Background: According to RISKESDAS in 2018, the prevalence of pregnant women at risk of Chronic Energy Deficiency (CED) in Indonesia was 17.3%. CED is a part of the underweight that needs to be addressed efficiently to prevent nutritional disorders. During pregnancy, one crucial nutrient is folate, which plays a role in preventing congenital defects and contributes to neurocognitive function. This study identifies the influence of DHA supplementation on serum folate levels in underweight pregnant women at the Made Surabaya Community Health Center.

Methods: The research follows a pre-experimental design with a one-group pre-and-post-test using 21 samples of underweight pregnant women. Physical examinations, obstetric assessments, ultrasonography, and venous blood collection for analysis were conducted before and after DHA supplementation.

Results: In this study, significant differences were found in underweight pregnant women before and after DHA supplementation in various parameters, namely body weight 51.76 ± 7.635 vs. 53.25 ± 7.310 (p = 0.018), BMI 22.171 ± 2.8173 vs. 22.814 ± 2.5908 (p = 0.034), UAC 24.238 ± 1.4545 vs. 25.243 ± 2.2288 (p = 0.003), folic acid 14.381 ± 4.8078 vs. 18.176 ± 5.8085 (p = 0.000), and fundal height 17.38 ± 7.606 vs. 19.14 ± 7.323 (p = 0.007).

Conclusions: The study found a significant influence on body weight, BMI, UAC, folic acid, and fundal height before and after DHA supplementation