Problems With the Placenta and Related Pregnancy Loss

A pregnant woman getting an ultrashound

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When a person becomes pregnant, a placenta develops inside their uterus. The main functions of the organ are to provide oxygen and nutrition to the growing baby. In most cases, the placenta does its job without any issues, but sometimes there are problems with the placenta that can result in a variety of complications, including preterm birth and pregnancy loss.

What Is the Placenta?

The placenta is a temporary organ that develops during pregnancy and is shed after the pregnancy ends. It is comprised solely of fetal cells and attaches to the mom's body inside the uterus by "invading" the mother's uterine wall in an intricate process called placentation. It is connected to the mother by a network of small blood vessels, and to the fetus through two arteries and a vein contained within the umbilical cord.

The placenta begins to form the moment the fertilized egg (which has already divided into a clump of cells called a blastocyte) implants in the uterine lining. The placenta continues to grow throughout pregnancy, ultimately becoming roughly disc-shaped, with an average weight of 1 pound at full term. It is delivered soon after childbirth.

A healthy, properly attached placenta is vital to the health and development of your growing baby.

Functions of the Placenta

The placenta serves a variety of essential functions during pregnancy, including the following:

  • Acting as a reservoir of blood for the fetus in case the mother’s circulation is compromised by changes in blood pressure
  • Carrying oxygen and nutrients from the mother’s circulatory system to the fetus
  • Carrying wastes and carbon dioxide from the fetal circulation to the maternal circulation
  • “Filtering” microbes to prevent a fetus from getting infectious diseases, though this function is not 100% effective
  • Protecting the fetus from the mother’s immune system, which normally attacks "foreign" elements in the body, by secreting various chemicals that "confuse" and suppress the immune system
  • Providing “passive immunity” to the fetus by transporting IgG antibodies
  • Secreting progesterone, human chorionic gonadotropin (hCG), human placenta lactogen (hPL), and estrogen, hormones which are necessary to maintain the pregnancy

If any of these functions are impaired, the pregnancy is at risk of preterm labor and/or pregnancy loss.

Potential Placental Problems

As noted above, in most cases, the placenta operates as intended. However, a number of placental problems can arise, including the following:

  • Chorioamnionitis: Chorioamnionitis is a bacterial infection of the membranes that make up the bag of waters. Usually, this infection travels up through the cervix from the vagina. This condition requires antibiotic treatment and rapid delivery of the fetus to prevent further complications for both mother and baby.
  • Placenta accreta: If the placenta attaches too deeply into the uterus, it is called an accreta. If the accreta grows into the uterus muscle, it's called an increta; if it grows all the way through the uterus, it's called a percreta. (The term accreta can be used to describe all three types.) In rare instances, an accreta can cause a life-threatening postpartum hemorrhage requiring a surgical intervention such as hysterectomy.
  • Placental abruption: When a placenta separates from the uterine wall prior to birth, it is called placental abruption. This condition can be fatal for a fetus, depending on the degree of separation. It can also be dangerous for the mother due to excessive blood loss. The only "cure" for a severe abruption is immediate delivery.
  • Placenta previa: When the placenta grows over or close to the internal opening of the cervix, it is called placenta previa. This condition can prevent safe vaginal birth. Previa is associated with a high risk of vaginal bleeding in pregnancy and can be a life-threatening emergency for both mother and baby.
  • Placental insufficiency: When the placenta does not attach sufficiently to the uterine wall, this causes sub-optimal levels of nutrients and oxygen to be transferred to the baby. This condition leads to fetal growth restriction and may impact the baby's development.

Signs and Symptoms

Sometimes, the pregnant woman has no indication that anything is wrong with the placenta until a problem is discovered during prenatal care. Other times, there are noticeable signs or symptoms that something is not right, including the following:

  • Abdominal pain
  • Back pain
  • Early contractions
  • Uterine tenderness
  • Vaginal bleeding


Often, the causes of placental problems are mysterious. However, some lifestyle factors may increase the risk of occurrence, including smoking and cocaine use. Additionally, other potential contributing factors include a history of diabetes, being over the age of 35, previous placental, uterine, or umbilical cord problems, and having high blood pressure. Injuries, such as from a car accident or physical abuse, can also result in placental issues.

