Uterus Involution

Uterus involution is a natural process that involves your pregnant uterus returning to its pre-pregnancy state. The process begins after you deliver your baby and the placenta and takes about six weeks to complete. You may experience postpartum cramps called afterpains during uterine involution.


What is uterus involution?

Uterus involution refers to the process where your pregnant uterus (womb) returns to the way it was before pregnancy. Your uterus goes through major changes when you’re pregnant. The lining of your uterus thickens, your blood vessels widen and your uterus grows several times its normal size. These changes transform your uterus into a space of nourishment and protection for a growing fetus.

Once you no longer need these changes to support your pregnancy, your uterus returns to its pre-pregnancy state.


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Why is uterine involution important?

Uterine involution is a significant post-pregnancy change that allows you to regain some comfort and fertility. Your uterus shrinks during involution, lessening the pregnancy weight your body has to carry. In addition, involution is necessary for you to begin menstruating. Instead of supporting a fetus, your uterus goes through changes that allow you to become pregnant again.

When does involution of the uterus begin?

Involution begins as soon as the placenta is delivered. The placenta is the organ that allows the mother, or gestational parent, to share nutrients with a fetus. It’s attached to your uterus during pregnancy. The placenta is delivered shortly after your baby is born.


What happens during uterine involution?

During uterine involution, your uterus returns to the condition and (approximate) size that it was before pregnancy. After your provider delivers your baby, your uterus contracts to deliver the placenta. The repeated squeezing and relaxing in your uterus muscle wall compresses the blood vessels. The narrowed blood vessels prevent you from losing too much blood at the site where the placenta was once attached to your uterus (postpartum hemorrhage).

Over the next several hours and days, your uterus continues to contract and decrease in size. It weighs less and takes up less space in your pelvic cavity as each day passes.

The lining of your uterus (endometrium) regenerates, or builds back up, too.

Uterus weight changes during involution

Uteruses generally decrease in weight along a similar timeline. That said, your uterus’s size and weight before pregnancy depend on various factors, including whether or not you’ve given birth before. Generally, people who’ve had a baby previously will have slightly larger uteruses than people delivering their first child.

The following breakdown offers an approximation of how much a uterus weighs soon after you’ve had your baby up until eight weeks.

  • After delivery: 1000 grams.
  • One week: 500 grams.
  • Two weeks: 300 grams.
  • Four weeks: 100 grams.
  • Eight weeks: 60 grams.

Uterus size changes during involution

Your uterus shrinks during involution, from roughly the size of a grapefruit that fills your entire pelvic cavity to the size of a pear.

  • After delivery: the top of your uterus is in between the joint in your pelvic bone called your pubic symphysis and your belly button.
  • Within 12 hours: The top of your uterus rises so that it’s just below your belly button.
  • Daily: the top of your uterus descends by about 1 or 2 centimeters each day until it’s between the joint in your pelvic bone and your belly button again (within about a week).

How long does involution of the uterus take?

It takes about six weeks for your uterus to return to its pre-pregnancy weight and size.


How does breastfeeding (chestfeeding) affect uterus involution?

Your uterus will shrink more rapidly if you breastfeed. When your newborn suckles, your body produces a hormone called oxytocin that causes your uterus to contract. The increased contractions narrow the blood vessels in your uterus, preventing bleeding. The contractions also cause your uterus to shrink back to its original size more quickly.

What are the symptoms of uterine involution?

You may experience pain from uterine contractions, called afterpains, and notice a discharge called lochia in the weeks following delivery. Both are normal signs of uterine involution.

Afterpains (postpartum cramps)

You may experience afterpains for a few days after having your baby, especially if this isn’t the first time you’ve given birth. As your uterus continues to contract, you may experience what feels like mild labor pains or menstrual cramps. The pain often intensifies when you’re breastfeeding your newborn. Afterpains usually become much milder and easier to manage by the third day after you’ve had your baby.


Vaginal discharge called lochia is normal after childbirth. Lochia consists of materials from your uterus that your body sheds after childbirth, including portions of your uterine lining, blood cells and bacteria. Lochia may smell musty or stale, similar to menstrual discharge. Its appearance will change as you get further away from your delivery date.

  • Days 1 to 3: dark red discharge, a few small blood clots (not larger than a plum).
  • Days 4 to 10: pinkish brownish discharge, more watery consistency.
  • Days 10 to 14: white or yellowy discharge.

It’s common to have a lochia discharge from four to six weeks after you’ve delivered your baby. You’ll likely have less lochia if you had a c-section instead of a vaginal delivery.

Diagnosis and Tests

How do you check for uterine involution?

During your postpartum checkup, your provider will check to see that your uterus is returning to its pre-pregnancy size. If your uterus isn’t decreasing in size as it should (a condition called subinvolution), your healthcare provider may order an ultrasound to see what’s happening. A uterus that is slow to involute is often the result of an infection or remaining debris in the uterus, like fragments of the placenta.

Living With

How do I take care of myself?

Wearing pads can help manage the lochia. Avoid using tampons or inserting anything inside your vagina until six weeks after having your baby or until your provider says it’s safe.

Afterpains can be intense, especially during breastfeeding. You may feel intense cramping lasting about five minutes and then gradually eases. To manage afterpains:

  • Take a walk.
  • Apply a heating pad to your stomach.
  • Lie on your stomach with a pillow under your lower belly.
  • Try the breathing and relaxation exercises you used to lessen labor pains.
  • Take an over-the-counter pain reliever recommended by your healthcare provider. Ibuprofen may work better than acetaminophen.

When should I contact my healthcare provider?

Cramping and discharge are normal after you’ve had your baby, but excessive bleeding or signs of infection require medical attention. See your provider if you notice any of the following:

  • Fever.
  • Foul-smelling discharge.
  • Blood clots that are larger than the size of a plum.
  • Severe pain or cramps lasting longer than three days after delivery.
  • Heavy bleeding (you have to change your pad more than once per hour).

A note from Cleveland Clinic

Your body changes rapidly to adjust to pregnancy. Similarly, your body rapidly reverts to its pre-pregnancy state. Consider that your uterus loses half of its pregnancy weight just one week after you’ve had your baby. You may notice unpleasant side effects in the meantime, like afterpains. Remember that mild cramping a few days after delivery is a good thing. It means that your body is returning to its new normal. Pain medications, heating pads and light exercise can help ease the discomfort as your uterus gets smaller.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 04/01/2022.

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