WebMD:
Congratulations, Jen! You’re 13 weeks pregnant. Your fully formed fetus, now in about its 11th week of development, measures 2.6 to 3.1 inches from crown to rump and weighs between half an ounce and seven-tenths of an ounce—about the size of a peach. The head is still disproportionately bigger than the body, but the rest of the body is starting to catch up. In fact, your baby is growing rapidly these days. The face is starting to look more human, with eyes moving closer together. Toes and fingers are clearly separate, and ankles and wrists have formed. External genitalia are becoming visible. Intestines are shifting into their proper place, too. Your uterus is filling your pelvis now and starting to grow upward into your abdomen. It probably feels like a soft, smooth ball. If you haven’t put on weight yet because of morning sickness, you’ll begin to now as you start to feel better.
Baby-Gaga:
This is your final week in the first trimester and your little weed continues to grow and grow and grow. Of the three trimesters, this one has been the most important for your little one’s development. Assuming you’ve carefully adopted a healthy diet, continue to exercise and get ample rest, your little one is set up perfectly for even more growth and development in tri-two! Way to go! He or she now weighs about 2.5 ounces and is roughly 3.5 inches in length. Little hairs, known as lanugo, will start to cover their body this week, as their sense of taste and smell are further refined. Their cozy little amniotic sac is also increasing in size and mass as it continues to fill with more fluid.