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Dangerous disorder prevents placenta from expelling after birth

Dangerous disorder prevents placenta from expelling after birth
Dr. Kathryn Elgin is chairwoman of the department of obstetrics and gynecology at MedStar Franklin Square Medical Center. (Handout)

After a woman gives birth, the placenta, which nourishes the growing baby in the uterus, is supposed to expel from the womb. But in some women the placenta attaches to the uterus, a rare condition called placenta accreta.

Reality star Kim Kardashian suffered from this condition and because of it chose to use a surrogate to carry her third baby. In her blog, she has called her experience with the condition "the most painful experience of my life."

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Dr. Kathryn Elgin, chairwoman of the department of obstetrics and gynecology at MedStar Franklin Square Medical Center, said the rising use of cesarean sections is leading to more women having placenta accreta. She answered some questions about the potentially deadly condition.

What is placenta accreta?

This is one of the most serious complications a woman can face during pregnancy. It is when the placenta adheres to the uterus and cannot be removed after the birth of the baby. The disorder can lead to maternal death; 7 percent of women with placenta accrete die from overwhelming blood loss. Treatment of the disorder includes blood transfusions and in many cases hysterectomy.

There are three levels of severity of this condition. Placenta accreta is superficial invasion. Placenta increta is invasion into the deeper layer of the uterine muscle. The most serious is placenta percreta, when the placenta goes through the uterus to surrounding tissues like the bladder and intestines.

This condition is occurring more frequently. In the 1950’s, it occurred in one in 30,000 deliveries. Now it occurs in as many as one in 2,500 deliveries.

What are the symptoms?

Prior to delivery, there are no symptoms of placenta accreta. It typically does not cause pain, bleeding or complications for the baby.

Many cases of placenta accreta happen in association with placenta previa. This is when the placenta grows in the lower part of the uterus close to or covering the cervix. In this complication, women can have bleeding during the pregnancy requiring hospitalization and in many cases leading to premature delivery due to maternal hemorrhage, or bleeding.

Placenta accreta is not usually diagnosed by ultrasound unless it is seen in association with placenta previa. In these cases, high-risk obstetrics specialists will perform an ultrasound to see if there is evidence of abnormal invasion of the uterine wall.

Some specialists would recommend an MRI, which may detect some cases, including placenta percreta, where the placenta extends through the uterus to surrounding organs.

However, if ultrasound or MRI does not show placenta accreta, it can still exist. Therefore, obstetricians need to have a high suspicion for this problem and plan to deliver patients at a hospital that is equipped to handle this serious complication.

What causes it?

The placenta is the organ that nurtures the baby during pregnancy. It provides nutrients by interfacing with maternal blood. These nutrients are then carried from the placenta to the baby. In order to establish this connection, the placenta invades into the superficial layers of the uterus and invades maternal blood vessels. In normal placental development, there is a protective layer preventing the placenta from invading too deeply into the uterus. This is called Nitabuch’s layer.

When this layer is not present or disrupted, the placenta sticks to the uterus and cannot release after the birth of the baby. If the placenta cannot be removed from the uterus, then massive hemorrhage occurs.

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What are the risk factors and who is more likely to get it?

Woman at risk for this condition include any with prior uterine surgery, procedures or conditions that may have disrupted Nitibach’s layer.

This would include a prior cesarean section, myomectomy to remove uterine fibroids, ablation to remove the endometrial lining of the uterus and having had multiple pregnancies.

Women aged 35 and older, those with in vitro fertilization pregnancies and women who smoke have higher rates of this complication.

If a woman had placenta accreta in a prior pregnancy, she is also at higher risk.

The rising use of cesarean sections in the United States is the leading cause of the increasing rates of this condition. If a woman has had two or three C-sections and has a placenta previa, then the risk for accreta is 30 percent to 40 percent.

How can it affect birth?

Placenta accreta usually is not diagnosed until after the birth of the baby. In normal pregnancies, the placenta typically will deliver within 20 minutes without special procedures. If the placenta does not deliver on its own, then the obstetrician or midwife will attempt to manually remove the placenta. During this procedure, the provider places their hand into the uterus and tries to separate the placenta. In normal placentation, the provider is able to find the natural division between the uterus and placenta.

With placenta accreta, the normal separation does not exist. Therefore the provider cannot get the placenta to easily separate. Attempts to forcibly remove the placental tissue can then lead to a massive hemorrhage. Sometimes it involves the entire placenta, sometimes only partially.

When the provider encounters this problem, they will mobilize a team including anesthesia and nursing staff. The patient will be taken to the operating room to be examined in a more controlled setting. The provider also will order blood products to be ready in the event that massive hemorrhaging occurs.

If the placenta remains adherent, the obstetrician will need to counsel the patient on the options of hysterectomy versus conservative measures to try to save the uterus. Conservative measures are not always successful, resulting in complications. Maternal infection or hemorrhage can occur up to 6 months later.

Should women with this complication avoid future pregnancies?

There is limited research to guide patients and their providers. In the past, most women were treated with a hysterectomy, so future pregnancies were not an option.

Most obstetricians advise against future pregnancies due to the high risk of maternal death. Obstetric textbooks report a 30 to 40 percent risk of recurrence in future pregnancies. However, large studies are not available to say if this is accurate.

One study in France followed women that had conservative treatment in their prior pregnancies. Of the women that chose to attempt another pregnancy, 30 percent had recurrence.

Women with a history of placenta accreta or significant risk factors, including two or more prior cesarean sections, should discuss future childbearing with their providers.

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