What is Twin To Twin Transfusion Syndrome?
Twin-to-Twin Transfusion Syndrome (TTTS) is a rare condition that can happen in identical twins who share a placenta. In TTTS; blood flows unevenly between the twins through shared blood vessels, causing one twin to get too much blood (the recipient) and the other too little (the donor), which can cause to serious health problems for both babies.
Statistics About Twin-to-Twin Transfusion Syndrome (TTTS):
📊 General Statistics
- Occurs in about 10-15% of monochorionic diamniotic (MCDA) twin pregnancies — these are identical twins who share a single placenta but have separate amniotic sacs.
- Monochorionic twins happen in about 1 in 250 pregnancies, so TTTS affects roughly 1 in 1,500 pregnancies overall.
👶 Impact on Babies
- Without treatment, up to 80-100% of babies affected by severe TTTS can die or suffer serious complications.
- With modern treatments like fetoscopic laser surgery, survival rates improve to about 70-85% for at least one baby and about 60% for both.
- Around 15% of survivors may have long-term health problems, including neurological issues like cerebral palsy.
📅 When TTTS Happens
- It most often develops between 16 and 26 weeks of pregnancy but can happen at any time during the second trimester.
Summary of Statistics About Twin-to-Twin Transfusion Syndrome
| Category | Statistic / Fact |
|---|---|
| Occurrence in pregnancies | Affects ~1 in 1,500 pregnancies overall |
| Risk in monochorionic twins | Occurs in 10–15% of MCDA twin pregnancies |
| Monochorionic twin rate | ~1 in 250 pregnancies |
| Onset period | Most common between 16–26 weeks of gestation |
| Untreated mortality rate | 80–100% risk of death or serious complications |
| Survival rate (with treatment) | ~70–85% for at least one twin; ~60% for both |
| Risk of long-term complications | ~15% of survivors may have neurological or developmental issues |
| Common treatment | Fetoscopic laser photocoagulation |
What is The Survival Rate For Twin To Twin Transfusion Syndrome?
✅ With Treatment (Fetoscopic Laser Surgery):
- Survival of at least one twin: ~70–85%
- Survival of both twins: ~60%
This is currently the most effective treatment, and it’s typically performed between 16 and 26 weeks of pregnancy.
❌ Without Treatment:
- Survival rate is very low, with up to 80–100% of affected pregnancies resulting in the loss of one or both babies due to complications like heart failure, preterm labor or stillbirth.
What Are the Causes of Twin-to-Twin Transfusion Syndrome (TTTS)?
🧬 1. Shared Placenta (Monochorionic Placenta)
- Twins share one placenta In about 70% of identical twin pregnancies.
- The placenta contains interconnected blood vessels that supply both babies.
- TTTS does not happen in fraternal twins or identical twins with separate placentas.
🔁 2. Abnormal Blood Vessel Connections
- The placenta may have artery-to-vein connections between the two babies.
- These are called anastomoses and they allow blood to flow unevenly from one twin (the donor) to the other (the recipient).
- The imbalance is not caused by the babies themselves but by the way the blood vessels are laid out in the shared placenta.
⚖️ 3. Imbalance in Blood Flow
- The donor twin gives away too much blood, leading to:
- Growth restriction
- Low amniotic fluid (oligohydramnios)
- Anemia
- The recipient twin receives too much blood, which can cause:
- Heart strain or heart failure
- Too much amniotic fluid (polyhydramnios)
- High blood pressure
❗ Important Note:
TTTS is not caused by anything the mother does — it’s a random complication of twin development that occurs early in pregnancy (typically in the first trimester).
What Are the Symptoms of Twin-to-Twin Transfusion Syndrome (TTTS)?
🤰 Symptoms in the Pregnant Mother
These may be the first noticeable signs of TTTS:
| Symptom | Description |
|---|---|
| Rapid weight gain | Due to excess amniotic fluid building up quickly |
| Sudden abdominal swelling | The belly may feel overly tight or large for the gestational age |
| Abdominal pain or discomfort | Caused by a quick increase in uterine size |
| Feeling of pressure | From excess fluid or rapid uterine expansion |
| Premature contractions | Can be a sign of preterm labor due to fluid imbalance |
| Decreased fetal movement (in some cases) | One or both babies may move less than expected |
🍼 Symptoms in the Babies (seen on ultrasound)
TTTS is most reliably diagnosed through ultrasound. Doctors look for these signs:
| Ultrasound Finding | What It Indicates |
|---|---|
| Amniotic fluid imbalance | One twin has too much (polyhydramnios), the other too little (oligohydramnios) |
| Bladder not visible in donor twin | Due to dehydration from low blood volume |
| Size difference between twins | The donor twin may appear much smaller |
| Hydrops (fluid buildup) | In the recipient twin, due to heart failure or overload |
| Heart strain in recipient twin | The heart works harder to handle excess blood |
🚨 When to Seek Medical Attention
If you’re pregnant with identical twins and experience rapid belly growth, discomfort or contractions before 30 weeks, it’s important to call your doctor right away. Early diagnosis of TTTS can save lives.
What Are the Stages of Twin-to-Twin Transfusion Syndrome (TTTS)?
