The relationship between antenatal body attitudes, pre-pregnancy body mass index, and gestational weight gain

Author’s Accepted Manuscript The Relationship between Antenatal Body Attitudes, Pre-Pregnancy Body Mass Index, and Gestational Weight Gain Bianca Andrews, Briony Hill, Helen Skouteris www.elsevier.com/locate/midw

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S0266-6138(17)30103-1 https://doi.org/10.1016/j.midw.2017.10.012 YMIDW2121

To appear in: Midwifery Received date: 13 February 2017 Revised date: 8 October 2017 Accepted date: 14 October 2017 Cite this article as: Bianca Andrews, Briony Hill and Helen Skouteris, The Relationship between Antenatal Body Attitudes, Pre-Pregnancy Body Mass Index, and Gestational Weight Gain, Midwifery, https://doi.org/10.1016/j.midw.2017.10.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

The Relationship between Antenatal Body Attitudes, Pre-Pregnancy Body Mass Index, and Gestational Weight Gain Bianca ANDREWS, BSocSc (Psychology & Forensic Science), Briony HILL, PhD*, Helen SKOUTERIS, PhD School of Psychology, Deakin University, Locked Bag 20000, Geelong, Australia, 3220

*Corresponding author. Dr Briony Hill. School of Psychology, Deakin University, Locked Bag 20000, Geelong, Australia, 3220. Ph: +613 9244 6538. [email protected]

Abstract
 Objectives An estimated 50% of women experience excessive gestational weight gain (GWG). Maternal body attitudes are associated with GWG, however this relationship is complex and may differ based on pre-pregnancy body mass index (BMI) or gestational age. The aim of this study was to explore the moderating role of maternal pre-pregnancy BMI on the relationship between body attitudes in early-to-mid and late pregnancy and GWG. Design/Participants Pregnant women less than 18 weeks gestation were recruited for a postal questionnaire study via Australian pregnancy online forums, pregnancy and parenting magazines, and antenatal clinics. In early-mid pregnancy (Time 1; mean (M) = 16.81 weeks gestation, standard deviation (SD) = 1.18), participants reported demographics, pre-pregnancy weight, height, and body attitudes (salience of weight and shape, attractiveness, strength and fitness and feeling fat). In late pregnancy, body attitudes (Time 2; M = 32.65 weeks gestation, SD = 0.91) and weight (Time 3; M = 37.15 weeks gestation, SD = 1.55) were reported. Prepregnancy BMI and total GWG were calculated. Moderation analyses were conducted. Findings In early-mid pregnancy, pre-pregnancy BMI moderated the relationship between feeling fat and GWG. Pre-pregnancy BMI did not moderate the relationship between body attitudes and GWG for salience of weight and shape, attractiveness or strength and fitness in early-mid

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pregnancy. In late pregnancy, pre-pregnancy BMI moderated the relationship between all four body attitude facets (salience of weight and shape, attractiveness, feeling fat and strength and fitness) and GWG. Conclusion/Implications for practice The relationship between body attitudes and GWG was moderated by pre-pregnancy BMI, particularly in late pregnancy. It is recommended that antenatal health care providers monitor women’s body attitudes throughout pregnancy to aid in the management of healthy GWG and promote positive maternal and infant health outcomes. This is particularly important for women entering pregnancy with an underweight/normal weight BMI.

Keywords Body image; gestational weight gain; body mass index

INTRODUCTION An estimated 50% of women across all pre-pregnancy body mass index (BMI) categories exceed pregnancy weight gain recommendations, defined as BMI-specific weight gain exceeding internationally recognised cut offs (Institute of Medicine [IOM], 2007; IOM, 2009). Excessive gestational weight gain (GWG) places the mother at increased risk of gestational hypertension, caesarean delivery, preeclampsia (Haugen et al., 2014), post-partum weight retention (Siega-Riz et al., 2010; Amorim et al, 2007), obesity, and diabetes (Al Mamun et al., 2013). In addition, excessive GWG is associated with increased risk of infant macrosomia (IOM, 2007), and offspring obesity throughout childhood and into adulthood (Schack-Nielsen et al., 2010). Maternal body image has been shown to influence weight gain during pregnancy. Body image is defined as the internal representation an individual has of his or her own outer appearance (Thompson et al., 1999). Body image can be delineated in many ways, often as body dissatisfaction (“the negative self-evaluation of bodily size, shape, weight and musculature”; Joseph et al., 2016, p. 216-217) or body attitudes (an attitudinal aspect of body image that is reflected in positive or negative affect, cognitions and behaviour towards ones’ body; McArthur et al., 2005; Brown et al., 1990). The nature of the relationship between body image and GWG appears to be complex and multifactorial (Hill et al., 2013; Sui et al., 2013). For instance, several studies have found that body dissatisfaction and negative weight gain attitudes were associated with higher GWG (DiPietro et al., 2003; Sui et al., 2013).

