Amniocentesis is a test which you can have between weeks 15 and 18 of your pregnancy. Amniotic fluid is extracted from your uterus and this fluid is tested for chromosomal abnormalities. Such tests will show Down syndrome, genetic diseases such as Tay-Sachs or sickle cell anemia, and neural tube defects such as spina bifida. The test can also be used if the baby needs to be delivered a week or two early to show if the baby’s lungs are developed enough to induce labour.
This test is carried out when indicated by the results of a screening test or when the mother is over the age of 37.
A needle is inserted into your womb through your abdomen and about one or two tablespoons of amniotic fluid is taken. The test is guided by an ultrasound and will take approximately 30mins. Most of this time is spent preparing for the test – the needle part only takes a couple of minutes.
Although this seems like a scary procedure, most women say that it is not as bad as they expected. The needle is very thin and so doesn’t case much pain. There may be slight cramping during the procedure as the needle pierces through the uterus and you may feel a pulling sensation as the fluid is drawn out. Try and arrange to have someone drive you home after the procedure and take it easy for the rest of the day.
It carries a 1% risk of miscarriage so the risks are fairly low. Other side effects may also include light bleeding or fluid leakage but these will go away after a day or two and will not harm the baby.
You can discuss with your doctor if this is a test you want to take, based on your pregnancy history, your own medical history, your age, family history and the results of your screening test.