BACKGROUND: Fetal growth requires n-3 docosahexaenoic acid (DHA), which is derived from the essential n-3 fatty acids in the maternal diet. DHA is accumulated in the developing brain and is critical for normal neural and visual function. Available estimates suggest that 67 mg DHA/d is accumulated by the fetus during the third trimester of gestation. Little is known about n-3 fatty acid intakes in pregnant women, although human milk concentrations of DHA have decreased in recent years.

OBJECTIVE: We prospectively determined the n-3 and n-6 fatty acid intakes of 55 pregnant Canadian women.

DESIGN: A food-frequency questionnaire was completed at 28 and 35 wk, and plasma n-3 and n-6 fatty acids were measured at 35 wk gestation. The fatty acid composition of approximately 500 foods was analyzed to allow analysis of dietary intakes from specific foods.

RESULTS: Intakes, as a percentage of energy, were (macro x +/- SEM) total fat, 28.0 +/- 3.6%; saturated fat, 9.8 +/- 0.3%; monounsaturated fat, 11.2 +/- 0.4%; polyunsaturated fat, 4.7 +/- 0.2%; linoleic acid, 3.9 +/- 0.2%; and alpha-linolenic acid, 0.54 +/- 0.05%. The daily intakes (range) were 160 +/- 20 (24-524) mg DHA/d, 121 +/- 8 (15-301) mg arachidonic acid/d, and 78 +/- 2 (4-125) mg eicosapentaenoic acid/d. The plasma phospholipids had (mg/100 g fatty acid) 5.0 +/- 0.18 DHA, 8.7 +/- 0.18 arachidonic acid, and 0.52 +/- 0.32 eicosapentaenoic acid.

CONCLUSION: The low intake of DHA among some pregnant women highlights the need for studies to address the functional significance of maternal fat intakes during pregnancy on fetal development.