Understanding how maternal social and biological factors are related to fetal growth in an urban South African cohort

Prenatal exposure to multiple environmental chemicals and birth size

BACKGROUND

Epidemiological studies addressing the combined effects of exposure to chemical mixtures at different stages of pregnancy on birth size are scarce.

OBJECTIVE

To evaluate the association between prenatal exposure to chemical mixtures and birth size.

METHODS

Our previous study repeatedly measured the urinary concentrations of 34 chemical substances among 743 pregnant women and identified three distinct clusters of exposed population and six dominant principal components of exposed chemicals in each trimester. In this study, we assessed the associations of these exposure profiles with birth weight, birth length, and ponderal index using multivariable linear regression.

RESULTS

We found that compared with women in cluster 1 (lower urinary chemical concentrations), women in cluster 2 (higher urinary concentrations of metals, benzothiazole, benzotriazole, and some phenols), and women in cluster 3 (higher urinary concentrations of phthalates) were more likely to give birth to children with higher birth length [0.23 cm (95% CI: -0.03, 0.49); 0.29 cm (95%CI: 0.03, 0.54), respectively]. This association was observed only in 1st trimester. In addition, prenatal exposure to PC3 (higher benzophenones loading) was associated with reduced birth length across pregnancy [-0.07 cm (95% CI: -0.18, 0.03) in 1st and 2nd trimester; -0.13 cm (95% CI: -0.24, -0.03) in 3rd trimester]. Exposure to PC6 (higher thallium and BPA loading in 2nd trimester) was associated with increased birth length [0.15 cm (95% CI: 0.05, 0.26)]. Compared with other outcomes, associations of both clusters and PCs with birth length were stronger, and these associations were more pronounced in boys.

IMPACT STATEMENT

Exposure to multiple chemicals simultaneously, the actual exposure situation of pregnant women, was associated with birth size, indicating that chemical mixtures should be taken more seriously when studying the health effects of pollutants.

A qualitative analysis of community health worker perspectives on the implementation of the preconception and pregnancy phases of the Bukhali randomised controlled trial

Community health workers (CHWs) play an important role in health systems in low- and middle-income countries, including South Africa. Bukhali is a CHW-delivered intervention as part of a randomised controlled trial, to improve the health trajectories of young women in Soweto, South Africa. This study aimed to qualitatively explore factors influencing implementation of the preconception and pregnancy phases of Bukhali, from the perspective of the CHWs (Health Helpers, HHs) delivering the intervention. As part of the Bukhali trial process evaluation, three focus group discussions were conducted with the 13 HHs employed by the trial. A thematic approach was used to analyse the data, drawing on elements of a reflexive thematic and codebook approach. The following six themes were developed, representing factors impacting implementation of the HH roles: interaction with the existing public healthcare sector; participant perceptions of health; health literacy and language barriers; participants' socioeconomic constraints; family, partner, and community views of trial components; and the HH-participant relationship. HHs reported uses of several trial-based tools to overcome implementation challenges, increasing their ability to implement their roles as planned. The relationship of trust between the HH and participants seemed to function as one important mechanism for impact. The findings supported a number of adaptations to the implementation of Bukhali, such as intensified trial-based follow-up of referrals that do not receive management at clinics, continued HH training and community engagement parallel to trial implementation, with an increased emphasis on health-related stigma and education. HH perspectives on intervention implementation highlighted adaptations across three broad strategic areas: navigating and bridging healthcare systems, adaptability to individual participant needs, and navigating stigma around disease. These findings provide recommendations for the next phases of Bukhali, for other CHW-delivered preconception and pregnancy trials, and for the strengthening of CHW roles in clinical settings with similar implementation challenges. Trial registration: Pan African Clinical Trials Registry; PACTR201903750173871, Registered March 27, 2019.

