When I was expecting my first child, Pilates prepared me better than all the parenting books on my shelf put together. Because I have a bad back—a really bad back, fused throughout the thoracic spine and immobilized by two stainless-steel rods, thank you scoliosis—I worried about what all the baby carrying, feeding and bent-forward baby-gazing would do to me. So in the months leading up to my son’s arrival, I did Pilates religiously: private lessons once a week and classes twice a week, in addition to home practice. When I finally held my son for the first time, I was the strongest I had ever been. Without so much as a twinge or strain, I could lift him and carry him for hours on end—all 26 pounds of him.

Go ahead, uncross your legs: My first child came to me at the age of 19 months, through adoption. With my second child, born almost a year ago, I expected Pilates to be just as big a helper. But here was the thing: Very early on, around 10 weeks, I found that I couldn’t do my regular routine anymore. After every Pilates class, I’d come home with a piercing pain in my pelvis so fierce I could hardly walk. It didn’t take long for me to realize I needed a break—or at least a change—in my routine. So for the next couple months, I took a Pilates hiatus. I got my exercise by walking and doing water aerobics, but I still felt myself getting weak. My body was changing rapidly, and I knew I needed Pilates to stay strong.

One of my favorite things about Pilates is how flexible and accommodating it is; I knew I could adapt my routine to my pelvic issues. With a lot of research and a very good Pilates instructor, I was able to bring Pilates back into my life in a way that worked for me. What I learned in the process is that Pilates really is the perfect exercise during (and after) pregnancy: It’s all about creating space and encouraging good posture, balance, and body awareness—just what my then pregnant body needed.

Pilates Through the Changes

In the 40 weeks or so between conception and childbirth, a woman’s body goes through a seemingly impossible metamorphosis: the uterus, which previously fit neatly inside the pelvis, eventually expands all the way up to the rib cage—pushing and squishing anything in its path; blood volume increases by about 50 percent; ligaments loosen, thanks to the pregnancy hormone relaxin; and oh yeah, there’s the 25 (or more) pounds of weight gain.

It’s little wonder pregnant women get sore, tired, and just a little cranky, considering that you’re walking around with the equivalent of a pair of bowling balls strapped to your belly. As your center of gravity moves ahead of you, your spine curves forward in the lumbar and cervical areas, and the pelvis shifts back. These changes are an inevitable part of pregnancy, of course, but there are ways to minimize their impact, and Pilates offers a whole system of tools to do just that. “The five basic principles we teach clients—breathing, pelvic placement, rib cage placement, shoulder girdle movement and stabilization, and head and neck placement—educate the client on how to work out safely and effectively,” says Moira Merrithew, mother-of-two and cofounder/executive director of education for STOTT Pilates.

I eventually learned the reason for my pelvic discomfort: Relaxin had caused my ligaments to loosen, resulting in Symphysis Pubis Dysfunction (SPD). As Lynne Robinson, founder of Body Control Pilates and author of Pilates Pregnanacy Guide (Firefly Books, 2006), explains it, SPD is a relatively common condition in which the cartilage that connects the front of the pelvis slips or moves, causing sharp pains in the pubic area or groin. “The problem is often associated with sacroiliac dysfunction,” she points out, “as it is often a feature of pelvic instability.” Because pelvic instability is common in pregnancy even when it doesn’t lead to SPD, Robinson emphasizes pelvis-stabilizing exercises (targeting the pelvic floor, deep abdominals, and posterior fibers of the gluteus medius) in any pregnancy program.

Unstable joints and the shifting center of gravity work together to do a real number on a pregnant woman’s balance. I was never the most graceful person to begin with, but as my belly started to grow and my pelvis weakened, I found myself bumping into things and tripping over my son’s toys more than usual. In my defense, I couldn’t see my feet, let alone what they were about to step on. The good news is that Pilates can help with this, too. “Pilates helps your proprioception and your awareness, the ‘where I am in the world,’” explains Alycea Ungaro, PT, mom to two kids, author of the 15 Minute Everyday Pilates (DK Adult, 2007) book and DVD and owner of Real Pilates in New York City.

Toward the end of my pregnancy, as the baby continued to crowd out everything else in my abdomen, I experienced two other uncomfortable side effects: Breathing became more difficult, and I felt a burning sensation in the muscles below my rib cage. The first problem stemmed from the fact that my lungs now had to share space with the squatters in my rib cage—my stomach and intestines had migrated upward to make way for baby. Pilates breathing helped my lungs manage their new arrangement. “The concept of lateral breathing is really helpful, because as it becomes harder and harder to breathe abdominally, you learn to expand your rib cage,” Ungaro says. By placing one hand on each side of my rib cage and breathing with the intention of spreading my hands apart, I was able to find plenty of room to breathe.

The second problem, the burning under my ribs, resulted from the separation of my rectus abdominis (or six-pack) muscle, also making room for you-know-who. Apparently this condition is common enough in pregnancy to have a name. “Diastasis recti is the separation of the rectus abdominis that happens often during pregnancy,” explains Nicole Dooley Collet, new mom and owner of The Pilates Boutique in Brooklyn’s Carroll Gardens neighborhood. Unfortunately, Pilates can’t do anything to prevent diastasis, but some modifications can prevent it from worsening. “Avoid any forward thrustful movements,” Dooley Collet advises. According to Robinson, many women aggravate their diastasis by ignoring it and continuing to work the rectus abdominis during pregnancy. “If you strengthen your abdominals while separated, you may damage them and it will be even harder to achieve the flat stomach you crave after the birth,” she warns.

>> READ MORE: Pilates for Birth and Beyond