According to Crawford (1995), the first pregnancy-related need for PUFAs (both omega-6 and omega-3) occurs during the three months prior to conception. This critical period for cell commitment and division requires ARA and DHA to facilitate growth and development. It has been suggested that supplementation with fish oil, or increased fish intake, during pregnancy prevents the pregnancy-induced hypertension, prolongs gestation, increases birth weight and reduces the incidence of premature birth (Gerrard et al, 1991, Olsen et al, 1992). Recent data support the view that the intake of DHA during pregnancy should be in the amount of at least 0.1-0.4 g/day (Crawford, 1995).

Fetal stage

DHA is important for optimal nervous system development. During the last trimester of pregnancy, when the fetal demand for neural and vascular growth are greatest, there is an elevated accretion of DHA in the liver and brain of the fetus. A maternal diet high in DHA will greatly enrich the DHA concentration in the blood of the newborn infant. Even levels as low as 0.7g EPA+DHA/day during the period from 25th to 35th week of pregnancy seem to be beneficial (Connor et al, 1995). DHA levels in maternal plasma are lower in multigravidae compared to primigravidae and the smaller the baby, the lower DHA-level (Al et al, 1995). Consequently, it is therefore especially important for multigravidae to increase the intake of DHA.