Placenta Previa
The placenta is vital in pregnancy, serving as the lifeline between the fetus and uterine wall through umbilical cord, delivering nutrients and oxygen.
However, complications like Placenta Previa can cause painless bleeding in later trimesters and pose risks to both mother and baby.
What is Placenta Previa?
Placenta Previa occurs when the placenta is positioned abnormally in the lower uterus, blocking or encroaching on the cervix.
This improper placement can obstruct normal vaginal delivery, creating risks that necessitate specific management strategies.
Is Placenta Previa dangerous?
The condition carries risks for both mother and baby:
● For the mother, it increases the likelihood of heavy bleeding (haemorrhage), which may require blood transfusions and can lead to shock.
● For the baby, the main concerns include preterm birth, low birth weight, and potential fetal distress due to reduced placental function.
Types of Placenta Previa
Placenta Previa is categorised into four types based on how the placenta relates to the cervix:
- Minor or Low-lying Placenta Previa: The placenta is lower than usual but does not cover the cervix.
- Marginal Placenta Previa: Here, the placenta is adjacent to, but not covering, the cervix. It may cause bleeding, particularly in the third trimester.
- Partial Placenta Previa: The placenta partially covers the cervix, obstructing the birth canal.
- Complete (Central) Placenta Previa: The placenta covers fully the cervix, posing the greatest risks of bleeding and complications.
Placenta Previa Causes
While the exact cause is unknown, certain risk factors may contribute to developing Placenta Previa:
- Previous Cesarean Section: Uterine scars from prior surgeries may affect placental implantation.
- Multiple Pregnancies: The more pregnancies a woman has had, the higher the risk.
- Advanced Maternal Age: Women over 35 are more prone to Placenta Previa.
- Previous Placenta Previa: A history of the condition raises the likelihood of recurrence.
- Uterine Abnormalities: Issues like fibroids or an irregularly shaped uterus may interfere with normal placental placement.
- Smoking or Drug Use: These habits can disrupt blood flow, leading to abnormal implantation.
Placenta Previa Symptoms
The most prominent symptom is painless vaginal bleeding, typically in the second or third trimester. Additional indicators include:
- Abnormal Position of the Baby: The baby may adopt a breech or transverse position due to limited space.
- Premature Labour Symptoms: Signs such as contractions or pelvic pressure might occur if the placenta detaches from the uterine wall.
How to diagnose Placenta Previa?
Diagnosing Placenta Previa involves thorough evaluation, often using non-invasive methods:
- Ultrasound Imaging: A transabdominal or transvaginal ultrasound is highly effective at identifying the placenta's position.
- Physical Examination: Although physical exams are limited to avoid triggering bleeding, external evaluations can guide further diagnostics.
- Fetal Monitoring: This assesses the baby’s well-being, especially if there are concerns about bleeding or distress.
Vasa Previa vs. Placenta Previa
Feature
Vasa Previa
Placenta Previa
Definition
Rare condition where fetal blood vessels cross the cervix unprotected, risking rupture during labour.
The placenta is abnormally positioned, partially or completely covering the cervix.
Cause
Linked to velamentous cord insertion, with blood vessels unprotected by tissue crossing the cervix.
Abnormal placental implantation in the lower uterus, often due to previous surgeries or conditions.
Symptoms
Painless vaginal bleeding, often during labour or membrane rupture.
Painless vaginal bleeding, typically in the second or third trimester.
Risk to Baby
High risk of fetal haemorrhage and death if vessels rupture.
Preterm birth, low birth weight, and fetal distress due to placental issues.
Diagnosis
Detected via ultrasound, identifying unprotected fetal blood vessels across the cervix.
Diagnosed using abdominal or transvaginal ultrasound to determine placental location.
Management
Requires planned caesarean delivery to avoid vessel rupture during labour.
Managed with monitoring and caesarean delivery if placenta obstructs the cervix.
