How we worked it out
Updated as you change the numbers.
- Pre-pregnancy BMI = 63.5 kg ÷ 1.651² = 23.3.
- The range comes from the IOM 2009 table for that BMI category.
Method and assumptions
The 2009 Institute of Medicine guidelines set total gain by pre-pregnancy BMI: 28–40 lb if underweight, 25–35 lb at a healthy weight, 15–25 lb if overweight and 11–20 lb with obesity. For twins the ranges are 37–54, 31–50 and 25–42 lb (no guideline for underweight). Most of the gain comes after the first trimester.
Questions
How much weight should I gain if my BMI was normal before pregnancy?
25 to 35 lb for one baby, or 37 to 54 lb for twins.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.