Note that while there are things you can do to reduce your risk of developing placental problems, such as not smoking or using unprescribed drugs during your pregnancy, placental problems often have no clear cause and are out of your control—so don't blame yourself.

Treatment Options

Your treatment options will depend on the type of placental complication you have. However, generally, the focus of treatment will be on staving off labor until the fetus is viable, often using close monitoring, bed rest at home or in the hospital, and/or prompt delivery of the baby. In the case of infection, antibiotics are used as well. Preterm delivery is likely.

If these issues occur before viability, the likelihood of pregnancy loss is greater. After viability (around 23 weeks), each week your baby can stay in the uterus provides a greater chance that your baby will survive and have fewer complications at birth or in the long term. Preterm babies may need extended care in neonatal intensive care units (NICU) and may have developmental problems and/or lasting impairment.


Finding out that you have an issue with your placenta that threatens the health and safety of your growing baby—and yourself—is understandably scary and stressful. Aim to educate yourself about your condition and treatment options. Be sure to get all your questions answered by your medical provider and/or seek out the care of a physician experienced in caring for this type of high-risk pregnancy.

Coping with the prospect of delivering early, needing a hysterectomy, or having a miscarriage or stillbirth can be traumatic, devastating, and confusing. Seek out support from loved ones and/or an experienced counselor. Be patient with yourself and let yourself grieve and feel your likely complicated feelings as you work through whatever outcome you are faced with.

Know that not all placenta problems end in tragedy. In fact, especially if you are several weeks beyond viability and get prompt, experienced medical care, your chances of a positive outcome are greatly increased.

After Delivery

Problems with the placenta are such a common cause of pregnancy loss that doctors will often recommend that a pathologist examines the placenta after delivery. A placental exam is also an essential part of an autopsy of an infant in the case of miscarriage or stillbirth. While it is your choice whether or not you want to have an autopsy done, consider that it may result in helpful information about the cause of your loss.

Some cultures have special practices regarding the placenta after birth. Some, like the Maori of New Zealand, the Navajo of North America, and Cambodians, bury the placenta. Among the Ibo in Nigeria, full funeral rites are given to each placenta. Practices worldwide are wildly diverse, including exposing the placenta to the elements, planting the placenta along with a tree, or even eating the placenta. The placenta is also an ingredient in some Eastern medicines.

In the case of pregnancy loss, if you wish to have your placenta buried or cremated along with your baby, notify your physician.

A Word From Verywell

Experiencing problems with the placenta in pregnancy can be shocking, stressful, and disheartening, and certainly, coping with preterm labor or stillbirth can be devastating. Know that often, babies and their mothers do well despite issues with the placenta. However, there is no getting around that these complications are a leading cause of pregnancy loss.

It can be excruciating to accept, but whatever happens, it's largely out of your control—and if an adverse outcome comes to pass, know that it's not your fault. Recovery takes time, grace, and love.

6 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Farquhar CM, Li Z, Lensen S, et al. Incidence, risk factors and perinatal outcomes for placenta accreta in Australia and New Zealand: a case-control studyBMJ Open. 2017;7(10):e017713. doi:10.1136/bmjopen-2017-017713

  3. March of Dimes. Placental abruption.

  4. March of Dimes. Placenta previa.

  5. Gillam L, Wilkinson D, Xafis V, Isaacs D. Decision-making at the borderline of viability: Who should decide and on what basis?J Paediatr Child Health. 2017;53(2):105-111. doi:10.1111/jpc.13423

  6. American Family Physician. Examination of the placenta.

By Elizabeth Czukas, RN, MSN
Elizabeth Czukas is a writer who who has worked as an RN in high-risk obstetrics, antepartum care, and with women undergoing pregnancy loss.