By the end of this week, most babies will be in a head-down (vertex) position in preparation for birth. They will likely stay in this position until they are born, although they may still change positions a few times before then. Your baby is still growing rapidly; you can expect them to gain an additional 900 grams (2 pounds) before birth, in addition to their current weight of around 1.5 kg (3.3 pounds). The baby's crown-to-rump length is 29 cm (11.4 inches), and they weigh between 1700-1800 grams (3.75-4 pounds). They are storing iron, phosphorus, and calcium, which are essential for bone development and other bodily functions after birth. If you're having a boy, his testicles may have descended into the scrotal sac by now.