New research funded in part by March of Dimes has found that pregnant women in their first and second trimester with the lowest blood levels of long-chain n-3 fatty acids - the kind found in fish oil -- were at 10 times greater risk of early preterm birth compared with women who had higher levels. The findings suggest that eating fish that are good sources of the fatty acids EPA and DHA may help reduce the risk of preterm birth.
The study will be published online today in EBioMedicine by a team led by Sjurdur F. Olsen, M.D., from Centre for Fetal Programming at Statens Serum Institut in Copenhagen, Denmark. He is a former March of Dimes grantee and undertook the study with colleagues at the Harvard T.H. Chan School of Public Health and Johns Hopkins Bloomberg School of Public Health.
“March of Dimes is committed to finding solutions to preterm birth and to giving all babies the best possible start in life,” says Kelle H. Moley, M.D., senior vice president and chief scientific officer at March of Dimes. “It will be important to replicate these findings in other populations outside of Denmark, but we are very impressed by the power of these results and the weight of evidence. March of Dimes recommends that women who are pregnant or thinking of having a baby eat fish that are low in mercury and good sources of EPA and DHA, like herring, salmon, trout, and anchovies, as well as orange juice, milk and eggs that have EPA and DHA added to them. Pregnant women should get 200 mg (micrograms) of DHA each day from food or supplements.”
Premature birth affects 15 million babies each year worldwide and is on the rise in the United States. Recently released provisional data for 2017 from the National Center for Health Statistics show that the preterm birth rate in the U.S. has reached 9.93 percent, up from 9.85 in 2016, the third consecutive annual increase after steady declines over the previous seven years.
Dr. Olsen has been studying for many years the hypothesis that low levels of the long-chain fatty acids eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA) may be a major risk factor for preterm birth. For this new study, the team examined data from the Danish National Birth Cohort, a nationwide study following 96,000 children in Denmark through questionnaires and registry linkages. They analyzed blood samples from 376 women who gave birth very prematurely (prior to 34 weeks of gestation) between 1996 and 2003 and 348 women who did not, all during their first and second trimesters of pregnancy.
Analysis of the blood samples showed that women who with the lowest serum levels of EPA and DHA - 1.6 percent or less - had a 10 times higher risk of early preterm birth when compared with women in the highest levels.
“Plasma Concentrations of Long Chain N-3 Fatty Acids in Early and Mid-Pregnancy and Risk of Early Preterm Birth,” Olsen S.F., Halldorsson T.I., Thorne-Lyman A.L., Strøm M., Gørtz S., Granstrøm C., Nielsen P.H., Wohlfahrt J., Lykke J.A., Langhoff-Roos J., Cohen A.S., Furtado J.D., Giovannucci E.L., Zhou W., appeared online July 31, 2018, EBioMedicine, doi: 10.1016/j.ebiom.2018.07.009