A Comprehensive Exploration of the Relationships between Structural Vulnerability Factors and Gestational Weight Gain Pre-COVID-19: A Scoping Review

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A Comprehensive Exploration of the Relationships between Structural Vulnerability Factors and Gestational Weight Gain Pre-COVID-19: A Scoping Review

https://doi.org/10.21203/rs.3.rs-3060015/v1

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Background:Insufficient and excessive gestational weight gain (GWG) have emerged as rising public health concerns affecting the majority of pregnant women in high-income countries, and are associated with a multitude of adverse maternal and infant health outcomes. The goal of this scoping review was to identify key structural vulnerability factors related to GWG and to examine the extent, range, and nature of research examining associations between those factors and GWG before the advent of the COVID-19 pandemic.

Methods: Electronic searches were performed in October 2018, and updated in August 2019 in the databases MEDLINE(R) ALL, EMBASE, PsycINFO, CINAHL, and Sociological Abstracts. Studies included needed to be set in high-income countries, have pregnant participants and an observational methodological design with inferential statistics performed between one or more structural vulnerability factors and GWG.

Results: Of the 11,382 citations identified through database searches, 157 articles were included in the review. The structural vulnerability factors most commonly studied in association with GWG were race and ethnicity (n=91 articles), age (n=87), parity (n=48), education (n=44), income (n=39), marital status (n=28), immigration (n=19) and abuse (n=12). Moststudies were conducted in the USA (77%), a majority reported significant associations between these factors and GWG and 34% were specific to a population where all individuals were affected by one of more structural vulnerability factors. Race and ethnicity stood out as the most extensively studied factor; i.e., for the longest period (since 1976), with the highest number of published articles, the largest sample size (n=7,966,573) and the second highest (79%) proportion of studies reporting a significant relationship with GWG, with immigration status having the highest proportion (95%).

Conclusions: To advance knowledge on the causes and consequences of excessive and insufficient GWG, research should extend beyond the USA and adopt an intersectional approach to unravel the complex interplay between social context, interacting structural vulnerability factors and specific measures of GWG. Such knowledge is required for the prevention of detrimental impacts on both maternal and offspring health.

Gestational weight gain

race/ethnicity

age

parity

marital status

immigration status

abuse

income

education

pregnancy

Excessive and insufficient gestational weight gain (GWG) have emerged as growing public health issues affecting a substantial proportion of pregnant women in high-income countries (1–4). The prevalence of excessive GWG is notably higher than insufficient GWG, particularly in the United States (51% vs. 21%) and in Europe (51% vs. 18%) (2). Although the pattern appears to differ in Asia (37% vs. 31%), similar trends emerge when applying ethnic-specific cut points for body mass index categories (51% vs. 16%) (2). The alarming prevalence of excessive and insufficient GWG raises significant concern, as both are associated with a wide range of adverse maternal and offspring health outcomes (1,2,5–11). In women, insufficient GWG is associated with gestational diabetes mellitus and greater risk of mortality (5,11), while in offspring it is associated with preterm birth, small for gestational age (SGA), and increased risk of perinatal death (1,2,5–7,9,11). Excessive GWG is associated with maternal preeclampsia, caesarian section, gestational diabetes, and mortality (1,2,5–11), as well as large for gestational age (LGA) offspring, macrosomia, and neonatal death (1,2,5–7,9,11). One of the most prominent evidence-based guidelines defining adequate GWG ranges were established in 1990 and revised in 2009 by the Institute of Medicine (IOM) (12) and remain widely used by healthcare professionals, researchers, and pregnant women across the world. Despite these guidelines, the persistently high occurrence of inadequate GWG (excessive and insufficient) underscores the necessity to enhance our understanding of its complex and interconnected determinants to better address this growing perinatal health issue affecting the maternal-offspring dyad.

