Fish consumption and fish oil intake in pregnancy from our cohort have frequently been studied with respect to end points such as preterm delivery and size at birth, but fewer studies have addressed pregnancy complications such as gestational hypertension and preeclampsia. Some randomized controlled trials have suggested potential benefits of fish oil intake on hypertensive disorders during pregnancy, while other studies have not found any association. However, one cohort study reported that high intake of fish liver oil might be positively associated with pregnancy hypertension. As regular intakes of fish and even fish oil are frequently encouraged for pregnant women, it is important to investigate their associations with pregnancy complications. Our results suggest that high intake of fish liver oil in pregnancy may be associated with an increased risk of gestational hypertension and moderate consumption of fish liver oil, thus, should be recommended. We can not rule out that substances other than n-3 LCPUFA in fish liver oil as vitamin A (retinol) and PCBs may influence gestational hypertension.