My wife delivered 7 weeks ago. She lifted into the 3rd trimester. I really like Beau's advice; the reverse linear progression seems spot on. A couple of other pregnancy-specific things to be mindful of:

- The vena cava runs along the back and returns blood from the lower body to the heart. Bench pressing might compress this vein...which would not be good for the uterus & baby. If your wife wants to bench, make sure she speaks with her Dr. about the warning signs that she's compressing the vena cava.

- The hormone relaxin will grant your wife never-before-experienced range of motion at her various joints. She's got to be super careful about over/hyperextension. Around week 25, my wife turned into gumby.

- the lower back is just a shit-show in late pregnancy. Your wife's lumbar spine is basically going to disappear into her body. This extreme lordosis coupled with little ab support makes the low back particularly susceptible to injury during pregnancy (and for quite a while afterwards). My wife stopped all fast lifts & went super easy with deadlifts.