Many people say they weren’t properly warned about just how intense the pain could be.

On social media, users seem to have reached a surprising consensus about what may be the most painful physical experience a person can endure—and it’s left many feeling angry and misled.

When the topic of extreme physical pain comes up, the usual answers are predictable. For men, it’s often described as a brutal kick to the groin. For women, childbirth is commonly cited.

For some, those experiences truly are the most painful they’ve ever faced. But others argue that pain can go far beyond that. In fact, some studies have suggested that passing kidney stones can be even more painful than either of those experiences.

Recently, however, a Reddit discussion introduced another contender—one that many women insist surpasses even childbirth in terms of pain.

Unlike kidney stones, this experience applies only to women. Still, numerous commenters said they had endured long, painful labor or C-sections and would still rate this as worse.

So what is it?

According to many users, it’s the insertion of an IUD.

An IUD (intrauterine device) is a small, T-shaped form of birth control placed inside the uterus to prevent pregnancy. The UK’s National Health Service (NHS) states that IUDs are about 99% effective and do not rely on hormones, though they aren’t suitable for everyone.

Women on Reddit shared their personal experiences with IUD insertion, describing severe pain and frustration—particularly over how little they were warned beforehand. Many said medical professionals minimized the procedure, leaving them unprepared for how intense it could be.

Some commenters argued that stronger pain management should be standard, including painkillers, gas, or other medication to reduce suffering during the procedure.

One person commented: “I’ll preface this by saying that I’ve broken my femur, arm, and hand. I’ve broken a molar in half. I sliced my eyeball. I suffered a third degree burn on my hand. I’ve had two reconstructive surgeries on my shoulder. I had 3 holes drilled in my skull and underwent brain surgery.

“My most painful experience was getting an IUD inserted.”

Another wrote: “Yes! I’ve broken my ankle to the point only tendons were holding it together, 2 Csections one after hours and hours of labouring, but that IUD is the worst! At one point he was twisting it to get better placement, I thought I was going to barf.”

A third wrote: “Same for me. They didn’t give me any warning either, ‘just a pinch’ they said. Yeah, a pinch so bad I kicked the doctor in the face to get her to stop, threw up, and blacked out. I had to drive myself home afterwards, pulling over every couple of minutes to puke from the pain. That went on for days.”

With another adding: “They’ve known for decades many women are under medicated when getting an IUD, and their complaints of pain are often dismissed. If you’re obese, or a smokier, or a minority, or whatever the trigger may be, you’ll tend to be treated even worse.

“This is why I constantly compliment and write thank-you notes to my good providers – mostly for treating me like a human and listening to my needs.”

While some people did note that they had very painful experiences, some women noted that their own experience with the contraception was completely fine. It is important to speak extensively with your healthcare professionals before considering getting one implanted.