Most prenatal supplements lack the amount of omega-3 fatty acids that could help prevent preterm birth, meaning delivery before 37 weeks’ gestation. This is a key finding of a new study, published by my team, in the American Journal of Perinatology.
Omega-3 fatty acids are essential nutrients that are found largely in fatty fish. They help prevent inflammation and, by doing so, decrease the risk of preterm birth.
Our study, however, showed that roughly 1 in 6 prenatal supplements on the market in the U.S. that contain omega-3 fatty acids provide the amount that is needed by most pregnant women.
My colleagues and I used the U.S. Department of Agriculture’s Dietary Supplement Label Database to identify prenatal supplements that contained omega-3 fatty acids. We then compared the stated amount of omega-3s on the product labels with the recommended amounts in the new guidelines published in the American Journal of Obstetrics and Gynecology Maternal-Fetal Medicine by a team of experts representing international obstetric and child health organizations.
The guidelines recommend different doses of omega-3 fatty acids depending on whether a woman’s baseline intake prior to pregnancy was adequate or inadequate.
We found that 70% of the prenatal supplements that contained omega-3s provided the amount that is recommended for women with adequate intakes. However, previous research has shown that only 5% of pregnant women and women of childbearing age consume adequate amounts of omega-3 fatty acids. Thus, for women with insufficient intakes, a prenatal supplement with a higher amount of omega-3s would be helpful.
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Why it matters
Preterm birth is the leading cause of infant mortality worldwide. It is also the leading cause of infant illnesses that lead to costly stays in neonatal intensive care units. And then there is the heavy emotional toll that it has on parents and families.
Preterm birth also significantly increases a child’s risk for long-term health consequences such as intellectual disability, chronic diseases such as hypertension and diabetes and psychiatric illness in adulthood.
Yet there are few treatment options for preterm birth.
This is where omega-3 fatty acids come in. They lower risk of preterm birth by decreasing production of the signaling molecules that kick-start labor.
A Cochrane review of 26 randomized controlled trials demonstrated that 1,000 milligrams of supplemental omega-3 fatty acids per day can decrease risk of preterm birth by 11%, and risk of early preterm birth – delivery before 34 weeks’ gestation – by 42%.
Considering that prenatal supplements often don’t contain the required amount of omega-3s, one option is to simply take an additional omega-3 supplement alongside a prenatal vitamin to supply the difference and obtain the benefit.
Nevertheless, omega-3 supplements are not always necessary. The new guidelines recommend that all women of childbearing age should consume 250 milligrams of omega-3s per day. This amount can be obtained from roughly two 3-ounce servings per week of fatty fish such as salmon, mackerel, herring, sardines and anchovies.
When women increase their intake of omega-3 fatty acids prior to pregnancy, the recommended intake levels during pregnancy are lower. This is a way to eliminate the need for supplements in the first place.
However, women of childbearing age must also consider levels of mercury in fish because of its adverse effects on fetal neurodevelopment. While most species of salmon are low in mercury, certain fish that are rich in omega-3s can be moderately high in mercury. It’s important to consult local public health guidelines on mercury levels in fish to ensure safe consumption levels.
What still isn’t known
Omega-3 fatty acids are chemically unstable molecules that are inherently fragile, and thus prone to oxidation, a process whereby oxygen degrades the molecule, rendering it ineffective. Studies have shown wide variation in the oxidation levels in commercial omega-3 supplements. Worse yet, there are few predictors of omega-3 supplement quality.
Nevertheless, despite their high risk for oxidation, commercially available omega-3 supplements have exhibited demonstrable benefits in clinical trials.
What’s next
Taking into consideration the inconsistent levels of omega-3 fatty acids in prenatal supplements, their instability and the potential for dietary sources prior to pregnancy offsetting the need for supplements, more research is needed to understand how to motivate increased omega-3 intakes in women of childbearing age.
Recognizing that many women will still require omega-3s from supplemental sources, longitudinal studies tracking omega-3 levels in prenatal supplements will be crucial.
In addition, ongoing efforts are needed to foster the translation of this information into clinical settings to ensure that pregnant women, and the health care professionals who care for them, are able to make use of the great potential for omega-3 fatty acids in the prevention of preterm birth.
Mary Scourboutakos does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
