TTTS has five stages. The condition can stay at stage 1 during your whole pregnancy or can quickly progress. It is important to carefully monitor pregnancies with TTTS.

Stage 1: We can see the donor twin’s bladder on ultrasound.

Stage 2: We can’t see the donor twin’s bladder on ultrasound.

Stage 3:  The Doppler waveforms (blood flow patterns) are not normal in one or both twins. We use a Doppler ultrasound because a regular ultrasound can’t see blood flow.

Stage 4: There are signs of fetal hydrops. Fetal hydrops is heart failure that leads to fluid building up in your baby.

Stage 5: One or both twins have died.

TTTS may not cause any symptoms. As your pregnancy progresses, you may feel:

• Full, tight or uncomfortable in your belly.
• Pressure on your diaphragm that makes it hard to breathe.
• Pain or pressure in your belly or back that makes it hard to lay down.

These are not symptoms of TTTS, but may be signs of pre-term labor. If you have these or other symptoms, talk to your doctor.

TTTS can start at any time during pregnancy, but usually starts between 16 and 26 weeks. The uneven blood flow between your babies is not caused by anything you did or didn’t do.

Because TTTS usually causes no symptoms in early stages, it is usually found during a routine ultrasound. When twins share a placenta, we look for differences in the amount of fluid in each amniotic sac. If we see differences, we find out how severe the condition is by using Doppler ultrasound to look at blood flow.

This minimally invasive surgery is the preferred treatment for TTTS that starts before 26 weeks of pregnancy. OHSU is the only hospital in Oregon that offers this treatment. We recommend this treatment for most pregnancies with TTTS.

This surgery is also called fetoscopic laser surgery. We use a laser to seal or close off the blood vessels in the placenta that connect your babies and cause uneven blood flow. This allows each twin to get equal amounts of blood and nutrients directly from the placenta.

What to expect

• You will have local anesthesia and conscious sedation so you can be awake during the surgery.
• Surgery takes about one hour.
• We will make a small incision (less than 5 millimeters, or the size of a pencil eraser) in your belly.
• We will insert a thin tube with a fetoscope (tiny camera) and laser.
• We will map exactly where the shared blood vessels are.
• We will use the laser to close off the shared blood vessels.
• We will remove excess fluid from the recipient twin’s amniotic sac.
• We will monitor you overnight. Most people go home the next day.
• We will closely monitor you throughout the rest of your pregnancy.

Sometimes we see differences in fluid between your twins but no other problems. We may recommend watching and waiting in some cases.

We will monitor your pregnancy about twice a week with routine and Doppler ultrasound. We will also check your cervix to make sure it stays stable.

For this treatment, we use a needle to remove extra amniotic fluid. This can reduce your symptoms and help the recipient twin. However, it can’t fix the uneven blood flow or help the donor twin get more fluid. It often needs to be done more than once, because extra fluid builds up again over time.

We may recommend amnioreduction in cases that start after 26 weeks of pregnancy. We also remove excess fluid during laser photocoagulation.