Supplementation with Omega-3 Fatty Acids has been proposed to reduce the risk of preeclampsia, but the effects of this intervention are still uncertain. Aim: The aim of this study is divided into two parts: 1) to analyze previous studies related to supplementation of omega-3 fatty acids and occurrence of preeclampsia utilizing systematic review approach and 2) to examine the impact of a nutritional protocol of omega-3 fatty acids on the occurrence of preeclampsia among high risk pregnant women (randomized controlled trial). Design: A combination of two designs was used for this study, a systematic review of previous studies as well as a randomized controlled trail. Setting: The randomized controlled trial was conducted at antenatal outpatient, El Manial University hospital. In addition to, delivery ward (section 10) and post natal unit in the department of obstetrics and gynecology. Sample: Concerning sample characteristics among the included studies, all were healthy pregnant women with risk factors for developing preeclampsia and not diagnosed with any medical disorder.