Pregnancy and Weight Gain

Weight problems can start in pregnancy so there’s never a more important time in life to eat healthily and control weight gain. WLR’s Dietitian, gives advice to ensure a happy, healthy pregnancy.

Your Weight During Pregnancy

By Dietitian Juliette Kellow BSc RD

Every mum-to-be dreams of having a happy, healthy pregnancy – and the good news is, that’s exactly what happens for most women. Stopping smoking, eating a healthy diet, ditching booze and taking regular exercise will all help to ensure you and your baby remain in tip-top form. But it’s also important to monitor your weight during pregnancy.

Here’s the low down…

Hurrah! You’re pregnant. It’s fantastic news for you and your family, but potentially not such great news for your waistline.

Many experts say that pregnancy is often the time when weight problems first start for women – and many women couldn’t agree more! In fact, according to the Association for the Study of Obesity, up to 80% of women blame their weight problem on pregnancy. This means there’s never a more important time in life to eat healthily and control the amount of weight you gain, especially if you are already overweight or obese. Nevertheless, now is definitely not the time to diet or worry about losing weight.

When it comes to how much weight you should gain during pregnancy, there are currently no official recommendations in the UK. In general, a weight gain of 12.5kg is considered normal, although a healthy range is thought to be around 11-16kg.

Here’s an approximate breakdown of where all the extra weight goes:

Baby 3-3.5kg
Placenta 0.5-1kg
Amniotic fluid 1kg
Uterus 1kg
Increased breast tissue 1kg
Increased blood 1.5kg
Increased fluids 1kg
Mother’s fat stores 3.5kg

In general, when large amounts of weight are gained during pregnancy, it’s due to an increase in the mother’s fat stores – and unfortunately, it’s this excess fat that many women find so difficult to lose when they’ve had their baby. More worryingly, around half the body fat gained during pregnancy is stored around the stomach, where it carries the greatest health risk.

Most experts agree the more weight that’s gained during pregnancy, the greater the amount of weight that will stay with the mother afterwards. Indeed, research shows that women who gain more than 16kg during their pregnancy are likely to be 4-9kg heavier one year after giving birth than they were before they got pregnant.

To help prevent being left with even more excess pounds after giving birth, most experts agree that women who are overweight or obese before becoming pregnant should aim to gain less weight than women who are a healthy weight before pregnancy.

Although official guidelines don’t exist in the UK, in America it’s recommended that women with a pre-pregnancy BMI of 26 to 29 aim to gain around 7-11.5kg, while women with a BMI of more than 29, aim for 6kg. However, Dr Rajasingham takes this advice one step further and suggests that women who are extremely obese should aim to keep their weight steady throughout their pregnancy, although they should be closely monitored by their GP, midwife, practice nurse or a dietitian.

Avoiding putting on excessive amounts of weight has many benefits during pregnancy, too, and helps to lower the chances of pre-eclampsia, gestational diabetes, backache, leg pains, varicose veins, haemorrhoids, shortness of breath, extreme tiredness and even stretchmarks!

Top Tips - Your Weight During Pregnancy

  • If you haven’t already changed your diet, use your pregnancy as a time to evaluate your overall eating habits and lifestyle and move towards healthier choices that will benefit you, your family and your baby both now and in the future.
  • Give up dieting but don’t fall into the trap of thinking you need to eat for two. The Department of Health suggest you only need an extra 200 calories each day – and that’s only in the last three months of your pregnancy! In reality, that’s equivalent to two slices of toast with low-fat spread, a banana and a pot of natural yogurt or a bowl of wholegrain cereal with semi-skimmed milk. Stick to a balanced, varied diet that includes lots of foods from each of the four main food groups. It’s vital to top up your nutrient stores to help you cope with the demands of labour – and a new baby.
  • If you were inactive before you became pregnant, now’s not the time to start strenuous exercise. However, being regularly active will help you to have a healthy pregnancy, easier labour and will help you get back in shape once you’ve given birth. Swimming and walking are both great options.
  • Keep on taking those folic acid supplements for the first 12 weeks of your pregnancy and eat more foods rich in this vitamin such as broccoli, spinach, sprouts, pulses, breakfast cereals, wholemeal bread and oranges. The good news is, these foods are also packed with other nutrients.
  • In addition to avoiding shark, marlin and swordfish and limiting tuna (see above) pregnant women should also have no more than two weekly portions of oily fish like salmon, sardines, trout and mackerel as they may contain chemicals such as dioxins. You should also avoid raw shellfish when you’re pregnant as it can sometimes contain bacteria and viruses that could cause food poisoning.
  • Pregnant women can become deficient in iron so make sure you have plenty of iron-rich foods in your diet. These include lean red meat, pulses, fortified breakfast cereals, vegetables and dried fruit. Although liver is rich in iron, you should avoid it when you are pregnant because it contains large amounts of vitamin A.
  • Continue to avoid taking vitamin A supplements and eating liver or liver products.
  • Take a supplement containing 10 micrograms of vitamin D each day.
  • Avoid foods that may contain high levels of listeria, a germ that can cause miscarriage, stillbirth or severe illness in a newborn baby. These include soft mould-ripened cheese, such as Camembert, Brie, chevre (a type of goats cheese) and blue-veined cheese. You should also avoid all types of pâté as it may contain listeria. (Cheddar, Parmesan, feta, ricotta, mascarpone, cream cheese, mozzarella, cottage cheese and processed cheese are all fine, as are live or bio yogurts, probiotic drinks, fromage frais, crème fraiche and soured cream.)
  • Always cook eggs until the white and yolk are solid to prevent salmonella food poisoning – and don’t eat foods containing raw or partially cooked eggs.
  • Only eat meat that has been well cooked to prevent food poisoning. This is especially important for chicken, sausages, burgers and food made from minced meat.
  • Stick with an alcohol-free diet.
  • Cut down on caffeine as high intakes can result in low birth weight or miscarriage. The FSA recommends no more than 300mg caffeine daily – that’s the equivalent of three mugs of instant coffee, three cups of brewed coffee or six cups of tea. Limit caffeine-containing cola and energy drinks like Red Bull, too.
  • If you or your family has a history of hayfever, asthma, eczema or other allergies, you may want to avoid eating peanuts while you are pregnant or breastfeeding.

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More Information

Visit the Food Standards Agency website at for advice on healthy eating and information about diet before and during pregnancy.

Visit the British Nutrition Foundation at

Your midwife should be able to give you advice on healthy eating during pregnancy, suitable weight gain and breastfeeding.

The Pregnancy Book 2007 by the Department of Health is available on line at

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