What procedure does amniocentesis refer to?

Amniocentesis is a medical procedure that involves obtaining a sample of amniotic fluid, which is the fluid surrounding a developing fetus in the uterus. This procedure is commonly performed during the second trimester of pregnancy, typically between 15 and 20 weeks of gestation, and is used for various diagnostic purposes.

The amniotic fluid contains fetal cells and various chemicals that can provide important information about the health of the fetus. By analyzing this fluid, healthcare providers can detect genetic conditions, chromosomal abnormalities, and certain infections, which can be crucial for informing prenatal care and planning for the delivery.

In contrast, the other options refer to different medical procedures: testing for ketones in urine is related to assessing metabolic conditions; obtaining a sample of blood pertains to a different diagnostic approach; and performing an ultrasound involves imaging techniques to visualize the fetus but does not involve the collection of amniotic fluid.