Healthy food is very important for you and your growing little one. Good nutrition during pregnancy helps you in:

• Meeting your nutritional needs as it has increased during pregnancy
• Providing nutrition to your little one's growth and development
• Building networks in the placenta, uterus and your breasts
• Preparing to breastfeed

Instructions to eat well during 9 months:

• Eating enough food and do exercise regularly to maintain the pace of weight gain stable
• Eating a variety of foods to get the different nutritional benefits from each food
• Add more fruits and vegetables in your diet
• Increase your milk intake, dairy products and other food that are rich in calcium
• Avoid eating meat and seafood that are raw and undercooked
• Limit your caffeine intake
• Drink at least 8 glasses of fluid every day, especially water
• Plan what to eat daily
• Take supplements only if prescribed by your doctor

References:

http://www.webmd.com/baby/guide/eating-right-when-pregnant?