The placenta is one of the most remarkable organs in the human body. Unlike other organs that develop permanently, the placenta is temporary, existing only during pregnancy to support the developing baby. Understanding how the placenta functions, what can go wrong, and how to recognize warning signs is essential for every pregnant woman. This comprehensive guide will help you understand everything you need to know about this vital pregnancy organ.
What Is the Placenta?
The placenta is a temporary organ that develops inside the uterus during pregnancy. It begins to form shortly after conception and continues to grow throughout pregnancy, typically reaching about 9 inches in diameter and weighing approximately 1 to 1.5 pounds at full term.
This remarkable organ serves as the critical interface between mother and baby, facilitating the exchange of nutrients, oxygen, and waste products. The placenta connects to the developing fetus through the umbilical cord, which contains blood vessels that transport these essential substances back and forth.
In a healthy pregnancy, the placenta typically attaches to the uterine wall at the top, side, front, or back of the uterus. The exact location can vary, but the position of the placenta plays an important role in pregnancy health and delivery planning.
Essential Functions of the Placenta
The placenta performs multiple life-sustaining functions throughout pregnancy:
Nutrient and Oxygen Delivery
The placenta acts as the baby’s lifeline, transferring oxygen and essential nutrients from the mother’s bloodstream to the developing fetus. These nutrients include glucose, amino acids, fatty acids, vitamins, and minerals that are crucial for proper growth and development.
Waste Removal
Just as it delivers nutrients, the placenta removes waste products from the baby’s blood, including carbon dioxide and metabolic byproducts. These waste materials are transferred to the mother’s bloodstream for elimination through her kidneys and lungs.
Immune Protection
The placenta transfers antibodies from mother to baby, providing the developing fetus with passive immunity against various infections. This protection continues to benefit the newborn during the first months of life.
Hormone Production
The placenta produces several essential hormones that maintain pregnancy and prepare the mother’s body for childbirth and breastfeeding. These include human chorionic gonadotropin (hCG), progesterone, estrogen, and human placental lactogen.
Protective Barrier
While not completely impermeable, the placenta acts as a selective barrier, preventing many harmful substances from reaching the baby while allowing beneficial compounds to pass through. However, certain substances like alcohol, drugs, and some medications can cross the placental barrier, which is why avoiding these substances during pregnancy is crucial.
Risk Factors That Affect Placental Health
Several factors can increase the risk of complications involving the placenta:
Maternal Age
Women who become pregnant after age 35, and particularly after age 40, face increased risks of placental complications. Advanced maternal age is associated with higher rates of placenta previa, placental abruption, and other placental abnormalities.
Previous Uterine Surgery
Prior cesarean sections, fibroid removal procedures, or other uterine surgeries can affect how the placenta attaches to the uterine wall. Scar tissue from previous surgeries may increase the risk of placenta accreta and related conditions.
Multiple Pregnancies
Carrying twins, triplets, or more babies increases the demands on the placenta and raises the risk of various placental complications. Each baby typically has its own placenta, though twins may sometimes share one.
High Blood Pressure
Both chronic hypertension and pregnancy-induced high blood pressure (preeclampsia) can reduce blood flow to the placenta, potentially affecting the baby’s growth and development. Managing blood pressure is crucial for placental health.
Blood Clotting Disorders
Conditions that affect blood clotting, whether causing excessive clotting or insufficient clotting, can impact placental function. These disorders may interfere with proper blood flow between mother and baby.
Premature Rupture of Membranes
When the amniotic sac breaks before labor begins, known as premature rupture of membranes or “water breaking,” it increases the risk of placental complications and infections.
Lifestyle Factors
Smoking cigarettes or using illicit drugs, particularly cocaine, significantly increases the risk of placental abruption and other complications. These substances can restrict blood flow to the placenta and directly harm the developing baby.
Abdominal Trauma
Physical injury to the abdomen from car accidents, falls, or domestic violence can cause the placenta to separate from the uterine wall prematurely, creating an emergency situation.
Previous Placental Problems
Women who experienced placental complications in previous pregnancies have an increased risk of encountering similar issues in subsequent pregnancies.
Common Placental Complications
Placental Abruption
Placental abruption occurs when the placenta separates from the uterine wall before delivery, either partially or completely. This serious condition can deprive the baby of oxygen and nutrients while causing dangerous bleeding in the mother.
Symptoms of placental abruption include:
- Vaginal bleeding, ranging from light to severe
- Abdominal or back pain
- Uterine tenderness
- Rapid contractions
- Abnormal fetal heart rate patterns
Placental abruption is a medical emergency that often requires immediate delivery of the baby to protect both mother and child.
Placenta Previa
Placenta previa happens when the placenta covers part or all of the cervix, the opening to the uterus. This condition is more common in early pregnancy and often resolves as the uterus grows and expands.