This scoping review explores the individual and social determinants of inadequate GWG by drawing on the ‘structural vulnerability’ framework linking adverse health outcomes of individuals and groups with socioeconomic, political and cultural/normative hierarchies (13). A number of potential predisposing factors of inadequate GWG have been identified in various contexts, including socioeconomic status (SES) or poverty (14,15), marital status (11), education (16), pre-pregnancy body mass index (2,11,14,17,18), lifestyle (diet and physical activity)(18,19), smoking (11,17,18), age (11,17), ethnicity (2,11,14,15,17) and parity (11,17,18), but these are often interacting, complex and inconsistently associated with GWG. While a limited number of reviews have examined health interventions for the management of GWG (20–22), only three have focused on socioeconomic factors in observational studies (16,23,24). First, a narrative review by Campbell et al. (2016) aimed to address “some” of the SES factors and maternal characteristics influencing weight gain and the impact of excessive GWG on health outcomes (23). It sought to provide a brief overview rather than capturing all the current literature on this topic (23). Second, O’Brien et al. (2017) conducted a systematic review of 16 studies, focusing on 8 measures of SES and found that only educational attainment was associated with GWG (16). Third, a narrative review by Athar et al. (2021) focused on psychosocial factors associated with inadequate GWG in studies published between 2015 and 2020 and found 9 relevant studies exposing social factors (e.g. intimate partner violence, lack of social support, financial distress) and psychological factors (e.g. chronic stress, depression, low self-esteem) (24). The limited scope and/or non-systematic approaches employed (i.e. for defining vulnerability factors or for conducing article search/analysis) underpin the need for a comprehensive and rigorous investigation into the influence of structural vulnerability factors (SVF) on GWG.

The overarching goal of this scoping review was to identify key structural vulnerability factors related to GWG and to examine the extent, range, and nature of research examining associations between those factors and GWG before the advent of the COVID-19 pandemic. This approach examines a broad range of articles studying the relationships between structural vulnerability and gestational weight gain. Increasing the breadth of synthesis better addresses the question of heterogeneity of approaches in the study on GWG while identifying challenges and consideration for future research. Identifying common SVFs that drive inadequate GWG is critical for developing effective strategies to address this growing issue that profoundly affects the health and well-being of both the mother and the offspring, particularly among the most vulnerable groups of the population.

This scoping review draws on an adaptation of Arksey and O’Malley’s (2005) framework (25,26). An iterative process was used for refining both the research question and the SVFs, ensuring a comprehensive assessment of the literature. To identify relevant SVFs, this scoping review draws on “structural vulnerability” defined as “an individual's or a population groups' condition of being at risk for negative health outcomes through their interface with socioeconomic, political and cultural/normative hierarchies” by Bourgois et al. (2017) (13). An information specialist and the lead researchers collaboratively identified an a priori list of factors and keywords associated with the structural vulnerability framework. The detailed list of factors is provided in Supplemental Table 1. An initial compilation of SVFs was performed among eligible studies based on the selection process described below. All studies underwent subsequent thorough analysis resulting in the final identification of 8 SVFs, namely race/ethnicity, age, parity, marital status, income, education, immigration status and abuse (physical, psychological and sexual). Other SVFs were found to be associated with GWG including employment and working conditions, adverse childhood events, food security, social support, neighborhood composition and characteristics, familial responsibilities, language preference, and opportunities for upward mobility. However, they were reported at a low frequency in the literature (one to six studies in total per factor) and were operationalized such that findings were difficult to compare between studies. Therefore, they were not included in our analyses. Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews (PRISMA-ScR) guidelines were used to ensure comprehensive reporting (27).

Inclusion Criteria

The articles included in this review needed to focus on pregnant women, with at least a subsample of women in each study having experienced one or more SVF. Studies were limited to those with an observational design (prospective, retrospective or cross-sectional) that performed inferential statistics to analyze the relationship between SVFs and GWG. Descriptive studies without statistical comparison were not included in this review. A post hoc decision was made to eliminate qualitative studies, as they did not directly address the research question. Only peer-reviewed articles published in high-income countries, as classified by the World Bank in 2018, were considered. Studies published in a language other than English or French, as well as conference abstracts, were excluded. There was no restriction on the publication year of articles. For detailed information regarding the exclusion of studies, please refer to Fig. 1for reasons of exclusion.

Search Strategy

Electronic searches were performed by an information specialist from inception of databases up to October 22nd, 2018, and updated August 1st, 2019 in MEDLINE(R) ALL (1946 to July 30th 2019, Ovid), EMBASE (1947 to July 30^th, 2019, Ovid), PsycINFO (1806 to July Week 4 2019, Ovid), CINAHL (1976 to 2019, EBSCOhost), and Sociological Abstracts (1904 to 2019, Proquest). Studies were identified using a combination of each database’s unique subject headings and keywords pertaining to the SVF and weight gain among vulnerable pregnant women. Databases’ limits were used to remove non-peer-reviewed research when feasible (editorials, comments, letter to the editors) and a limit to English and French Languages was applied when possible (see Supplemental Table 2 for the search strategies). Exact duplicate records (n = 4,508) were removed using the automatic feature in EndNote X9 (Thompson Reuters, San Francisco, CA, USA) and close duplicate records (n = 15) were reviewed and removed manually.