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Similarly, the findings of a recent systematic review seeking to summarise the relationship between psychological factors and trimester-specific GWG also revealed that negative body image and negative weight gain attitudes were a risk factor for excessive GWG (Kapadia et al., 2015). However, contrary to these findings, it has been reported that specific aspects of body image, such as feeling fat in late pregnancy and feeling attractive in mid-pregnancy are associated with lower GWG (Hill et al., 2013). Explanations for the conflicting associations between body image and GWG should be explored. One such theory may be that the relationship between body image and GWG differs based on a woman’s pre-pregnancy BMI; that is, BMI is a moderator of the relationships between body image and GWG. Due to more restrictive weight gain recommendations for overweight and obese women, women entering pregnancy with a higher BMI are more likely to gain weight excessively (IOM, 2009; Hill et al., 2013), despite lower total mean GWG (Daemers et al., 2013). In non-pregnant populations, BMI and body image are consistently related, such that BMI has been shown to be associated with several facets of body image among women: body dissatisfaction and perceptions of being too fat (Algars, 2009). In fact, higher BMI has been consistently associated with increased body dissatisfaction (Algars, 2009; Eisenberg et al., 2006; Van der Berg et al., 2007). In pregnancy, few studies have investigated pre-pregnancy BMI in addition to both body image and GWG. In one study, it was found that increased distress about pregnancy weight gain was associated with higher pre-pregnancy BMI, larger GWG and greater body dissatisfaction (Walker, 1998). More specifically, Copper et al. (1995) found that obese women (BMI > 26.6) were more likely to hold negative attitudes towards weight gain during pregnancy, while thin women (BMI < 19.6) were more likely to hold positive weight gain attitudes.1 Furthermore, discrepancy between current and ideal body shape has been associated with excessive GWG such that women with a higher BMI with a preference to be thinner are less likely to gain excessive GWG, while women with a higher BMI who preferred to be heavier are at an increased risk of excessive GWG (Mehta et al., 2011). Interestingly, despite the increasing knowledge that body image is an important consideration during pregnancy (Hill et al., 2013), and well-established rates of high prepregnancy BMI, and excessive GWG (IOM, 2009), to our knowledge, no study has explored 1

It should be noted that the BMI classifications used by Copper et al. (1995) differ from current international categorisations of BMI (World Health Organisation, 2000), with Copper et al.’s classifications for obese women most closely aligning with the current overweight (BMI 25.0-29.9 kg/m2) and obese (BMI ≥ 30 kg/m2) categories, and ‘thin’ women most closely aligning with the current underweight classification (BMI < 18.5 kg/m2).

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whether pre-pregnancy BMI moderates the relationship between antenatal body image and GWG. Further exploration into the mechanisms of the inter-relations between these three factors is required to better understand contributors to excessive GWG. This may aid in the development of suitable and effective interventions to promote healthy BMI, GWG and positive body image during pregnancy. Therefore, the aim of this study was to explore the moderating role of maternal pre-pregnancy BMI on the relationship between body attitudes in early-to-mid and late pregnancy (specifically salience of weight and shape, attractiveness, strength and fitness and feeling fat), and GWG.

METHODS Participant Recruitment and Enrolment After approval from the XXXX, the study was advertised on Australian pregnancy online forums, pregnancy and parenting magazines from February 2010 to July 2012, and a maternity clinic at a large tertiary hospital in Melbourne, Australia from December 2011 to January 2013. Eligible women were over 18 years of age, pregnant, and between 10 and 18 weeks gestation. Twin pregnancies were excluded.

Procedure This study was part of a larger study exploring the wellbeing of mothers and their infants from early-mid pregnancy up to 12 months post-birth. Only data pertaining to pregnancy were used for the current study. Specifically, after written, voluntary informed consent was obtained, participants were asked to complete questionnaires which were mailed out to their homes and returned using the provided replied paid envelopes. For the current study, questionnaires completed at 16 to 18 (T1), 32 (T2) and 36 weeks gestation (T3) were used. Participants were asked to complete questionnaires within one to two weeks of the desired gestational age and indicate their actual gestational age at time of completion. Questionnaires collected demographic information including age, family income, education, and parity, as well as information regarding maternal and infant health and wellbeing. Maternal weight at time of completion of each questionnaire was collected, as were method of weight and height measurement. Measures Pre-Pregnancy BMI.

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At T1, participants were asked to self-report their height and weight at one month prior to their pregnancy. Pre-pregnancy BMI was then calculated by dividing pre-pregnancy weight (kg) by the square of height (m). Gestational Weight Gain. Total GWG was calculated by subtracting self-reported pre-pregnancy weight (collected at T1) from the pregnancy weight reported at T3. Participants were asked to indicate whether the measurement was taken by their midwife/obstetrician/doctor, or if they weighed themselves. Total GWG and pre-pregnancy BMI were then used to classify women according to the 2009 IOM recommendations for weight gain during pregnancy, where it is recommended that women who are classified as underweight (BMI <18.5) gain 12.5 to 18 kg, women who are normal weight (BMI 18.5–24.9) gain 11.5 to 16 kg, overweight women (BMI 25–29.9) gain 7 to 11 kg, while obese women (BMI ≥ 30) gain 5 to 9 kg. Women were then classed as gaining weight inadequately (below recommendations), adequately (within recommendations) or excessively (above recommendations). Body Attitude. Body attitudes were assessed at T1 and T2 using the Ben-Tovim Walker Body Attitudes Questionnaire (BAQ; Ben-Tovim & Walker, 1991). For the current study, four subscales relevant to pregnancy were included; salience of weight and shape (salience), attractiveness, strength and fitness, and feeling fat (Skouteris, 2011). The disparagement and lower body fatness subscales are not deemed relevant during pregnancy and were not included in this study. Participants were asked to rate each item on a Likert scale from 1 (‘strongly disagree’) to 5 (‘strongly agree’) based on how they had felt over the past month. Negatively worded items (‘I hardly ever feel fat’) were reverse scored. Item scores were then summed to create a total score for each subscale. The BAQ has satisfactory test-retest reliability and validity in non-pregnant populations (Ben-Tovim & Walker, 1991) and good internal consistency in pregnant populations (Duncombe et al. 2008). The 28-item BAQ in the present study showed acceptable reliability at T1 (Cronbach’s α: salience = .79, attractiveness = .67, strength and fitness = .76, feeling fat = .92), and T2 (Cronbach’s α: salience = .80, attractiveness = .65, strength and fitness = .76, feeling fat = .93). Statistical Analyses Data were screened and cleaned prior to analyses. Missing data analyses were performed and results reveal that Little’s Missing Completely at Random (MCAR; Little, 1988) test was not significant, X 2= 1672.31, df = 1626, P =.207, indicating that missing data were MCAR. No variable had more than 5% missing data. Missing data were replaced using 5

