Recommendations for pregnant women  what to eat and which food not to eat during pregnancy apply as well to the time trying to conceive. Eat the same before pregnancy as if you were already pregnant. 

One of the most important things you can do for yourself and your baby is to eat a balanced diet. Eat smaller portions spread over the day, rather than big and few meals. There are a few foods that you should be more careful about eating while you are pregnant.

• Meat, eggs and fish that are not fully cooked could put you at risk for an infection.
• Eat fish regularly about 2 or 3 servings of fish per week because it provides the developing baby with essential Omega-3 oils. Do not eat shark, swordfish, king mackerel or tilefish because these fish may have high levels of mercury, which could hurt your baby. If you eat tuna, make sure it is light tuna and eat no more than 6 ounces per week of albacore tuna and tuna steaks. It is safe to have 12 ounces per week of canned light tuna.
• Wash all fruit and vegetables. Keep cutting boards and dishes clean.
• Eat 4 or more servings of dairy foods each day. This will give you enough calcium for you and your baby.
• Do not drink unpasteurized milk or eat other unpasteurized products.
• Soft cheeses such as Brie, feta, Camembert, blue cheese and Mexican-style cheeses such as queso fresco may have bacteria that can cause infections.
• Do not eat prepared salads or cold cuts cut in a deli as they may carry certain organsims of concern.
• If you drink coffee or other drinks with caffeine, do not have more than 1 or 2 cups each day. Limit also decaffeinated coffee to 1-2 cups a day.
  
  

It is okay to use artificial sweeteners such as aspartame (some brand names: Equal, NutraSweet) and sucralose (brand name: Splenda) while you are pregnant, but you should use them in moderation. If you have a genetic disease called phenylketonuria, or PKU, you shouldn't use aspartame at all.

Check with your doctor before taking any medicine, including pain relievers or over-the-counter medicines. Even medicine you can buy without a prescription may cause birth defects, especially if it's taken during the first 3 months of pregnancy.