The fetus reaches viability (can survive with medical help if born). Lungs are still maturing. Rest if you feel tired.
Week 2 - Embryonic Stage
Week 17 - Fat Layers Develop
Week 13 - Rapid Growth Phase
Week 32 - Nail Growth
Week 26 - Eye Opening
Week 11 - Gender Differentiation
Week 20 - Halfway Point
Week 18 - Hearing Develops