Expectation Maximisation. Univariate outliers were replaced with a value one unit higher or lower than the next valid unit. Two cases with multivariate outliers were deleted. As prepregnancy BMI, total GWG and BAQ salience subscale violated normality, bias-corrected bootstrapping with 1000 bootstrap samples was used (Field, 2013). Descriptive analyses were conducted on demographic variables. A moderation analysis examined whether the relationship between body attitudes and GWG was moderated by pre-pregnancy BMI. One model was conducted for each BAQ subscale at T1 and T2, respectively. Each model was repeated, firstly as an unadjusted model, and secondly after adjusting for age, annual family income, level of education, and parity (consistent with prior research exploring body image and GWG; Hill et al., 2013). All analyses were run using a dichotomous categorisation of pre-pregnancy BMI: underweight/normal weight vs. overweight/obese. A conceptual illustration of the proposed model is depicted in Figure 1. All analyses were conducted using IBM SPSS Statistics version 23. The PROCESS macro (v2.16) was used to conduct the moderation analyses (model 1; Hayes, 2012). Variables were mean centred, heteroscedasticity was controlled for and 1000 samples bias corrected, accelerated bootstrapping was used.

FINDINGS Participant Characteristics Of the 734 pregnant women who expressed interest in the study, 474 (64.6%) consented and completed a baseline questionnaire. Only participants who provided height, pre-pregnancy weight, a final weight measurement taken at greater than or equal to 35 weeks’ gestation, and completed the BAQ at T1 and T2 were eligible for analysis, resulting in a final sample of 280 women (59.1%). Participant characteristics are presented in Table 1. Women were 16.81 weeks pregnant at T1 (standard deviation [SD] = 1.18, range 15-22), with a mean age of 30.85 years (SD = 4.58, range 19-44). Participants had a relatively high socioeconomic background: 81.8% were born in Australia, 65.7% had completed an undergraduate or postgraduate degree, and 38.2% had a combined family income in excess of AUD$125,000. At time of the study, the average household income in Australia for a couple with children under 5 years was $87,152 (Australian Bureau of Statistics, 2013). For 47.9% of women, it was their first pregnancy. Women had a mean pre-pregnancy BMI of 25.36 (SD = 5.61, range 16 - 43), 40.0% of women were classified as overweight or obese prior to pregnancy and 42.5% exceeded the 2009 IOM recommendations for GWG (IOM, 2009). Table 2 presents the means and standard deviations for pre-pregnancy BMI, GWG, and body 6

attitude subscales at T1 and T2, and bivariate correlations between continuous variables. Women who were retained for analyses reported a higher annual family income (P = .004), and were more likely to be born in Australia (P = .006) than women who were excluded; there were no other statistical differences between women retained in the study and those who were excluded. Moderation at T1 Results of the moderation with T1 body attitudes are displayed in Table 3 (unadjusted) and Table 4 (adjusted). Findings did not differ between unadjusted and adjusted analyses, therefore findings for unadjusted analyses are reported only in Table 3 and findings for adjusted analyses are summarised in Table 4 and below. Salience. In the adjusted model, when controlling for age, family income, education, and parity, 10% of the variance in GWG was significantly explained by salience, pre-pregnancy BMI and their interaction F(7,272) = 3.94, P < .001, R2 = .10. Lower pre-pregnancy BMI was significantly associated with higher total GWG (b = -2.28, P < .001) and higher salience scores were also associated with higher GWG (b = .27, P = .007). However, the relationship between salience and GWG was not moderated by pre-pregnancy BMI (b = -.32, P = .084). Attractiveness. In the adjusted model, 10% of the variance in GWG was significantly explained by attractiveness, pre-pregnancy BMI and their interaction F(7,272) = 3.30, P = .002, R2 = .10. Lower pre-pregnancy BMI was significantly associated with higher total GWG (b = -2.18, P = .003). Attractiveness was not a significant predictor of GWG (b = -.19, P = .115). The relationship between attractiveness and GWG was not moderated by pre-pregnancy BMI (b = .47, P = .050). Feeling Fat. In adjusted analyses, 12% of the variance in GWG was significantly explained by feeling fat, pre-pregnancy BMI and their interaction F(7,272) = 3.93, P < .001, R2 = .12. Lower pre-pregnancy BMI was significantly associated with higher total GWG (b = -1.96, P = .004). Higher scores on the feeling fat subscale were associated significantly with higher GWG (b = .07, P =.028). The relationship between feeling fat and GWG was moderated by pre-pregnancy BMI (b = -.20, P = .002). Further exploration of conditional effects displayed in Feeling fat was associated significantly with GWG for normal/underweight women (b = .07, P = .029) and overweight/obese women (b = -.13, P = .023). That is, for women entering pregnancy with an underweight/normal BMI, higher scores for feeling fat were associated 7

