Pregnancy is the time to gain weight; however, women should not use this time as an excuse to eat more than is necessary. The amount of food a woman needs during pregnancy depends on many factors such as your body mass index before pregnancy, the rate at which you gain weight, age and appetite. All pregnant women should eat a variety of nutrient rich foods every day and may also need to take a vitamin and mineral supplement if recommended by your doctor.
Many women start off pregnancy by being overweight or obese or many may gain weight in amounts more than is healthy during their pregnancy. Risks of problems during pregnancy and delivery are lowest when weight gain is kept within a healthy range and thus obesity during pregnancy is risky for both mother and child.
Weight Gain Guidelines
The latest weight gain guidelines by the Institute of Medicine are based on a women’s BMI before pregnancy. Your body mass index (BMI) measures your weight in relation to your height. It is an accurate way of telling whether your weight is within a healthy range. To calculate your BMI, divide your weight in kilograms by your height2 (meaning height x height) in meters.
The amount of weight you should gain depends on what category your pre-pregnancy BMI lands in:
Total weight gain
Rates of weight gain
2nd and 3rd trimester (average range/week)
Less than 18.5
13 - 18 kg
0.5 - 0.6 kg
18.5 to 24.9
11 - 16 kg
0.4 - 0.5 kg
25 to 29.9
7 - 11 kg
0.2 - 0.3 kg
30 or more
5 - 9 kg
0.2 - 0.3 kg
The overall weight gain will be divided among:
- At birth, a baby weighs about 3.3kg
- While the rest of the weight could account for the placenta, amniotic fluid and various body changes such as increasing the uterus muscle layer, increasing your blood volume, extra fluids and 3-4 kg of fat storage needed for energy during breastfeeding.
Now if you are pregnant with twins, eating right and gaining the recommended amount of weight is even more important especially that there is a higher risk of preterm labor and low birth weight in a multiples pregnancy. Weight gain is especially important between weeks 20 to 24 of pregnancy. If a mother of twins gains 11 kg by the 24th week of pregnancy she reduces her chance of preterm labor. Early weight gain is also vital for the development of the placenta which aids in the passing of nutrients to the babies.
Most women who are carrying twins are encouraged to gain 16 to 18 kg and women carrying triplets are advised to gain 22 to 27 kg. At this time there is not enough information on quadruplets and quintuplets to suggest any guidelines. Because opinions vary, it is important to discuss your specific weight gain with your healthcare provider who will be most familiar with you specific healthcare needs.
If you had a high BMI before you conceived you should try to limit the amount of weight you put on. Putting on a lot more weight is not good for you or your baby. It may increase your risk of complications during your pregnancy and labor. These complications could include:
- Gestational hypertension (high blood pressure)
- Gestational diabetes
- Back pain
- Extra strain on your heart
- Having a big baby(NCCWCH 2008b:34)
- Cesarean delivery
- Birth defects
However, don’t think that dieting during pregnancy is the key. It won't reduce your chances of developing high blood pressure. It's also unlikely to affect your risk of pre-eclampsia, which is related to blood pressure. Instead, have yourself and your baby a healthy diet and gain just the right amount of “healthy” weight! Cut out snacks that are high in fat and sugar, such as chips, biscuits, cakes, sweets and ice cream, and replace them with more nutritious snacks such as fresh fruit, wholegrain cornflakes or grain, low fat dairy products (cheese, milk and yogurt) or a handful of dried fruit or unsalted non roasted nuts.
If you are underweight pre-pregnancy, you may be more likely to have a premature of low birth weight baby. Babies who are born early and small sometimes need extra care when they are born. (NCCWCH 2008)
Your baby is not a parasite, it will not feed off your own stores and thus your body will provide you with nutrients before your baby, who will only get what’s left. This is why it is crucial to have a balanced diet filled with plenty of nutrient rich food, in addition to a multivitamin/mineral prescribed by your health care provider. Keep in mind that the more variety there is in your diet, the less likely you are to go short on any necessary nutrient.
In general, pregnant women need between 2000 calories and 2900 calories a day, but of course the exact calorie amount should be assessed with the help of a dietitian. A gradual increase of calories as the baby grows is the best strategy to go around this. Here is an overview of how calorie needs change during each trimester:
- The first trimester does not require any extra calories.
- The second trimester requires an added 347 calories a day.
- The third trimester requires 452 calories more a day.
So you see, you don’t really need huge amounts of calories if you are pregnant (not the eat for 2 theory) so avoid extra calories by cutting down on sugary and fatty foods. Replace regular soda, sweets and fried foods with healthy options like low fat milk, whole fruit and whole grains!