Pregnancy Weekly Guide
[Week 16 Baby] Mommy, my room got bigger!
The amniotic fluid is increasing, and your baby has joints, making it easier for your baby to freely move own limbs.
The muscle and nerve systems are sufficiently developed, and your baby is swimming and staying active inside the fluid.
Through such activities, your baby develops muscles, and you may feel "quickening" starting from around week 16.
But often, we mistake them for gassy discomfort in the stomach. In other words, don't worry too much if you don't feel the movements at this point.