Are you expected to have twins? Identical twin pregnancies double the happiness of expecting parents, but sometimes, they come with unique conditions. One such serious condition is twin-to-twin transfusion syndrome (TTTS), which affects twins sharing the same placenta. Although a rare condition in pregnancies involving identical twins, TTTS can be a potentially life-threatening complication where blood flow between the twins becomes imbalanced, leading to severe complications if left untreated. 

So, can TTTS be managed or treated? If yes, how do you manage twin-to-twin transfusion syndrome? In this article, we will be discussing some key life-saving interventions in fetal medicine to manage twin-to-twin transfusion syndrome.

What is Twin-to-Twin Transfusion Syndrome?

A rare but serious condition, twin-to-twin transfusion syndrome (TTTS), develops in monochorionic pregnancies, i.e., pregnancies involving identical twins who share one placenta and their circulations are connected via anastomoses.

In normal identical twin pregnancies, most identical twins share an equal amount of blood and nutrients from the same placenta. However, in the TTTS condition, the proportion of blood shared between the twins is unequal. What happens is that the blood flow is uneven, and one twin receives less blood supply (known as the donor twin) than the other twin (known as the recipient twin).

This condition arises from abnormal blood vessel connections within the placenta, causing the donor twin to have less blood volume and the recipient twin to have more blood volume.

There are five stages of twin-to-twin transfusion syndrome:

Stage I	Although the donor twin has little to no amniotic fluid compared to the recipient twin, who has too much amniotic fluid, there are no major changes in blood flow or organ function.
Stage II	The donor twin's bladder is no longer visible on ultrasound
Stage III	A significantly abnormal blood flow between twins sometimes impacts one twin’s heart function.
Stage IV	One or both twins show signs of body or skin swelling.
Stage V	It’s the most severe stage, wherein one or both twins pass away.

Symptoms and Causes of Twin-to-Twin Transfusion Syndrome

This section outlines the symptoms and causes of twin-to-twin transfusion syndrome:

Symptoms of Twin-to-Twin Transfusion Syndrome

Often, twin-to-twin transfusion syndrome doesn’t cause any symptoms, but if some do, they can experience the following symptoms:

• Rapid uterine growth due to excess amniotic fluid.

• Abdominal pain or tightness.

• Sudden weight gain or discomfort.

• Reduced foetal movements of one or both twins.

Causes of Twin-to-Twin Transfusion Syndrome

For managing TTTS risks for both twins, it’s crucial to know the root cause of the condition.  TTTS develops in twin pregnancies when the blood vessels connect abnormally in the shared placenta, allowing blood volume to be distributed unequally among twins, with the recipient twin receiving more blood and the donor twin receiving less.

Expecting women should also know that how their placenta develops is beyond their control. TTTS doesn’t occur because of something you did or didn’t do during pregnancy. Also, there’s no way to prevent this condition, but you can manage it thanks to interventions in fetal medicine.

How is Twin-to-Twin Transfusion Syndrome Diagnosed?

Early and accurate diagnosis is key to twin-to-twin transfusion syndrome management. The first step to diagnose TTTS is performing an ultrasound, and then if your healthcare provider suspects TTTS, he will suggest other diagnostic tests:

Regular Ultrasound	TTTS is often detected during a standard second-trimester ultrasound, where a healthcare professional observes fluid levels and size discrepancies between the twins.
Doppler Ultrasound	This is the advanced imaging technique that helps doctors evaluate blood flow patterns in the umbilical cords and hearts of twins.
Amniotic Fluid Index (AFI)	If there is an imbalance in amniotic fluid levels between the two sacs (polyhydramnios in one and oligohydramnios in the other), it could indicate TTTS.
Fetal Echocardiography	Foetal echocardiography can provide detailed heart scans, helping doctors assess potential cardiac complications, particularly in the recipient twin.

Fetal Medicine Interventions to Manage Twin-to-Twin Transfusion Syndrome

Advances in fetal medicine have led to the introduction of various life-saving treatments for TTTS. Your healthcare provider tailor the treatment approach depending on your pregnancy’s gestational age and stage of TTTS you have: 

Amnioreduction

During this TTTS treatment, your doctor will insert a small, hollow needle into your uterus through your abdominal wall, guided by ultrasound imaging, to drain excess amniotic fluid from the sac of the recipient twin. Doing so will reduce the pressure inside your uterus, relieve maternal symptoms like shortness of breath or abdominal pain, and stabilise your pregnancy temporarily. 

Amnioreduction is usually recommended during stage 1 of TTTs or in more advanced stages of the condition occurring later in pregnancy. Now that this treatment does not address the underlying cause of TTTS, patients might need to have to undergo amino reduction more than once if the amniotic fluid increases again.

