Childbirth, as anyone who's been through it knows, can feel very much like an extreme sport. And, it turns out, some childbirth-related injuries are surprisingly like sports injuries, including the very long time they need to heal.

That's the conclusion of a recent study that tracked 68 pregnant women at risk for pelvic injuries and followed up using diagnostic imaging techniques more typically used in sports medicine.

The report by a team of researchers at the University of Michigan found that some women sustain long-lasting pelvic injuries after childbirth — and these aren't the kinds of injuries that Kegel exercises alone can fix. (For the uninitiated, Kegels are pelvic floor strengthening exercises that involve squeezing and releasing certain muscles.) The research team also found that some childbirth-related injuries may take longer to heal, but ultimately do.

Janis Miller, an associate professor at Michigan's School of Nursing, and the study's lead author, says just like elite athletes, new mothers should acknowledge what their bodies have been through.

"If you've just run a marathon, it may take longer to heal than if you've just run a mile," Miller said in an interview. "Some women's birthing experiences are more strenuous than others, so one of the main points is to let women know their bodies will recover...but it can take a long time."

And while many doctors give new moms the green light to resume normal activities — from sex to exercise — after the standard six-week postpartum exam, the reality is that it can take far longer to feel "normal" again. (I remember dragging my still-sore, depleted body in to that six week follow-up exam, and feeling I was decidedly not good to go.)

Indeed Miller calls the six-week marker for postpartum recovery "arbitrary." "There is no rationale for that six-week time frame in terms of the body's responses and healing," she said.

The study, published earlier this year in the American Journal of Obstetrics and Gynecology, concludes that a clinical examination alone may not be able to detect the range of pelvic injuries from childbirth; and in certain women, specialized MRI scans may be warranted if there is "unexplained or prolonged pain after delivery," or other complications, Miller says.

One surprising new finding was related to the types of injuries sustained by the women, who were all at higher risk for pelvic muscle tears because they had a long pushing phase during delivery or they were older women.

Miller said that the conventional wisdom at the start of the study was that postpartum pelvic injuries were primarily nerve-to-muscle or muscle-stretch related, but the researchers discovered that in this higher risk group of women, "one-quarter of them showed fluid in the pubic bone marrow or sustained fractures similar to a sports-related stress fracture, and two-thirds showed excess fluid in the muscle, which indicates injury similar to a severe muscle strain. Forty-one percent sustained pelvic muscle tears, with the muscle detaching partially or fully from the pubic bone."

I asked how the injuries Miller and her group saw on the MRI scans compared specifically to athletic injuries and she said some were very much like common injuries sustained by runners while others looked more extreme.

"A hamstring tear is a fairly good comparison to the Levator ani, or Kegel muscle, tear," she said. "And when a little piece of bone separates as sometimes occurs along with a hamstring tear, that type of bone fracture is similar to the worst two fractures that we saw; the other 15 fractures were more like stress fractures that runners experience... As for the fluid in the muscles, fluid [edema] is a physiological marker of almost any sort of exercise-induced swelling, stiffness and muscle soreness -- it’s normal and goes away, but again the time it takes to go away depends on how extreme the 'exercise' was. When a muscle is truly damaged from very, very strenuous use, it can take a long time to go away..."

The researchers were able to determine all this by using imaging techniques typically employed by sports medicine doctors, Miller said. "We could see a level of detail — fluid in the muscle, fractures in the bones and precision about the tear," she said, adding: "if there is a woman who gets to let's say three, six or nine months post-birthing and she feels something just doesn't seem right, it may be worth her time to see a specialist" and possibly get a fluid sensitive MRI.

The bottom line, Miller says, is: "if women don't feel that their body is back to what they expected after six weeks, it's not in their heads. Women do some self blame or feel like they're not as robust as their sister or friend. But they may have one of these injuries not visible on clinical exam."

Miller described one woman who came in with a pelvic floor injury after giving birth, who said: "'I know this is all my fault because I didn't do Kegels.' It was so sad but I hear the same story over and over," Miller said.

Jessica McKinney, a Boston-area physical therapist who specializes in pelvic floor and obstetrical therapy, says Miller's study is important because it provides evidence that at least among certain women, childbirth injuries and trauma can require extensive time to heal.

In an interview, McKinney reiterated that there's nothing magical about the six-weeks postpartum time frame and women should be asked more specific questions to determine if, in fact, there's long-term damage to their bodies. She said:

Women should be asked at that six week checkup: What's your level of pain or discomfort. Do you have impaired function? We should specifically ask about pelvic floor symptoms, such as urinary or anal incontinence, worries about making it to the bathroom on time or bothersome pelvic pressure. Also, how is their sexual function? Women are being seen for the standard six-week followup and are asked great questions about mental health and family planning, but I've not seen that we are systematically asking about what has been the physical and functional impact for the woman following pregnancy and delivery...

So what else can be done?

McKinney says several approaches can help, including targeted strengthening and manual therapies and education regarding bowel, bladder and sexual health.

"We tend to focus on the pelvis after childbirth, but we should be thinking beyond that, for instance, what is the woman's posture like? Is she able to transition in and out of bed and can she pick up the baby in ways that minimize the stress on healing or weakened tissue? The goal is to set things up so that everything the woman is doing protects the pelvic floor and aids the healing process. It's not only about squeezing and getting stronger. It's a more holistic approach."