Exercise and polyunsaturated fatty acid (PUFA) supplementation independently improve lipid profiles. The influence of both exercise and PUFAs on lipids during pregnancy remains unknown. This study evaluated exercise, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations on lipids during pregnancy. Participants were randomized to aerobic exercise or control groups. From 16 weeks gestation until delivery, groups met 3x/week; exercisers performed moderate-intensity aerobic activity, controls performed low-intensity stretching and breathing. At 16 and 36 weeks’ gestation, maternal blood was analyzed for lipids (total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG)), DHA and EPA. In intent-to-treat analysis, the aerobic group (n = 20), relative to controls (n = 10), exhibited a higher HDL change across gestation (p = 0.03). In a per protocol analysis, the aerobic group, relative to controls, exhibited 21.2% lower TG at 36 weeks (p = 0.04). After controlling for 36-week DHA and EPA, exercise dose predicts 36 weeks’ TG (F (1,36) = 6.977, p = 0.012, r² = 0.16). Aerobic exercise normalizes late pregnancy TG. During pregnancy, exercise dose controls the rise in TG, therefore maintaining normal levels. DHA and EPA do not have measurable effects on lipids. Regardless of PUFA levels, exercise at recommended levels maintains appropriate TG levels in pregnant women. Normal TG levels are critical for pregnancy outcomes, and further studies are warranted to investigate this association in broader populations.

Although discrete maternal exercise and polyunsaturated fatty acid (PUFA) supplementation individually are beneficial for infant body composition, the effects of exercise and PUFA during pregnancy on infant body composition have not been studied. This study evaluated the body composition of infants born to women participating in a randomized control exercise intervention study. Participants were randomized to aerobic exercise (n = 25) or control (stretching and breathing) groups (n = 10). From 16 weeks of gestation until delivery, the groups met 3×/week. At 16 and 36 weeks of gestation, maternal blood was collected and analyzed for Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA). At 1 month postnatal, infant body composition was assessed via skinfolds (SFs) and circumferences. Data from 35 pregnant women and infants were analyzed via t-tests, correlations, and regression. In a per protocol analysis, infants born to aerobic exercisers exhibited lower SF thicknesses of triceps (p = 0.008), subscapular (p = 0.04), SF sum (p = 0.01), and body fat (BF) percentage (%) (p = 0.006) compared with controls. After controlling for 36-week DHA and EPA levels, exercise dose was determined to be a negative predictor for infant skinfolds of triceps (p = 0.001, r² = 0.27), subscapular (p = 0.008, r² = 0.19), SF sum (p = 0.001, r² = 0.28), mid-upper arm circumference (p = 0.049, r² = 0.11), and BF% (p = 0.001, r² = 0.32). There were no significant findings for PUFAs and infant measures: during pregnancy, exercise dose, but not blood DHA or EPA levels, reduces infant adiposity.

A total of 83 third trimester pregnant women were recruited to examine the role of pre-pregnancy versus late-pregnancy physical activity on maternal insulin resistance. Principal component analysis plots demonstrated a distinction between the high and low Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) groups. The variation was driven primarily by exercise prior to and during pregnancy. Specifically, higher levels of physical activity prior to pregnancy was associated with a lower HOMA-IR and is not modified by other variables. Women who were active prior to pregnancy were more active during pregnancy. These results suggest that being active before pregnancy may be a good strategy for mitigating the risk of insulin resistance during late pregnancy.

In the United States, pregnant women have low concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are essential for fetal development. Although maternal blood provides accurate polyunsaturated fatty acid (PUFA) concentrations, venipuncture is expensive and not always accessible. PUFA-containing foods consumption, both omega-3 ad omega-6 is supposed to reflect in the status (plasma, RBC, adipose tissue) of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). De novo synthesis of DHA and EPA during pregnancy is supposed to be higher compared to pre and/or post-pregnancy periods. Thus, this study aimed to determine the association between maternal self-reported dietary intake of foods high in DHA and EPA, along with vegetable oils as a source of omega-6 fatty acids, with maternal blood DHA and EPA concentrations. Pregnant women (13–16 weeks gestation) were recruited and asked to complete a food-frequency questionnaire (FFQ) and blood draw at enrollment and 36 weeks. Circulating concentrations of DHA and EPA were quantified and change scores were calculated. Correlations were done to determine associations between FFQ results and EPA/DHA maternal blood concentrations. Regression analyses were run to examine significant predictors of the main outcomes. Overall, PUFA-food consumption and RBC’s DHA levels decreased from early to late pregnancy; self-reported PUFA-rich food consumption positively correlated with DHA and EPA levels. DHA concentration was predicted by self-reported PUFA-rich oils (sunflower/soy/corn/olive) consumption, but EPA concentration was predicted by maternal BMI. These findings suggest that EPA and DHA consumption decreased across pregnancy and the FFQ can be utilized as an effective method for estimating PUFA blood concentration during pregnancy.