Diet quality before or during pregnancy and the relationship with pregnancy and birth outcomes: the Australian Longitudinal Study on Women’s Health.

OBJECTIVE
To assess whether diet quality before or during pregnancy predicts adverse pregnancy and birth outcomes in a sample of Australian women.

DESIGN
The Dietary Questionnaire for Epidemiological Studies was used to calculate diet quality using the Australian Recommended Food Score (ARFS) methodology modified for pregnancy.

SETTING
A population-based cohort participating in the Australian Longitudinal Study on Women's Health (ALSWH).

SUBJECTS
A national sample of Australian women, aged 20-25 and 31-36 years, who were classified as preconception or pregnant when completing Survey 3 or Survey 5 of the ALSWH, respectively. The 1907 women with biologically plausible energy intake estimates were included in regression analyses of associations between preconception and pregnancy ARFS and subsequent pregnancy outcomes.

RESULTS
Preconception and pregnancy groups were combined as no significant differences were detected for total and component ARFS. Women with gestational hypertension, compared with those without, had lower scores for total ARFS, vegetable, fruit, grain and nuts/bean/soya components. Women with gestational diabetes had a higher score for the vegetable component only, and women who had a low-birth-weight infant had lower scores for total ARFS and the grain component, compared with those who did not report these outcomes. Women with the highest ARFS had the lowest odds of developing gestational hypertension (OR=0·4; 95 % CI 0·2, 0·7) or delivering a child of low birth weight (OR=0·4; 95 % CI 0·2, 0·9), which remained significant for gestational hypertension after adjustment for potential confounders.

CONCLUSIONS
A high-quality diet before and during pregnancy may reduce the risk of gestational hypertension for the mother.