fetal-development

Pregnancy Week by Week: Complete Trimester Guide and Fetal Development

Pregnancy Week by Week: Complete Trimester Guide Every week of pregnancy brings new developments. From a cluster of cells smaller than a poppy seed to a fully-formed baby ready for the world, the transformation is nothing short of miraculous. Quick orientation: Pregnancy lasts 40 weeks and is divided into three trimesters. The first trimester (weeks 1-13) is when all major organs form. The second trimester (weeks 14-27) is when baby grows rapidly and you start feeling movement. The third trimester (weeks 28-40) is when baby gains weight and prepares for birth. Many parents check what's happening week by week obsessively -- first flutters commonly show up around week 19, the anatomy scan lands at week 20, and OBs typically recommend starting kick counts at week 28. A baby might arrive anywhere from 37 to 42 weeks, with 40 weeks and 3 days being a common full-term example. That week-by-week tracking...