This is a diagnostic invasive examination and involves the analysis of cells, DNA and metabolites in the baby’s fluid (amniotic fluid). Amniotic fluid cells are mainly derived from the fetus and so the chromosomes of these cells are the same as those of the fetus.
Under ultrasound, a very fine needle (thinner than that used in the chorionic villus biopsy) passes through the mother’s abdominal skin and 15-20 ml of amniotic fluid are taken from the amniotic sac around the embryo and sent to the laboratory. The amniotic fluid obtained consists of fetal urine and therefore the amount taken for examination is replenished in only a few hours.
The process lasts for one minute and we hear the baby’s heart immediately afterwards.
According to women’s testimonies, amniocentesis does not hurt. However, a slight discomfort in the sense of pressure is justified. Local anesthetic is not used since the amniocentesis needle is thinner than the local anesthetic and lasts for one minute.
Amniocentesis can be performed after the 15th week of pregnancy and until the end of pregnancy. Nevertheless, it is ideally recommended to have amniocentesis during the period between the 16th and the 20th week of gestation, while for the chromosomal testing is proposed as the upper limit the 32nd week of gestation because, due to increased dissolution of amniotic fluid, it is more likely after this stage of pregnancy to do not have results from the lab.
It is expected that you will have during the first 24 hours period pains or even pain in the lower abdomen. It is normal, as it is also normal to sometimes be described as vaginal spotting. Many times it helps to get a simple and safe painkiller tablet such as paracetamol (Depon).
It is not normal to feel acute abdominal pain, high fever, vaginal bleeding or amniotic fluid (“waters break”). In all these cases you should seek immediate medical advice.
The first results for chromosomal abnormalities such as Down syndrome are usually available within two to three days (PCR). Fetal karyotype (culture) and information on other abnormalities / syndromes / diseases / infections are available within two weeks of receiving the amniotic fluid. Once we have the results we will contact you immediately.
The risk of miscarriage as described by international literature is about 1/1000. A very low risk of maternal infection (1 in 1000) is described and therefore it is recommended to record the maternal temperature for the next two days. In cases of fever, clinical evaluation and possible initiation of antibiotic therapy are recommended.