This means ending your pregnancy with no hope of either baby surviving. For some families, this option seems the best because of the dangers to the mother, difficulty of the treatment or the possibility of damage to one or both babies already existing. In selected cases beyond 22 weeks gestation, approval may be required from a hospital ethics committee. Procedural alternatives for pregnancy termination include induction of labor and vaginal delivery or surgical termination (called D&E) before 20 weeks. After 20 weeks, labor induction/delivery is used. These procedures carry similar low risks of maternal complication.

For these procedures, some of the excess amniotic fluid is removed with a needle. Under ultrasound guidance, a needle is positioned in the recipient's sac and 2-3 liters of fluid are gently removed. This therapy aims to prevent the risk of preterm delivery from over-distention of the uterus. Because the mechanism of TTTS continues, the fluid in the sac re-accumulates. Therefore, amniodrainage has to be repeated again when the over-distention recurs.

Serial amniodrainage can be performed in many centers without major preparation. It is technically easy and most obstetricians are able to perform this procedure. The major disadvantage is that the underlying cause of TTTS is not treated by draining the fluid. The procedure itself has a small (1%) risk of preterm rupture of membranes, preterm labor, miscarriage and infection. This risk applies to each repeated procedure. The procedures may have to be done every 3-4 days, but even then may not succeed in preventing premature birth and death of the babies. The drainage of large volumes of amniotic fluid may result in unpredictable changes in blood flow across the vessel connections. This may cause sudden changes in fetal blood pressure and abnormal blood flow to various organs in both twins. In case of death of one of the twins there is still a risk of losing large amounts of blood volume across the vessel connections.

The outcomes with serial amniodrainage reported in the literature vary widely. Two twins may survive in up to 42%, one twin in 18% and in 40% of cases both twins are lost. In addition a 20 % risk of variable neurological damage ("brain damage") remains for the surviving babies.

Polyhydramnios/oligohydramnios. On the left, the recipient twin has a huge amount of amniotic fluid – the baby is not even in the picture. On the right, the only fluid remaining around the donor is a small amount between her legs (indicated by the crosses on the image).

During a septostomy, some fluid is also drained, then needle is used to make a small hole in the membrane between the twins' two amniotic cavities. Amniotic fluid can now pass into the sac of the donor. A randomized study of this form of treatment has shown that while it is not harmful it does not produce any improved outcomes over amniodrainage alone.