Findings support fish intake, supplements to prevent early preterm birth

by Molly Walker, Staff Writer, MedPage Today
August 04, 2018

Danish women with low plasma concentrations of the long-chain fatty acids eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA) during pregnancy had a higher risk of subsequent preterm birth, researchers found.

Pregnant women in the lowest quintile of EPA+DHA concentrations had a significantly increased risk of early preterm birth (adjusted OR 10.27, 95% CI 6.80-15.79, P<0.00001) compared with women in the three aggregated highest quintiles, reported Sjurdur F. Olsen, MD, of Staten Serum Institut in Copenhagen, Denmark, and colleagues.

Moreover, women in the second lowest quintile also had a higher risk of early preterm birth compared with those in the three highest quintiles (adjusted OR 2.86, 95% CI 1.79-4.59, P<0.00001), the authors wrote in EBioMedicine.

They cited a 1986 study in the Lancet that found that “a high intake of the long chain n-3 fatty acids can delay timing of spontaneous delivery,” but other studies found inconsistent findings — the result is that the clinical relevancy of this “modest effect size” has been questioned, Olsen and co-authors explained.

“It seems no one has been able to examine the association between n-3 fatty acids quantified in blood samples obtained in early and mid-pregnancy and the woman’s subsequent risk of early preterm birth,” the authors wrote. “This is the first study to examine if a low plasma concentration of long-chain n-3 fatty acids in early and mid-pregnancy is associated with increased risk of subsequent early preterm birth.”

Co-author Andrew Thorne-Lyman, ScD, of Johns Hopkins Bloomberg School of Public Health in Baltimore, added in a statement that the findings “support the importance of ensuring adequate intake of these nutrients during pregnancy, either through fish intake or supplements, to help prevent early preterm birth.”

The team performed a case-control study within the Danish National Birth Cohort, comparing 376 early preterm cases (defined as <34 gestational weeks, excluding preeclampsia cases) and 348 random controls. Participants were recruited in the first trimester at the first prenatal visit for a blood sample, and then a second sample was taken during a routine second trimester visit, and a mean of the first and second sample measurements was taken.

Over half of mothers in the study were ages 21 to 30, and two-thirds of the mothers of cases were nulliparous, compared with less than half of the controls. Early preterm risk “varied with age, parity, pre-pregnancy body-mass index, and daily smoking, and these factors also tended to be associated with EPA+DHA concentrations in both the first and second samples,” the researchers wrote.

They added that when the study population was limited to the concordant quintiles, being in the lowest quintile on both occasions was linked with a significantly higher increased risk of early preterm birth (adjusted OR 48.3, 95% CI 20.2-129.0), albeit with an extremely wide confidence interval.

The authors also noted that “spline curves showed a threshold effect at EPA+DHA concentrations somewhere between 2.0% and 2.5%, with a sharp increase in risk at low levels, which then flattens rapidly out at higher levels.”

“It will be important to replicate these findings in other populations, but the results of this study certainly suggest that assessment of plasma EPA+DHA status in women has the potential to be used in the future to help predict women’s risk,” said another of the co-authors, Jeremy Furtado, ScD, of the Harvard T.H. Chan School of Public Health in Boston, in a statement.