Dr Emma Derbyshire spoke about this topic at "Nutrition in the Childbearing Years" at the Nutrition & Health Live event.
Her speech focused on the importance of preparing the body pre-pregnancy, especially in the UK where the unplanned pregnancy rate is 60 per cent.
She said: "It's the same as putting fuel in a car, you can't enter pregnancy with a half-full tank and expect a perfectly healthy outcome."
As with other ideas she proposed, Dr Derbyshire made it clear there was need for further randomized controlled trials to help establish some much needed dietary guidelines for vitamin D and omega-3 intake during pregnancy
The maternal nutrition specialist added that: "UK dietary reference values are in need of updating, with many still based on data from 1991."
This lack of data can lead to poor advice at times she claimed, with many women often failing to take folic acid supplements until too late into their pregnancy.
Her overall call for women to focus on nutrition throughout their childbearing years was backed by many at the conference, with session chair Prof Peter Aggett saying that it was "a clear message that focusing on nutrition can never start too early".