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Developmental biology - Premature Birth

Low level of omega-3 tied to preterm births

Low levels of omega-3 fatty acids in first and second trimesters meant significantly higher risk of early births...

Low plasma levels of omega-3 fatty acids associated with preterm birth https://www.eurekalert.org/pub_releases/2018-08/htcs-lpl073118.php Pregnant women who had low plasma levels of long chain n-3 fatty acids in their first and second trimesters are at significantly higher risk of preterm birth when compared with women with higher levels of these fatty acids. New research from Harvard T.H. Chan School of Public Health in collaboration with Statens Serum Institut in Copenhagen suggests low concentrations of certain long chain fatty acids - eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) - may be at strong risk for preterm birth.

"At a time when many pregnant women are hearing messages encouraging them to avoid intake of fish altogether due to mercury content, our results support the importance of ensuring adequate intake of long chain omega-3 fatty acids in pregnancy. Consumers should consult the guidance issued last year by the U.S. Food and Drug Administration and Environmental Protection Agency to make informed choices about the best types of fish to consume or avoid in pregnancy," according to lead author Sjurdur F. Olsen, adjunct professor of nutrition at Harvard Chan School and head of the Centre for Fetal Programming at Statens Serum Institut in Copenhagen, Denmark.

The study is published in EBioMedicine.

Preterm birth is a leading cause of neonatal death and is associated with intellectual deficiencies and cardiometabolic problems later in life among survivors. For decades, it has been hypothesized that high intake of EPA+DHA, which is found in cold-water fish such as Atlantic mackerel, anchovies, salmon, and tuna and also in leaner species such as cod and haddock, can reduce the risk of preterm birth. While some studies have supported this hypothesis, findings from research have been inconsistent.

For this new study, research data was gathered from the Danish National Birth Cohort, a nationwide study following 96,000 children in Denmark using questionnaires and registry links. Researchers analyzed blood samples from 376 women who gave birth very prematurely (prior to 34 weeks gestation) between 1996 and 2003 and 348 women who had full-term births in the same time period. All of the women gave blood samples during their first and second trimesters of pregnancy.

Analysis of these blood samples showed that women who were in the lowest quintile of EPA+DHA serum levels - with EPA+DHA levels of 1.6% or less of total plasma fatty acids - had a 10 times higher risk of early preterm birth when compared with women in the three highest quintiles with EPA+DHA levels at 1.8% or higher. Women in the second lowest quintile had a 2.7 times higher risk compared with women in the three highest quintiles.
The findings suggest pregnant women with low levels of EPA+DHA, should eat more fish or take a fish oil supplement as it could potentially lower their risk for preterm birth. The authors cautioned, however, that broad generalizations about the study's findings may be limited by the fact it was conducted in Demark, where preterm birth rates are low. The results should be replicated in other populations. They also caution their findings may not only reflect variation in diet as variation in underlying genetic factors can also play a role.

"An effect of this magnitude is rare, but tight precision of the estimate supports the reliability these findings. 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," explains co-author Jeremy Furtado, senior research scientist at Harvard Chan School.

"Early preterm birth has immense health, economic, and emotional costs. Our findings are consistent with the results of most randomized trials of long chain omega-3 fatty acid supplements in pregnancy. They support the importance of ensuring adequate intake of these nutrients during pregnancy, either through fish intake or supplements, to help prevent early preterm birth," says co-author Andrew Thorne-Lyman, Associate Research Scientist, Johns Hopkins Bloomberg School of Public Health, who worked on this study while a faculty member at Harvard Chan School.

Fish oil supplementation has been shown to delay spontaneous delivery, but the levels and clinical significance remain uncertain. We examined the association between plasma fatty acids quantified in pregnancy and subsequent risk of early preterm birth.

In a case-control design nested in the Danish National Birth Cohort, we identified 376 early preterm cases (<34 gestational weeks, excluding preeclampsia cases) and 348 random controls. Plasma eicosapentaenoic acid plus docosahexaenoic acid (EPA+DHA% of total fatty acids), were measured twice in pregnancy, at gestation weeks 9 and 25 (medians). Odds ratios and 95% confidence intervals (CI's) for associations between EPA+DHA and early preterm risk were estimated by logistic regression, adjusted for the woman's age, height, pre-pregnancy BMI, parity, smoking, and socioeconomic factors. Hypotheses and analytical plan were defined and archived a priori.

Analysis using restricted cubic splines of the mean of 1st and 2nd sample measurements showed a strong and significant non-linear association (p?=?1.8%).

Low plasma concentration of EPA and DHA during pregnancy is a strong risk factor for subsequent early preterm birth in Danish women.

Authors: S.F. Olsen, T.I. Halldorsson, A.L. Thorne-Lyman, M. Strøm, S. Gørtz, C. Granstrøm, P.H. Nielsen, J. Wohlfahrt, J.A. Lykke, J. Langhoff-Roos, A.S. Cohen, J.D. Furtado, E.L. Giovannucci, W. Zhou

This work was supported by grants from Veterans Administration 1I01BX001716 and NIH R01 CA204430 to K.K.S., and partial support from NIH grants 1R01AR071189-01A1 and R01AR073004 to A.S.

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Aug 6, 2018   Fetal Timeline   Maternal Timeline   News   News Archive

Omega-3 supplements made from the flesh of fish, are safe in pregnancy. Nothing else.
Supplements made from fish liver - cod liver oil - are not safe in pregnancy.

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