Given all the stretching that your ab muscles go through during pregnancy to accommodate your growing baby, you wouldn't be the first woman to wonder if there must be something you can do to strengthen them and speed recovery after birth.

The good news: You can take steps to maintain your fitness and keep your core strong while pregnant. In fact, exercising your abs during pregnancy (with your practitioner's go-ahead) has lots of benefits, including reduced risk for back pain and potentially even a speedier labor.

Nonetheless, certain physical changes can make it more difficult to stick to the abs routine you practiced before you were pregnant. Here's what you need to know about your abs during and after pregnancy, along with some safe core exercises you can try while you're expecting.

Are ab exercises safe during early pregnancy?

Unless your practitioner has restricted exercise during pregnancy, most abdominal exercises (with some modifications, as there are some exercises to avoid while you're pregnant) are safe early on.

What's more, your baby bump — which can make some abdominal exercises more difficult as you progress throughout pregnancy — likely won't make an appearance until the second trimester.

What happens to your abs during pregnancy?

Late in your first trimester, you may notice something different about your belly besides, of course, a baby bump: an accentuated ridge that runs from the bottom of the breast bone down the middle of the belly.

Known as diastasis recti, this gap between the left and right sides of your abdominal muscle affects up to an estimated half of new moms. It sometimes widens by a few centimeters as your baby grows and puts tension on the area. Women who are carrying multiples or have already been through several pregnancies are particularly prone to separation.

By the 12-week mark, be sure to look for diastasis recti. Since the condition often doesn't develop until later in pregnancy, continue to check periodically. If, at any point, you do notice a gap in your abdomen that's wider than three finger-widths apart, you will need to modify your ab workouts during and after pregnancy.

The good news is that diastasis recti heals on its own (with a little help from you) after birth.

Is it safe to do ab workouts while pregnant?

With your practitioner's okay, it's safe to exercise your abs throughout your entire pregnancy with the proper modifications.

In fact, strengthening your abs when you're expecting supports your pelvic organs as your baby bump gets bigger. Strong abs can also alleviate pressure on your back and promote proper posture, fending off the lower back pain that's so common during pregnancy.

And a strong core may help increase your sense of control during labor as well as help you recover more quickly after giving birth.

Ab exercises to avoid during pregnancy

Throughout your pregnancy, you'll want to skip full sit-ups and double leg lifts because they put more pressure and pull on the abdomen. Also, avoid moves that involve contortions or bending over backward. Be sure to breathe steadily as you exercise to ensure you and your baby are getting a steady flow of oxygen.

After you've reached the end of your first trimester, you'll want to avoid any exercises that involve lying face-up on your back, like crunches. They can put too much pressure on the vena cava, the vein that carries blood to your heart.

Instead, prop yourself up so your heart is above your navel using your forearms, a wedge, a couple of pillows or a Swiss ball. Or practice exercises performed in alternative positions, like lying on your side, standing upright or on all fours.

If you discover you have diastasis recti with a gap of more than three fingers-width, avoid crunches, sit-ups and other exercises where your abs bulge, since they put extra strain on the area.

Most importantly, always listen to your body: If an exercise doesn't feel right (and especially if it feels painful), stop right away. Check in with your practitioner and a personal trainer if you're concerned, since there are many alternative ab exercises that are perfectly safe for expecting women.

Can you do planks while pregnant?

Yes, planks are safe for most women throughout pregnancy. Static, endurance-based exercises like planks are actually ideal for expecting women because they strengthen both your abs and your back. They also put less pressure on the spine than dynamic exercises, like crunches.

Again, listen to your body: If you feel too much strain, hold your plank for several shorter sets of 5 to 10 seconds. If it's still too difficult, keep your knees bent slightly or rest them on the floor.

