Major influences on nutrient intake in pregnant New Zealand women

To investigate factors associated with maternal diet during pregnancy and rank these in order of influence using data from a prospective cohort of 196 pregnant women, aged between 18 and 35 years of mostly European origin.

Anthropometric measurements were taken, questionnaires administered and 16 days of weighed diet intakes recorded, eight in the fourth and eight in the seventh month of pregnancy. Twenty four hours activity records were kept for 3 days at these times. Factors investigated were education, age, occupational status, welfare dependence, smoking, number of children, morning sickness, activity level, height, weight, body mass index, and sum of skinfolds.

Univariate analyses showed median weight of food and nutrient intakes were significantly lower in the less educated, the young, welfare dependants, smokers, and those who vomited during pregnancy. Almost all subjects had intakes of Vitamin D, folate, iron, and selenium below the estimated average requirement. Multivariate analyses of each nutrient against all predictors showed that in decreasing order of importance, education, maternal height, welfare dependence, smoking, and morning sickness had the greatest overall effect on the women's diets, mostly through their influence on energy intake. Age and number of children had less association with nutrient intake but along with education had a strong association with energy adjusted quality of diet. Weight and activity had weak associations with the quantity and quality of intake. After adjusting for energy intake, morning sickness ceased to be relevant.

To maximize effectiveness, education, welfare dependence, smoking, morning sickness, age, and parity are important factors to consider when attempting to change maternal diet during pregnancy.