Yes - it should be a priority whilst pregnant! A developing foetus has heightened nutritional needs, especially for essential fatty acids. If a mother to be does not include sufficient EFAs in her meals, the foetus' needs will cause her to drain herself of omega 3. This often causes worsened post-natal mood swings from a "drained brain". By ensuring a good supply, not only does the mother nourish her child, she also safeguards her ongoing sanity.
Another fabulous reason to keep good fats high when pregnant is the benefits of skin suppleness - well fed skin is less likely to stretch and scar in the same way dry, brittle skin is and when the baby is born, should return to its former glory more promptly.