Picture of fetus at 37 weeks of pregnancy. At 37 weeks of pregnancy, the development of the fetus is very complete and ready for birth. Now, let\’s take a look at the growth and development of the fetus at 37 weeks. Physical Characteristics At 37 weeks, the fetus is approximately 48.6 cm tall and weighs approximately 3 kg. By this time, the fetus\’s skin has become smooth and its hair and nails are fully formed. The fetus\’ head is larger than its body