It’s a normal thing to gain weight during pregnancy. It’s important to help you grow your baby.
By the time you are due, just over a third of your extra weight will come from your baby, the placenta and amniotic fluid. Here are some averages:
At birth, a baby weighs about 3.3kg.
The placenta, which keeps your baby nourished, weighs 0.7kg.
The amniotic fluid, which supports and cushions your baby, weighs 0.8kg.
The other two thirds of extra weight is due to the changes that happen to your body while you’re pregnant. On average:
The muscle layer of your womb (uterus) grows dramatically, and weighs an extra 0.9kg.
Your blood volume increases, and weighs an extra 1.2kg.
You have extra fluid in your body, weighing about 1.2kg.
Your breasts weigh an extra 0.4kg.
Weight-gain guidelines
Single gestation
A woman who was average weight (BMI 18.5 to 24.9) before getting pregnant should gain 11 to 16 kg after becoming pregnant. Underweight women (BMI < 18.5) should gain 13 to 18 kg. Overweight women (BMI 25 to 29.9) should gain 7 to 11 kg during pregnancy. And obese women (BMI 30 or more) may need to gain only 5 to 9 kg during pregnancy.
Multiple gestation (twins and other multiples)
A woman who was average weight (BMI 18.5 to 24.9) before getting pregnant should gain 17 to 25 kg after becoming pregnant. Overweight women (BMI 25 to 29.9) should gain 14 to 23 kg during pregnancy. And obese women (BMI 30 or more) should gain 11 to 19 kg during pregnancy.
In general, you should gain about 1 to 2kg during the first three months you’re pregnant and 0.5kg a week during the rest of your pregnancy. If you are expecting twins this would be an average of 0.7kg per week after the usual weight gain in the first three months.







https://drleonardconsultation./2016/02/07/weight-gain-in-pregnancy-3/