If you’re carrying identical twins, you’ve probably heard the term "monochorionic" – it means the twins share one placenta. That shared placenta can sometimes cause a problem called twin‑to‑twin transfusion syndrome, or TTTS. In plain English, one twin ends up stealing blood from the other, which can hurt both babies if it’s not caught early.
TTTS usually shows up between weeks 16 and 26 of pregnancy. The bigger twin (the donor) can become dehydrated, while the smaller twin (the recipient) gets too much blood and may develop swelling in the liver and heart problems. By the time you get an ultrasound, the doctor might notice a big size difference or fluid buildup in one or both babies.
The placenta has tiny blood vessels that connect the twins. In a healthy monochorionic pregnancy, those vessels share blood evenly. In TTTS, some vessels act like one‑way pipes – blood flows from one twin to the other. The exact reason those one‑way connections form isn’t fully understood, but they’re more common when the twins are identical and share the same chorion.
Because the donor twin isn’t getting enough blood, it can have low urine output, leading to less amniotic fluid around it (known as oligohydramnios). The recipient twin, on the other hand, gets excess fluid, which shows up as too much amniotic fluid (polyhydramnios). Doctors use these fluid patterns on ultrasound to stage the severity of TTTS.
Early detection is the key. Most obstetricians will do a targeted ultrasound around the 20‑week mark if you’re carrying monochorionic twins. If TTTS is spotted, the first step is usually a procedure called amnioreduction – draining some of the excess fluid from the recipient twin’s sac to relieve pressure.
For more serious cases (stage II or higher), a specialist may suggest laser photocoagulation. This tiny laser burns the abnormal blood‑vessel connections on the placenta, stopping the one‑way flow. The procedure is done through the mother’s abdomen while the baby’s still in the womb, and success rates are pretty good when performed early.
Some families opt for medication to slow the twins’ growth a bit, buying more time for the laser treatment. In rare, severe cases where interventions aren’t possible, doctors might discuss early delivery, which brings its own set of risks and decisions.
After treatment, you’ll have regular follow‑up scans to see how the twins are doing. Most babies who survive TTTS go on to have normal development, especially when the problem is caught before the third trimester.
If you ever feel unsure about the info you get, don’t hesitate to ask for a second opinion or talk to a fetal medicine specialist. Understanding the stages, treatment options, and what to expect can make a scary diagnosis feel a lot more manageable.
Bottom line: TTTS is a rare but serious condition that only affects twins sharing one placenta. With early ultrasound screening, timely treatment like laser surgery, and close monitoring, many families see healthy outcomes. Keep your prenatal appointments, ask questions, and stay informed – that’s the best way to give both babies the strongest start possible.
Jesy Nelson, who has been hospitalized since March due to twin-to-twin transfusion syndrome during her pregnancy, sent a heartfelt message to boyfriend Zion Foster as he prepared for the London Marathon. She shared a glimpse into their limited but cherished time together, highlighting their ongoing resilience.
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