This procedure involves the introduction of catheters between fetal body cavities and the amniotic space to drain excess fluid accumulation. These catheters are inserted under ultrasound guidance using a purpose built introducer.

The areas in which this technique has been used include the following:

• Vesico-amniotic
• Pleuro-amniotic
• Ventriculo-amniotic

Vesico-amniotic

This technique has been used to drain the fetal bladder when there is outlet obstruction, largely caused by posterior uretheral valves. If performed early enough, it may prevent the development of pulmonary hypoplasia, which almost invariably results from oligohydramnios in the second trimester of pregnancy. It is debatable whether significant renal damage is prevented and unfortunately the diagnosis is usually made too late to prevent significant lung damage.

  

Pleuro-amniotic

Fetal pleural effusions are not uncommon and may be transient. They often spontaneously resolve in the neonatal period (e.g. chylothorax) although they can also interfere with fetal lung development in the second trimester of pregnancy and cause fetal cardiac failure if severe. The insertion of one or two pleuro-amniotic shunts may allow normal pulmonary development and can both prevent and treat cardiac failure (hydrops).

    

 

 

Ventriculo-amniotic

This procedure was developed in the early 80's to treat fetal ventriculomegaly with a view to preventing hydrocephalus and subsequent brain damage. Unfortunately, follow-up of fetuses treated this way confirmed an extremely high level of handicap and the technique has subsequently been abandoned.