Psychological predictors of dietary intentions in pregnancy

Consuming a healthy diet in pregnancy has the potential to improve obstetric outcome, including minimising the risk of macrosomia. Effective promotion of dietary change depends on identifying and targeting determinants of gestational diet. The present study aimed to model psychological predictors of intentions to reduce intake of high-fat and high-sugar foods, and increase fruit and vegetable consumption, among pregnant women.

One hundred and three pregnant women completed questionnaire measures of intentions to modify the consumption of the target foods, current intake, perceived vulnerability to and severity of adverse outcomes of unhealthful consumption of these foods (i.e. 'threat'), benefits of dietary change to mother and baby, barriers to dietary changes, and social approval for dietary change ('subjective norms'). A cross-sectional design was used. Logistic regression analyses were undertaken to model dietary change intentions.

Participants who reported excessive current intake of high-fat and high-sugar foods were more likely to intend to reduce the intake of these foods. Perceived benefits for mother and baby enhanced intentions to eat more fruit and vegetables and eat less high-fat, and marginally significantly increased high-sugar reduction intentions. There were no effects of threat, barriers or subjective norms.

Lack of effects for barriers, threat and subjective norms may indicate that pregnant women discount barriers to health-promoting behaviour, understand the threat posed by unhealthy eating and perceive social approval from others. Dietary change interventions for pregnant women should emphasise likely positive outcomes for both mother and child.