7 Warning Signs of Placenta Accreta Every Pregnant Woman Should Know

Placenta accreta is a serious pregnancy complication where the placenta attaches too deeply into the uterine wall, failing to detach properly after delivery. This condition occurs in approximately 1 in 500 pregnancies and has become increasingly common due to rising cesarean section rates. While placenta accreta often shows no symptoms during pregnancy and is typically detected through ultrasound examinations, understanding the potential warning signs is crucial for early detection and management.

The condition ranges in severity from accreta (placenta attaches to the uterine muscle), increta (placenta penetrates into the uterine muscle), to percreta (placenta penetrates through the uterine wall). Early diagnosis is essential because placenta accreta can lead to severe complications, including life-threatening hemorrhage during delivery. Most cases are diagnosed during routine prenatal ultrasounds, but being aware of certain symptoms and risk factors can help ensure proper medical care.

1. Vaginal Bleeding During the Third Trimester

Vaginal bleeding in the later stages of pregnancy can be one of the warning signs of placenta accreta, though it’s important to note that many women with this condition experience no bleeding at all. When bleeding does occur, it typically happens during the third trimester and can range from light spotting to heavy bleeding.

This bleeding occurs because the abnormally attached placenta may cause disruption to the uterine wall and blood vessels. The bleeding may be:

• Painless and bright red in color
• Intermittent or continuous
• Variable in amount, from minimal spotting to significant hemorrhage
• Sometimes accompanied by cramping or contractions

Any vaginal bleeding during pregnancy should be reported to your healthcare provider immediately, as it can indicate various complications beyond placenta accreta, including placenta previa or placental abruption.

2. Absence of Typical Symptoms (Silent Presentation)

Ironically, one of the most characteristic features of placenta accreta is the absence of noticeable symptoms during pregnancy. The majority of women with placenta accreta feel completely normal throughout their pregnancy and have no idea they have this condition until it’s detected on ultrasound or discovered during delivery.

This silent presentation makes routine prenatal care and ultrasound examinations absolutely critical. The condition is usually suspected when:

• Ultrasound imaging shows abnormal placental attachment patterns
• The placenta appears to be in an unusual position, particularly covering the cervix (placenta previa)
• There’s a history of previous cesarean sections or uterine surgeries
• Blood flow patterns in the uterus appear abnormal on Doppler ultrasound

The lack of symptoms doesn’t diminish the seriousness of the condition, making adherence to all scheduled prenatal appointments essential for detection.

3. Severe Hemorrhage During or After Delivery

The most critical and dangerous symptom of placenta accreta typically manifests during or immediately after delivery. When the placenta fails to separate from the uterine wall as it normally should following birth, it can cause severe, life-threatening bleeding.

During normal delivery, the placenta detaches within 30 minutes after the baby is born. With placenta accreta, the placenta remains firmly attached, and attempts to remove it can cause:

• Massive hemorrhage requiring blood transfusions
• Rapid blood loss leading to shock
• Drop in blood pressure and increased heart rate
• Pale skin and dizziness due to blood loss
• Difficulty breathing and weakness

Medical teams prepared for this complication can take measures to minimize blood loss, but undiagnosed placenta accreta discovered during delivery represents a true obstetric emergency requiring immediate intervention.

4. Abnormal Ultrasound Findings

While not a symptom experienced by the patient, abnormal findings on prenatal ultrasound examinations serve as the primary diagnostic indicator of placenta accreta. Women who have high-risk factors should undergo detailed ultrasound evaluations, particularly in the second and third trimesters.

Ultrasound findings suggestive of placenta accreta include:

• Loss of the normal hypoechoic (dark) zone between the placenta and uterine wall
• Presence of placental lacunae (irregular vascular spaces that appear as Swiss cheese-like holes in the placenta)
• Thinning or disruption of the bladder wall-uterine interface
• Abnormal blood vessel growth extending from the placenta into the uterine muscle
• Bulging of the placenta into the bladder or other organs

If your healthcare provider mentions any concerning ultrasound findings, you may be referred to a maternal-fetal medicine specialist for more detailed imaging, possibly including MRI scans for better visualization.

5. Elevated Alpha-Fetoprotein (AFP) Levels

Some women with placenta accreta may show elevated levels of alpha-fetoprotein (AFP) in routine prenatal blood screening tests. AFP is a protein produced by the developing fetus, and it’s normally measured during the second trimester to screen for neural tube defects and other abnormalities.

