Patient's question:
My wife was advised by a local doctor to have an amniocentesis because she had taken a medication that is contraindicated for pregnant women. Since it was the first time I heard about amniocentesis, I didn't know what it meant.Doctor's answer:
Amniotic fluid is the liquid filled in the amniotic cavity. In the early stages of pregnancy, it is primarily composed of dialysate from the mother's serum entering the amniotic cavity through the fetal membrane. After the mid-pregnancy period, fetal urine becomes a significant source of amniotic fluid. As the gestational weeks increase, the amount of amniotic fluid gradually increases. At week 10, it is approximately 30ml, at week 16 it is about 200ml, at week 20 it is about 400ml, and at term it can reach up to 1000ml. During genetic testing between weeks 16 and 22, 20 to 30ml of amniotic fluid is extracted, which is only 1/10 of the total volume and does not affect fetal development.Amniocentesis is a procedure where a doctor, guided by an ultrasound probe, uses a thin, long needle to pierce the abdominal wall, uterine muscle layer, and amniotic membrane to enter the amniotic cavity, extracting 20 to 30ml of amniotic fluid to examine fetal cells' chromosomes, DNA, biochemical components, etc. It is currently the most commonly used prenatal diagnostic technique. The procedure is simple, and no anesthesia or hospitalization is required before the.
Amniocentesis has been used for prenatal diagnosis for 30 years, and its accuracy and safety are widely recognized in the medical community. The difficulty of amniocentesis varies from person to person, primarily depending on factors such as the position of the placenta, fetal position, amniotic fluid volume at the puncture site, and fetal activity. Approximately 2 to 3% of expectant mothers may experience mild uterine contractions and vaginal bleeding after the procedure, which usually subsides with rest or treatment to promote fetal well-being. Only about 0.5% of expectant mothers may develop amnionitis, membrane rupture, or miscarriage. Since the procedure is now always performed under ultrasound guidance, the risk of fetal injury is extremely low. Additionally, amniocentesis for prenatal diagnosis is typically conducted between weeks 16 and 22, when the fetal body and limbs have fully developed, making it even less likely to cause fetal malformations.
This procedure can be performed in a hospital or a doctor's examination room. The patient lies on their back, the area is disinfected and anesthetized, and a needle with a sheath, 58.42 to 60.96 cm long, is inserted into the uterus (if an ultrasound map can be prepared in advance to determine the position of the fetus and placenta, it is safer). The required amount of amniotic fluid is extracted and stored in a container for examination. The procedure is simple and easy to perform but must be done with caution to avoid unnecessary harm to the mother and fetus.