Your size increase or weight gain doesn't necessarily have to be exact - every woman is different obviously! There are certain guidelines, however. Keeping a pregnancy weight gain chart will help keep you on track.

Studies suggest that maintaining a healthy weight during pregnancy will keep you and your baby healthy. It should also help prevent certain pregnancy-related illnesses, such as gestational diabetes .

How Much Weight Should You Gain During Pregnancy?

Generally, an average-weight woman should gain between 25 and 35 pounds throughout the entire pregnancy. Women who are overweight should try to aim for a 15-pound weight gain, and underweight women should gain about 35-45 pounds.

Mothers who are expecting multiples may be required to gain more weight than those carrying only one baby.

How Should the Weight Be Gained?

Although there are now two of you occupying your body, you're not necessarily "eating for two"! This will almost undoubtedly end up in too much weight gained. Generally, you should consume an extra 300 calories per day than you normally would have consumed. Make these calories count by focusing on healthier choices in food .

Where Does the Weight Go?

The following pregnancy weight gain chart illustrates where these extra pregnancy pounds go:

Baby - 7-8 pounds
Placenta - 2-3 pounds
Amniotic Fluid - 2-3 pounds
Breast Tissue - 2-3 pounds
Blood Supply - 2-3 pounds
Uterus - 4 pounds
Fat - 2-5 pounds
Total - 25-35 pounds

Some women may gain a lot of weight during the first trimester , while others may not gain any at all (especially if they are quite nauseous!). The majority of the weight will be evenly spread over the last two trimesters. Your pregnancy size by week may vary.

Weight Gain Rate Per Week

The following is just a guideline of how much cumulative weight you should gain by the week. It will give the low end and high end of the range in which you should aim to gain:

2 weeks - 1-4 pounds
4 weeks - 3-6 pounds
6 weeks - 3-7 pounds
8 weeks - 4-9 pounds
10 weeks - 4-11 pounds
12 weeks - 5-12 pounds
14 weeks - 5-14 pounds
16 weeks - 6-15 pounds
18 weeks - 7-16 pounds
20 weeks - 7-18 pounds
22 weeks - 8-19 pounds
24 weeks - 9-20 pounds
26 weeks - 10-21 pounds
28 weeks - 11-22 pounds
30 weeks - 13-24 pounds
32 weeks - 15-26 pounds
34 weeks - 17-28 pounds
36 weeks - 19-30 pounds
38 weeks - 21-32 pounds
40 weeks - 23-35 pounds

On average, you'll gain about 3-4 pounds per month, with a little more near the end. It is also common not to gain any weight at the very end of the pregnancy.