Understanding Selective Fetal Growth Restriction (sFGR) in Monochorionic Twins

With monochorionic twins you might hear about a condition called selective intrauterine growth restriction (sIUGR or sFGR). This condition happens when one of the twins doesn’t get as much blood flow or nutrients as the other leading to uneven growth.

What Does Monochorionic Mean?

Monochorionic twins share one placenta. This is different from other twins who each have their own placenta. Because they share, it’s possible for the placenta to distribute resources unevenly. This can lead to one twin growing slower than the other, which is what happens in selective fetal growth restriction (sFGR).

What are the Types of sFGR?

Dr. Mehra classifies sFGR into three types based on how the blood flows in the smaller twin:

Type I: Blood flow in the smaller twin is steady and normal. This type is usually less severe and has a better outlook.
Type II: Blood flow is persistently abnormal, such as being very weak or even reversed. This type has a higher risk of complications.
Type III: Blood flow is sometimes normal and sometimes abnormal, making it unpredictable and harder to monitor.

Why Does sFGR Happen?

The main reason for sFGR is that the placenta is not evenly shared. Some factors that can contribute include:

The part of the placenta supplying the smaller twin might not work as well.
There may be abnormal blood vessel connections between the twins.
Rarely, one twin might have a genetic or structural issue.

How is sFGR Diagnosed?

Dr. Mehra will diagnose and closely monitor your twins during pregnancy using the following tools.

Ultrasound: To check each baby’s size, growth, and how much fluid surrounds them.
Doppler studies: To measure blood flow in the umbilical cords.
Fetal testing with Non stress tests and Biophysical profiles: To see how well each baby is doing overall.

Regular check-ups are essential to keep track of both twins and catch any changes early.

What Are the Treatment Options for sFGR?

Treatment depends on how severe the condition is and how far along you are in your pregnancy. Here are some common approaches:

Close monitoring: If the condition is mild, Dr. Mehra might recommend frequent check-ups to ensure both twins are doing well.
Procedures: In more severe cases, a procedure called fetoscopic laser surgery can be done to improve the blood flow between the twins.
Early delivery: If either twin is at serious risk, Dr. Mehra might suggest delivering the babies early to protect them both.

What Challenges Can Arise?

sFGR can be stressful for parents and may lead to complications for the babies, such as:

For the smaller twin: Higher risks of stillbirth or developmental issues later on.
For the larger twin: Potential complications due to shared placenta problems or treatments.

What Can You Do as a Parent?

Stay informed: Ask Dr. Mehra questions and understand what each test and result means.
Seek support: Connect with other parents of twins or a counselor who understands the emotional challenges of a high-risk pregnancy.
Focus on care: Attend all appointments and seek Dr. Mehra's advice for monitoring and treatment.

Looking Ahead

While sFGR is a serious condition, many twins go on to have positive outcomes thanks to careful monitoring and advances in medical care. By working closely with Dr. Mehra's team and understanding the condition, you’re giving your twins the best chance at a healthy start.

If you have questions or concerns about your twins’ growth or health, don’t hesitate to reach out to Dr. Mehra's team. They are there to guide you every step of the way.

While this can sound scary, understanding the condition and how it’s managed can help you feel more informed and prepared.