The uterus returning to a normal size after delivery generally takes 6 weeks, it could take 8 weeks.
At that time the bleeding has resolved, the lining has returned to a quiet state, and it has become the size it will remain until pregnant, medical changes (growth of fibroids) or menopause.
This process is called uterine involution and this process naturally occurs after all pregnancies, including miscarriages or terminations of pregnancy. If a pregnancy only lasted a month the involution sequence can occur at a much more rapid pace.
Uterine involution is part of the reason for the abdomen getting ‘flatter’ after delivery, but overall weight gain, muscle tone, and muscle separation affect the abdominal flatness. The involution of the uterus will not be the deciding factor as to when you can start to exercise. EmSculpt technology can help close the diastasis or muscle separation..
In some women the uterus will not shrink as much as in others, but there’s no medical evidence that the ultimate size of the uterus has any effect on the health of the uterus.
After the placenta is expelled from the uterus, immediately the walls made of a muscle layer known as the myometrium begins to contract, so that process of returning to normal size begins immediately. The contraction of the muscle layer helps to seal blood vessels that fed the placenta and are a critical step in reducing the bleeding after delivery. This is why administration of medications that enhance this muscular contraction, such as pitocin or misoprostol, helps a woman to lose less blood after pregnancy.
The top of the uterus reaches the bottom of the rib cage at full term, but with in the first day it’s located around a woman’s belly button. It will then shrink back at the pace of about one centimeter per day, and be about half way the distance between your belly button and your pubic bone by the first week!
By two weeks out the top of the uterus cannot be felt on abdominal exam.
Women who had twins (or more!) or a very over distended uterus will take slightly longer to go through the process.
The smaller the uterus is, the thinner the lining tissue is. As the lining thins, the bleeding will generally decrease and stop. Some placental fragments may still persist, but they should be small or microscopic, and not change the size of the uterus immediately post delivery.
Since the uterus is a bit larger if you have already had a baby, and the muscles of the uterus contract better when you breastfeed, lots of factors will actually impact the final process of uterine involution and the ultimate size of the uterus between babies. One more good reason to breastfeed your baby!
The uterus weighs about 60 grams before pregnancy, about 1000 grams at full term, and it shrinks back to about 60-70 grams. The amount of bleeding and the exact size of the uterus do not always go hand in hand.