Understanding motivations for dietary supplementation during pregnancy: A focus group study

Highlights

• Perceived maternal and fetal health benefits motivate supplement use during pregnancy.

• Supplements provide insurance against inadequate nutrient intake from food alone.

• Women consider supplements an easier and more reliable source of nutrients than food.

• Cost is not a barrier to supplement use in pregnancy, but is a barrier post-birth.

Abstract

Objective

to increase understanding of psychosocial factors (behavioural, normative and control beliefs) motivating vitamin and mineral supplement use during pregnancy.

Design

ten focus group discussions and two in-depth interviews were conducted using a script comprising questions based on study objectives. All discussions were recorded, transcribed verbatim and analysed using a framework approach.

Setting

South Australia, Australia.

Subjects

40 women aged 21–45 years who were either pregnant or<12 months postpartum. Groups were stratified by education level (secondary education only vs. post-secondary) and gravidity (first vs. subsequent pregnancy).

Results

all women, except one, used dietary supplements during pregnancy. Most women took supplements to achieve peace of mind knowing that nutrient requirements were ‘definitely’ being met. Other common factors motivating supplement use were the beliefs that supplementation: benefits maternal and fetal health; corrects known nutritional deficiencies; and is a more efficient method of obtaining required nutrients relative to food. Advice received from healthcare providers and marketing of supplements also motivated supplementation, while forgetting to take supplements was the most common barrier to use. Cost was only a barrier when considering whether or not to continue supplementation post-birth.

Key conclusions and implications for practice

women believe that supplements are an easier and more reliable source of nutrients than food intake alone, and rely on dietary supplementation as an insurance policy during pregnancy. Further studies are needed in larger and more representative samples to validate these findings and to test the effectiveness of information and intervention strategies targeting appropriate supplement use during pregnancy.

Introduction

Dietary supplementation of a range of nutrients is becoming common practice among pregnant women in developed countries. Studies published during the last decade report that 66% to 97% of women took a vitamin and/or mineral supplement during their current or most recent pregnancy (Arkkola et al., 2006, Conlin et al., 2006, Gahche et al., 2013, Nilsen et al., 2006, Pouchieu et al., 2013, Timmermans et al., 2008, Watson et al., 2006). Despite this high prevalence of supplementation during pregnancy, adherence to supplement recommendations remains low. This is concerning because leading health authorities only recommend supplementation of a few select nutrients, for example, folic acid and iodine (National Health and Medical Research Council, 2010, World Health Organisation, 2012). For most healthy women with normal (uncomplicated) pregnancies, a sufficient intake of other nutrients can be achieved by consuming a diet in line with Government-endorsed dietary recommendations for pregnancy (National Health and Medical Research Council, 2013).

Previous studies have found supplement use to be more probable among individuals at lowest nutritional risk. This includes women who are older, have higher household incomes, higher educational attainment, who planned their pregnancy, live with a partner, are primigravid or nulliparous, do not smoke, and have a healthier weight (Knudsen et al., 2007, Malek et al., 2016b, Nelson et al., 2014, Pouchieu et al., 2013, Timmermans et al., 2008, Watson et al., 2006). While previous research has examined sociodemographic factors that help to predict supplement users, only a few studies have explored the psychosocial factors underlying the use of supplements during pregnancy (Barbour et al., 2012, Bodecs et al., 2011, Fulford et al., 2014, Mazza and Chapman, 2010, Tessema et al., 2009). Yet, considering the low adherence rates published in the literature, it is evident that more effective intervention strategies are required (Maats and Crowther, 2002, Malek et al., 2015, Malek et al., 2016b, Watson et al., 2006). Therefore, understanding the underlying factors motivating women to use supplements during pregnancy (e.g. attitudes, perceived social pressure and perceived behavioural control), may allow more effective framing and communication of messages targeting appropriate supplement use during pregnancy.

To address this gap in the literature, we used focus group research methods to gain a comprehensive understanding of women's knowledge, attitudes and practices regarding nutrition during pregnancy. Importantly, we also used the Theory of Planned Behaviour (TPB) as a framework to assist us in developing a better understanding of beliefs that may motivate supplement use during pregnancy (Ajzen, 2002b). In particular, behavioural, normative and control beliefs were constructs borrowed from the TPB framework.

The TPB framework is commonly used in health and nutrition research to identify determinants of various health and diet-related behaviours (Conner et al., 2001, McEachan et al., 2011). The TPB positions ‘behavioural intention’ and ‘perceived behavioural control’ as the main determinants of performing or not performing a desired behaviour. Intention is said to be predicted by several factors, including: an individual's ‘attitude’ towards a targeted behaviour; ‘subjective norm’ (or perceived social pressure to perform the behaviour) and ‘perceived behavioural control’. These constructs, which directly influence ‘behavioural intention’, are influenced by underlying behavioural, normative and control beliefs. While behavioural beliefs refer to beliefs about the outcomes of the target behaviour; normative beliefs refer to beliefs about whether other people, who are important to the individual, perform the behaviour themselves or whether they want the individual to perform the behaviour. Control beliefs refer to factors, which may make performing the behaviour easy or difficult.

The aim of the present study was to gain a deeper understanding of the behavioural, normative and control beliefs motivating supplementation during pregnancy.