The impact of the COVID-19 pandemic on SVFs, healthcare and community services, as well as health outcomes is widely documented (28–31). Including studies published during the pandemic would have required further considerations of context-dependent or timing-specific factors (e.g. confinement), thus complexifying further the analyses of the results. Therefore, the search strategy was not updated to include research from the COVID-19 period.

Selection Process

Covidence systematic review software (Veritas Health Innovation, Australia, 2019; available at www.covidence.org) was utilized for the study selection process (32). Initially, all citations underwent title and abstract screening by three reviewers independently (JML, CS, EC) followed by a full-text screening of relevant articles, which was conducted by two reviewers (JML, EC) independently. Discrepancies among reviewers were resolved by the lead researcher (BFB). To ensure consistency and coherence in the interpretation of citations and the predetermined eligibility criteria, a calibration exercise was conducted with 75 articles prior to the title and abstract screening. Citations deemed irrelevant at the full-text stage were assigned an exclusion reason.

Data Charting and Synthesis

Data charting was undertaken in two phases. In the first phase, eligible articles were recorded in a pre-piloted Excel data charting file. This file was used to extract relevant information, including study characteristics, GWG assessment, SVF, and key findings related to GWG. The second phase was initiated after the selection of the final 8 SVFs. In the data charting file, associations between each SVF and GWG were documented as “S” for significant, “NS” for non-significant, or left blank if the SVF was not assessed in the study. In cases where studies reported both significant and non-significant associations for a specific SFV due to variations between subgroups (e.g., non-significant relationship among normal weight participants but significant relationships among overweight and obese participants), the association was reported as “S & NS” in supplemental material and as significant in the “Results” section below. This approach aimed to ensure that associations between SFVs and GWG among any subset of women were adequately represented in the review. When multiple statistical models with different adjustments were presented, the most adjusted model was kept for data charting. The iterative process and multiple revisions of each article were instrumental in identifying the final 8 factors and ensuring the accuracy of the charted information.

The final Excel file, which contains comprehensive data charting, includes information on the first author, year of publication, country, study design, information on GWG (measurement and guideline used), sample characteristics and size, key findings, additional notes and references. The complete file is available in the Supplemental Table 3.

Terminology Associated With GWG

The terminology and reference values associated with GWG guidelines varied by publishing date and geographical context. In this review, the terms “insufficient” and “excessive” are used to describe GWG that is below or above GWG guidelines, respectively. “Adequate” GWG is used to designate GWG that falls within guidelines, and “inadequate” describes GWG that is either above or below GWG guidelines. The most commonly used were the IOM 2009 guidelines, followed by the IOM 1990 guidelines (12), however, other GWG guidelines were applied such as guidelines determined by a country’s health department.

Selection of articles

Database searches using the identified criteria yielded 11,382 articles. Following duplicate removal, 6,874 articles originally were screened in two stages (titles and abstracts followed by full text), and 157 articles were included in the final dataset (see Fig. 1 for details).

Synthesis of Results

This review identified 8 SVFs that are commonly assessed in association to GWG: race/ethnicity, age, parity, marital status, income, education, immigration status, and abuse (physical, psychological or sexual). GWG was reported either as a continuous outcome or categorized and compared between groups of pregnant women (i.e., one group having a higher or lower GWG than the other) or between GWG adequacy groups (i.e., insufficient, adequate, excessive). The characteristics of each study and their association with the 8 SVFs are reported in Supplemental Table 3. Most studies (60%) had a retrospective design, 32% were prospective, and 9% were cross-sectional. GWG data were retrieved from medical charts (39%) or birth certificates (20%), participant self-report (20%), or measured by the study team (17%); 5 studies (3%) used two different methods for collecting GWG data, and 2 studies (1%) did not clearly state their GWG collection method. A synthesis of studies that examined the relationship between each SVF and GWG is detailed below.

