When a person becomes pregnant, they undergo many visible transformations, including changes to the belly button. This change, where an “innie” navel flattens or protrudes to become an “outie,” is formally known as umbilical eversion. It is a normal physical development signaling significant growth within the abdomen. This temporary reshaping of the navel is a noticeable milestone in pregnancy.
The Mechanism: Why the Belly Button Changes Shape
The primary reason for the navel’s change is the increasing pressure exerted by the expanding uterus. As the fetus grows, the uterus rises out of the pelvis and pushes against the abdominal wall. The belly button is an area of slightly weaker tissue, as it is the remnant of the umbilical cord scar.
This internal pressure stretches the surrounding skin and connective tissue, causing the “innie” indentation to push outward. The abdominal muscles, specifically the rectus abdominis, also stretch and often separate along the midline connective tissue called the linea alba. This combination of forces causes the navel to flatten and, in many cases, protrude into an “outie”.
It is important to distinguish this normal eversion from an umbilical hernia, which is a different condition. An umbilical hernia occurs when a small part of the intestine or fatty tissue bulges through a weak spot in the abdominal wall near the navel. While a protruding navel can signal a hernia, the eversion of a pregnant belly button is usually just skin being pushed out. If the protrusion is painful or feels like a distinct, firm lump, a healthcare provider should evaluate it.
Typical Timing and Variability of Umbilical Eversion
The navel’s appearance typically changes in the late second or early third trimester, when the uterus has expanded considerably. Most individuals notice their navel beginning to flatten or protrude around 26 weeks, but timing varies widely. By this stage, the top of the uterus, known as the fundus, has usually grown well above the level of the navel.
The exact timing is not uniform and depends on factors including the individual’s body shape and the strength of their abdominal muscles. For people who have been pregnant before, the navel may change earlier because the abdominal muscles and connective tissues have already been stretched. It is also common for the navel to simply flatten out, becoming flush with the surrounding skin, rather than completely protruding.
Some individuals experience mild discomfort or irritation when their newly protruding navel rubs against clothing. A simple remedy for this friction is to cover the area with a soft bandage or wear loose-fitting clothes. Not every pregnant person will experience their navel changing from an innie to an outie, and this lack of change is also considered completely normal.
Postpartum Resolution and Long-Term Appearance
The transformation of the navel is temporary and typically reverts to its original shape after delivery. Once the baby is born, the internal pressure on the abdominal wall immediately decreases. The uterus then begins shrinking back to its pre-pregnancy size over the following weeks and months.
As the uterus recedes and the abdominal wall gradually regains some of its tone, the navel usually returns to its “innie” state. The timing of this return varies, but for most people, it happens within a few months postpartum. While the shape generally returns, the appearance may be slightly altered due to the stretching the skin endured.
The navel may appear a little wider or the skin around it may be looser than before the pregnancy. In some cases, a persistent outie postpartum may indicate an umbilical hernia, especially if it is accompanied by a separation of the abdominal muscles known as diastasis recti. In the vast majority of cases, the navel’s change is a harmless, temporary physical effect of carrying a baby.