Background: Fulfillment of nutritional needs in pregnant women greatly affects the nutritional status of the fetus in the womb and will determine the growth and development of the baby, especially during the growth period (golden age). In the mother's womb, brain cells undergo various stages of development, namely from proliferation, migration, synaptogenesis to apoptosis. Adequate nutrition is the main and most important factor that plays a role in determining the success of body and brain growth in the fetus. The purpose of this study was to determine the effect of DHA intake on TNFa levels in underweight pregnant women. Methods: The research approach used was cross-sectional and interviews were conducted directly with 21 pregnant women patients in Made Suarabaya District. Results: The average levels of TNFa in underweight pregnant women before and after DHA administration were as follows: 163,746±66,591 and 133,339±39,159 respectively. Conclusions: There is a significant positive effect of providing DHA intake to underweight pregnant women.