Princess Charlotte Elizabeth Diana Was Born In Just 2.5 Hours: Why Second Babies Come Faster.

Was your second born a speedier deliver than your first? You can thank your strong uterus. (Photo: Getty Images)

As news trickles out about the birth of the new British baby princess Charlotte, one tidbit stands out: Kate Middleton’s labor was very short.

According to reports, the Duchess of Cambridge went into labor early Saturday morning, arrived at the hospital at 6 a.m., and delivered her baby girl just two and a half hours later. When she had Prince George in 2013, however, she reportedly labored for 11 hours.

Kate’s speedy delivery isn’t rare: Many second-time moms swear labor is faster and easier the second time around. But is this a real phenomenon or is it just mental?

It’s definitely real, says board-certified obstetrician/gynecologist Peter Ahlering, M.D., medical director at the Missouri Center for Reproductive Medicine. “Each labor tends to be a little faster and more efficient,” he tells Yahoo Health.

The average active labor (when a woman is dilating about one centimeter per hour) lasts about 12 hours, he says. The average second labor is about 25 percent faster than that, which explains why Middleton’s experience was so fast this time.

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The duchess may have even had what’s called a “precipitous labor,” an abnormally quick active labor that can last less than three hours, says Jason James, M.D., the chairman of the department of obstetrics and gynecology at the Baptist Hospital of Miami. (They typically happen in less than five percent of labors, he tells Yahoo Health.)

While a three-hour active labor is incredibly fast (and somewhat rare), many women can expect a six-hour active labor the second time they give birth, says James.

Here’s why: The uterus is a muscle and, just like any muscle, it becomes “hypertrophied” or stronger when it has been used before, says Ahlering. If a woman has already had a child, she’s more likely to have a stronger uterus that can work more efficiently the next time she delivers a baby.

The pelvic tissues, i.e. the vagina and perineum, have also been relaxed from previous vaginal deliveries. “That makes the process of getting the baby through more effective,” he says.

Relaxation can play a role, too. “Many patients are very nervous and anxious in the first pregnancy—sometimes that results in a slower process,” James says. “With a subsequent delivery, they’re more mentally relaxed, which allows the pelvis to relax.”

But there’s one very important change in a woman’s body during her second pregnancy: Her cervix is usually already dilated, even before she goes into labor. “Pregnant patients who have had a previous delivery often walk around dilated two to three centimeters before they even get into pre-active labor stage,” says Ahlering. “It’s like you’re starting a 100-yard dash on the 20-yard mark.”

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Finally, moms going through labor for the second time tend to just not notice the pain as much—especially if they’re fit like Middleton. Ahlering says many women will pass off early contractions as “cramps” and just don’t notice the early stages of labor. “Women who have already had a baby often don’t feel intense pain until the end, when the baby is literally coming out,” he says.

While most pregnant women wouldn’t complain about a faster labor, James notes that it’s crucial to be aware of how quickly the labor is progressing, especially if a woman plans to have pain medication. “If your labor progresses very rapidly you may not have time for an epidural,” he says.

Ahlering says women tend to take a more relaxed mindset when it comes to following the rules of labor and delivery the second time around, but stresses that it’s important to get a refresher from your doctor ahead of time on when to act—even though you’ve already been there, done that.

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