Race and ethnicity. Ninety-one studies (58%) assessed the relationship between race/ethnicity and GWG (Supplemental Table 4). Seventy-two studies found a significant association between GWG and race/ethnicity, while 19 studies found no significant association. Studies were published from 1976 to 2019 and were conducted in the USA (75 studies), Canada (3 studies), Australia, the Netherlands (2 studies each), Belgium, Czech Republic, New Zealand, Norway, Singapore, Spain, Sweden, Switzerland (1 study each), and one study was conducted in multiple countries (New Zealand, Australia, and Ireland). Samples sizes ranged from 56 to 7,966,573 individuals. Twenty-eight studies included a population that was primarily affected by a SVF (adolescents, women with a low income, unmarried women, and/or women from a racial or ethnic minority group). The most studied racial or ethnic groups were White, Black, and Hispanic, with some studies specifying both a woman’s racial group and their Hispanic/non-Hispanic identity. One of the least studied groups was Indigenous women.

Age. Eighty-seven studies (55%) considered the association between age and GWG (Supplemental Table 5). Forty-six studies found a significant association and 41 studies found no significant association. A comparison of GWG between adolescents and adults was conducted in 36 of these studies, with 25 studies finding a significant association and 11 finding no significant association. Articles were published from 1977 to 2019 and took place in the USA (67 studies), Taiwan (3 studies), Canada, Japan, Korea (2 studies each), Australia, Austria, Belgium, the Netherlands, Norway, Saudi Arabia, Singapore, Slovenia, Sweden, Switzerland (1 study each), and one study involved 3 countries (New Zealand, Australia, Ireland). Sample sizes ranged from 55 to 3,960,796 individuals; thirty-five studies were specific to women with a SVF (adolescents, women with a low income, women of a racial or ethnic minority group, unmarried women, low education, and/or multiparous women). Age was primarily assessed as a categorical variable, with a diverse range of age categories being used (e.g., < 25 years vs. ≥25 years; and < 20 years, 20–29 years, 30–39 years, and ≥ 40 years). The age range for adolescents and adults varied between studies, with some studies categorizing individuals as young as 17 as adults.

Parity. Forty-eight studies (31%) examined the relationship between parity and GWG (Supplemental Table 6). Significant associations between these factors were reported in 38 studies, while 10 studies reported none. Publication years ranged from 1990 to 2019. Studies were conducted in the USA (37 studies), Canada, Sweden (2 studies each) Australia, Belgium, Korea, the Netherlands, New Zealand, Singapore, and Switzerland (1 study each). The smallest sample size was 55 individuals, while the largest was 2,976,805 individuals. Twenty-two studies had a population that primarily included women with a SVF (racial or ethnic minority, adolescents, and/or women with a low income). The terms ‘nulliparous’ and ‘primiparous’ were often used to refer to women whose first delivery was the one examined in the study. The GWG of nulliparous or primiparous women was generally compared to that of multiparous women. A more in-depth assessment of parity was performed in 15 studies, where either more categories of parity were included (e.g., 0, 1, 2, or ≥ 3 previous births) or parity was assessed as a continuous variable.

Marital status. Twenty-eight studies (18%) assessed the association between marital status and GWG, with 15 studies finding a significant association and 13 studies found no significant association (Supplemental Table 7). Studies were published between 1985 and 2019 in the USA (25 studies), Belgium, Canada, and Sweden (1 study each). Sample sizes ranged from 101 to 251,342 individuals, with half the studies involving a population affected by one or more SVF (women with a low income, a racial or ethnic minority group, multiparous, and/or adolescents). Categories used to assess marital status varied between studies; the general categories of ‘married’ and ‘unmarried’ were commonly used, but some studies opted for more specific categories such as ‘married/cohabitating with partner’, and ‘single/separated’, or ‘married/partnered’, ‘separated/divorced’, or ‘single/no partner’.

Income. Thirty-nine studies (25%) examined the impact of income on GWG (Supplemental Table 8). Twenty studies found a significant association, while 19 found no significant association. Article publication years ranged from 1995 to 2019. Studies were conducted in the USA (33 studies), Canada, Korea (2 studies each), the Netherlands, and Singapore (1 study each). The smallest sample size was 75 individuals and the largest was 515,148 individuals. Thirteen studies were restricted to a population that had one or more SVF (adolescents, women from a racial or ethnic minority group, and/or women with a low income). Studies seldom used the same income categories (e.g., $0-500, $501-1,000, and ≥$1,000; <$20,000 v ≥$20,000; or < 100% of federal poverty line vs. >100% federal poverty line). Nearly half (18 of 39) of all studies used a proxy measure to assess a woman’s income status (e.g., use of Medicaid, or enrollment in the Special Supplemental Nutrition Program for Women, Infant and Children (WIC) in the USA).

