Abstract
Background: The amount and type of fat in the maternal diet during pregnancy are important contributors to fetal growth. The importance of plant-based omega-3 fatty acid (α-linolenic acid, ALA) intake in fetal growth has not been previously examined. Objective: We sought to determine the association of maternal ALA intake during pregnancy with birth weight and body composition of the offspring. Methods: Mothers and their newborn infants (n = 224) were recruited from the Royal Prince Alfred Hospital, Australia. Maternal diet during pregnancy was assessed using a validated food frequency questionnaire. Plasma fatty acid composition was analyzed in a subset of mothers (n = 41). Newborn body composition was assessed using air-displacement plethysmography. All analyses were adjusted for gestational age, sex, physical activity, and total energy intake. Results: Dietary fatty acid intakes were positively associated with plasma phospholipid fatty acids for total omega-3 fatty acids (β = 0.452, P = 0.003), ALA (β = 0.339, P = 0.03), linoleic acid (β = 0.353, P = 0.03), eicosapentaenoic acid (β = 0.407, P = 0.009), and docosahexaenoic acid (β = 0.388, P = 0.01). Higher maternal intake of ALA (% total fat) was associated with higher offspring birth weight [189.7-g increase per 1% higher ALA (95% CI: 14, 365 g); P = .04], although individually neither newborn fat mass nor fat-free mass was significant. Birth weight increased across tertiles of maternal ALA intake (P ANOVA = 0.05), with birth weight being 221 g (95% CI: 12, 429 g) higher in those with the highest maternal ALA intake compared with those with the lowest intake (P = 0.04). Mothers of infants born small for gestational age (n = 32) had a lower ALA intake than those born appropriate for gestational age (n = 162) or large for gestational age [(n = 21); P = 0.05]. Conclusions: In otherwise healthy women giving birth at a major tertiary hospital in Australia, intake of ALA during pregnancy is associated with higher offspring birth weight. This may have implications for dietary strategies aimed at optimizing fetal growth via modification of maternal diet.
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Key Points
Low birth weight is a major cause of adverse perinatal outcomes and is associated with increased morbidity and mortality in infancy and adulthood. In developing countries, higher circulating levels of ALA in early pregnancy are linked to better birth outcomes and inadequate maternal dietary ALA intake was associated with lower birth weights. This study determined the association of maternal fatty acid intakes during pregnancy with birth weight and assessed whether individual n–3 and n–6 PUFA in the maternal diet are associated with offspring birth weight and body composition. The study found that maternal ALA intake is associated with offspring birth weight, such that a 1% higher ALA intake (% total fat) was associated with an estimated 197-g increase in birth weight. In conclusion, the current findings indicate that increased intake of ALA during pregnancy is associated with higher offspring birth weight. This may have implications for prevention strategies aimed at improving fetal growth via modification of maternal diet.