Pregnancy Spotlight, Vol. VII: Placental Abnormalities

Every day, our nurses and attorneys receive calls from expectant mothers with concerns about symptoms they’re experiencing during their pregnancy. They’re curious if their symptoms are normal, and they wonder what their next steps should be. Patients should always visit a medical professional with concerns like these and receive appropriate care for maternal-fetal conditions and illnesses that can arise during pregnancy. We kickstarted the Pregnancy Spotlight Series, a monthly column that highlights specific pregnancy health concerns, to empower patients in contacting their medical providers. Today, we’re focusing on Placental Abnormalities.


What Is the Placenta?

The placenta is an organ that grows in the uterus during pregnancy. It provides nutrients and oxygen to the baby and removes waste from the baby’s blood.


What Are the Most Common Placental Problems That Can Happen During Pregnancy?

Sometimes things can go wrong with the placenta in terms of its growth, function, or its attachment to the uterus. The most common placental issues that can arise during pregnancy include:

Placenta Previa

Placenta previa: Placenta previa is a condition in which the placenta lies unusually low in the uterus, where it partially (marginal or partial previa) or completely (complete or total previa) covers the mother’s cervix and may block the baby’s passage out of the womb. 

Placenta Previa

If the placenta partially covers the mother’s cervix, it is called marginal or partial previa, and if it completely covers the mother’s cervix, it is called complete or total previa. Placenta previa occurs in about 0.5 – 1% of pregnancies. When diagnosed early in pregnancy, placenta previa is usually not a serious problem; as the baby grows, the placenta expands and lifts up and away from the cervix on its own. This is known as “placental migration.” Sometimes, however, placenta previa can lead to:

  • Life-threatening hemorrhagic bleeding for the mother and baby
  • Cesarean delivery
  • Placental tear
  • Contractions
  • Preterm labor
  • Vaginal bleeding in the third trimester
  • Increased risk of fetal infection
  • Injuries such as hypoxic-ischemic encephalopathy (HIE) in the baby

Women may be at greater risk of developing placenta previa if they:

  • Have a history of cesarean delivery, uterine surgery, or abortion
  • Experience vaginal bleeding: The main symptom of placenta previa is vaginal bleeding. The amount of bleeding and the its persistence can vary. Therefore, it is important that any vaginal bleeding be reported to your OB/GYN immediately.
  • Are over 35
  • Are black or of another minority race
  • Are carrying multiples
  • Smoke

Placenta Abruption

Placental AbruptionPlacental abruption: A condition in which the placenta separates from the uterus. Placental abruption is the most common placental disorder, occurring in 1 out of every 100 pregnancies. It usually occurs in the third trimester, but can occur anytime after the 20th week of pregnancy. Placental abruption can lead to:

Women may be at greater risk of developing placenta abruption if they:

  • Have a history of cesarean delivery, uterine surgery, or abortion
  • Have had trauma to the abdomen
  • Have a history of a prior placental abruption
  • Have a circumvallate placenta,
  • Have hypertension
  • Have preeclampsia
  • Have defects of the uterus
  • Have had a premature membrane rupture
  • Smoke

Symptoms of placental abruption include:

  • Abdominal pain
  • Rapid contractions
  • Vaginal bleeding
  • Uterine tenderness
  • Fetal heart rate abnormalities
  • No symptoms at all early on

The main symptom of placental abruption is vaginal bleeding. The amount of bleeding and its persistence can vary. Therefore, it is important that any vaginal bleeding be reported to your OB/GYN immediately. Placental abruption can lead to placental insufficiency.

Placenta Accreta

Placenta accreta: In a normal pregnancy, the placenta is attached to the wall of the uterus until birth. Once the baby is delivered, the placenta then naturally separates from the uterine wall and leaves the body through the birth canal. Placenta accreta occurs when the blood vessels and other parts of the placenta have grown too deeply into the uterine wall so the placenta is unable to detach properly. This complicates the natural separation of the placenta from the uterine wall and can mean that parts of the placenta are left attached to the uterine wall. Placenta increta is a similar but more rare placental pathology, which occurs when the placenta is attached deeper into the uterine wall and into the actual uterine muscle. Still rarer is placenta percreta, in which the placenta fully penetrates the uterus and attaches to another organ in the body. All of these conditions can lead to:

  • Vaginal bleeding in the third trimester
  • Cesarean delivery
  • Severe postpartum hemorrhage
  • Hysterectomy

Women who have had cesarean deliveries or placenta previa in the past are said to have a higher chance of acquiring placenta accreta. According to the American Pregnancy Association, 1 in 2,500 pregnancies involves one of these types of placenta placements: accreta, increta, or percreta. The main symptom of placenta accreta is vaginal bleeding. The amount of bleeding and the its persistence can vary. Therefore, it is important that any vaginal bleeding be reported to your OB/GYN immediately.

Placental Insufficiency

Placental insufficiency: A condition which occurs when the placenta is not able to transfer the necessary nutrients to the baby. Placental insufficiency can lead to:

Symptoms of placental insufficiency may not be present, but any of these can lead to or signify placental insufficiency:

Anterior Placenta

Anterior placenta: A condition in which the placenta develops in the front side of the uterus with the baby behind it. Anterior placenta commonly moves during pregnancy into the more common placement of posterior placenta. An anterior placenta may make it difficult for you to feel baby’s kicks or make it more difficult for medical professionals to find fetal heart sounds. It is possible that anterior placenta can signify placenta previa as well, which has its own risks for mother and baby. With an anterior placenta, there is an increased risk of fetal bleeding and hypovolemia requiring blood transfusions


What Will My Doctor Do If I Show Signs of Placental Complications?

An ultrasound will be administered to diagnose placental issues. he clinical history of and signs and symptoms are also important to the diagnosis. Medical professionals should closely monitor patients with placental abnormalities and administer routine tests and evaluations. Failure to properly diagnose or treat placental abnormalities can be very dangerous for both mother and baby. Another key aspect to treating patients with placental abnormalities is preparing properly for delivery and delivering at the right time. Your doctor should refer you to a Maternal-Fetal Medicine specialist. The MFM specialist will monitor the condition along with your OB/GYN and determine a safe time for birth. If you have a placental abnormality, your doctor should establish a team of medical professionals who will work together to make a specific plan of action for each aspect of the delivery.

In the case of placental insufficiency, your doctor may recommend more frequent office visits, bed rest, education on self-monitoring for symptoms of preeclampsia, steroid injections before 34 weeks if preterm labor is a risk, or kick count records.

If you have a placental abnormality, it is very important that your doctor educate you properly on your condition, increase monitoring in the presence of the placental abnormality, and recommend that you see a MFM specialist to receive proper care and preparation for delivery.


Will My Doctor Check for Placental Abnormalities Even Without Symptoms?

All of the possible placental abnormalities can be diagnosed during prenatal care when medical practitioners conduct routine ultrasounds. For this reason, it is imperative that medical professionals administer ultrasounds on a regular basis and interpret them meticulously. If you notice any signs or symptoms of placental abnormalities, however, and feel you need to be examined via ultrasound, you have the right to request one at any point during the pregnancy. Because placental abnormalities are often associated with vaginal bleeding, It is especially important that any vaginal bleeding be reported to your OB/GYN immediately.


Disclaimer: The information presented above is intended only to be a general educational resource. It is not intended to be (and should not be interpreted as) medical advice.


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