Elevated AFP levels can indicate:

• Abnormal placental function or structure
• Increased permeability between maternal and fetal blood circulation
• Disruption of the normal placental-uterine interface

It’s important to understand that elevated AFP is not specific to placenta accreta and can occur with many other conditions. However, when elevated AFP is found in combination with risk factors such as previous cesarean delivery or placenta previa, it may prompt more thorough investigation for placenta accreta.

6. Premature Contractions or Preterm Labor

Some women with placenta accreta may experience premature contractions or signs of preterm labor, though this is not a universal symptom. The abnormal placental attachment may trigger uterine irritability or contractions before the pregnancy reaches full term.

Signs of premature contractions include:

• Regular tightening or cramping of the uterus occurring more than four times per hour
• Pelvic pressure or feeling that the baby is pushing down
• Low, dull backache that comes and goes
• Abdominal cramping similar to menstrual cramps
• Change in vaginal discharge, including increased discharge or mucus

Women diagnosed with placenta accreta are often monitored closely for signs of preterm labor, as the optimal timing for delivery must balance fetal maturity against the risk of complications from the condition.

7. Pelvic Pain or Discomfort

While uncommon, some women with placenta accreta, particularly those with placenta percreta (the most severe form), may experience persistent pelvic pain or discomfort during pregnancy. This pain can occur when the placenta grows through the uterine wall and into adjacent organs such as the bladder.

The pain characteristics may include:

• Persistent or intermittent lower abdominal pain
• Pain that’s difficult to pinpoint or localize
• Discomfort when urinating if the bladder is involved
• Pain that doesn’t respond to normal pregnancy comfort measures
• Feeling of pressure in the pelvis or lower abdomen

Any unexplained or persistent pain during pregnancy warrants evaluation by a healthcare provider, as it may indicate various complications requiring assessment and management.

Main Causes and Risk Factors

Placenta accreta develops when the placenta attaches directly to the myometrium (uterine muscle) rather than to the endometrial lining due to deficiency or absence of the decidua basalis (the modified endometrial lining during pregnancy). Understanding the causes and risk factors is essential for identifying women who need closer monitoring.

Primary Causes:

• Uterine scarring: Previous cesarean sections, uterine surgeries, or D&C procedures create scar tissue that disrupts the normal decidua layer, providing inadequate barrier between placenta and uterine muscle
• Placenta previa: When the placenta covers the cervix, especially over a previous cesarean scar, the risk of accreta increases significantly
• Abnormal endometrial development: Conditions affecting the uterine lining can prevent proper placental attachment
• Previous uterine procedures: Myomectomy, endometrial ablation, or repeated curettage procedures damage the uterine lining

Major Risk Factors:

• Previous cesarean deliveries: The risk increases with each cesarean section – from 0.3% with one prior cesarean to over 6% with five or more
• Maternal age over 35: Advanced maternal age is associated with increased risk
• Multiple pregnancies: Women with several previous pregnancies face higher risk
• Previous placenta accreta: History of this condition significantly increases recurrence risk
• Asherman’s syndrome: Intrauterine adhesions from previous procedures
• Submucous fibroids: Uterine fibroids affecting the endometrial cavity
• In vitro fertilization (IVF): Some studies suggest slightly increased risk with assisted reproductive technologies
• Smoking: Tobacco use during pregnancy may contribute to abnormal placentation

The most significant risk factor is the combination of placenta previa with previous cesarean delivery, which can increase the risk of placenta accreta to 40% or higher in women with multiple previous cesareans.

Prevention Strategies

While placenta accreta cannot be completely prevented, certain strategies can reduce risk and ensure early detection when it does occur:

Reducing Overall Risk:

• Avoid unnecessary cesarean sections: When safe and appropriate, vaginal delivery reduces the risk of uterine scarring that contributes to placenta accreta in future pregnancies
• Careful consideration of timing between pregnancies: Allowing adequate time for uterine healing between pregnancies may reduce risk
• Minimize uterine procedures: Avoid unnecessary surgical interventions on the uterus when possible
• Smoking cessation: Quitting smoking before and during pregnancy reduces multiple pregnancy complications including abnormal placentation
• Manage chronic conditions: Control of diabetes, hypertension, and other health conditions optimizes uterine health

