What you need to know about pregnancy weight gain

Most women are ecstatic about having a baby, but dread the idea of gaining weight. The fact is that during pregnancy, you will gain weight and you will look bigger.

No matter how you feel about weight gain, the reality is that you should gain the right amount of weight during pregnancy to ensure that your baby is getting all the nutrients he or she needs to be healthy and grow at a steady rate.

The best way to ensure this, is to eat a healthy and balanced diet. You do not need to “eat for two”. In fact, your body only needs about 1200 kilojoules more than you ate before you fell pregnant. (This is about the same as a slice of whole-wheat toast with two teaspoons peanut butter or a cup of cereal with half a cup of milk and a small banana.)

Eating a balanced diet and gaining a healthy amount of weight does have its benefits: it may help you have a more comfortable pregnancy with fewer complications. Women who gain too much weight frequently suffer from problems such as backaches, constipation, cramps, exhaustion or breathlessness. And that is not even mentioning the more serious complications like gestational diabetes, high blood pressure and premature birth.

How much should I gain?

Usually a woman gains between 500g and 2kg in the first trimester, and around 500g for ever week thereafter, with a little more towards the end of pregnancy.

The main reason for the quick weight gain in the first trimester is mainly because of increased fluids. Many important changes happens during the first trimester, therefore it is very important not to deprive your baby of important nutrients.

The healthy amount of weight you should gain is measured by your weight and BMI before you fall pregnant. Any weight conscious person knows that BMI stands for Body Mass Index and it is a tool that calculates your weight to height ratio.

You can use an online BMI calculator, but you can also calculate it as follows:
Weight in kilograms / your height x2 = Your BMI.

If you were underweight when falling pregnant (BMI less than 18.5) you should gain between 13-18kg. Women of normal weight (BMI 18.5-24.9) should gain 11-16kg. Overweight women (BMI 25-29.9) should gain 7-11kg and obese women (BMI 30 and above) should aim for 5-9kg.

Where does the weight go?

The good news is that not all of your pregnancy weight gain is fat. The breakdown of pregnancy weight for a woman with a normal BMI looks somewhat like this:

Blood: 1.4-1.8kg
Breasts: 500g-1,4kg
Uterus: 1 kg
Baby: 3-3.5kg
Placenta: 700g
Amniotic fluid: 1kg
Fat: 2.7-3.6kg
Retained water: 2kg

(These numbers are for women expecting single babies, it would differ somewhat for multiples.)

You will lose weight straight after giving birth but any sudden or severe weight loss or weight gain should be reported to your health care provider immediately.

Want to know more about pregnancy weight?
Claiming back your pre-pregnancy body
The overweight pregnancy

Are you concerned about gaining weight during your pregnancy?

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