31 weeks

Chances are your diaphragm is feeling a little cramped these days. Okay, a lot cramped. That's because your uterus is pushing up against it, crowding your lungs and making it more difficult for them to expand fully. The result: Your body is spare on air, and will be until your baby drops near the end of pregnancy in preparation for birth. Your baby, however, is happy as a clam since he gets all the oxygen he needs through the placenta. Weighing in at three-plus pounds and measuring 18 inches long, he's quickly approaching his birth length though he's got to pack on another three to five pounds before D-day. Also developing at an impressive clip: your baby's brain connections (he's got to make trillions of them!). He's now processing information, tracking light, and perceiving signals from all five senses. He's also putting in longer stretches of sleep, which is why you're probably noticing more defined patterns of awake (and moving) periods and sleeping (pretty still) periods.

As far as growth goes, your baby's still on a roll, measuring an impressive 18 inches and weighing in at more than three pounds. At 31 weeks pregnant, you can still expect your baby to gain at least three to five pounds, possibly more, before you two meet.

Your baby's brain is working overtime these days, developing faster than ever. Connections between individual nerve cells are growing at a frenetic clip, and your baby can now perceive information from all five senses. Sure, your baby can't smell anything right now, but that's only because he or she is still submerged in amniotic fluid and needs to be breathing air to get a whiff of anything. Lucky for you — and your baby — yours will be one of the very first scents your baby breathes in, a scent that will quickly become his or her very favorite.

So what's your little dove doing all day while you're busy feathering your nest for his or her arrival? Making faces, hiccupping, swallowing, breathing, pedaling with little hands and feet along your uterine wall, and even sucking his or her thumb. In fact, some babies suck their thumbs so vigorously while in the womb that they're born with a callus on their thumb (what a little sucker!).