34 weeks.
Your baby could be as tall as 20 inches right now and about five pounds. Need a visual? Hold a five-pound bag of flour in your arms and imagine it's your soon-to-be-born baby (cradle it, and you'll only get strange looks in the baking aisle). Then stack three such bags one on top of the other (and get ready for some more strange looks, maybe from the same clerks who saw you grinning and holding that one-pound box of sugar a few weeks ago). That's how tall your baby is now. (Now go bake some oatmeal raisin cookies with all that flour!)
If your little doughboy is, well, a boy, then you'll be pleased to know that this week his testicles are making their way down from his abdomen to his scrotum. (Some baby boys - three to four percent - are born with undescended testicles, but they usually make the trip down sometime before the first birthday.)
Your baby's fingernails now reach the end of the fingertips and may even curl over the tip, making a manicure one of the first things you'll need to do for your little bundle.
Her fat layers - which will help regulate her body temperature once she's born - are filling her out, making her rounder. Her skin is also smoother than ever. Her central nervous system is maturing and her lungs are continuing to mature as well. If you've been nervous about preterm labor, you'll be happy to know that babies born between 34 and 37 weeks who have no other health problems generally do fine. They may need a short stay in the neonatal nursery and may have a few short-term health issues, but in the long run, they usually do as well as full-term babies.