There are several types of placenta previa:
- Complete previa: The placenta completely covers the cervical opening
- Partial previa: The placenta partially covers the cervical opening
- Marginal previa: The placenta reaches the edge of the cervix
- Low-lying placenta: The placenta is near the cervix but doesn’t cover it
Placenta previa can cause painless vaginal bleeding, typically occurring in the second or third trimester. If the condition persists late in pregnancy, a cesarean delivery is usually necessary to avoid severe bleeding during labor.
Placenta Accreta, Increta, and Percreta
These conditions, collectively known as placenta accreta spectrum disorders, occur when the placenta attaches too deeply into the uterine wall:
- Placenta accreta: The placenta attaches too deeply to the uterine wall but doesn’t penetrate the muscle
- Placenta increta: The placenta invades into the uterine muscle
- Placenta percreta: The placenta penetrates through the uterine wall and may attach to nearby organs
These conditions prevent the placenta from separating normally after delivery, which can cause life-threatening hemorrhaging. Treatment typically involves cesarean delivery followed by surgical removal of the uterus (hysterectomy) to control bleeding and protect the mother’s life.
Retained Placenta
Normally, the placenta delivers within 30 minutes after the baby is born. When the placenta remains in the uterus beyond this timeframe, it’s called a retained placenta. This can occur because:
- The cervix closes before the placenta can pass through
- The placenta remains attached to the uterine wall
- A piece of the placenta breaks off and stays in the uterus
A retained placenta can lead to severe bleeding and infection. Your healthcare provider may need to manually remove the placenta or perform a procedure to ensure all placental tissue is removed from the uterus.
Placental Insufficiency
Placental insufficiency occurs when the placenta doesn’t function properly, failing to deliver adequate oxygen and nutrients to the baby. This can result in:
- Intrauterine growth restriction (IUGR)
- Low birth weight
- Premature delivery
- Birth defects
- Stillbirth in severe cases
Risk factors for placental insufficiency include maternal smoking, high blood pressure, diabetes, blood clotting disorders, and certain medications.
Placental Infarction
Placental infarction occurs when part of the placenta dies due to inadequate blood supply. Small infarctions are common and usually don’t cause problems, but larger areas of damage can impair placental function and affect fetal growth.
Warning Signs and Symptoms
Contact your healthcare provider immediately if you experience any of these symptoms during pregnancy:
- Vaginal bleeding: Any amount of bleeding during pregnancy warrants medical evaluation, especially heavy bleeding or bleeding accompanied by pain
- Severe abdominal pain: Sharp, persistent pain in your abdomen or pelvis
- Back pain: Constant, severe back pain that doesn’t improve with rest
- Rapid contractions: Frequent, painful contractions before full term
- Abdominal tenderness: Your abdomen feels hard or unusually sensitive to touch
- Decreased fetal movement: Noticeable reduction in your baby’s normal movement patterns
These symptoms may indicate a placental problem requiring urgent medical attention. Don’t hesitate to seek care, as early intervention can be crucial for protecting both you and your baby.
Diagnosis of Placental Complications
Healthcare providers use various methods to diagnose placental problems:
Ultrasound
Ultrasound imaging is the primary tool for evaluating the placenta. It can identify the placenta’s location, appearance, and potential abnormalities. Transvaginal ultrasound may provide more detailed images when needed.
Physical Examination
Your healthcare provider will perform regular physical exams throughout pregnancy, checking for signs of placental problems such as abnormal uterine size, tenderness, or unusual bleeding.
Non-Stress Test
This test monitors the baby’s heart rate in response to movement, helping assess whether the placenta is providing adequate oxygen.
Blood Tests
Certain blood tests can indicate placental problems, including tests for anemia, blood clotting issues, or specific pregnancy hormones.
MRI
Magnetic resonance imaging may be used in complex cases to provide detailed information about the placenta’s attachment and any invasion into surrounding tissues.
Treatment and Management
Treatment for placental complications varies depending on the specific condition, its severity, and how far along the pregnancy is:
Monitoring
Some placental conditions, like low-lying placenta early in pregnancy, may simply require careful monitoring as they often resolve on their own as the uterus grows.
Bed Rest and Activity Restriction
Your healthcare provider may recommend limiting physical activity or complete bed rest if you’re diagnosed with certain placental conditions, particularly placenta previa with bleeding.
Hospitalization
Severe placental complications may require hospitalization for close monitoring of both mother and baby, with immediate access to emergency care if needed.
Blood Transfusions
If placental complications cause significant blood loss, blood transfusions may be necessary to replace lost blood and maintain the mother’s health.