with higher GWG, while for women entering pregnancy with an overweight/obese BMI, higher feeling fat scores were associated with lower GWG (Figure 2). Strength and Fitness. In adjusted analyses, 11% of the variance in GWG was explained by strength and fitness, pre-pregnancy BMI and their interaction F(7,272) = 3.44, P = .002, R2 = .11. Lower pre-pregnancy BMI was significantly associated with higher total GWG (b = -2.09, P = .003). Strength and fitness did not predict GWG (b = -.11, P = .163). There was a significant interaction effect indicating that pre-pregnancy BMI moderated the relationship between strength and fitness and GWG (b = .36, P = .030). However, exploration of the conditional effects showed that there was no moderation present when pre-pregnancy BMI was classified as underweight/normal (b = -.11, P = .163) or overweight/obese (b = .24, P = .089), indicating the interaction holds no clinical relevance. Moderation at T2 Results of the moderation with body attitudes measured at T2 are displayed in Table 5 (unadjusted) and Table 6 (adjusted). Findings did not differ between unadjusted and adjusted analyses, therefore findings for unadjusted analyses are reported only in Table 5 and findings for adjusted analyses are summarised in Table 6 and below. Salience. In an adjusted model, when controlling for age, family income, education, and parity, 12% of the variance in GWG was significantly explained by salience, pre-pregnancy BMI and their interaction F(7,272) = 4.13, P < .001, R2 = .12. Lower pre-pregnancy BMI was associated significantly with higher total GWG (b = -2.24, P = .002). Higher scores on the salience subscale were associated significantly with higher GWG (b = .31, P = .002). The relationship between salience and GWG was moderated by pre-pregnancy BMI (b = -.54, P = .020). Further exploration of conditional effects displayed in Figure 3 indicated that for women entering pregnancy underweight/normal weight, high levels of salience were associated significantly with higher GWG (b = .31, P = .002). This relationship did not hold true for overweight/obese women (b = -.23, P = .274). Attractiveness. In adjusted analyses, 12% of the variance in GWG was significantly explained by attractiveness, pre-pregnancy BMI and their interaction F(7,272) = 4.35, P < .001, R2 = .12. Lower pre-pregnancy BMI was associated significantly with higher total GWG (b = -2.25, P = .002). Lower feelings of attractiveness were associated significantly with higher GWG (b = -.28, P = .009). Body mass index moderated the relationship between attractiveness and 8

GWG (b = .63, P = .004). Further exploration of conditional effects displayed in Figure 4 indicated that attractiveness was associated with GWG for normal/underweight women (b = .28, P = .009) but not overweight/obese women (b = .36, P = .065). Thus, for women entering pregnancy with an underweight/normal weight BMI, low attractiveness scores were associated with higher GWG. Feeling Fat. In adjusted analyses, 13% of the variance in GWG was significantly explained by feeling fat, pre-pregnancy BMI and their interaction F(7,272) = 5.20, P < .001, R2 = .13. Lower pre-pregnancy BMI (b =-2.33, P = .001) and higher scores of feeling fat (b = .13, P < .001) were associated significantly with higher GWG. Pre-pregnancy BMI moderated the relationship between feeling fat and GWG (b = -.21, P = .004). Further exploration of conditional effects displayed in Figure 5 indicated that for women entering pregnancy with an underweight/normal BMI, higher feeling fat scores were associated with higher GWG (b = .13, P < .001). This relationship did not hold true for overweight/obese women (b = -.08, P = .224). Strength and Fitness. In adjusted analyses, 12% of the variance in GWG was significantly explained by strength and fitness, pre-pregnancy BMI and their interaction F(7,272) = 3.71, P < .001, R2 = .12. Lower pre-pregnancy BMI (b = -2.16, P = .002) and lower strength and fitness scores (b = -.15, P = .050) were associated with higher GWG. Pre-pregnancy BMI moderated the relationship between strength and fitness and GWG (b = .50, P = .008). Exploration of conditional effects displayed in Figure 6 indicated that strength and fitness was not associated with GWG for normal/underweight women (b = -.15, P = .050), but for overweight/obese women, high scores on the feeling fat subscale were associated with higher GWG (b = .35, P = .043).

DISCUSSION The aim of the present study was to explore the moderating role of pre-pregnancy BMI on the relationship between maternal body attitudes in early-to-mid and late pregnancy and GWG. To knowledge, only three other studies have explored pre-pregnancy BMI, maternal body attitudes, and their relationship with GWG, and none explored this relationship prospectively throughout pregnancy (Walker, 1998; Copper et al., 1995; Mehta et al., 2011). All three studies found associations between GWG, pre-pregnancy BMI and body image-related constructs such as maternal feelings towards antenatal weight gain, body 9