Education. Forty-four studies (28%) examined the association between GWG and education level (Supplemental Table 9). Of these, 34 reported a significant association while 10 reported no significant association. Studies were conducted between 1992 and 2019 in the USA (33 studies), Sweden (3 studies), Canada (2 studies), Belgium, Croatia, Korea, the Netherlands, Norway, and Spain (1 study each). Sample sizes ranged from 55 to 2,796,805 participants. Fifteen studies were specific to women with a SVF (racial or ethnic minority group and/or women with a low income). Education was measured as a continuous variable in 3 studies, with the remaining studies measuring education as a categorical variable. Categories varied between studies, with some studies only including two categories (e.g., less than high school vs. high school or more), and others including up to 5 categories (e.g., 0–8 years, 9–11 years, 12 years, 13–15 years, or ≥ 16 years of education).

Immigration status. Nineteen studies (12%) assessed the relationship between immigration status and GWG, with all but one finding significant associations between these factors (Supplemental Table 10). Studies were published from 1997 to 2018 in the USA (14 studies), Canada (3 studies), France (1 study), and one study included multiple countries (New Zealand, Australia, and Ireland). The smallest sample size was 46 individuals and the largest was 250,857. Nine studies were limited to women with an SVF (racial/ethnic minority, adolescent, and/or low-income). Approximately half of the studies considered immigration status as a dichotomous variable (i.e. born in their country of residence or foreign-born), and 6 studies categorized individuals according to their length of time in their country of residence (e.g., US-born, lived in the USA ≥ 10 years, lived in the USA < 10 years). In all 6 studies, the length of time since an individual’s immigration had a significant effect on GWG.

Physical, psychological, and sexual abuse. Twelve studies (8%) considered the impact of experiencing abuse on GWG (Supplemental Table 11). Nine studies found a significant association and 3 found no significant association. Studies were published from 1996 to 2017 in the USA (10 studies), Iceland, and Taiwan (1 study each). Sample sizes ranged from 337 to 251,342 individuals. Half of the studies included a population with one or more SVF (adolescents, low-income, and/or racial/ethnic minority). Studies primarily assessed the impact of physical abuse on GWG, but sexual and psychological abuse were also examined. The timing of abuse (e.g., during childhood, before pregnancy, or during pregnancy) and the perpetrator of abuse (e.g., intimate partner) were considered in some studies.

The current scoping review, focusing on the period prior to the COVID-19 pandemic, reveals that associations between SVFs and inadequate GWG have been widely studied over the years in the hope of better understanding and preventing its associated adverse health outcomes in mothers and children living in a vulnerable context. The most frequently studied SVFs in relation to GWG, in descending order, were race and ethnicity (58%), age (55%), parity (31%), education (28%), income (25%), marital status (18%), immigration (12%) and abuse (8%). Among all 157 studies that were included in this review, 121 were conducted in the USA (77%) and reported more significant associations (e.g., 51% for income to 95% for immigration status) than non-significant associations with GWG. While the impact of race/ethnicity and age on GWG have been studied since the 1970s, other factors have started to gain researchers’ attention a decade or two later (e.g., 1980s for marital status, and 1990s for parity, income, education, immigration status and abuse). For all factors analyzed, study samples ranged from small groups to entire populations (from 46 individuals to close to 8 million). The studies included in this review encompassed various observational study designs and populations, 34% of which were specific to a sample where all individuals were affected by one of more structural vulnerability factors (e.g., only women from a specific racial/ethnic group such as Black women or age group such as adolescents). Among all SVFs examined in this scoping review, race and ethnicity stood out from other factors as having been studied for the longest period, with the highest number of studies examining this factor, the largest sample size, and the second highest proportion of studies reporting a significant relationship with GWG (79%), with immigration status having the highest proportion (95%). Lastly, the scope of this review emphasizes the great heterogeneity among studies in GWG. The following sections identify key challenges and considerations for future research.

