Okay, I am down to the wire. One week, two days to go until my due date. Since the 6th week or so I have done at least 10 sets of 100 Tupler Contractions every day. I truly feel this has made all the difference in my pregnancy. Even more sets are recommended towards the end of the pregnancy, because obviously the growing uterus is giving you a constant forward forceful motion which tends to make the abdominal separation or diastasis wider. Doing the Tupler contrations, bringing "in" the transverse, fights back against this as you use your muscles to approximate the abdominals. So, I have been doing 12-13 sets (of 100), although I know I would benefit from 15x100.
With all these exercises, I have been strengthening my abdominals for the "marathon of labor" as well. I have practied using the transverse to push the baby out (done by bringing the abdominals back towards the spine and relaxing the pelvic floor). This can/should be practiced every day during a bowel movement, so this will not be something "new" to try during labor.
Last pregnancy I pushed out baby girl number two in just a few pushes - slowing down - so I didn't tear, but using my abdominals to push instead of holding my breath and bearing down - which is more likely to make the diastasis bigger, and pop blood vessels than give you a very effective push. I held a splint to approximate my muscles while I pushed, protecting my diastasis, but also for strength, since the muscles fire better when approximated.
I had a scare two weeks ago, when they thought my baby girl was breech, but last appointment she was not, and I pray she will be head down so I can use my trained abs to push her out.
Email me with questions for more info about training your abs for labor, and, if you are anywhere near Baltimore or D.C., I can train you personally before, during, or after pregnancy to teach you the tupler technique® to rehab or prevent a diastasis.