Congratulations, Ashley! You're 17 Weeks Pregnant. Your baby measures about 4.4 to 4.8 inches from crown to rump and has doubled its weight in the last two weeks to about 3.5 ounces. Fat begins to form aiding heat production and metabolism, the lungs are beginning to exhale amniotic fluid, and the circulatory and urinary systems are working. Hair continues to grow on baby's head and his eyebrows and eyelashes are filling in. You're showing more, with an obvious swelling in your lower abdomen. A five- to 10-pound weight gain is typical by now. You also may be noticing an increase in appetite.