Olsen SF, Halldorsson TI, Li M, et al. - In this 3-group parallel randomized controlled trial performed in regions of China with low (median: 2.1 g/d) and higher (14.3 g/d) fish consumption, researchers investigated if and how 2 doses of supplemental long-chain (LC) n-3 PUFAs could influence gestation duration. At midgestation, they randomly allocated unselected women (median: age, 26.2 y; BMI, 20. kg/m²) to take four 0.72-g identical gelatin capsules per day, containing fish oil [high fish oil group (60% w/w LC n-3 PUFAs)], a 1:3 mixture of fish oil to olive oil [low fish oil group (20%)], or olive oil [control group (0%)], affording 2.0, 0.5, and 0 g/d of LC n-3 PUFAs, respectively. The participants were asked to continue taking these capsules until the last day of the preterm period (< 259 days of gestation). Possibly due to too low statistical power, this investigation did not substantiate that preterm birth in Chinese women can be prevented by fish oil supplementation.