Maternal plasma fatty acid composition and pregnancy outcome in adolescents

Adolescents are at a greater risk of adverse pregnancy outcome, including spontaneous preterm delivery and fetal growth restriction, and typically have a poorer-quality diet than adults have. In the present study, we addressed the hypothesis that low maternal dietary intake of n-3 long-chain PUFA (LCP) status adversely influences pregnancy outcome. A total of 500 adolescents (14-18 years) were recruited at ≤ 20 weeks' gestation. The frequency of consumption of oily fish was determined by questionnaire (at recruitment and during the third trimester). The fatty acid composition of plasma lipids during the third trimester was determined in 283 subjects. Principal components analysis (PCA) was used to derive components, which were divided into tertiles. The pregnancy outcomes were then compared by tertile, adjusting for potentially confounding variables. Of the participants, 69% reported never eating oily fish during pregnancy, although consumption was not associated with a shorter duration of gestation (P=0·33), lower customised birth weight (P=0·82) or higher incidence of small-for-gestational age (SGA) birth (P=0·55). PCA of the fatty acid composition of maternal plasma lipids identified a 'low PUFA:SFA (P:S) ratio' component and a 'high n-3 LCP' component. There were no differences between tertiles of the 'high n-3 LCP' component and gestational age at delivery (P=0·62), customised birth weight (P=0·38) or incidence of SGA birth (P=0·25), nor were there any associations between the 'low P:S' ratio component and pregnancy outcome. Lower proportions of n-3 LCP in plasma lipids are not associated with greater risk of adverse pregnancy outcomes in UK adolescents.