Much has changed since the days when a pregnant woman was exhorted to eat for two and avoid any undue ‘stress' or exertion. From how much weight you should gain to getting enough calcium, omega-3 oils and B vitamins, here's plain-talking food advice and easy tips:

1. Eating for you, not for two

Whilst it is important to gain the right amount of weight during pregnancy, the old advice of eating for two is not the way to do it. The extra kilojoules needed don't really become significant until the last trimester when they add up to only 800 kilojoules (190 Calories) extra a day - or the equivalent of an extra slice of bread plus a glass of milk.

2. Count the weeks, not the kilojoules

Put dieting aside for the next nine months. Pregnancy is not the time to skimp on kilojoules, even if you need to shed a little excess. Gaining anywhere from 10 to 14 kg is vital for your baby's growth and development.

3. Avoid the backlog

Constipation is a common complaint, so keep your fiber and fluid intake high. Best foods for regularity are those in insoluble fibre such as bran cereals and wholegrain breads. Also plenty of fruit and vegetables helps, along with prunes, prune juice, raisins and liquorice plus a daily walk.

4. Bone building

If you don't have enough calcium during pregnancy, the store of calcium in your own bones will be ‘drained' for your baby's developing bones and teeth. Keep your bones safe from osteoporosis by making sure you get four serves of calcium rich foods a day from low-fat milk, yoghurt and cheeses.

5. Brain food

Essential omega-3 fats are vital to your baby's brain, nervous tissues and eyes. So include fish and seafood, lean meat, canola oil, omega enriched eggs and linseeds regularly in your diet.

Low intakes of fish and seafood during pregnancy can increase the risk of pre-term delivery and low birth weight, according to a new study from Denmark. Surveying over 8,000 pregnant women through antenatal clinics, Danish researchers determined how often they ate fish during their pregnancy. Frequency of pre-term deliveries fell from 7.1 per cent in women never eating fish to 1.9 per cent in those eating fish at least once a week.

6. Alcohol and caffeine

Although the occasional drink or cappuccino is unlikely to do harm, they are probably best avoided in early pregnancy and limited to once or twice a week in the last trimesters.

7. ‘B' sure

Folate is a B vitamin required for baby's neural tube and spinal cord. You need more folate in the first three months of pregnancy which can be met with folate-rich foods such as leafy vegetables, avocados, wholemeal bread, fortified breakfast cereals, nuts (almonds, hazel nuts, peanuts, walnuts), yeast extract (Vegemite, Marmite), oranges and orange juice. If you opt for a supplement, look for one with 400 micrograms.

8. Protect your baby

Listeriosis is an illness that can be picked up from the common foods we all eat. It causes few symptoms in healthy people, but can lead to serious illness or miscarriage in the unborn. Risk of infection can be greatly reduced by good hygiene practices at home and taking care with ready-to-eat foods when out (see table).

Listeria - high risk foods

• Pate
• Smoked seafood
• Soft cheeses such as brie, camembert, ricotta
• Cold deli meats
• Pre-prepared or stored salads
• Raw seafood such as oysters and sashimi
• Pre-prepared sandwiches
• Foods that are not kept ‘piping' hot

9. Iron it out

Iron-rich foods will keep your energy levels up and help build baby's iron stores. Red meat is the best source of easily absorbed iron, with lesser amounts found in chicken and fish.

Fish and mercury guidelines

Due to mercury accumulation in large long-living fish, recent guidelines recommend that pregnant and breast feeding women LIMIT (not avoid completely) their intake of certain fish species to protect the baby. Here's the fish types to watch for:

1. Eat no more than one serve per fortnight of Shark (Flake) or Billfish (Broadbill, Swordfish and Marlin) AND eat no other fish that fortnight.
2. Limit Orange Roughy (Deep Sea Perch) or Catfish to one serve per week AND have no other fish that week.
3. All other fish species, including canned tuna and salmon, are safe to eat at the recommended levels of 2 to 3 times per week.