type preference, and discrepancy between current and ideal body. The current study extended these findings by exploring the potential moderating effect of pre-pregnancy BMI on the relationship between body image and GWG in both early-mid and late pregnancy. In early-mid pregnancy (T1), the relationship between body attitudes and GWG was moderated by pre-pregnancy BMI under one facet of the BAQ: feeling fat. When women were classified as underweight/normal weight versus overweight/obese, feeling fat in earlymid pregnancy was associated with higher GWG only for women who began pregnancy underweight/normal weight. For women who began pregnancy overweight/obese, feeling fat in early-mid pregnancy was associated with lower GWG. A possible explanation for the moderating effect of underweight/normal weight pre-pregnancy BMI on the relationship between feeling fat in early-mid pregnancy and GWG is that women who gain a large amount of weight in early pregnancy may experience feelings of fatness, and this early weight gain (by 12 to 14 weeks gestation) is strongly predictive of total GWG (Overcash et al., 2015). Given that overweight and obese women are more likely to experience less GWG overall (Daemers, et al., 2013; de Jersey et al., 2012), it is possible that overweight and obese women have not experienced a significant increase in their weight to the point that they report greater feelings of fatness in early-mid pregnancy. Furthermore, they may not ‘feel fat’ due to their current pregnant state not differing greatly from their usual shape and form. Despite the fact that women tend to accept the pregnant body as a functional being, which can mitigate body image concerns (Watson et al., 2015), it is conceivable that women entering pregnancy at an underweight or normal weight BMI may find the associated change in body shape more difficult to accept, particularly in early pregnancy where women may experience a thickening around the middle without necessarily “looking pregnant”. Qualitative research supports this hypothesis (Nash, 2012; Earle, 2003; Watson et al., 2015). In contrast to the null findings in early-mid pregnancy for strength and fitness, salience, and attractiveness, in late pregnancy, pre-pregnancy BMI moderated the association between all four facets of body attitudes and GWG. For women who began pregnancy underweight/normal weight, feeling fat and salience of weight and shape were associated with higher GWG, and attractiveness was associated with lower GWG; these relationships did not hold for overweight/obese women. As such, it can be proposed that body image concerns are more salient in late pregnancy due to a greater change in body shape and weight, and that women with an underweight or normal preconception BMI are more susceptible to these three body image concerns in late pregnancy. However, strength and fitness was associated with higher GWG for women who began pregnancy overweight/obese; there was 10

no association between strength and fitness and GWG for women who entered pregnancy underweight/normal weight. We can speculate that being heavier (i.e., gaining more gestational weight) leads to overweight/obese women feeling strong and fit because weight gain is associated with growing a healthy baby – particular with societal norms such as eating for two and the negative connotations linked with poor GWG (Kraschnewski & Chuang, 2014; Chuang et al., 2014). In underweight/normal weight women, this relationship may be overshadowed by the salience of their body image concerns and dramatic changes in body size, shape, and functionality during pregnancy (Watson et al., 2015; Earle, 2003). The findings of this paper shed some light on the complex and oft-reported contradictory nature of the impact of body image concerns on GWG (Kapadia et al., 2015; Hill et al., 2013), highlighting that pre-pregnancy BMI moderates the relationship between body attitudes and GWG under certain conditions. However, it is possible that other factors are implicated in this relationship, particularly in early-mid pregnancy where the moderating role of pre-pregnancy BMI was less consistent. For instance, Hill et al. (2016) reported that depression, body image, self-efficacy and motivation were associated with excessive GWG. Specifically, higher dissatisfaction with buttock size was associated with low levels of readiness to consume a healthy diet, and the relationship between body image (specifically buttocks dissatisfaction) and GWG was mediated by motivation (Hill et al., 2016). Similarly, higher levels of depression and lower perceived social support are consistently associated with excessive GWG (Hartley et al., 2015). Future research should consider psychosocial, motivation and behaviour change factors when exploring body image concerns in pregnancy in association with GWG. Limitations The authors acknowledge several limitations within the present study. Firstly, the accuracy and objectivity of weight and height measurements have the potential to affect the pre-pregnancy BMI and total GWG calculations used within the present study. All women self-reported their pre-pregnancy weight and 61.4% of women self-reported their height. However, pregnant woman are reasonably accurate in reporting their pre-pregnancy weight (Herring et al., 2008). Furthermore, given the practical difficulties associated with recruiting women prior to pregnancy and following them until they become pregnant, the use of selfreported weight to compute pre-pregnancy BMI is considered acceptable practice in GWG research (IOM, 2009). Secondly, the current study included a homogenous sample that consisted of highly educated Australian women from a high socio-economic background. The relationship 11

between pre-pregnancy BMI and GWG may differ based on ethnicity (Bahadoer et al. 2015). Maternal education is also reported to affect GWG, an interaction which is dependent on ethnicity and socio-economic status (Huynh et al., 2014). We attempted to account for these factors by controlling for annual family income and maternal education in analyses. Thirdly, underweight and normal weight women were grouped together for the categorical moderation analyses, which assumes that the relationship between body attitudes and GWG is similar for underweight and normal weight women. The analyses were repeated excluding the nine underweight women with no meaningful difference in findings. Hence, the full sample was retained for analyses. Finally, whilst prospective relationships (between body attitudes in early-mid and late pregnancy and total GWG) were explored, it should be noted that causality cannot be inferred. As such, it is possible that weight gained throughout the course of pregnancy and therefore contributing to total GWG may impact on body attitudes during gestation. The possibility that weight gain is the perpetuating factor in antenatal body image concerns cannot be overlooked. Implications and Conclusions In conclusion, the results of our study suggest that for women with an underweight or normal weight preconception BMI (who are therefore not typically at risk for high GWG), attention to body image concerns should be a priority. Identifying and understanding modifiable risk factors such as pre-pregnancy BMI, body attitudes and their inter-relationship is needed to gain a comprehensive understanding of these multifaceted relationships. Such knowledge may aid in the development and implementation of suitable screening tools to help healthcare professionals accurately identify women who are at risk of excessive GWG, which may facilitate healthy GWG and promote positive maternal and infant health outcomes. In particular, identifying and addressing body image concerns earlier in pregnancy, where the associations between body image and GWG are less significant, but where impact on future body image concerns can be made, may be a useful opportunity with a potential impact on overall GWG. Furthermore, careful monitoring of GWG throughout pregnancy may facilitate women to maintain a positive body image. Ethical Statement

Conflict of Interest

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The authors have no conflicts of interest to disclose. Ethical Approval Ethical approval was granted by the Human Research Ethics Committees of Deakin University (36-2009) and Melbourne Health (2011.133). Funding Sources This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Clinical Trial Registry and Registration Number Not applicable. Acknowledgements Dr Briony Hill is funded by an Alfred Deakin Postdoctoral Research Fellowship.

