Diastasis rectus abdominis

A diastasis of the rectus abdominis muscle is a gap that has formed between the two bellies of the rectus abdominis, or "six-pack" muscles. During pregnancy, as the uterus grows in size, the stomach muscles must stretch to accommodate this. Towards the later stages of pregnancy many women notice a bulging or dome shape in the middle of their abdomen when they perform activities like getting up off the floor or out of the bath. So what exactly is it, and what should women do about it?

Anatomy first
The rectus abdominis is the most superficial of all abdominal muscles, meaning that in people with low body fat, the rippled outline of the muscle can sometimes be seen just below the surface of the skin, hence the term six-pack. It runs from the end of the sternum (chest bone) right down the centre of the abdomen and inserts into the pubic bone. Its main function is to help flex the trunk, or perform an action like that of a sit-up or abdominal crunch. Running centrally between the two bellies of the muscle is a region of connective tissue called the linea alba. In many pregnancies, this connective tissue can stretch apart or separate. When this happens, many women will become aware of a characteristic bulge around the area of the belly button when they perform certain activities, such as getting out bed.

According to the literature, a diastasis or separation of the rectus abdominis (DRA) muscles occurs in approximately 35-62% of pregnant women and is most commonly seen in the second and third trimesters. The diastasis may range from a small 2-3 cm gap, to a 12-20cm separation, most commonly seen at the level of the umbilicus or belly button, but potentially extending the whole length of the muscles. Hormones released during pregnancy cause softening of the joints of the pelvis and spine. This hormonal infuence is believed to be one of the predisposing factors in DRA. In addition, the mechanical strain placed on the abdominals by the enlarging uterus is another causative factor.

Am I at risk?
Risk factors such as older maternal age, having your second or further child, multiple gestations, larger babies and a larger overall weight-gain for the mother have all been reported in studies. It is important to note however, that it is still quite possible to have a woman in her first pregnancy, with a relatively small abdomen, but quite a large separation when measured for DRA post-natally. I quite frequently see this when teaching post-natal classes. A possible explanation is that we all have differences in our connective tissues - a prime example being that many lean women still experience stretch marks, while some larger women have never seen one in their lives!

It is thought that the presence of already weakened abdominals, or incomplete recovery from a previous pregnancy, may be related to the higher incidence of DRA in second and subsequent pregnancies. In addition, any repetitive activity that results in an increase in intra abdominal pressure (such as lifting other children, coughing etc) can lead to the development or worsening of DRA. Some studies have also shown a link between DRA and a lack of regular exercise during pregnancy.

Long-term problems
For some women, a DRA is a normal change associated with pregnancy. However, if a woman is unaware of this condition she is more likely to unintentionally exacerbate the problem by performing activities that may make it worse. Similarly, while some small DRAs will resolve spontaneously in the post-natal period, others may not. A large diastasis left unattended may not resolve and can lead to problems such as decreased control of the spine, worsening low-back pain, abnormal posture, and possible cosmetic defects. A recent study published in the International Urogynecology Journal even found that there was  a relationship between the presence of a DRA and incontinence.

How to check for DRA
If you are pregnant, or in the early post-natal period, and have noticed the characteristic bulge, I would recommend asking your midwife, physiotherapist or obstetrician to check it for you. If you have already had your baby, you can do a self-check for a diastasis at any point in the postnatal period.

Lie down on your back with your knees bent. Then place your fingers length ways (pointing towards your pubic bone), in the middle of your abdomen at the level of your belly button and press gently towards the floor. Now lift your head and shoulders off the floor, pressing down with your fingers at the same time. If you can feel the edges of the rectus muscles on either side of your fingers then this may indicate a gap or DRA. A gap of approximately two fingers or less is considered relatively minor and not a problem. As a general rule, anything larger than this requires attention. If you find this hard to feel, or aren't sure but still concerned that you may have a gap, then ask your midwife, physiotherapist or doctor to check it for you. Not all health professionals in New Zealand routinely screen for DRA, so you may need to ask.

I have a gap. What should I do?
During pregnancy, I would recommend certain activity modifications where possible, along with regular activation of the transversus abdominis (TVA) muscle. This is the deepest of the abdominal muscles and functions a bit like a corset to help stabilise the spine and pelvis. By bracing your TVA, you are actively helping support your spine and this can assist in decreasing the characteristic bulging of the abdominal wall during physical activities.

Core muscle (TVA) activation: Start by sitting well supported, or lying on your side with a gentle curve in your lower back (neutral spine). Now let your abdomen relax completely. Very gently draw your lower tummy area towards your spine. The movement should be very subtle. Ensure you aren't sucking in your ribs and that you continue to breathe gently. Nothing above your belly button should move. Then relax completely and let it go.

Some women find that their pelvic floor muscles contract gently when they do this, which is normal. If you are still pregnant, you might like to think of this exercise as gently "hugging" your baby. TVA activation can be done regularly throughout pregnancy and the post-natal period to help strengthen this region and to help your muscles recover post-natally. It is safe to do after a C-section or with a large DRA.

Recommendations during pregnancy
Avoid sit-ups. These place unnecessary stress on the abdominal muscles and it isn't a good idea to lie flat on your back after the second trimester.

Engage or brace your TVA every time you perform an activity such as picking up other children, lifting the washing basket or groceries etc.

When getting out of bed, engage your core (TVA) by flattening the lower tummy and roll onto your side while pushing up through your arms, rather than hauling yourself up with your tummy muscles.

When getting into or out of the bath, use your arms rather than your abdominals to help yourself in and out, and don't forget to engage your TVA muscle.

Try and avoid any activity that causes the characteristic bulge to occur. For example, use the ladder to get out of the swimming pool, rather than hauling yourself up with your arms and abdominals.

Recommendations post-pregnancy
If possible attend a physiotherapy-based post-natal class while still in hospital, or ask your midwife or doctor to check your tummy for you. If a significant DRA is found, you should ideally be referred to a women's health physiotherapist.

Try to wear supportive underwear, or a long fitted top such as a tube top, under your clothing for a few weeks after the birth. This provides external support and proprioceptive feedback to the abdominals (reminding them which direction we want them to go in).

Avoid any heavy lifting where possible, for at least six weeks. If you do have to lift something (like another small child), make sure you engage your TVA to provide extra support. This is even a good habit to get in to when lifting up your baby.

Avoid carrying heavy and awkward baby capsules. Leave them in the car and transfer baby to a sling or a push-chair.

Make sure you are doing regular TVA holds. In the immediate post-partum period, start in side-lying position and try holding for five to six seconds at a time, repeating up to 10 times. Ensure you don't hold your breath, and try and do them regularly throughout the day, such as when feeding your baby.

Avoid any crunches or sit-ups, as this could make the separation worse or prevent it from healing.

Be sure you are also doing pelvic floor exercises. Ask your LMC if you are unsure.

When you feel comfortable, it is fine to gradually return to a low impact exercise such as walking. Always be aware of your posture and avoid any activity that places pressure on your recovering abdominal muscles.

Ideally, you need to progress your abdominal stabilisation exercises. This is best done under the guidance of a women's health physiotherapist. 

Lisa Yates is the mother of two young girls and an experienced physiotherapist with a special interest in women's health. She is passionate about obstetric and continence physiotherapy and is also a women's personal trainer and wellness coach.