Ethnic differences in fetal size and growth in a multi-ethnic population

OBJECTIVES

Impaired or excessive fetal growth is associated with adverse short- and long-term health outcomes that differ between ethnic groups. We explored ethnic differences in fetal size and growth from mid pregnancy until birth.

METHODS

Data are from the multi-ethnic STORK-Groruddalen study, a population-based, prospective cohort of 823 pregnant women and their offspring in Oslo, Norway. Measures were z-scores of estimated fetal weight (EFW), head circumference (HC), abdominal circumference (AC) and femur length (FL), in gestational week 24, 32 and 37, measured by ultrasound, and similar measures at birth. Differences in fetal size and growth were assessed using separate Linear Mixed Models including all four time points, with ethnic Europeans as reference.

RESULTS

In week 24 South Asian fetuses had smaller AC, but larger FL than Europeans, and slightly lower EFW (-0.17 SD (-0.33, -0.01), p=0.04). Middle East/North African fetuses also had larger FL, but similar AC, and hence slightly higher EFW (0.18 (0.003, 0.36), p=0.05). Both groups had slower growth of AC, FL and EFW from this time until birth, and had -0.61 SD (-0.73, -0.49) and -0.28 SD (-0.41, -0.15) lower birth weight respectively. Ethnic East Asians, on the other hand, were smaller throughout pregnancy and had -0.58 SD (-0.82, -0.34) lower birth weight. Significant ethnic differences remained after adjusting for maternal factors.

CONCLUSION

We observed ethnic differences in fetal size and body proportions already in gestational week 24, and in fetal growth from this time until birth, which were only partly explained by key maternal factors.