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Figure Captions Figure 1. Conceptual illustration of the moderating role of pre-pregnancy BMI in the relationship between body attitudes and GWG. Adapted from Model Templates for Process for SPSS and SAS © 2013-2015. Andrew F. Hayes and The Guilford Press. (Model 1).

Figure 2. Graphical representation of the relationship between Feeling Fat at T1 and GWG, when pre-pregnancy BMI is categorised as underweight/normal (BMI < 25) and overweight/obese (BMI ≥ 25; adjusted for age, family income, education and parity). Figure 3. Graphical representation of the relationship between Salience at T2 and GWG, when pre-pregnancy BMI is categorised as underweight/normal (BMI < 25) and overweight/obese (BMI ≥ 25; adjusted for age, family income, education and parity).

Figure 4. Graphical representation of the relationship between Attractiveness at T2 and GWG, when pre-pregnancy BMI is categorised as underweight/normal (BMI < 25) and overweight/obese (BMI ≥ 25; adjusted for age, family income, education and parity).

17

Figure 5. Graphical representation of the relationship between Feeling Fat at T2 and GWG, when pre-pregnancy BMI is categorised as underweight/normal (BMI < 25) and overweight/obese (BMI ≥ 25; adjusted for age, family income, education and parity).

Figure 6. Graphical representation of the relationship between Strength and Fitness at T2 and GWG, when pre-pregnancy BMI is categorised as underweight/normal (BMI < 25) and overweight/obese (BMI ≥ 25; adjusted for age, family income, education and parity). Table 1. Participant Characteristics Demographic Value Weeks gestation at T1, M (SD)

16.81 (1.18)

Weeks gestation at T2, M (SD)

32.65 (0.91)

Weeks gestation at T3, M (SD)

37.15 (1.55)

Age, years, M (SD)

30.85 (4.58)

Education Level, n (%) Year 12 or below

32 (11.4)

Certificate or Diploma

78 (22.9)

Undergraduate or

170 (65.7)

Postgraduate Degree Income, n (%) Under AUD$45,000

19 (6.8)

AUD$45,001-$85,000

66 (23.6)

AUD$85,001, $125,000

88 (31.4)

Above AUD$125,000

107 (38.2)

Parity, n (%) Primiparous

134 (47.9)

Multiparous

146 (52.1)

Birth Location, n (%)

18

Australia

229 (81.8)

New Zealand

10 (3.6)

United Kingdom/Europe

20 (7.1)

United States

6 (2.1)

Asia

13 (4.6)

Middle East

1 (0.4)

Africa

1 (0.4)

Pre-pregnancy BMI, kg/m2, M (SD)

25.36 (5.61)

Pre-pregnancy BMI Category, n (%) Underweight (< 18.5)

9 (3.2)

Normal weight (18.5-24.9)

159 (56.8)

Overweight (25.0 – 29.0)

66 (23.6)

Obese (

46 (16.4)

30)

13.37 (5.41)

GWG, kg, M (SD) GWG category,a n (%) Inadequate

60 (21.4)

Adequate

101 (36.1)

Excessive

119 (42.5)

Abbreviations: BMI, body mass index; GWG, gestational weight gain; M, mean; SD, standard deviation; T1, time 1; T2, time 2; T3, time 3. a categorised according to the 2009 IOM recommendations.2

Table 2. Means, SD and Ranges of Pre-pregnancy BMI, GWG and the 4 BAQ subscales at T1 and T2 with Bivariate Correlations Measu

1

2

3

4

5

6

7

8

9

1

M

SD

Ran

19

res 1. BMI

0 1

(kg/m2

ge 25.

5.6

16 –

36

1

43

13.

5.4

-4 -

37

1

26

16.

3.1

8-

56

0

23

31.

10.

12 -

76

57

56

18.

4.3

8–

36

2

29

11.

3.8

5–

41

2

24

16.

3.0

7-

49

9

25

29.

10.

12 -

59

29

55

) 2. GWG (kg) 3. ATT (T1)

-

1

.398 ** -

.04

.213

5

1

** 4. FAT (T1)

5. STR (T1)

.368

-

-

**

.08

.454

8

**

-

.06

.302

-

.227

5

**

.292

** 6. SAL (T1)

1

**

.226

.02

-

.757

-

**

9

.309

**

.239

** 7. ATT (T2)

8. FAT (T2)

1

1

**

-

-

.662

-

.289

-

.157

.01

**

.448

**

.349

**

2

.191

.07

-

.635

-

.528

-

**

4

.378

**

.276

**

.594

**

**

1

** 1

**

20

9. STR (T2)

-

.06

.347

-

.648

-

.175

0

**

.328

**

.210

.360

**

**

** 10.

.056

SAL

**

.417

-

1

.05

-

.536

-

.545

-

.781

-

9

.269

**

.272

**

.479

**

.272

(T2)

**

**

**

1

17.

4.0

8-

80

1

28

11.

