Postural shifting during pregnancy creates uncomfortable strains on the pregnant woman's musculoskeletal system, particularly her weight-bearing joints, and is one of the most common reasons women seek prenatal massage.

As the fetus gets bigger, the uterus expands from the pelvis to the abdominal region. To accommodate this growth, the abdominal muscles stretch, weaken and separate, creating the diastasis recti abdominis, or the separation of the two bellies of rectus muscle along the linea alba. The separation is not painful or harmful to the mother or baby and usually is located above and below the umbilicus where the abdomen is stretched the most, but can run the entire length of the linea alba. This loss of core integrity, coupled with the bulk and weight of the uterus, encourages an anterior pelvic tilt and increased lumbar compression. With the help of the hormone relaxin, a hormone synthesized in the ovaries and stored in the placenta which relaxes the elastic ligaments of the pelvic bones, the hips widen and the ribs expand as much as 2 to 3 inches anterio-lateral. Relaxin also softens the connective tissue to provide room for the growing uterus and making the joints more flexible. In order to maintain an erect posture, she leans backwards, further compressing the lumbar spine and musculature. Her shoulders laterally rotate and her cervical spine compensates by protracting her neck (thereby compressing the cervical vertebrae and contributing to hand weakness and carpal tunnel syndrome). To support a pregnant woman's weight and maintain balance below the pregnant pelvis, the hips laterally rotate, the knees hyperextend and the medial arches might collapse.

While it's not possible to stop this process from occurring, it is possible to minimize this maladaptive posture by strengthening the core muscles during pregnancy and restoring some of the weakened structural integrity. When the abdominal muscles stay as intact as possible, many of the common discomforts of pregnancy and postpartum recovery, particularly those associated with back problems, can be reduced or eliminated. The gravida will experience more lumbar stability during pregnancy and be able to recruit strengthened abdominal muscles during birth.

A large majority of the pregnant population, as much as 80 percent to 90 percent, will develop a diastasis by their final trimester. Other non-pregnancy causes of this muscle separation are obesity and chronic, obstructive lung disease. Unless pregnant and postpartum women learn to exercise and use their abdominal muscles correctly, these complaints might plague their pregnancies and extended recoveries. Traditional crunches and sit-ups actually do more harm than good by increasing the separation of the rectus bellies. The missing link to abdominal strength and core integrity during pregnancy, postpartum recovery (as well as everyday life for everyone), is to recruit the deepest of the abdominal muscles, the tranverse abdominis.

There are four pairs of abdominal muscles: the rectus abdominis, the external/internal obliques and the transverse abdominis. The rectus has its origin at the costal cartilages of the fifth, sixth and seventh ribs and the xiphoid process of the sternum. Fibers run longitudinally along the anterior abdominal wall and insert at the pubic crest and symphasis. Its posterior lamina fuses with the aponeurosis of the transverse abdominis to form the dorsal layer of the rectus sheath. Muscle bellies on either side are connected by the linea alba. Its action is to flex the vertebral column (forward bending).

The second and third layers are the external and internal obliques. The anterior fibers of the external obliques originate at the external surfaces of the fifth through eighth ribs and the lateral fibers originate at ribs 9 through 12. Its fibers run inferomedially and attach anteriorly as an aponeurotic sheath at the linea alba, inguinal ligament, anterior superior spine and pubic tubercle. The lateral fibers attach into the external lip of the anterior half of the iliac crest. Bilateral action flexes the vertebral column and unilaterally they rotate the vertebral column. The lower fibers of the internal obliques, which run horizontally at the level of the anterior inferior iliac spine (AIIS), obliquely upward superior to the AIIS and obliquely downward inferior to the AIIS, originate at the lateral 2/3 of the inguinal ligament and iliac crest. They insert with the transverse abdominis into the pubic crest and linea alba. Its fibers also attach anteriorly as an aponeurotic sheath. The lower anterior fibers compress and support the lower abdominal viscera in conjunction with the transverse. The lateral fibers originate in the middle third of the intermediate line of the iliac crest and thoracolumbar fascia. Insertion is at the inferior borders of ribs 10 through 12 and linea alba. Bilaterally, these muscles flex the vertebral column while unilaterally they rotate the vertebral column.