Septostomy

This is an obsolete procedure now a days previously was used in specific cases where laser ablation might not be an option. In the septostomy procedure, a surgeon uses a small needle or catheter to make a small hole in the thin membrane that separates the twins’ amniotic sacs. This hole is made to create an opening that allows amniotic fluid to flow freely between the sacs, equalising fluid levels.

While septostomy is a relatively low-risk procedure and can alleviate the symptoms of TTTS and reduce the pressure caused by polyhydramnios, it doesn’t treat the underlying cause of twin-to-twin transfusion syndrome. 

Fetoscopic Laser Ablation 

Fetiscopic laser ablation is the procedure of choice for TTTS

The first step of the fetoscopic laser ablation procedure is to make a small incision in the patient’s abdomen under local or general anaesthesia. The surgeon then inserts a thin instrument called a fetoscope, equipped with a camera and laser, into the patient’s uterus.

With the help of the fetoscope, the surgeon identifies abnormal blood vessel connections on the placenta’s surface that are causing uneven blood flow between the twins. Once located, he uses a laser beam to close these vessels, preventing the unequal transfer of blood between the twins. 

This procedure's goal is to shift blood flow from one twin to the other, allowing each to have its own blood volume rather than sharing. Fetoscopic laser ablation is usually advised for mothers with stage 2 TTTS or higher and ones between 16 and 26 weeks of gestation. 

Umbilical Cord Occlusion

This fetal medicine intervention is suggested as a last resort for rare cases of severe TTTS, wherein one of the twins has a life-threatening condition, or the survival of both is not possible.  Umbilical cord occlusion surgery is performed to block the blood flow in the umbilical cord of one twin via a small device or electrode to increase the chance of survival of the other twin. 

Close Monitoring and Delivery

Healthcare providers perform ultrasounds, echocardiography and regular fetal monitoring to track the progression of twin-to-twin transfusion syndrome. If the condition becomes severe or your pregnancy reaches a viable gestational age (a time when an infant can survive out of the mother’s body), your doctor might recommend early delivery to optimise outcomes for you and your twins.

The Bottom Line

Twin-to-twin transfusion syndrome is a serious condition, making pregnancy highly emotional and stressful for parents. However, you can potentially manage this condition via early diagnosis and advanced fetal medicine interventions. 

Seeking guidance on how to manage or treat twin-to-twin transfusion syndrome for delivering healthy twins? Reach out to expert fetal medicine specialist at Medanta today for early diagnosis and a tailored treatment plan!

FAQs

1. What is the primary treatment for TTTS? 

The primary treatment is fetoscopic laser photocoagulation, a procedure that seals off abnormal blood vessels in the placenta to correct blood flow.

2. Can TTTS be treated non-surgically?

Yes, in mild cases, amnioreduction (removing excess amniotic fluid) or close monitoring might be used to manage symptoms and delay the progression.

3. Are medications used in managing TTTS? 

Mostly TTTS can be managed in early stage conservatively or main stay of treatment is fetoscopic laser ablation. 

4. What is the prognosis after treatment for TTTS? 

Prognosis varies; early and appropriate treatment improves survival rates and reduces the risk of complications like preterm birth, cotwin demise or neurological damage.

5. Can TTTS recur after treatment?

Recurrence is possible but rare, especially if laser photocoagulation is performed effectively; ongoing monitoring is crucial.

Citations

Anh, N. D., Hung, H. S., Sim, N. T., Ha, N. T. T., Nguyen, D. L., Nguyen, B., Van Tong, H., Ville, Y., & Thuong, P. T. H. (2022). Fetoscopic laser ablation for the selective fetal reduction in Twin-Twin transfusion Syndrome Stage II–IV: the experience of a new Fetal Medicine Center. International Journal of Women S Health, Volume 14, 555–563. https://doi.org/10.2147/ijwh.s350433

Borse, V., & Shanks, A. L. (2022a, October 10). Twin-to-Twin transfusion syndrome. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK563133/

Borse, V., & Shanks, A. L. (2022b, October 10). Twin-to-Twin transfusion syndrome. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK563133/

Nakata, M., Chmait, R. H., & Quintero, R. A. (2004). Umbilical cord occlusion of the donor versus recipient fetus in twin–twin transfusion syndrome. Ultrasound in Obstetrics and Gynecology, 23(5), 446–450. https://doi.org/10.1002/uog.1034

Zaami, S., Masselli, G., Brunelli, R., Taschini, G., Caprasecca, S., & Marinelli, E. (2021). Twin-to-Twin transfusion syndrome: diagnostic imaging and its role in staving off malpractice charges and litigation. Diagnostics, 11(3), 445. https://doi.org/10.3390/diagnostics11030445