Amniocentesis

Amniocentesis is a procedure for removing fluid from the amniotic sac to be analysed. The amniotic sac is located within a pregnant uterus and is filled with fluid. A long needle is used to remove fluid from the amniotic sac.

The fluid is used for evaluation for several reasons. It can determine the lung maturity of the fetus, evidence of a birth defect of development of the spinal cord (spina bifida) and genetic evaluation. Chromosome analysis can also take place, which takes around two weeks. The results of such evaluations help women to make informed decisions about their pregnancies.

What Amniocentesis Testing Can Show

When amniocentesis is used to test lung maturity it can help doctors determine the timing of delivery, as well as assessing delivery for those with certain medical conditions. If the lungs are mature enough then the baby may be delivered prematurely, though if they are not yet mature certain medication will help prevent premature delivery of the baby. The test is not 100% fool proof as occasionally babies will still be born with breathing difficulties.

If the amniocentesis shows elevated AFP blood levels then there could be a defect in the brain or the spinal cord of the fetus. If the level is low then this could indicate Down’s syndrome. Other inherited disorders may also show in the results of amniocentesis testing. In general there is around a three percent chance of there being any birth defect in the pregnancy. Certain defects (such as hernia, cleft lip and extra fingers or toes) can only be viewed through an ultrasound.

In some cases amniocentesis testing will be used on pregnant women who have a fever without an obvious cause of infection. The test helps to determine whether the fever is caused by an intrauterine infection.