Complications of the Placenta

The placenta is an organ that develops during pregnancy and attaches to the wall of the uterus to nourish the growing baby. Oxygen and nutrition flow through blood vessels into the placenta, then through the umbilical cord to the amniotic sac, which holds and cushions the baby.

Placenta Previa

The placenta develops near the top of the uterus. Placenta previa occurs when the placenta develops low in the uterus which can obstruct the passageway to the cervix. This condition is detected during a routine ultrasound around the 20th to 22nd week of pregnancy.

Risk factors

  • Are older than 35
  • Have had more than one previous delivery
  • Have scarring from many abortions
  • Are carrying twins or more babies
  • Have scarring from a previous cesarean section or other surgery
  • Have had a previous placenta previa
  • Use tobacco

Monitoring Placenta Previa

If placenta previa does occur, care is focused on preventing bleeding. You’ll be asked to refrain from sexual intercourse and to avoid lifting heavy objects. If there is bleeding, you’ll need to be hospitalized for monitoring.

Sometimes, as the baby continues to grow, the placenta moves away from the cervix and no longer blocks the birth canal. An ultrasound in the final weeks of pregnancy will determine if this has happened.

If bleeding occurs near the due date, delivering the baby is often recommended. Because the placenta obstructs the birth canal, the baby is delivered by cesarean section.

Monitoring the Baby

If a bleeding episode occurs early in pregnancy, an ultrasound exam determines the location of the placenta, and blood tests can be performed to determine how much blood has been lost. Regular ultrasounds and non-stress tests are performed to make certain the baby is well.

Most bleeding stops when you get care in the hospital. If there are more episodes of bleeding, you may need to stay in the hospital until your baby is born.

Invasive Placenta

The placenta is firmly attached to the wall of the uterus. However, sometimes it attaches too strongly or grows into the wall. This is called an invasive placenta. Depending on how deeply the placenta has grown into the uterine wall, it could be called placenta accreta, placenta increta or placenta percreta. These can be life-threatening conditions.

Risk factors

  • Placenta previa (a low-lying placenta)
  • Prior cesarean delivery or other scarring on the uterus
  • Pregnancy after the age of 35

Invasive placentas don’t typically cause any symptoms. They’re usually first suspected during an ultrasound in women with multiple risk factors. An MRI may be done to confirm the diagnosis. When symptoms do occur, the most likely one is vaginal bleeding.

An invasive placenta can cause serious blood loss during childbirth and complications can arise quickly. To prepare for the birth, you’ll be admitted to the hospital late in your pregnancy.

The baby is delivered by cesarean section. In severe cases, removing the invasive placenta can also involve a hysterectomy – removing the uterus.

Placenta Abruption

After the baby is born, the placenta releases from the uterine wall and is delivered. Placental abruption occurs when the placenta releases too early – most often late in pregnancy. This can cause serious problems, including blood loss, preterm delivery and prolonged hospitalization, for both you and your baby.

Risk factors

  • High blood pressure
  • Diabetes
  • History of previous placenta abruption
  • Cocaine/methamphetamine use
  • Premature membrane rupture
  • Twins or triplet pregnancy
  • Pregnancy after the age of 35


  • Vaginal bleeding
  • Tenderness or pain in the abdominal area
  • Contractions that won’t stop

Blood tests and ultrasound exams can help determine if placental abruption has occurred.

Treatment depends on the stage of pregnancy, your baby’s condition and other factors. If the abruption is confined to a small area, treatment may include IV fluids, bed rest and/or blood transfusions. If not, your baby might have to be delivered.

Fortunately, abruption tends to happen late in pregnancy, when babies are fully formed. When needed, they get the care they need in our Neonatal Intensive Care Unit.