1. Collecting, analyzing, and comparing GWG

Several methodological challenges need to be acknowledged when comparing a wide breadth of studies examining inadequate weight gain during pregnancy. First, there is much heterogeneity in the way that GWG was collected: close to 60% of studies extracted information on GWG from medical charts or birth certificates while most of the remaining was measured by researchers or came from self-reported information. Second, guidelines used to categorize GWG adequacy also varied between studies; the most commonly used were the IOM 2009 guidelines, followed by the IOM 1990 guidelines. In less than 10% of studies, other GWG guidelines were applied such as guidelines determined by a country’s health department. The two IOM guidelines only differ by their recommendations for women with obesity: in 1990, a GWG of at least 15 pounds was recommended, while in 2009 this was changed to 11–20 pounds (12). A difference in classification of inadequate GWG is thus possible between studies, however, the guidelines selected in each study would have been deemed appropriate for the study’s population during the specific period in which the study was conducted. Third, statistical analyses used to assess the relationship between SVFs and GWG also differed between studies, where some examined the influence of SVFs at a superficial level comparing frequencies of inadequate GWG among different groups of women (e.g., vulnerable vs. less vulnerable), while others performed more in-depth analyses using multivariate models with covariate adjustment (e.g., odds of excessive GWG for a racial/ethnic minority group compared to White, adjusted for age, income, education, etc.). As such, confounding variables and covariates were not always controlled for or comparable between studies. Furthermore, comparator groups varied such that in some studies, the likelihood of inadequate GWG was compared between two distinct groups (e.g., adults vs. adolescents), while in others, the likelihood of inadequate GWG was compared to that of adequate GWG within the same group of women (e.g., likelihood of excessive vs. adequate GWG among adolescents). Thus, the great heterogeneity in the ways GWG was measured, compared to guidelines, and analyzed limits the ability to associate SVFs with the risk of insufficient or excessive GWG between the various groups of women studied.

2. Defining, Categorizing, and Comparing Structural Vulnerability Factors

Differences in definitions and categorizations of each SVF add complexity when comparing study results. Inconsistencies arose in the definition of SVF constructs across studies, with the assumption that certain groups were equivalent without considering their social context. For example, women who were ‘single’ and those who were ‘unmarried’ are not necessarily comparable when it comes to relationship status. Additionally, depending on the SVF and the study, factors could have been analyzed as continuous variables or as categorical variables (e.g., full age range vs. age groups). When variables were categorized, variations in thresholds used and the choice of the reference group for comparison frequently differed between studies. For example, education could have been categorized by the highest level of educational attainment (e.g., high school, college, or university diploma) or by total years of study; income could have been defined as household income, percentage of federal income, poverty-to-income-ratio; age could have been analyzed as adults compared to adolescents (with varying cut points for teen years), or in total years of age. Also, the frequent practice of dichotomizing parity (nulliparous vs. multiparous) limits the ability to assess the impact of an increasing number of children in a woman’s care on her GWG. Thus, the systematic differences in reporting and comparing SVFs will inevitably interfere with the ability to generate clear comparisons between studies and subsequently to determine the association between each SVF and GWG.

3. Inherent Intersectionality of Vulnerability Factors

Drawing on the concept of intersectionality, the relationship between each of the socially constructed vulnerability factors is complex as they can be experienced concomitantly and thus cannot be easily disentangled (33,34). Intersecting several dimensions of SVFs can reveal the existence of within-group diversity but also the synergistic effect of their combination on health inequality (34). For example, a pregnant adolescent is more likely to have a low educational attainment and most likely not be married and have a low income. Trying to identify which of these factors would have the most important impact on GWG would be reductionist as they are all part of the person’s biography and social context. Huynh et al. demonstrated that excessive GWG was more likely to be experienced by educated Hispanic, and less likely among educated White women, but more likely among educated women living in a low or medium socioeconomic neighbourhood (35). Studying the combination of SVFs with an intersectional approach, within similar social contexts and using comparable groups may reveal a clearer picture of health disparities and help to better predict which combination of factors, contexts, or living circumstances may put women at greater risk of inadequate GWG.

4. Varying Social Contexts of Vulnerability Factors

While all studies in this review have exclusively taken place in high-income countries, the social, economic, cultural, structural, and political contexts nevertheless exhibited tremendously within and between countries. For instance, comparing women from different regions of the United States cannot be considered as equivalent to comparing women between the United States and Japan. The social environment surrounding a woman’s racial and ethnic identity will influence the extent of discrimination or racism she may face. Moreover, the repercussions of immigration on health disparities vary depending on factors such as a woman’s country of origin, age at immigration, and the length of time since immigration. However, these factors have received limited consideration in the context of GWG research. Similarly, the burdens of poverty and material deprivation bear dissimilar weight depending on whether one resides with other underprivileged individuals within a marginalized neighborhood, or conversely, stands as a stigmatized minority in a wealthier setting. These variations inevitably constrain the comparison of GWG when assessing studies on a global scale. Many of these factors are recognized to be the underlying causes of health inequality through the unequal allocation of power and resources (36), far surpassing the realms of factors such as age, race/ethnicity, income, and parity. In light of these circumstances, it becomes evident that comparisons conducted within specific countries and regions may provide a more accurate portrayal of a SVF’s impact on GWG, as this approach enables the consideration of the distinct contextual nuances at play.

