Polyunsaturated fatty acids and risk of preterm delivery

Preterm delivery (PD) is characterized both by increased neonatal morbidity and mortality and by important late pathologic sequelae. From a clinical stand-point, PD may results from a medical condition where the continuation of pregnancy could bring about a marked risk for the foetus and/or for the mother, or from an adverse event where the pregnancy is going to end spontaneously before 37 weeks of gestation. In the past few years some epidemiological studies have shown that diet may interfere with complex multifactorial processes contributing to the preterm triggering of labour. The attention has been focused on polyunsaturated fatty acids (PUFA) such as alpha-linoleic acid, precursor of Omega-3 series, and linoleic acid, precursor Omega-6 series. Their importance in modulating Prostaglandin concentrations at different levels is already known. Moreover, it has been reported that in clinical situation, such as PD, the endogenous levels of PUFA are unbalanced, with a Omega-6 predominance. Experimental, observational and clinical studies suggest that dietary intake of Omega-3 fatty acids is capable of significantly prolonging the duration of gestation in the range of 4-7 days; such prolongation would possibly occur through the inhibition of prostaglandins E2 and F2 alpha. In Western population dietary intake of Omega-3 appears to be marginal, and recommended assumption could be reached only by a ten-fold increase in blue fish ingestion. The recommended intake of EPA + DHA should be 1.4 g/daily with a 1:2.5 EPA:DHA. It is therefore possible to conclude that in light of controlled clinical studies and of the actual categories of risk for preterm delivery, the dietary supplementation of Omega-3, in addition to other pharmacological measures (17α-hydroxyprogesterone caproate), could be implemented for the secondary and/or tertiary prophylaxis of preterm delivery.