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Fish oil could help overweight women to better pregnancies and healthier children

Fish oil could help overweight women to better pregnancies and healthier childrenWomen who are overweight before becoming pregnant have an increased risk of abnormal fetal growth and low birth weight. However, it appears that fish oil supplementation can lower the risk of these complications, according to a new pilot study that is published in the science journal, Nutrients. The scientists behind the study explain how omega-3 fatty acids in fish oil support a healthy pregnancy and help control inflammation, insulin sensitivity, and lipid metabolism, all of which tend to be off balance in overweight pregnant women.

In our part of the world, the percentage of women who are overweight or obese before becoming pregnant is rising every year. Overweight women have a higher risk of a number of different pregnancy complications, and there is also a risk that the baby is born prematurely and with too much fat. Overweight is often associated with low-grade chronic inflammation that can lead to a variety of different health problems. Inflammation in connection with pregnancy may also be linked to disrupted lipid metabolism and intra-uterine insulin signaling that can result in excessive nutrient transport, causing fat accumulation in the fetus. Inflammation in the placenta can cause different imbalances and premature delivery. The earlier the baby is born, the greater the risk of complications and late sequelae. It is essential to ensure a healthy pregnancy, not just for the mother’s sake but also for the benefit of the baby.

Omega-3 fatty acids are essential

The unborn baby needs all the nutrients to develop properly, including the essential omega-3 fatty acids. The two omega-3 forms, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), are located in the cell membranes where they undertake a host of physiological functions. Oily fish and fish oil supplements contain EPA and DHA that the body can easily utilize.
Omega-3 fatty acids work in a biochemical interplay with omega-6 fatty acids. It is important to get the right type and in the proper amounts. Getting too little omega-3 sets the stage for different imbalances. This can easily affect an otherwise healthy pregnancy, especially because omega-3 is vital for normal brain development. Also, omega-3 fatty acids help regulate inflammation, insulin sensitivity, and lipid metabolism.
A recent Cochrane review shows that women who are overweight are more likely to lack omega-3 fatty acids and that supplementation with omega-3 is likely to lower their risk of giving birth too early or that their baby has low birth weight.
As mentioned before, it is important to maintain the right ratio between omega-3 and omega-6. Just for the record, modern diets often contain far too much omega-6 from sources such as plant oils, margarine, ready meals, junk-food, French fries, chips, and cookies. The scientists behind the new study write that women who are overweight prior to becoming pregnant and who get too much omega-6 and too little omega-3 have an increased risk that the fetus does not develop properly and is born preterm. Still, it remains unclear whether omega-3 supplementation can affect the development of the fetus and the duration of the pregnancy, especially when it comes to women who are overweight before conceiving.


BMI stands for Body Mass Index and is method for comparing height and weight in order to determine if a person has normal weight, weight too much, or weight too little. Body composition is also important. It is particularly unhealthy to have enlarged waist circumference.

Below 18.5: Underweight
18.5 – 25: Normal weight
25 – 30: Overweight
Higher than 30: Obese

The new study is unique

The new double-blinded pilot study included 48 healthy women. Twenty-four women got a fish oil supplement and 24 got matching placebo during the early part of their pregnancy. All women had a BMI that was higher than 25. This study is unique because it only included overweight pregnant women with an increased risk of preterm delivery. They all had a disrupted metabolism characterized by low-grade chronic inflammation, oxidative stress, and an unhealthy omega-3/omega-6 ratio. The women visited the research department of the MetroHealth Medical Center for the first time during the period between their 8th and 16th week of pregnancy. Their second visit was between week 34-36 where they got a routine checkup and received their supplements.
The scientists could see how omega-3 supplementation systematically lowered intra-uterine inflammation. In the second analysis, the scientists observed that the omega-3 supplements also reduced fat accumulation in the uterus.
This study suggests that omega-3 supplementation results in healthier fetal development and prolonged pregnancy, just like it helps ensure that the baby is born with normal fat mass. The scientists also found that omega-3 supplements only were relevant for women who got too much omega-6 in relation to omega-3 from their diet. This indicates that omega-3 supplements are particularly important for women with unhealth eating habits and metabolic dysfunction. It is relevant to mention that many overweight individuals suffer from insulin resistance with impaired glucose uptake.
Moreover, insulin resistance is part of metabolic syndrome, an early stage of type 2 diabetes. The scientists could also see that omega-3 supplementation had greater effect on baby boys compared with baby girls. This was not observed in previous studies.
The new pilot study suggests that women who are overweight before becoming pregnant and take omega-3 fatty acids have healthier pregnancies and a lower risk of preterm delivery. The study is published in Nutrients.

Danish research: Oily fish can lower the risk of preterm deliver

Pregnant women with low levels of the omega-3 fatty acids, EPA and DHA, have a statistically significant increased risk of preterm delivery compared with pregnant women that have high levels of these two essential fatty acids, according to a Danish study that is conducted in collaboration with Harvard T.H. Chan School of Public Health in Boston, USA.
The results of this study suggest that pregnant women can lower their risk of preterm delivery substantially by eating more oily fish or supplementing with fish oil. The study was published in EBiomedicine in 2018.

Eat fish from the lower part of the food chain or take supplements of purified fish oil

Pregnant women should avoid eating predatory fish such as tuna, pike, perch, swordfish, and halibut that are more likely to accumulate mercury and other environmental toxins. It is generally safer to get the essential omega-3 fatty acids from oily fish such as herring, anchovies, salmon, and mackerel that are from the lower part of the food chain. Still, salmon from the Baltic Sea may be more polluted than fish from other regions. A good idea is to stick with salmon from cleaner waters or organic salmon. Another solution is to take a high-quality supplement with purified fish oil if you dislike fish or just don’t eat enough seafood.


Catalano P.M. et al. Effect of Omega-3 Supplementation in Pregnant Women with Obesity on newborn Body Composition, Growth and Length of Gestation: A randomized Controlled Pilot Study. Nutrients. 2021

Nikki Hancocks. RCT links omega-3 to healthy fetal growth in overweight mothers. 2021

Jamie Violet de Seymor and Mary Beatrix Jones. An analysis of omega-3 fatty acid status in a population of pregnant women with obesity, at higher risk of preterm birth. European Journal of Clinical Nutrition. March 2020

M Makrides, L Duley, SF Olsen. Fish oil and other prostaglandin precursor supplementation during pregnancy for reducing pre-eclampsia, preterm birth, low birth weight and intrauterine growth restriction. Cochrane review, 2018

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