Strengths and Limitations of the Scoping Review

The breadth of this scoping review is unique in the fact that it reviewed a substantial number of articles with varying samples, methodologies and statistical approaches. An iterative process was used to refine the research question and identify the final 8 SVFs in relation to GWG. This approach enabled us to unravel the complex nature of the relationship between SVFs and GWG, and to highlight the barriers when attempting to establish the likelihood of inadequate GWG for each independent SFV, as it is typically done in systematic or meta-analysis reviews, due to the substantial variability in published data and the intersecting nature of these factors. As a limitation, this review did not include articles published in languages other than English or French. Studies conducted in low- or middle-income countries were also excluded due to the significant variations in the impacts of SFVs on GWG across vastly different contexts. For instance, when considering the effect of immigration status, the experience of a refugee displaced from a low-income country to a high-income country would differ from that of a refugee displaced in an adjacent low-income country. Nonetheless, the exclusion of the low- to middle-income countries limits the scope of our findings to more affluent environments.

This scoping review aimed to examine the extent, range and nature of published associations between our 8 identified SVFs and inadequate GWG before the advent of the COVID-19 pandemic to highlight the social distribution of health inequalities during pregnancy. It is important to exercise caution when attempting to prioritize specific factors that may be associated with inadequate GWG, as all factors may play a significant role depending on the context and interact in a complex manner. Future research should consider adopting an intersectional approach by studying clusters of SVFs to better understand how differing individual characteristics, living conditions, and social contexts influence pregnancy health outcomes. Some structural factors can affect a woman’s perceptions, beliefs, and attitudes toward weight gain and perinatal care, subsequently influencing her lifestyle choices and use of healthcare, which in turn affect the health outcomes of both mother and child. Researchers, healthcare professionals, and policymakers should focus on better understanding and addressing SVFs in the context of pregnancy, as numerous long-term health impacts can result from various exposures during pregnancy and early childhood. This can be achieved by improving maternal health practices and lifestyle choices through social, structural, and policy measures, addressing the root causes of health inequality, and ultimately reducing the disparities early in life.

Gestational weight gain (GWG), Institute of Medicine (IOM), Socioeconomic status (SES), Structural vulnerability factor (SVF)

Ethics approval and consent to participate: Not applicable
Consent for publication: Not applicable
Availability of data and materials: All studies analyzed for this scoping review are included in supplementary information files.
Conflict of Interests: The authors declare that they have no competing interests nor they have received funding to undertake this analysis.
Funding: Not applicable
Authors' contributions: JML contributed to screening titles and abstracts, reviewing full-text articles, extracting and synthesizing data, and writing the manuscript; EC contributed to reviewing full-text articles, extracting and synthesizing data, and writing the manuscript; AD contributed to the design of the review, supervised the conduct of the review, and to writing the manuscript; CS contributed to the design of the review, screening titles and abstracts, reviewing full-text articles and reviewing the manuscript; KF performed the literature search; SO contributed to the design of the review and reviewing the manuscript; ASM contributed to the design of the review and reviewing the manuscript; BFB contributed to the design of the review, solving the conflicts, supervised the conduct of the review and to writing the manuscript. All authors read and approved the final manuscript.
Acknowledgements: Not applicable

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No competing interests reported.

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A Comprehensive Exploration of the Relationships between Structural Vulnerability Factors and Gestational Weight Gain Pre-COVID-19: A Scoping Review

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Abstract

Figures

Background

Methods

Inclusion Criteria

Search Strategy

Selection Process

Data Charting and Synthesis

Terminology Associated With GWG

Results

Selection of articles

Synthesis of Results

Discussion

1. Collecting, analyzing, and comparing GWG

2. Defining, Categorizing, and Comparing Structural Vulnerability Factors

3. Inherent Intersectionality of Vulnerability Factors

4. Varying Social Contexts of Vulnerability Factors

Strengths and Limitations of the Scoping Review

Conclusion

Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

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