September 15, 2020

By Emeline Mugisha, M.S.N., M.P.H., R.N.

Many consider the delivery of a baby as the final event of the childbearing process. However, your pregnancy is not complete until the placenta fully detaches from the uterus and exits your body as well. If all or part of your placenta remains in your womb after delivery of your baby, it’s known as a retained placenta. This complication affects roughly 1-3% of vaginal births and may affect less than 0.2% of cesarean deliveries based one U.S. study.

What is a placenta, and how is it removed?

The placenta is an organ that attaches to your uterine wall and grows in your uterus during pregnancy. It supplies oxygen and nutrients to your developing baby and removes waste products such as carbon dioxide from your baby’s blood.

Most women who deliver vaginally will spontaneously deliver the placenta minutes after the baby passes through the birth canal during the third and final stage of labor.

Before receiving a retained placenta diagnosis, some women who deliver vaginally may require active management to help separate the placenta from the uterus. After the birth of your baby, you will continue to experience mild uterine contractions. Your healthcare provider may give you a medication called oxytocin to maintain contractions and reduce bleeding. Your provider may also massage your lower abdomen to stimulate contractions and deliver the placenta.

Studies show that these active management strategies help reduce postpartum bleeding risk, though we do not know whether they prevent retained placenta.

On occasion, the bulk of the placenta is delivered, but pieces remain inside the uterus. Your provider may suspect this if the delivered placenta does not look whole.

If you deliver your baby by cesarean section, your healthcare provider will manually remove the placenta from your uterus during the surgical procedure.

What causes a retained placenta?

There are three types of retained placenta which reflect the way the complication occurs:

• Placenta adherens. An abnormally adherent, or sticky, placenta clings to the uterine wall and cannot separate and exit naturally from the womb.

• Trapped placenta. The placenta separates from the uterine wall but cannot naturally exit the womb due to the closure of the cervix before placental delivery.

• Placenta accreta. An abnormally invasive placenta grows into the uterus's deeper layer and is unable to detach from the womb naturally.

What are the signs and symptoms of a retained placenta?

The most apparent sign that you have a retained placenta is if the entire organ fails to naturally separate from your uterus after birth, with or without active management. In most cases, your healthcare provider will detect if a part of your placenta is absent.

If the bulk of the placenta was delivered, but pieces are retained, your provider may miss the signs. This may result in irregular bleeding in the days or weeks following delivery.

An additional sign of this delivery complication is severe bleeding (or postpartum hemorrhage) in the absence of placental delivery. Untreated retained placenta can result in fatal blood loss and is the second leading cause of postpartum hemorrhage.

Who is at risk for a retained placenta?

Several factors increase the risk of experiencing a retained placenta, including:

• Previous retained placenta
• Preterm delivery
• Five or more previous births
• Low placental weight
• Prolonged oxytocin use
• Preeclampsia (a pregnancy complication associated with high blood pressure)
• Previous abortion
• Two or more previous miscarriages
• History of uterine surgery
• IVF (in vitro fertilization) pregnancy
• Genetic uterine abnormality

If you have one or more of the above risk factors for a retained placenta or have experienced one in the past, speak with your healthcare provider before giving birth another time. Your healthcare provider will help you prepare for optimal birth outcomes in your next pregnancy.

How is a retained placenta treated?

Treatment for a retained placenta entails the removal of the source of the problem: your placenta. Your healthcare provider may use various strategies to achieve this, such as:

• Manual removal. If you have a retained placenta, the first solution is usually manually removal of the organ from the uterus under anesthesia. This process may increase the risk of endometritis (inflammation of the uterine lining) and blood loss. Due to the risk of endometritis, you will be given antibiotics shortly before or after manual removal.

• Medications. Medications such as nitroglycerin may ease manual removal, particularly in the case of a trapped placenta. Drugs such as oxytocin that stimulate uterine contractions may also help expel the placenta from the womb.

• Surgery. If all or part of the placenta remains in the uterus after attempting manual removal, or if bleeding continues days to weeks after placental delivery, the next step is usually surgery. Surgical management will often occur by suction curettage (also called vacuum aspiration), a procedure used to remove tissue from your uterus.

Occasionally, the above treatments may be unsuccessful, and a portion of placental tissue may remain in your uterus, with or without your provider's knowledge. If this occurs, you may experience a delayed postpartum hemorrhage (abnormal bleeding days to weeks after delivery).

Thankfully, the outlook is generally good for women with a retained placenta. However, timing is essential. The sooner you and your provider initiate treatment, the better the outcome.

Sources:

Endler, M., Grünewald, C., & Saltvedt, S. (2012). Epidemiology of retained placenta: oxytocin as an independent risk factor. Obstetrics and Gynecology, 119(4), 801–809. https://doi.org/10.1097/AOG.0b013e31824acb3b

Moragianni, V. A., Aronis, K. N., & Craparo, F. J. (2011). Risk factors associated with retained placenta after cesarean delivery. Journal of Perinatal Medicine, 39(6), 737–740. https://doi.org/10.1515/jpm.2011.076

Perlman, N. C., & Carusi, D. A. (2019). Retained placenta after vaginal delivery: risk factors and management. International Journal of Women's Health, 11, 527–534. https://doi.org/10.2147/IJWH.S218933



Emeline Mugisha, M.S.N., M.P.H., R.N. - Emeline Mugisha is an award-winning, master's-prepared nurse with over a decade of experience in community/public health and clinical health services at the field and management levels. She has co-authored two professional manuscripts in Women's Health Issues and the Journal of Midwifery and Women's Health. She has an M.S. in Public Health Nursing and an M.P.H. from Johns Hopkins University.