Early Detection Strategies:

• Comprehensive prenatal care: Attend all scheduled prenatal appointments and ultrasound examinations
• High-risk screening: Women with risk factors should undergo detailed ultrasound evaluation in the second trimester (18-20 weeks) and again in the third trimester
• MRI confirmation: When ultrasound suggests placenta accreta, MRI can provide additional detailed imaging
• Specialist consultation: Referral to maternal-fetal medicine specialists for suspected cases ensures expert evaluation and delivery planning
• Informed family planning: Women with previous cesarean sections should discuss future pregnancy risks with their healthcare providers

Preparation and Planning:

• Delivery at specialized centers: When placenta accreta is diagnosed, delivery should be planned at a tertiary care center with experience managing this condition
• Multidisciplinary team assembly: Coordinated care involving obstetricians, anesthesiologists, urologists, and blood bank services
• Scheduled cesarean delivery: Planned delivery before labor begins, typically around 34-37 weeks, reduces emergency complications
• Blood product availability: Ensuring adequate blood products are available for potential transfusion
• Patient education: Understanding the condition and planned management approach reduces anxiety and ensures informed decision-making

The most effective “prevention” is early diagnosis through careful prenatal screening, allowing time to plan appropriate management and delivery at a facility equipped to handle this serious complication.

Frequently Asked Questions

Can placenta accreta be detected during pregnancy?

Yes, placenta accreta is typically detected during routine prenatal ultrasound examinations, particularly in the second and third trimesters. Women with risk factors such as previous cesarean sections or placenta previa should undergo more detailed ultrasound evaluation. MRI may be used for additional confirmation when ultrasound findings are suspicious.

Is placenta accreta painful during pregnancy?

Most women with placenta accreta experience no pain or symptoms during pregnancy. The condition is usually “silent” and only detected through imaging or during delivery. Rarely, women with severe cases (placenta percreta) may experience pelvic discomfort, especially if the placenta invades adjacent organs.

What is the difference between placenta accreta, increta, and percreta?

These terms describe the depth of abnormal placental attachment: Placenta accreta (most common, 75% of cases) occurs when the placenta attaches to the uterine muscle; placenta increta (15% of cases) occurs when it penetrates into the uterine muscle; and placenta percreta (most severe, 5% of cases) occurs when it penetrates through the uterine wall and may invade nearby organs like the bladder.

Can I have a vaginal delivery with placenta accreta?

No, vaginal delivery is not recommended when placenta accreta is diagnosed before delivery. A planned cesarean delivery with possible hysterectomy is typically necessary to safely manage this condition and minimize the risk of life-threatening hemorrhage. Delivery should be scheduled at a specialized medical center with appropriate resources.

Will I need a hysterectomy if I have placenta accreta?

Hysterectomy (removal of the uterus) is often necessary with placenta accreta to control bleeding and ensure maternal safety, as attempting to remove the abnormally attached placenta can cause severe hemorrhage. However, in select cases at specialized centers, conservative management approaches may be attempted to preserve fertility, though this carries additional risks and requires careful consideration.

Can placenta accreta cause problems for my baby?

Placenta accreta primarily affects the mother rather than the baby. However, the condition may lead to premature delivery, which can affect the baby. Additionally, if the mother experiences severe bleeding or complications, this could potentially impact the baby. With proper prenatal diagnosis and planned delivery at an appropriate facility, outcomes for babies are generally good.

If I had placenta accreta once, will I have it again in future pregnancies?

Women who have had placenta accreta face an increased risk in subsequent pregnancies, particularly if they retained their uterus. The recurrence risk varies but can be significant. Women considering future pregnancies after placenta accreta should discuss the risks thoroughly with their healthcare provider and receive early, comprehensive prenatal care with specialized monitoring.

How common is placenta accreta?

Placenta accreta occurs in approximately 1 in 500 pregnancies, though rates have been increasing over the past several decades. This increase is largely attributed to rising cesarean section rates, as uterine scarring from previous cesarean deliveries is the primary risk factor for developing this condition.

References:

• American College of Obstetricians and Gynecologists (ACOG) – Placenta Accreta Spectrum
• Mayo Clinic – Placenta Accreta
• National Institute of Child Health and Human Development – Placenta Accreta
• StatPearls – Placenta Accreta
• Royal College of Obstetricians and Gynaecologists – Placenta Accreta Guidance