Use a cloth measuring tape (you can buy one on Amazon here). Ideally, take the measurements at around the same time each week. Here is how to take the measurements:
- Chest circumference
Measure the circumference along the widest part of your chest, along the nipple line. See images below.
- Waist circumference
Measure the circumference along the narrowest part of your waist, in line with the belly button. See below images.
- Thigh circumference
Measure the circumference of the widest part of your thigh. See images below.