# Learn How to Calculate Weekly Weight Gain during Pregnancy - Tutorial

## How to Calculate Weekly Weight Gain during Pregnancy Tutorial with Formula, Example

##### Example :

Sarah's pre-pregnancy weight was 60 kg and her current height is 170 cm, current weight is 70 kg. She wanted to find her weight gain at 17th week. Calculate her weight gain for 40th week and 17th week.

##### Given :

Pre pregnancy Weight = 60 kg Current Height = 170 cm = 1.7 m Current Weight = 70 kg

##### To Find,

Weight gain for 17th week and weight gain for 40th week

##### Formula:

Body Mass Index = Weight / Height2

##### Solution
###### Step 1:

Calculate the BMI of Sarah before pregnancy BMI = 60 / (1.7 x 1.7) BMI = 60 / 2.89 BMI = 20.76

###### Step 2:

Find Category of Sarah based on BMI from the following table

BMICategoryWeight gain (kgs)
< 18.5Underweight12.7 - 18.1
18.5 - 24.9Normal weight11.3 - 15.9
25 - 29.9Overweight6.8 - 11.3
> 30Obese5 - 9.1

Sarah was Normal weight. So, Sarah will gain weight between 11.3 - 15.9 kgs at 40th week.

###### Step 3:
Sarah's Weight at 17th week is calculated as follows:
 Weight gain at 17th week = 2.5 - 4.9 kgs [From Pregnancy weight gain chart] = (60 + 2.5) - (60 + 4.9) kgs Weight should be = 62.5 - 64.9 kgs
###### Step 4:

Sarah's Weight at 40th week is calculated as follows:

 Weight gain at 40th week should be = (60 + 11.3) - (60 + 15.9) kgs = 71.3 - 75.9 kgs
###### Step 5:

Sarah's current weight is 70 kgs, but the current weight should be between 62.5 -64.6 kgs. So she is considered as overweight.