Is It Safe to Do Sit-Ups or Crunches While Pregnant?

Staying fit during pregnancy is important for your health, and there are many benefits to working your abdominal muscles during this time. However, doing sit-ups or crunches while pregnant is probably not a good idea.

ACE-certified fitness trainer Caitlin Sacasas explains that after the first trimester, or after you begin to have a noticeable uterine growth, it's best to avoid these core exercises. Fortunately, there are plenty of alternatives or modifications you can try instead to keep your core strong while pregnant.

Benefits of Ab Work in Pregnancy

Keeping your core strong throughout your pregnancy and the postpartum period has several important benefits. First and foremost, core work can help support your pelvic floor muscles, which are responsible for supporting your digestive organs and controlling your bladder. Strengthening them can help prevent issues like frequent urination during pregnancy.

Working on your core can also improve back pain caused by the pull of your baby bump. When you strengthen your core, it helps support your entire body, which takes some of the (literal) weight off of your back muscles. This means you have more muscles working to support you, which can ease the strain on your back.

Finally, it can help you have an easier labor and postpartum recovery. Though studies show no clear association between abdominal strength and delivery outcomes, anecdotal evidence suggests that a stronger core may help you push more effectively.

Risks of Ab Work During Pregnancy

Despite these benefits, not all types of core work are safe to continue when you are expecting. Sit-ups and crunches in particular present a few issues. These movements cause the abdominal muscles to bulge out, which can contribute to diastasis recti, the separation of your rectus abdominis (your ab muscles) at the midline.

During pregnancy, your body experiences hormonal changes meant to support your baby's growth and your own physical health. Increased levels of the hormones relaxin and progesterone relax your muscles and loosen your ligaments and joints to make room for your growing baby and minimize the physical stress on your body.

If this stretching is exaggerated, like when you crunch up for a sit-up, the two sides of your abdominal muscles can separate completely. This separation can worsen over time and can become permanent, requiring surgery. Avoiding crunches throughout your pregnancy can help prevent this.

Complications of Lying on Your Back While Pregnant

Besides the crunching motion, any ab exercise that has you lay on your back can pose a risk to your and your baby's health. Lying on your back during pregnancy can compress the vena cava, the large vein that carries blood to the heart from other areas of the body.

During pregnancy, your uterus and its contents (the baby, placenta, and amniotic fluid) weigh a lot more than when you are not pregnant. When you lie on your back, this weight falls upon the vena cava and can constrict blood flow.

According to Sacasas, the start of your second trimester is generally the time at which it becomes unsafe to continue exercises in the supine position because of this increased weight. But since every pregnancy is different, always check with your healthcare provider if you're unsure what exercises you can do.

Pregnancy-Safe Core Exercises

There are several options for safe ab work during pregnancy. Some examples include:

Cat-cow pose: On all fours, inhale while gently bending your spine in toward the floor and exhale while rounding your spine.

Seated pelvic tilts: While seated, inhale with a straight spine and exhale while tucking the pelvis in and up towards the navel. Repeat five times or more.

Bird dog: On all fours, raise your right arm and left leg, keeping your shoulders and hips parallel to the floor. Hold for a few seconds, lower down, and switch sides. Repeat about 10 times.

Modified side plank: Prop yourself up with your right arm (or forearm) and right knee. Lift your hips so that your body forms a straight line. Hold for a few seconds and then switch sides.

When Can I Do Sit-Ups or Crunches After Birth?

Immediately following childbirth, your body will undergo a gradual healing process. "After you've had your baby, it's still best to avoid sit-ups and crunches until your abs have fully healed," Sacasas advises.

The healing process might take anywhere from six weeks to six months or longer. Because every body is different, have your OB/GYN or healthcare provider check your ab muscles to see how they're healing.

Getting back into your regular ab routine doesn't have to be immediate either. "Starting back, stick with exercises like planks that work on whole core stability and obliques to help rebuild strength," Sacasas says.

A Word From Verywell

Pregnancy is a natural, biological process during which your body experiences many changes. These changes, such as the stretching and softening of your muscles are normal and help you have a healthy baby and pregnancy.

During the postpartum period it is normal and healthy for these changes to reverse gradually. There is no need to rush, and feeling your best should be your focus. The most important part of staying fit during and after pregnancy and childbirth is your long-term health.