Delay of preterm delivery in sheep by omega-3 long-chain polyunsaturates

A positive correlation has been shown between dietary intake of long-chain omega-3 fatty acids in late pregnancy and gestation length in pregnant wome n and experimental animals. To determine whether omega-3 fatty acids have a n effect on preterm labor in sheep, a fish oil concentrate emulsion was con tinuously infused to six pregnant ewes from 124 days gestational age. At 12 5 days, betamethasone was administered to the fetus to produce preterm labo r. Both the onset of labor and the time of delivery were delayed by the fis h oil emulsion. Two of the omega-3-infused ewes reverted from contractions to nonlabor, an effect never previously observed for experimental glucocort icoid-induced preterm labor in sheep. Maternal plasma estradiol and materna l and fetal prostaglandin E-2 rose in control ewes but not in those infused with omega-3 fatty acid. The ability of omega-3 fatty acids to delay prema ture delivery in sheep indicates their possible use as tocolytics in humans . Premature labor is the major cause of neonatal death and long-term disabi lity, and these studies present information that may lead to a novel therap eutic regimen for the prevention of preterm delivery in human pregnancy.