Hi LaBelle,
Unless your body tells you otherwise, you can probably maintain the same or close to the same weightlevel... but ease off if you have joint discomfort (your joints have a lot of the hormone relaxin in them when you are pregnant...), or if you find yourself ever bearing down. You should always be working in oxygen. Also, it is more important than ever to keep yourself in correct alignment. After the first trimester, it's a good idea to avoid rotating your torso (can bring on diastasis... or make it worse if your abs are already split). When working with free weights, you might want to try sitting on a Resist-a-ball to keep your spine in correct alignment.
Whatever happens to your body, though, you need to be kind to yourself and understand that the extra fat that Mother Nature gives you during pregnancy is a gift to you and your baby. It allows you to create and nourish a beautiful new baby (a woman with extremely low body fat will often stop menstruating -- mother nature's way of making sure that the baby has enough nourishment). It is by design that women will typically carry a little bit of extra padding (even if they have lost all of the weight) until they are finished nursing -- the body simply needs this extra fuel to feed the baby.
I understand the concern with body image -- I was a dancer and I did some modeling as a teenager, and I did a lot of stupid things to stay skinny back then. I have always been weight conscious, and it is difficult to give up control when you are pregnant. It can be especially disconcerting when you have lost a great deal of weight (I have been there!) and you see the scale climbing up again... maybe higher than before your weight loss. Like most American women, I have a constant mental battle with the body image monster.
But let me tell you what pregnancy and prenatal exercise taught me...
1) The number one benefit of exercise is (and always should be) better health... I came out of my first pregnancy feeling great. I had a lot of energy, and I was able to get right back into the swing of exercising after my son was born.
2) The confidence gained from feeling strong and capable is sexier than any size 8 dress I've ever worn... I'm not as skinny as I was when I was 18... I have a grown woman's figure now, but my 32 year old body (even while pregnant) could definitely out-aerobicize and out-lift my former self.
3) My body is absolutely amazing. It can nourish and deliver a 9 lbs. 2 oz. baby... and on my breast milk alone, that same baby grew to a grew to 20 lbs. by 5 mos. (always in the 98th %ile for length, too). Now a toddler, that same little boy hasn't had more than a sniffle in nearly 2 years... the antibodies provided by my breast milk did that, too! I think that the extra cushioning mother nature provided me was well worth the sacrifice of my body for a short while.
4) Muscles have memory, and even though my hips widened, my rear end grew bigger, and my fit arms had a little extra layer of fat on them, I got the weight off and was fitter than before my pregnancy within 4 mos.
I think that the reason so many women are drawn to Sheila's Healthy Moms programs is that, for the first time, they find themselves in an exercise class where women aren't comparing their bodies or fitness levels with the others in the room. You don't have anyone in a thong to compare yourself to... there are women who are 9 mos. along with a little basket of baby in the front, and there are women who are 5 mos. along who have more typical pregnant bodies... but the environment is supportive, and nobody cares if you sluff through class because you are tired from spending the day barfing with morning sickness or energtic because you've reached your 2nd trimester and have a little energy boost that day. The women are there because the exercise gives them more energy, eases their strained back muscles, and makes them feel strong. The most pregnant woman in the room makes the decision of whether to add a few minutes to the 35-45 minute cardio portion, and in 16 mos. of prenatal and postpartum participation in her classes, I never once heard the most pregnant woman decline the challenge. I've been a constant exerciser in my adult life, but this was the first class wherein I met and made great friends because the environment was was so supportive. It was the coolest thing to bring my son back to class a few weeks after delivery -- I was so proud... like, "LOOK WHAT I DID!"
I've never read it, but I've always liked the title of that book, "Surrendering to Motherhood." I don't have to surrender to a weak body, but I'll be happy (well... maybe not happy about the varicose veins my genetics predispose me to... but I call them my battle scars LOL) to surrender to whatever my body needs to do to produce a healthy baby. I'll worry about getting skinny again later.
Susan