3.4

5-

09

1

22

**

Abbreviations: ATT, BAQ attractiveness; BAQ, Ben-Tovim Walker Body Attitudes Questionnaire; BMI, body mass index; FAT, BAQ feeling fat; GWG, gestational weight gain; M, mean; SAL, BAQ salience of weight and shape; SD, standard deviation; STR, BAQ strength and fitness; T1, time 1; T2, time 2. *Correlation is significant at .05. **Correlation is significant at .01.

Table 3. Moderated Pathways for Body Attitudes at T1 with Pre-Pregnancy BMI categorised as underweight/normal vs. overweight/obese (unadjusted) 95% CI Model

b

SE

t

P

Lower Upper

.25

.09

2.67

.008

.07

.43

BMI  GWG

-2.85

.67

-4.26

< .001

-4.17

-1.54

Salience × BMI 

-.28

.18

-1.56

.119

-.63

.07

.25

.09

2.67

.008

.07

.43

-.03

.15

-

.840

-.33

.27

Salience Pathway Salience  GWG

GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25)

.20

21

Attractiveness Pathway Attractiveness 

-.19

.12

-1.57

.118

-.42

.05

BMI  GWG

-2.66

.69

-3.87

< .001

-4.01

-1.30

.47

.24

1.98

.048

.00

.94

-.19

.12

-1.57

.118

-.42

.05

.28

.21

1.38

.169

-.12

.69

Feeling Fat

.07

.03

2.18

.030

.01

.14

BMI  GWG

-2.46

.65

-3.78

< .001

-3.74

-1.18

Feeling Fat × BMI

-.20

.07

-2.94

.004

-.33

-.06

.07

.03

2.18

.030

.01

.14

-.12

.06

-2.14

.033

-.24

-.01

GWG

Attractiveness × BMI  GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Feeling Fat Pathway

GWG

 GWG Conditional Effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25 Strength & Fitness

22

Pathway Strength & Fitness

-.12

.08

-1.56

.120

-.28

.03

-2.59

.67

-3.87

< .001

-3.90

-1.27

.36

.16

2.25

.025

.05

.68

-.12

.08

-1.56

.120

-.28

.03

.24

.14

1.71

.089

-.04

.52

 GWG BMI  GWG Strength & Fitness × BMI  GWG Conditional Effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Abbreviations: b, unstandardized regression coefficient; BMI, body mass index; CI, confidence interval; GWG, gestational weight gain; SE, standard error; T1, time 1.

Table 4. Moderated Pathways for Body Attitudes at T1 with Pre-Pregnancy BMI categorised as underweight/normal vs. overweight/obese (adjusted) 95% CI Model

b

SE

t

P

Lower Upper

.27

.10

2.73

.007

.07

.46

BMI  GWG

-2.28

.68

-3.34

< .001

-3.63

-.94

Salience × BMI 

-.32

.18

-1.73

.084

-.68

.04

Salience Pathway Salience  GWG

GWG Conditional effects

23

Underweight/Norm

.27

.10

2.73

.007

.07

.46

-.05

.15

-

.739

-.35

.25

al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25)

.33

Covariates Age

-.20

.08

-2.42

.016

-.37

-.04

Income

.28

.19

1.45

.149

-.10

.66

Education

-.06

.21

-.30

.765

-.49

.36

Parity

.82

.66

1.23

.219

-.49

2.12

Attractiveness 

-.19

.12

-1.58

.115

-.43

.05

BMI  GWG

-2.18

.72

-3.04

.003

-3.59

-.77

.47

.24

1.97

.050

.01

.93

-.19

.12

-1.58

.115

-.43

.05

.28

.20

1.35

.177

-.13

.68

Age

-.19

.08

-2.33

.021

-.36

-.03

Income

.21

.20

1.05

.295

-.18

.60

Education

-.08

.22

-.35

.725

-.50

.35

Attractiveness Pathway

GWG

Attractiveness × BMI  GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

24

Parity

.74

.69

1.08

.281

-.61

2.09

Feeling Fat

.07

.03

2.21

.028

.01

.14

BMI  GWG

-1.96

.68

-2.89

.004

-3.30

-.63

Feeling Fat × BMI

-.20

.07

-3.09

.002

-.33

-.07

.07

.03

2.21

.029

.01

.14

-.13

.06

-2.28

.023

-.24

-.02

Age

-.20

.08

-2.38

.018

-.36

-.03

Income

.22

.19

1.15

.250

-.16

.60

Education

-.15

.21

-.69

.493

-.57

.28

Parity

.84

.67

1.25

.212

-.48

2.15

Strength & Fitness

-.11

.08

-1.40

.163

-.27

.05

BMI  GWG

-2.09

.71

-2.96

.003

-3.48

-.70

.36

.16

2.19

.030

.04

.68

Feeling Fat Pathway

GWG

 GWG Conditional Effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

Strength & Fitness Pathway

 GWG

Strength & Fitness × BMI  GWG

25

Conditional Effects Underweight/Norm

-.11

.08

-1.40

.163

-.27

.05

.24

.14

1.71

.089

-.04

.53

Age

-.19

.08

-2.24

.026

-.35

-.02

Income

.23

.20

1.16

.249

-.16

.63

Education

-.11

.22

-.51

.612

-.55

.32

Parity

.83

.68

1.22

.224

-.51

2.16

al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

Abbreviations: b, unstandardized regression coefficient; BMI, body mass index; CI, confidence interval; GWG, gestational weight gain; SE, standard error; T1, time 1.