Qualitative exploration of the constraints on mothers' and pregnant women's ability to turn available services into nutrition benefits in a low-resource urban setting, South Africa

OBJECTIVES

Despite free primary healthcare services and social protection system for mothers and children, significant nutrition inequalities occur across the globe, including in South Africa. This study aimed to explore what determines mothers' ability to access and turn available services into nutrition benefits.

DESIGN

An exploratory qualitative study was conducted including semistructured interviews with employees from community-based organisations and focus groups with pregnant women and mothers. Discussions focused on existing services perceived as important to nutrition, differences in mothers' ability to benefit from these services, and the underlying unmet needs contributing to these disparities. Data were analysed thematically using a novel social needs framework developed for this study where social needs are defined as the requisites that can magnify (if unmet) or reduce (if met) variation in the degree to which individuals can benefit from existing services.

SETTING

A resource-constrained urban township, Soweto in Johannesburg.

PARTICIPANTS

Thirty mothers of infants (<1 year old) and 21 pregnant women attending 5 primary healthcare facilities participated in 7 focus groups, and 18 interviews were conducted with employees from 10 community-based organisations.

RESULTS

Mothers identified social needs related to financial planning, personal income stability, appropriate and affordable housing, access to government services, social support and affordable healthier foods. The degree to which these needs were met determined mothers' capabilities to benefit from eight services. These were clinic-based services including nutrition advice and social work support, social grants, food aid, community savings groups, poverty alleviation projects, skills training workshops, formal employment opportunities and crèches/school feeding schemes.

CONCLUSION

Findings demonstrate that while current social protection mechanisms and free health services are necessary, they are not sufficient to address nutrition inequalities. Women's social needs must also be met to ensure that services are accessed and used to improve the nutrition of all mothers and their children.

The impact of HIV and ART exposure during pregnancy on fetal growth: a prospective study in a South African cohort

BACKGROUND

In utero exposure to human immunodeficiency virus (HIV) and antiretroviral (ART) is associated with adverse birth outcomes, which are often attributed to alterations in placental morphology. This study used structural equation models (SEMs) to examine the impact of HIV and ART exposure on fetal growth outcomes and whether these associations are mediated by placental morphology in urban-dwelling Black South African women.

METHODS

This prospective cohort study included pregnant women living with HIV (WLWH, n = 122) and not living with HIV (WNLWH, n = 250) that underwent repeated ultrasonography during pregnancy, and at delivery, to determine fetal growth parameters in Soweto, South Africa. The size and the velocity of fetal growth measures (i.e., head and abdominal circumference, biparietal diameter, and femur length) were calculated using the Superimposition by Translation and Rotation. Placenta digital photographs taken at delivery were used to estimate morphometric parameters and trimmed placental weight was measured. All WLWH were receiving ART for the prevention of vertical transmission of HIV.

RESULTS

A trend towards a lower placental weight and significantly shorter umbilical cord length was reported in WLWH compared to their counterparts. After sex stratification, umbilical cord length was significantly shorter in males born to WLWH than in male fetuses born to WNLWH (27.3 (21.6-32.8) vs. 31.4 (25.0-37.0) cm, p = 0.015). In contrast, female fetuses born to WLWH had lower placental weight, birth weight (2.9 (2.3-3.1) vs. 3.0 (2.7-3.2) kg), and head circumference (33 (32-34) vs. 34 (33-35) cm) than their counterparts (all p ≤ 0.05). The SEM models showed an inverse association between HIV and head circumference size and velocity in female fetuses. In contrast, HIV and ART exposure was positively associated with femur length growth (both size and velocity) and abdominal circumference velocity in male fetuses. None of these associations appeared to be mediated via placental morphology.

CONCLUSION

Our findings suggest that HIV and ART exposure directly affects head circumference growth in females and abdominal circumference velocity in male fetuses; but may improve femur length growth in male fetuses only.

What values drive communities' nutrition priorities in a resource constrained urban area in South Africa?

