Abstract
Excess gestational weight gain increases health risks for mother and child in the short and longer term. Meta-analyses of trials designed to optimise gestational weight gain show positive fetal and maternal effects. However, studies show considerable heterogeneity in their interventions and effects. Intuitive eating, eating founded on hunger and satiety cues rather than emotional stimuli, is associated with lower body mass index in observational studies outside pregnancy. Higher levels of emotional eating have been associated with increased gestational weight gain.
The aim of this PhD was to investigate if intuitive eating could be used as part of a non-dieting intervention for the optimisation of gestational weight gain, to improve the outcomes for mother and child. The Medical Research Council complex interventions framework was used as the basis of the research design leading to a mixed method exploratory sequential design.
Phase one, a qualitative study, using a semi-structured interview with a cognitive think-aloud component, of 12 purposively selected pregnant women, investigated two objectives: (1) to explore the way women experience eating in pregnancy, and (2) to examine the content validity of the Intuitive Eating Scale in pregnancy.
Objective one was addressed using a general inductive analysis of interview data. Four themes regarding eating during pregnancy were identified: How women feel, External influences, Changed eating by choice, and Motivation to change. Findings supported Phelan’s model of pregnancy as a teachable moment for eating behaviours.
Objective two was met by comparing women’s ‘think-aloud’ responses for each item of the Intuitive Eating Scale (‘during pregnancy’ versus ‘pre-pregnancy’) using a directed content analysis approach to elucidate reasons for any differences. One core theme, food safety, was identified that potentially affected the content validity of the existing Intuitive Eating Scale; women reported that food safety issues altered their ‘during pregnancy’ answers to some items on the unconditional eating subscale. To standardise the way women interpreted the context for answering the instructions for completing the Intuitive Eating Scale were amended, an additional statement was added “Your answers may include consideration of food safety (e.g. listeria)”. The amended instrument (IES-P) was used in Phase two.
Phase two, an observational cohort study of 260 pregnant women at four time points was performed in Dunedin, New Zealand with two objectives: (3) investigate the test-retest reliability of the IES-P in pregnancy, and (4) investigate the relationship between intuitive eating and gestational weight gain. Bland Altman test-retest reliability of the IES-P, over approximately five weeks, showed a mean difference of -0.08 (95% limits of agreement -0.60 to 0.44) and a Pearson correlation coefficient of 0.79. Regression modelling demonstrated no statistically significant effect of baseline (mean 14 weeks) IES-P scores on gestational weight gain –1.2 kg (95% CI -2.65kg to 0.13kg, p=.075).
There was no convincing evidence to recommend an intuitive eating component as part of a complex intervention study to optimise gestational weight gain. However, there may be a role for an intuitive eating intervention during pregnancy, for women who have high baseline levels of emotionally driven eating; this requires further research.