Why belly button pain during pregnancy is still a mystery

Belly button pain.
Many women experience belly button pain during pregnancy, but doctors aren’t sure what causes it.

I frequently have patients talk about belly button pain, usually starting in the second trimester. Although I’ve heard this complaint often, I’m not exactly sure what could be causing the pain.

All I really know about belly button pain during pregnancy is that some patients are really, really sensitive to the touch of the ultrasound transducer, right around the belly button. Does belly button pain really start during the second trimester, or is it more a matter of my associating the symptom with the middle of pregnancy simply because that’s when I see these patients for their ultrasounds? It’s a good question, and I can’t be sure.

While we don’t have a satisfying explanation, I’ve seen the condition enough times in enough patients to know it’s real. So what are the possible reasons for this symptom?

Misconceptions about belly buttons

Let’s start with what does not cause belly button pain.

Many patients ask what their belly button is connected to, thinking there’s something tugging the navel from within the abdomen that could be responsible for their pain. Others believe their belly button is somehow connected directly to their uterus or the placenta or even the baby’s belly button.

This isn’t the case. As you can see in the picture below, the belly button normally isn’t connected to anything in adults. It does play an important role for developing fetuses, however.

Why do we have belly buttons?

Inside view of belly button.
This photo shows what the belly button looks like from inside the abdomen. As you can see, it is not attached to anything in the body.

The belly button is where the umbilical cord attaches to the fetus, connecting the developing baby to the placenta. Within the cord, there are blood vessels (the arteries) that carry waste away from the baby and another vessel that supplies the baby with oxygen and other nutrients.

Early in the baby’s development, a structure called the urachus connects the umbilical cord to the developing fetal bladder and acts as a bladder until the baby’s own becomes functional. Before birth, the urachus scars over and becomes a ligament (the median umbilical ligament, to be exact) that runs from below the belly button to the top of your bladder. In the picture above, it’s the shiny white line running the length of the image. 

Occasionally, scarring doesn’t occur and the connection between the bladder and the belly button persists after birth. This is extremely rare, however, and happens in only one of every 5,000 people. So, it’s unlikely that the urachus would persist throughout a woman’s adult life and cause her belly button pain during pregnancy.

Unexplained belly button pain

Generally, patients experience belly button pain when I push on that area. Some patients, however, are very sensitive and just touching the skin makes them flinch.

This confuses me even further, because nerves in the skin are entirely separate from everything within your abdomen. Sensitive skin, therefore, shouldn’t be caused by the changes happening in your abdomen during pregnancy.

And finally, the belly button is the thinnest part of the abdominal wall. Perhaps that’s why that area tends to be more sensitive as your pregnancy progresses. 

In my experience, the belly button pain typically gets better later in pregnancy. I don’t know if that because women just get used to it, or whatever was causing it goes away. Until then, local warmth, acetaminophen, or a maternity support belt might help alleviate the discomfort.

Belly button pain that I can explain

There are a few causes for belly button pain that make more sense. One is the development of an umbilical hernia, where intestines pouch out into the belly button. If the bowel gets trapped in this space, it can become inflamed and painful. This condition is easy to identify because you will feel a hard mass in the belly button. Contact your doctor if this happens.

Another possible source of pain is the stretching of scar tissue that might be attached to the belly button. The photo above shows the inside view of what the belly button usually looks like. If you’ve had previous surgery, other structures like the bowel or omemtum can be stuck there and might cause discomfort when tugged by the growing abdomen.

Looking into other explanations

I still don’t have a good understanding of why women develop belly button pain during pregnancy. I’ve asked experts in abdominal wall and pelvic surgery for their opinions, and no one can offer a satisfactory explanation.

But the phenomenon is absolutely real – I’ve seen it too often to doubt that it exists. You’re not crazy – but be assured that it probably isn’t serious.

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