BACKGROUND

Voices of under-resourced communities are recognised as important yet are often unheard in decisions about healthcare resource allocation. Deliberative public engagement can serve as an effective mechanism for involving communities in establishing nutrition priorities. This study sought to identify the priorities of community members of a South African township, Soweto, and describe the underlying values driving their prioritisation process, to improve nutrition in the first 1000 days of life.

METHODS

We engaged 54 community members (28 men and 26 women aged > 18 years) from Soweto. We conducted seven group discussions to determine how to allocate limited resources for prioritising nutrition interventions. We used a modified public engagement tool: CHAT (Choosing All Together) which presented 14 nutrition intervention options and their respective costs. Participants deliberated and collectively determined their nutritional priorities. Choices were captured quantitatively, while group discussions were audio-recorded. A thematic analysis was undertaken to identify the reasons and values associated with the selected priorities.

RESULTS

All groups demonstrated a preference to allocate scarce resources towards three priority interventions-school breakfast provisioning, six-months paid maternity leave, and improved food safety. All but one group selected community gardens and clubs, and five groups prioritised decreasing the price of healthy food and receiving job search assistance. Participants' allocative decisions were guided by several values implicit in their choices, such as fairness and equity, efficiency, social justice, financial resilience, relational solidarity, and human development, with a strong focus on children. Priority interventions were deemed critical to supporting children's optimal development and well-being, interrupting the intergenerational cycle of poverty and poor human development in the community.

CONCLUSION

Our study demonstrates how public engagement can facilitate the incorporation of community values and programmatic preferences into nutrition priority setting, enabling a responsive approach to local community needs, especially in resource constrained contexts. Findings could guide policy makers to facilitate more appropriate decisions and to improve nutrition in the first 1000 days of life.

Relationships between adiposity distribution and metabolic health in preconception women in South Africa

Objective

Adipose tissue is a central regulator of metabolic health and a contributor to systemic inflammation. Patterns of adiposity deposition are important to understand for optimizing health. This study aimed to asses relationships between adiposity deposition and metabolic and inflammatory biomarkers in South African women prior to conception.

Methods

Non-pregnant, healthy women (n = 298) were recruited for this cross-sectional study via home visits. Body composition was measured by Dual X-ray Absorptiometry. Inflammation markers C-reactive protein (CRP), alpha1-acid glycoprotein (AGP), hemoglobin A1c (HbA1c), and blood pressure were scored according to risk. A summative metabolic health risk score was created for women with obesity. Generalized regression models assessed relationships between adiposity deposition and outcomes with adjustment for potential confounders.

Results

Obesity was present in 22% of women (mean age = 20.93 years). Fat mass index was associated with inflammation and metabolic health risk (β = 0.58; p < 0.01). Visceral fat, trunk:limb ratio, android:gynoid ratio, body mass index, weight, and waist circumference were positively associated with CRP, AGP, and metabolic health risk (p < 0.01). Weight was associated with Hba1c (β < 0.01; p < 0.05). Participants with obesity and low metabolic health risk had lower fat mass index and visceral fat than participants with obesity and higher metabolic health risk.

Conclusions

Black South African women accumulated excess adipose tissue in abdominal regions. While fat mass and body mass were associated with inflammation and metabolic health risk, women with obesity and with lower fat mass index and lower visceral adipose tissue were metabolically protected. Identification of women at risk for metabolic disease preconception could help ensure future healthy pregnancies and prevent transference of risk to offspring.

Building knowledge, optimising physical and mental health and setting up healthier life trajectories in South African women (Bukhali): a preconception randomised control trial part of the Healthy Life Trajectories Initiative (HeLTI)

INTRODUCTION

South Africa's evolving burden of disease is challenging due to a persistent infectious disease, burgeoning obesity, most notably among women and rising rates of non-communicable diseases (NCDs). With two thirds of women presenting at their first antenatal visit either overweight or obese in urban South Africa (SA), the preconception period is an opportunity to optimise health and offset transgenerational risk of both obesity and NCDs.

