Good news! At the end of this week, you and your rapidly expanding fetus, who is now almost 3.5" (8.7 cm) long and 1.5 oz (43 g) in weight, will have reached the end of your first trimester!

This last week has seen an explosion in growth: your baby's weight has increased about 60% since week 13. Week 14 will see an explosion of hair as well. Lanugo, the fine hairs that grow all over the fetus's body and protect her skin, appear this week. The placenta is well developed at week 14. It has been providing the vital function of furnishing the fetus with fresh blood and nutrients and removing wastes and deoxygenated blood. Now it also produces hormones vital to the fetus's growth, including estrogen and progesterone. The placenta acts as a barrier to your own immune system, which would otherwise destroy the fetus as an invader.