Safe ab exercises for pregnancy

Try these core-strengthening moves at any point during pregnancy:

Transverse abdominis breathing

Sometimes called diaphragmatic breathing or belly breathing, transverse abdominis breathing targets your deepest core muscles (which maintain healthy posture and prevent back pain) as well as your pelvic floor. It’s a great way to begin any ab exercise and maintain good core stability throughout the movement.

  1. Stand or sit tall with hands on your sides. Inhale to expand through your sides, back and belly.
  2. Exhale to contract, pulling your belly in and up, while lifting with your pelvic floor
  3. Think of "hugging your baby" toward you while contracting and releasing the pelvic floor.

Do 3 sets of 10 reps.

Glute bridge

  1. Begin laying on your back with feet planted about hip-width apart and knees pointed up. Your heels should be close enough to your butt that you can reach the back of your heels with your fingertips. 
  2. Start with a deep core breath to brace your core.
  3. Press through your heels to lift your butt off the floor. Be careful not to over extend at the top, and avoid arching your back.
  4. Slowly roll back down to your starting position, releasing the pelvic floor when your hips come to the ground.

Do 3 sets of 10 to 15 reps.

Side plank

  1. Begin laying on your left side with your elbow underneath your shoulder. Hips should be stacked and facing forward, and legs should be long and stacked. To modify this ab exercise, bend your knees.
  2. Lift your right hip up to engage your obliques (the sides of your core). Balance on the side of your bottom foot or, to modify, balance on your bottom knee while extending your top leg straight, placing the foot on the floor for stability. 
  3. Hold for 20 seconds, then lower down with control. Repeat on the opposite side.

Do for 6 reps, 3 on each side, alternating every time. 

Bird dog

  1. Begin in a quadruped position (all fours, with hands below shoulders and knees below hips). 
  2. Extend your right hand and left leg and pause, reaching long through your fingertips to toes. Bring both down to the starting position. 
  3. Repeat on the opposite sides (left hand and right leg), and continue alternating. Tip: Shift your hips forward for more core engagement or shift them back for more stability. 

Do 3 sets of 30 seconds.

Squat with rotation

  1. Begin standing with your feet a little more than shoulder-width apart, toes turned slight out. Bend at the knees, coming into a deep squat. Keep your chest lifted and core engaged.
  2. Press through your heels to come to standing as you rotate through the knees, hips and torso, extending arms up to one side. 
  3. Squat back down, then repeat the rotation on the opposite side. Continue alternating. 

Do 3 sets of 30 seconds.

Knee lift

  1. Begin sitting on your butt with your knees bent, heels on the ground and arms behind you, fingertips pointed toward your heels. 
  2. Brace your core, and lift your hips to come into a "crab" position. 
  3. From there, inhale, then exhale to lift one knee, crunching it in toward your chest, then return your foot to the ground. Repeat on the opposite side. Continue alternating. 

Do 3 sets of 10 to 12 reps. 

What happens to your abs after pregnancy?

You can begin to exercise your abs as soon as 24 hours after vaginal delivery, assuming you had an uncomplicated pregnancy and delivery and the go-ahead from your doctor. Of course, it may be the last thing on your mind that soon after giving birth, so ask whenever you're ready to start exercising again.

If you've had a C-section, you'll have to wait a few weeks and until your incision heals before your practitioner gives workouts the green light.

If you do have a separation in your ab muscles, it can take a month or two after delivery for this opening to close. You'll have to mind the gap before you start those crunches or ab exercises again, lest you risk an injury. You'll want to avoid knee-to-chest exercises, full sit-ups and double leg lifts during the first six weeks postpartum.

After giving birth, you can help mend the gap with this simple exercise that activates your transverse abdominal muscles: 

  • Lie on the ground with your knees bent and your feet planted flat on the floor.
  • As you exhale, draw the sides of your abdominal muscles together with your fingers. At the same time, pull your belly button down toward your spine.

Doing pelvic tilts can also speed the recovery process along so that your core gets back to full strength — and you can get back to your usual ab workouts.