The role of n-3 fatty acids in gestation and parturition

Preterm birth is the most common cause of low infant birth weight and infan t morbidity and mortality. Evidence from human and animal studies indicates that essential fatty acids of both the n-3 and n-6 series, and their eicos anoid metabolites, play important and modifiable roles in gestational durat ion and parturition, and n-3 fatty acid intake during pregnancy may be inad equate. Prostaglandins (PG) of the 2-series are involved in parturition and connective tissue remodelling associated with cervical maturation and rupt ure of membranes. In the absence of infections, preterm birth is characteri zed by lower reproductive tissue PG production and decreased inducible cycl ooxygenase expression. Women who deliver prematurely have increased pools o f n-6 fatty acid and decreased n-3 fatty acids, despite the lower PG produc tion. Several human pregnancy supplementation trials with n-3 fatty acids h ave shown a significant reduction in the incidence of premature deliver and increased birth weight associated with increased gestational duration. Sup plementation with long chain n-3 fatty acids such as docosahexaenoic acid m ay be useful in prolonging the duration of gestation in some high-risk preg nancies. Evidence presented in this review is discussed in terms of the rol es of dietary n-3 and n-6 fatty acids in gestation and parturition, mechani sms by which they may influence gestational duration and the human trials s uggesting that increased dietary long-chain n-3 fatty acids decrease the in cidence of premature delivery.