Table 5. Moderated Pathways for Body Attitudes at T2 with Pre-Pregnancy BMI categorised as underweight/normal vs. overweight/obese (unadjusted) 95% CI Model

b

SE

t

P

Lower Upper

.32

.10

3.09

.002

.12

.52

BMI  GWG

-2.73

.69

-3.96

< .001

-4.09

-1.37

Salience × BMI 

-.55

.24

-2.28

.024

-1.03

-.07

Salience Pathway Salience  GWG

GWG Conditional effects

26

Underweight/Nor

.32

.10

3.09

.002

.12

.52

-.23

.22

-

.287

-.67

.20

mal (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25)

1.07

Attractiveness Pathway Attractiveness 

-.32

.11

-3.02

.003

-.52

.11

BMI  GWG

-2.70

.68

-3.99

< .001

-4.04

-1.37

.65

.22

2.98

.003

.22

1.08

-.32

.11

-3.02

.003

-.52

-.11

.34

.19

1.75

.082

-.04

.71

Feeling Fat

.14

.03

4.32

< .001

.08

.20

BMI  GWG

-2.76

.67

-4.09

< .001

-4.09

-1.43

Feeling Fat × BMI

-.21

.07

-2.91

.004

-.36

.07

.14

.03

4.32

< .001

.08

.20

GWG

Attractiveness × BMI  GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Feeling Fat Pathway

GWG

 GWG Conditional Effects Underweight/Norm

27

al (BMI ≤ 24.9) Overweight/Obese

-.07

.07

-1.12

.265

-.20

.06

-.15

.08

-1.94

.054

-.30

.00

-2.59

.66

-3.93

< .001

-3.89

-1.29

.49

.19

2.65

.009

.13

.86

-.15

.08

-1.94

.054

-.30

.00

.34

.17

2.03

.044

.01

.68

(BMI ≥ 25 Strength & Fitness Pathway Strength & Fitness  GWG BMI  GWG Strength & Fitness × BMI  GWG Conditional Effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Abbreviations: b, unstandardized regression coefficient; BMI, body mass index; CI, confidence interval; GWG, gestational weight gain; SE, standard error; T2, time 2. Table 6. Moderated Pathways for Body Attitudes at T2 with Pre-Pregnancy BMI categorised as underweight/normal vs. overweight/obese (adjusted) 95% CI Model

b

SE

t

P

Lower Upper

.31

.10

3.12

.002

.12

.51

-2.24

.71

-3.16

.002

-3.63

-.84

Salience Pathway Salience  GWG BMI  GWG

28

Salience × BMI 

-.54

.23

-2.35

.020

-1.00

-.09

.31

.10

3.12

.002

.12

.51

-.23

.21

-

.274

-.64

.18

GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25)

1.10

Covariates Age

-.19

.08

-2.32

.021

-.35

-.03

Income

.24

.19

1.24

.215

-.14

.61

Education

-.08

.22

-.39

.696

-.51

.34

Parity

.78

.66

1.19

.236

-.51

2.08

Attractiveness 

-.28

.10

-2.63

.009

-.48

-.07

BMI  GWG

-2.25

.71

-3.18

.002

-3.63

-.86

.63

.22

2.90

.004

.20

1.06

-.28

.10

-2.63

.009

-.48

-.07

.36

.19

1.85

.065

-.02

.74

Attractiveness Pathway

GWG

Attractiveness × BMI  GWG Conditional effects Underweight/Norm al (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

29

Age

-.17

.08

-2.08

.038

-.34

-.01

Income

.22

.20

1.13

.260

-.17

.61

Education

-.12

.22

-.58

.562

-.55

.30

Parity

.92

.67

1.38

.168

-.39

2.24

Feeling Fat

.13

.03

4.13

< .001

.07

.19

BMI  GWG

-2.33

.70

-3.34

.001

-3.70

.96

Feeling Fat × BMI

-.21

.07

-2.91

.004

-.35

-.07

.13

.03

4.13

< .001

.07

.19

-.08

.07

-1.22

.224

-.21

.05

Age

-.17

.08

-2.13

.034

-.33

-.01

Income

.19

.19

1.01

.316

-.18

.56

Education

-.10

.22

-.47

.639

-.53

.33

Parity

.80

.65

1.22

.225

-.49

2.09

-.15

.08

-1.98

.050

-.30

.00

Feeling Fat Pathway

GWG

 GWG Conditional Effects Underweight/Nor mal (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

Strength & Fitness Pathway Strength & Fitness  GWG

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BMI  GWG

-2.16

.70

-3.08

.002

-3.54

-.78

.50

.19

2.67

.008

.131

.86

-.15

.08

-1.98

.050

-.30

.00

.35

.17

2.04

.043

.01

.68

Age

-.18

.08

-2.23

.027

-.34

-.02

Income

.20

.20

1.00

.317

-.19

.59

Education

-.13

.22

-.59

.554

-.57

.30

Parity

1.00

.67

1.49

.137

-.32

2.32

Strength & Fitness × BMI  GWG Conditional Effects Underweight/Nor mal (BMI ≤ 24.9) Overweight/Obese (BMI ≥ 25) Covariates

Abbreviations: b, unstandardized regression coefficient; BMI, body mass index; CI, confidence interval; GWG, gestational weight gain; SE, standard error; T2, time 2.

Highlights 

Antenatal body attitudes are associated with gestational weight gain (GWG).



Body attitudes may differ based on pre-pregnancy BMI and gestational age.



Unhealthy GWG may be prevented through early assessment of antenatal body attitudes

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