The importance of healthy nutrition in pregnancy and pregnancy-related weight gain is well-established, but many women may not be aware of the impact their nutritional status can have on the outcome of their pregnancy. Poorly nourished women can experience illnesses and complications of pregnancy and labour. Inadequate nutrition in pregnancy can compromise fetal growth resulting in intrauterine growth restriction and low birth weight babies. Gaining more or less than the recommended weight in pregnancy can have consequences on both mother and baby with the incidence of pregnancy complications being higher at the upper and lower extremes of weight gain. This article examines the effects of good nutrition and pregnancy weight gain on achieving optimal pregnancy outcomes, and the midwife's responsibility in assisting her client to strive for a healthy pregnancy and successful birth outcome.