You may have heard that fish oil is beneficial to take during pregnancy. In fact, it is advised that all pregnant women have a minimum of 5 ounces of cooked, low mercury fish per week . Fish is rich in omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These play many roles in the body, and in pregnancy, they are essential for making new cells, for developing the baby’s brain and visual system, and can have an impact on the overall health of the pregnancy .
DHA is a necessary structural component in the central nervous system . Although the structural and neural foundation for the baby’s brain begins in the early days of pregnancy, the development of the brain tissue is accelerated in the third trimester. To accommodate this fast growth, the fetal brain requires high amounts of DHA, accumulating between 50 to 70 mg of DHA per day in the third trimester . This fast brain development process continues until the second year of life, and the DHA absorbed and used in the brain will remain throughout all the years of life .
While the brain requires high concentrations of DHA, it is also needed to develop the retina of the eye. The amount of DHA present in this stage of pregnancy has been found to have an impact on the child’s visual acuity later in life . Finally, the growth spurt of the third trimester sees an increase in fat tissues and overall weight . Although the fat tissues contain some smaller amounts of DHA compared to the brain and eyes, it is another example of the baby’s need for DHA at this time .
Despite the evident need for DHA, the baby can only accumulate as much DHA as is available. Since babies receive all of their nutrients through their mother, they will absorb only what is provided from the mother’s nutrient intake and stored nutrients . This is why DHA intake is extremely important in the third trimester, and might be a good time to include fish oil in your nutrition plan. But wait, there’s more.
Also of interest is the impact fish oils can have on the pregnancy itself, and the health of the child born. A full term birth can occur between 38 and 42 weeks while premature babies are born before 37 weeks, and may be susceptible to greater health risks . A recent review summarized the findings of over 70 clinical trials studying the impact of omega-3 fatty acids during pregnancy on the risk of premature births . It concluded that a daily intake of EPA and DHA reduced the risk of premature births (less than 37 weeks), early premature births (less than 34 weeks), and of having small babies (low birth weight) . These trials included a variety of dosages, and start times, although the authors concluded that 12 weeks of pregnancy was an optimal start time .
Other areas exploring infant health outcomes include the potential role of prenatal fish oil in reducing the risk of the child having eczema, allergies , and asthma . The fish oil was started at weeks 25 and 30, respectively [5,6]. While there have been some positive results, the overall conclusion is that more studies are needed to confirm these findings . Given the research, there seems to be a rationale to begin fish oil in the second trimester, and even at the end of the first trimester . But what about the earlier weeks of pregnancy?
What kind of results would be seen if the pregnant women studied had started taking fish oil earlier in the pregnancy? The truth is, we don’t really know. Most of these studies begin giving fish oil in the second and third trimester, with few starting at the middle or end of the first trimester [2-7]. However, there are several aspects of the first trimester that could benefit from fish oil intake. Omega 3 fatty acids are needed to support the creation of new cell membranes, the development of the placenta , and the establishment of the baby’s organ systems .
On top of that, many women experience nausea and vomiting in the first trimester. Commonly called morning sickness, these symptoms can occur at any time of the day, and can sometimes last all throughout pregnancy. Among the common foods that can trigger symptoms are coffee, meat, fish, eggs, spicy foods, and fatty foods . With this in mind, getting that recommended minimum of 5 ounces of cooked fish per week can be difficult. Women experiencing nausea and vomiting in pregnancy were found to have a decrease in protein, vegetable, and select vitamin and mineral intake . It is suggested that the symptoms of morning sickness can cause a lack of nutritional intake, which may cause health impacts on the pregnancy and developing fetus, including shorter gestation periods .
So the bottom line is, there might be many uses for fish oil in all stages of pregnancy. But there is still more to be learned about how the timing can influence the effects on pregnancy and the babies that follow. Any recommendation will depend on your unique needs, so talk to your doctor or naturopathic doctor about when you should start.