Where possible, pre-conception counselling is desirable for both prospective parents in order to address issues of lifestyle and nutrition so that pregnancy can proceed with the best possible start. If dieting is necessary this should be initiated as far in advance of the pregnancy as possible, because inadequate nutrition around the time of conception can influence the fetal growth trajectory and weight at birth. Regardless of BMI, women should also be encouraged to engage in regular aerobic exercise. Nutritional requirements in the pre-conception period include adequate amounts of oily fish to provide omega-3 fatty acids. All women planning a pregnancy should receive 400 #amp;#x00B5;g of folic acid daily, and vitamin B12 and vitamin D supplementation may be necessary, particular for vegetarians. Other vitamins and minerals should be considered, particularly iron and iodine, but most should be obtainable from a balanced diet. Harmful behaviours and environmental exposures should be avoided.