Frequency
Very rare, affecting approximately 1 in 2,500 pregnancies.
More common, occurring in about 1 in 200 pregnancies.
Delivery Approach
Cesarean section is mandatory to prevent vessel rupture.
Cesarean delivery, often required if placenta persists near or over cervix at term.
Abruptio Placenta vs. Placenta Previa
Feature
Abruptio Placenta
Placenta Previa
Definition
Premature detachment of the placenta from the uterine wall.
Placental implantation over or near the cervix.
Cause
Linked to high blood pressure, trauma, smoking, drug use, or prior placental complications.
Related to factors like uterine scarring or multiple pregnancies.
Symptoms
Severe abdominal pain, vaginal bleeding (sometimes hidden), and uterine tenderness.
Painless vaginal bleeding, usually in the second or third trimester.
Risk to Mother
High risk of haemorrhage and shock; immediate care is critical.
Risk of severe bleeding, requiring diligent monitoring and readiness for caesarean.
Risk to Baby
Fetal death and preterm birth due to oxygen deprivation.
Preterm birth, low birth weight, and possible fetal distress.
Diagnosis
Diagnosed through symptoms and confirmed with ultrasound or physical exams.
Detected through ultrasound, identifying placenta position over cervix.
Management
Emergency intervention, often caesarean delivery, depending on severity.
Planned caesarean section if placenta blocks or nears the cervix.
Frequency
Less common, appearing in about 1 in 100 pregnancies.
More frequent, affecting around 1 in 200 pregnancies.
Delivery Approach
Cesarean is required for severe cases; vaginal delivery may occur if detachment is minimal.
Cesarean delivery standard if cervix obstruction persists.
Placenta Accreta vs. Placenta Previa
Feature
Placenta Accreta
Placenta Previa
Definition
The placenta grows too deeply into the uterine wall, complicating normal detachment post-delivery.
Placenta implanted low in the uterus, covering or nearing the cervix.
Cause
Linked to uterine scarring from surgeries like caesarean sections.
Often connected to uterine abnormalities or scarring.
Symptoms
Difficult placental separation leading to severe postpartum bleeding.
Painless vaginal bleeding during later pregnancy stages.
Risk to Mother
High risk of haemorrhage and potential need for hysterectomy.
Severe bleeding and need for close observation or intervention.
Risk to Baby
Fetal distress, low birth weight, and risk of stillbirth in severe cases.
Preterm birth and related complications due to placental issues.
Diagnosis
Ultrasound or MRI confirm placenta invasion into the uterine wall.
Ultrasound determines abnormal placenta positioning.
Management
Planned caesarean delivery, often accompanied by hysterectomy.
Cesarean delivery recommended for continued cervix obstruction.
Frequency
Rare, occurring in 1 in 2,500 to 5,000 pregnancies.
More frequent, affecting 1 in 200 pregnancies.
Delivery Approach
Cesarean section and possible hysterectomy for safety.
Cesarean delivery is typically essential for safety.
How to treat Placenta Previa?
- Ongoing Prenatal Care: Regular check-ups help track the condition and catch any changes early.
- Monitoring Blood Levels: Keeping an eye on blood volume and hemoglobin is vital, particularly for managing blood loss.
- Preparedness for Emergencies: A clear plan ensures swift action is taken in severe cases, safeguarding both mother and child.
Ensuring Safe Pregnancy Outcomes
Placenta Previa, characterised by the abnormal positioning of the placenta, can pose serious risks, including vaginal bleeding, particularly in later pregnancy stages.
Immediate consultation with a healthcare provider is imperative if symptoms arise.
While mild cases may only require observation, severe forms often demand more intensive care, including hospitalisation and caesarean delivery.
At Prince Court Medical Centre in Kuala Lumpur, our team of expert obstetricians and gynaecologists provides world-class care for complex pregnancies.
With modern facilities and a patient-first approach, we ensure the best care for both mother and baby. Trust Prince Court for your maternity needs.