🩺 Stage I
- Key Signs:
- Amniotic fluid imbalance: One twin has too much (polyhydramnios), the other has too little (oligohydramnios)
- Bladders are visible in both twins
- Outlook: Often monitored closely without immediate treatment.
🩺 Stage II
- Key Signs:
- The donor twin’s bladder is no longer visible on ultrasound (due to low urine production from decreased blood flow)
- Fluid imbalance is more severe
- Outlook: Higher risk of worsening; treatment like fetoscopic laser surgery is often considered.
🩺 Stage III
- Key Signs:
- Abnormal blood flow in the umbilical cord or other vessels (seen on Doppler ultrasound)
- May show signs of heart strain in the recipient twin
- Outlook: Urgent intervention typically needed.
🩺 Stage IV
- Key Signs:
- Fetal hydrops (fluid buildup in the body of one or both twins)
- This is a sign of heart failure, usually in the recipient twin
- Outlook: Critical stage, high risk of fetal death if untreated.
🩺 Stage V
- Key Signs:
- One or both twins have died due to severe complications
- Outlook: Emergency care for the surviving twin is essential; future pregnancies may be evaluated for similar risks.
Summary Table:
| Stage | Description | Urgency |
|---|---|---|
| I | Fluid imbalance, bladders visible | Monitor closely |
| II | Donor bladder not visible | Likely needs treatment |
| III | Abnormal Doppler blood flow | Treatment needed |
| IV | Fetal hydrops (heart failure) | Emergency situation |
| V | Death of one or both twins | Critical condition |
What Are the Treatment Options for Twin-to-Twin Transfusion Syndrome (TTTS)?
🔍 1. Close Monitoring (Mild Cases – Stage I)
- Frequent ultrasounds (every few days or weekly) to track fluid levels, bladder function and growth.
- Sometimes, mild TTTS can stabilize or resolve on its own without intervention.
- Recommended for Stage I TTTS with no signs of progression.
💉 2. Amnioreduction
- Involves removing excess amniotic fluid from around the recipient twin using a needle.
- Helps relieve pressure in the uterus and reduce preterm labor risk.
- Does not correct the underlying cause but can improve comfort and prolong the pregnancy.
- May need to be repeated multiple times.
🔦 3. Fetoscopic Laser Surgery (Laser Photocoagulation)
- The gold standard treatment for moderate to severe TTTS (Stages II–IV).
- A tiny camera (fetoscope) is inserted into the uterus and a laser is used to seal off the abnormal blood vessels between the twins.
- Best performed between 16–26 weeks of pregnancy.
- Significantly improves survival:
- 70–85% chance of saving one twin
- 60% chance of saving both twins
💊 4. Septostomy (Rarely used)
- A small hole is created in the membrane between the twins to allow fluid to equalize.
- Less common and typically used when laser surgery is not available or not possible.
🏥 5. Early Delivery
- If the twins are far enough along (usually after 32–34 weeks), early delivery may be the safest option.
- TTTS can worsen quickly in the third trimester and delivery may be recommended if the condition is unstable.
🧠 What Happens After Treatment?
- Babies are monitored for complications like premature birth, brain injury or growth problems.
- Some may need NICU care after delivery.
- Long-term follow-up is important to check for neurological development.
What Are the Medical Advices for Twin-to-Twin Transfusion Syndrome (TTTS)?
🩺 1. Early and Frequent Monitoring
- Start specialist care early – ideally with a maternal-fetal medicine (MFM) doctor.
- Begin ultrasound monitoring by 16 weeks of pregnancy.
- Get ultrasounds every 1–2 weeks to check:
- Amniotic fluid levels
- Bladder visibility
- Blood flow (Doppler studies)
- Growth patterns
👂 2. Watch for Warning Signs
Contact your doctor immediately if you experience:
- Rapid weight gain in a few days
- Sudden belly swelling
- Increased pressure or pain
- Decreased fetal movement
💬 3. Ask About Treatment Options
If TTTS is diagnosed:
- Discuss fetoscopic laser surgery, the most effective treatment.
- Ask about amnioreduction if surgery is not available.
- Learn about risks and benefits of early delivery if you’re beyond 30 weeks.
🧘 4. Take Care of Your Health
- Stay hydrated and eat a balanced diet to support fetal growth.
- Follow all prenatal appointments and tests.
- Ask about activity restrictions if symptoms worsen or your doctor advises rest.
🧠 5. Educate Yourself
- Learn about the Quintero stages of TTTS so you understand your baby’s condition.
- Join support groups or communities (e.g., the TTTS Foundation).
- Ask your care team about NICU plans, delivery timing and postnatal care.
🏥 6. Choose a Specialist Center
- Consider delivering at a hospital that offers:
- Fetoscopic laser surgery
- High-level NICU (Level III or IV)
- 24/7 access to MFM specialists
📘 Summary Advice Table
| Advice | Why It Matters |
|---|---|
| Begin early ultrasound monitoring | Detects TTTS before it becomes severe |
| Know the warning signs | Allows fast response to potential complications |
| Understand treatment options | Helps make informed decisions quickly |
| Take care of yourself | Supports overall pregnancy health |
| Stay informed and supported | Reduces stress and helps with emotional preparation |
| Deliver at a specialized center | Ensures advanced care for both mother and babies |
We wish a healthy and heappy life to you. You can find details, success rates and how to perform fetoscopic laser surgery in below.
