21 Weeks Pregnant: Baby Development, Symptoms, and Tips for a Healthy Pregnancy by arovedalc Published: September 8, 2026 (6 days ago) Category Health and Beauty Link 21 Weeks Pregnant At 21 weeks of pregnancy, your baby is about the size of a banana or a carrot, measuring approximately 26.7 cm from head to toe. Your little one now weighs around 350 grams, which is more than the weight of the placenta!