Intensity and modifications
Congratulation on your pregnancy. How exciting! I looked at your list of tapes and the only tape that I would not recommend through pregnancy is Intervalmax. The reason being, that the goal of this tape is to push you to(and even somewhat above)your aerobic training zone which is something that you should not be doing during pregnancy. This is a time in your life where you should be maintaining your current level of fitness, not over achieving. So I would suggest tucking this tape(as well as all interval workouts)away for a while.
Your other step tapes are fine to do but you will need to modify them so that your intensity level never gets beyond that of feeling that you are working somewhat hard(a good indicator of this intensity is being able to say 2 to 5 word sentences). Current research(as well as the revised ACOG guidelines) supports using perceived exertion as a method of measuring your exercise intensity vs. taking a pulse check during your pregnancy. This is simply due to the fact that your heart rate is already beating at a faster rate when pregnant(especially in the first trimester)due to all of the hormone changes occuring in your body. Therefore, taking a pulse check would not be a true indicator of exercise intensity.
Your strength training tapes are fine to do as is. My only suggestion is that, again, you go for strength maintenance and not try to lift heavier than usual at this time. The main two reasons for this are 1) again, cautioning against elevating the heart rate too high 2) being careful to not over stress the joints and ligaments since they gradually become softer and softer as your pregnancy progresses(due to relaxin hormone). This softening process is very normal and is the body's way of naturally preparing for childbirth. If you have access to a spotter while weight training, that would be great, especially in the later stages of pregnancy when your balance and joint stability have altered quite a bit.
I would also strongly recommend that you begin to strengthen your pelvic floor muscles by doing kegel exercises throughout your pregnancy(even forever after is great). This will not only help to keep you from leaking urine when you sneeze, cough, or jump (since the baby puts more pressure on your bladder as he/she grows), but will keep your pelvic floor stronger overall(a big plus) since it will become stressed from holding the weight of the baby. We have many effective techniques described in other posts on this forum that will tell you how to work your kegels properly. Simply click on all posts(in the pregnancy forum) that have "kegel" listed in the title. Also, don't forget, if you do not see them listed for you on the first page, look at the top of the page and click on the number 2 to get the next list of thread titles(then 3, and 4, etc.)
As you get into your fourth month of pregnany, it is no longer recommended to stay flat on your back. For this reason abdominal work is recommended in an all fours position(please read other abdominal post in this forum for some exercise examples)and all flat bench work during weight training is recommended to be continued in an incline position.
As you end your second trimester and enter your third, you may find your center of gravity shifting, causing you to be a bit off balance at times. To compensate for this, when doing aerobics, it is better to lower your step height and modify all high impact moves so that you are more stable on your feet. You may find that you enjoy certain tapes over others during these times because they may contain choreography that is more comfortable to you or easier to modify. As for your weight training during these times, you may have to be more creative finding more comfortable positions to due certain exercises(or eliminating them altogether, if no safe modification is available, until after the baby comes). This is the time to especially take advantage of that spotter if you have one available.
You can continue to exercise right to the end of your pregnancy(of course, modifying more and more as you get closer to the end)as long as you are having no complications. Well I hope this helps.
Note to Sheila: Hop on in if you can think of anything else!