METHODS AND ANALYSIS

Bukhali is the first individual randomised controlled trial in Africa to test the efficacy of a complex continuum of care intervention and forms part of the Healthy Life Trajectories Initiative (HeLTI) consortium implementing harmonised trials in Canada, China, India and SA. Starting preconception and continuing through pregnancy, infancy and childhood, the intervention is designed to improve nutrition, physical and mental health and health behaviours of South African women to offset obesity-risk (adiposity) in their offspring. Women aged 18-28 years (n=6800) will be recruited from Soweto, an urban-poor area of Johannesburg. The primary outcome is dual-energy X-ray absorptiometry derived fat mass index (fat mass divided by height2) in the offspring at age 5 years. Community health workers will deliver the intervention randomly to half the cohort by providing health literacy material, dispensing a multimicronutrient supplement, providing health services and feedback, and facilitating behaviour change support sessions to optimise: (1) nutrition, (2) physical and mental health and (3) lay the foundations for healthier pregnancies and early child development.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Human Ethics Research Committee University of the Witwatersrand, Johannesburg, South Africa (M1811111), the University of Toronto, Canada (19-0066-E) and the WHO Ethics Committee (ERC.0003328). Data and biological sample sharing policies are consistent with the governance policy of the HeLTI Consortium (https://helti.org) and South African government legislation (POPIA). The recruitment and research team will obtain informed consent.

TRIAL REGISTRATION

This trial is registered with the Pan African Clinical Trials Registry (https://pactr.samrc.ac.za) on 25 March 2019 (identifier: PACTR201903750173871).

PROTOCOL VERSION

20 March 2022 (version #4). Any protocol amendments will be communicated to investigators, Institutional Review Board (IRB)s, trial participants and trial registries.

Understanding Sex Differences in Childhood Undernutrition: A Narrative Review

Complementing a recent systematic review and meta-analysis which showed that boys are more likely to be wasted, stunted, and underweight than girls, we conducted a narrative review to explore which early life mechanisms might underlie these sex differences. We addressed different themes, including maternal and newborn characteristics, immunology and endocrinology, evolutionary biology, care practices, and anthropometric indices to explore potential sources of sex differences in child undernutrition. Our review found that the evidence on why sex differences occur is limited but that a complex interaction of social, environmental, and genetic factors likely underlies these differences throughout the life cycle. Despite their bigger size at birth and during infancy, in conditions of food deprivation, boys experience more undernutrition from as early as the foetal period. Differences appear to be more pronounced in more severe presentations of undernutrition and in more socioeconomically deprived contexts. Boys are more vulnerable to infectious disease, and differing immune and endocrine systems appear to explain some of this disadvantage. Limited evidence also suggests that different sociological factors and care practices might exert influence and have the potential to exacerbate or reverse observed differences. Further research is needed to better understand sex differences in undernutrition and the implications of these for child outcomes and prevention and treatment programming.

Social vulnerability, parity and food insecurity in urban South African young women: the healthy life trajectories initiative (HeLTI) study

Social vulnerability indices (SVI) can predict communities' vulnerability and resilience to public health threats such as drought, food insecurity or infectious diseases. Parity has yet to be investigated as an indicator of social vulnerability in young women. We adapted an SVI score, previously used by the US Centre for Disease Control (CDC), and calculated SVI for young urban South African women (n = 1584; median age 21.6, IQR 3.6 years). Social vulnerability was more frequently observed in women with children and increased as parity increased. Furthermore, young women classified as socially vulnerable were 2.84 times (95% CI 2.10-3.70; p < 0.001) more likely to report household food insecurity. We collected this information in 2018-2019, prior to the current global COVID-19 pandemic. With South Africa having declared a National State of Disaster in March 2020, early indicators suggest that this group of women have indeed been disproportionally affected, supporting the utility of such measures to inform disaster relief efforts.