The deepest, most intrinsic abdominal muscle is the tranverse abdominis. It originates at the inner surfaces of the cartilages of the lower six ribs, the transverse processes of the first four or five lumbar vertebrae, thoracodorsal fascia, anterior internal lip of the iliac crest and lower third of the inguinal ligament. Its fibers run horizontally and attach anteriorly as an aponeurotic sheath at the linea alba, pubic crest and pectin of the pubic bone. Its action is to flatten the abdominal wall, compress the abdominal viscera and stabilize the lumbar spinal segment. When the transverse is contracted (pulled in), all of the overlying muscles contract at the site of their mutual connection, the linea alba, thereby minimizing the diastasis.

Flexion and rotation are major roles of the abdominal muscles. They also play an important role in postural stability and intra-abdominal pressure. An increase in intra-abdominal pressure is necessary for defecation, urination, childbirth and forced exhalation. It wasn't until recently that the intra-abdominal pressure could be tested on all four muscle groups. In 1992, a study showed the activity of the transverse abdominis was associated with increased intra-abdominal pressure. This discovery led researchers to believe that when the transverse abdominis is recruited, it provides considerable trunk stabilization.

In order to experience this stabilization and core integrity yourself, try this simple experiment: walk around the room with your body relaxed. Continue walking at the same pace and breathe normally as you tighten your transverse by bringing your navel to your spine. Keep breathing. How do you feel now? Taller? Stronger? Another way to experience the power of core integrity is to sit comfortably in a chair with your feet on the floor. Bring your arms above your head as if you were doing a dumbbell shoulder press. Lower and raise your arms repeatedly a few more times. For the next few "presses," breathe normally and tighten your transverse. Breathe normally. Do you notice how much stronger you feel?

With a strong, integrated core, a good deal of the postural problems and lumbar instability associated with pregnancy and postpartum recovery can be avoided. After the baby is born, the diastasis does not self-heal and repeated lifting of the (growing) baby and household chores can lead to long-term referred backaches. A new mother should remember to recruit her transverse abdominis whenever she lifts her child or does any type of physical activity.

How do you know if your pregnant client has a diastasis? There is a very simple way to test for it. Have your client lie on her back on the massage table with her knees bent. Stand at the side of the massage table facing your client and place your fingertips (usually three fingers) across her linea alba just above her pubic bone. Have her take a deep breath. As she exhales, have her tuck her chin to her chest and lift her head and shoulders off the table. This will cause her abdomen to protrude (she is actually doing a crunch). As she holds this position, gently (and quickly) glide your fingers across the linea alba from her pubic bone all the way up to her xyphoid process. If the space between the bellies of the rectus abdominus is wider than half a finger's width, she has a diastasis. The number of fingers that fit into the separation indicates how wide it is. Your client can also test herself. With her fingers placed below her ribs, she lifts her head as described above, and follows the linea alba down to the pubic bone.

A recent study done by students at the Columbia University School of Physical Therapy hypothesized that pregnant women who did not exercise had a 90 percent incidence of diastasis recti as compared with 12.5 percent in the exercising group who used their transverse abdominis during exercise. The non-exercising women also had larger separations than their exercising counterparts. Since pregnant women are advised to avoid supine positioning after the first trimester, another advantage of transverse abdominal work is that many of the exercises can be performed in a comfortable sitting position. This also is beneficial for older clients or for anyone who has difficulty lying down to exercise.

In order to help your pregnant and postpartum clients, as well as those clients with chronic backaches, don't overlook the importance of proper abdominal exercises - those that emphasize the use of the transverse abdominis - to stabilize the lumbar spine and minimize backaches.