What is placenta accreta?

When Kim Kardashian and Kanye West decided to have a third child, they used a surrogate because Kim was unable to carry another baby. In her first two pregnancies, she’d had a condition called placenta accreta, which left a hole and scar tissue in her uterus.

Placenta accreta occurs when the placenta grows too deeply into the wall of the uterus where it may not detach on its own after a baby is born. Though the placenta still functions normally to help the baby grow well, the condition can be dangerous to the mom, because trying to detach the placenta after birth can cause massive bleeding, and damage to other organs that the placenta has attached to. The deeper it’s attached, the more dangerous it is.

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The uterus is composed of an inner layer, which thickens up during pregnancy to create what’s called the decidua, and an outer layer of muscle called the myometrium. Placenta accreta occurs when the placenta grows through the inner layer and attaches to that outer muscle. But in some cases, it’s even more severe, growing into the outer muscle (called placenta increta), or even through that muscle where it may attach to other organs like the bladder (called placenta percreta).

A 2015 study published in the journal Obstetrics & Gynecology found that one in every 697 deliveries in Canada in 2009 and 2010 resulted in placenta accreta. The condition has been on the rise for decades due to an increase in Caesarean sections, explains Jonathan Tankel, an OB/GYN at the Royal Alexandra Hospital in Edmonton.

What are the risk factors for placenta accreta?

John Kingdom, a maternal-fetal medicine specialist at Toronto’s Mount Sinai Hospital and co-director of the hospital’s placenta clinic, explains that previous surgery on the uterus, which can weaken the decidua or the myometrium, is the most common risk factor for developing placenta accreta. “The more Caesareans you’ve had, the more this problem is likely to occur,” he says. But any other surgeries in this area, including fibroid removal, a dilation and curettage (D&C), and some fertility procedures, can create a weak spot in the uterus that can cause trouble if the placenta attaches to it. You’re also at risk of developing it if, like Kim Kardashian did, you’ve had placenta accreta before, says Tankel.

The biggest red flag for possible accreta is when a woman has what's called placenta previa (which is when the placenta implants low in the uterus and covers the cervix), or a low-lying placenta (where it’s close to the cervix), and they’ve had a previous C-section, because the operation would have left them with a scar at the bottom of the uterus. “When you combine a past C-section with a low-lying placenta, every family doctor, midwife, and general obstetrician should be thinking, ‘This patient could be at risk of this condition,’” says Kingdom. He advises that patients should then be referred to specialty care facilities where they can investigate for a possible accreta with an ultrasound (it can be seen as early as the 12-week ultrasound, if the patient has a full bladder and the technician knows what to look for), and is usually confirmed with an MRI.

Tankel also says a high result from an alpha-fetoprotein blood test, which is given between 15 to 20 weeks if you opt for integrated prenatal screening to check for neural tube defects, also indicate an increased risk for placenta accreta. If you have a high result from that test and no sign of neural tube defects on an ultrasound, then your healthcare provider should look for a possible accreta.

Having fresh, red vaginal bleeding in the third trimester can sometimes be a sign too. If this happens, check in with your care provider right away, and go to emergency if it’s severe.

But according to Kingdom, if the placenta isn’t sitting low, placenta accreta can be hard to diagnose, even for specialists. That’s why placenta accreta sometimes isn’t discovered until after the baby has been born, and the placenta won't come out.

What happens if you’re diagnosed with placenta accreta?

If you’re diagnosed with placenta accreta, then you’ll need to meet with a team of specialists who have experience with this condition, says Kingdom. If you live in a rural area, you may need to travel to a larger hospital as delivery and post-delivery care may be complicated and involve several experts, including radiologists, diagnostic imaging specialists, urologists and obstetricians. You may also need blood transfusions.

Because you’ll need to have that team ready for the birth, Kingdom says that a planned Caesarean section at 35 weeks is recommended. “After 35 weeks, every day the patient hasn’t delivered, they're at risk of bleeding and therefore having emergency surgery,” he explains. “So you'd be better to have planned surgery with all the team present at 35 weeks than remain pregnant and suddenly turn up at four o'clock in the morning for emergency surgery.”

Before delivery, Kingdom says women are also advised to stay close to a major hospital, ideally the one you plan to give birth at, in case of severe bleeding. The lower down the placenta is, the higher the risk of bleeding, so patients with previa are also told to avoid intercourse and vigorous exercise.

What treatments are available for placenta accreta?

Depending on how deeply the placenta has grown, and whether you plan to have more children, your healthcare provider may suggest a hysterectomy at the same time as your C-section, so that rather than taking the placenta out separately, they remove the uterus with the placenta in place. Tankel says this is the safest option. “Once you start disturbing the placenta, that's where you can start getting into massive bleeding,” he notes.

But a hysterectomy isn’t usually necessary with placenta accreta, the least severe form of the condition. The muscle is intact, though the placenta might need to be left in the uterus and surgically removed a few weeks after birth, says Kingdom.

In fact, once in a while even if it is severe, doctors may determine during surgery that a hysterectomy is not necessary and they can repair the uterus so a woman can go on to have more babies. Of course, the doctor's main goal is the woman's safety, so patients are advised accordingly.

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C-section recovery