Medications
Your healthcare provider may recommend certain treatments to manage symptoms or prevent complications. Always consult with your doctor before taking any medications during pregnancy, as they can advise you on safe options for your specific situation.
Early Delivery
Some placental complications require delivering the baby early, either through induction of labor or cesarean section, to protect the health and safety of both mother and baby.
Surgical Intervention
Severe cases of placenta accreta spectrum disorders may require planned cesarean delivery followed by hysterectomy to control bleeding and save the mother’s life.
Prevention and Risk Reduction
While you can’t prevent all placental complications, you can take steps to promote a healthy pregnancy and reduce your risk:
Attend All Prenatal Appointments
Regular prenatal care allows your healthcare provider to monitor your pregnancy, identify potential problems early, and take appropriate action. Follow the recommended schedule for checkups and don’t skip appointments.
Manage Chronic Health Conditions
If you have high blood pressure, diabetes, or other chronic conditions, work closely with your healthcare team to keep them well-controlled before and during pregnancy.
Quit Smoking and Avoid Drugs
Smoking and drug use significantly increase the risk of placental complications. If you need help quitting, ask your healthcare provider about available resources and support programs.
Maintain a Healthy Lifestyle
Eat a nutritious diet, stay physically active within your doctor’s guidelines, maintain a healthy weight, and get adequate rest throughout your pregnancy.
Avoid Abdominal Trauma
Take precautions to protect your abdomen from injury. Always wear your seatbelt correctly, with the lap belt below your belly and the shoulder belt between your breasts. Avoid activities with high risk of falls or impact.
Consider Your Delivery Options Carefully
If you’re considering elective cesarean delivery, discuss the risks with your healthcare provider. Previous cesarean sections increase the risk of placental complications in future pregnancies.
Plan Carefully for Future Pregnancies
If you’ve had placental complications in a previous pregnancy, talk with your healthcare provider before getting pregnant again. They can advise you on timing, risk factors, and strategies to reduce the likelihood of recurrence.
Delivery of the Placenta
Vaginal Delivery
After a vaginal birth, delivering the placenta is the third stage of labor. This typically occurs within 5 to 30 minutes after the baby is born. You’ll continue to have mild contractions as your uterus works to expel the placenta.
Your healthcare provider may gently pull on the umbilical cord while massaging your abdomen to help the placenta separate and deliver. You may be asked to push gently to help pass the placenta through the birth canal.
Cesarean Delivery
During a cesarean section, your surgeon removes the placenta from your uterus after delivering the baby. This is typically done before closing the incisions.
After Delivery
Once delivered, your healthcare provider carefully examines the placenta to ensure it’s complete and intact. Any retained placental fragments must be removed to prevent bleeding and infection.
Some parents choose to examine or keep the placenta for cultural or personal reasons. If you’re interested, discuss your wishes with your healthcare team before delivery.
Placenta Encapsulation and Consumption
Some women choose to consume their placenta after birth, either by encapsulation (drying and grinding into capsules), cooking and eating it, or adding it to smoothies. Proponents claim benefits including increased milk production, improved mood, and higher energy levels.
However, there is limited scientific evidence supporting these claimed benefits, and there are potential risks including infection. If you’re considering placenta consumption, discuss it with your healthcare provider first to understand the potential risks and ensure proper handling if you decide to proceed.
When to Seek Medical Care
Don’t hesitate to contact your healthcare provider if you have any concerns during pregnancy. Seek immediate medical attention if you experience:
- Heavy vaginal bleeding
- Severe abdominal or back pain
- Signs of shock (rapid heartbeat, dizziness, weakness)
- Decreased fetal movement
- Continuous contractions
- Fluid leaking from the vagina
Remember, it’s always better to err on the side of caution. Your healthcare team is there to support you throughout your pregnancy journey.
The Bottom Line
The placenta is a remarkable organ that plays an essential role in sustaining pregnancy and supporting fetal development. While most pregnancies proceed without placental complications, understanding how the placenta works, what can go wrong, and how to recognize warning signs empowers you to take an active role in protecting your health and your baby’s wellbeing.
Regular prenatal care, healthy lifestyle choices, and prompt attention to any concerning symptoms are your best strategies for promoting placental health. If you have questions or concerns about your placenta at any point during pregnancy, don’t hesitate to discuss them with your healthcare provider. They can provide personalized guidance based on your individual circumstances and medical history.
Sources:
- Mayo Clinic – Placenta: How it works, what’s normal
- American College of Obstetricians and Gynecologists – Placenta Accreta
- March of Dimes – Placenta Conditions
- MedlinePlus – Placenta
- National Institute of Child Health and Human Development – Pregnancy Complications
- Centers for Disease Control and Prevention – Pregnancy
The information on this page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions related to your health.
Read the full Disclaimer here →