Testing fetal cells for chromosomal abnormalities like Down syndrome or cystic fibrosis.

Checking for the presence of harmful bacteria or viruses in cases of suspected intrauterine infection. The Procedure at a Glance

Measuring alpha-fetoprotein levels to detect conditions like spina bifida.

Becomes a mixture of fetal urine, lung secretions, and exfoliated fetal cells.

Mostly water and electrolytes derived from maternal plasma.

According to WebMD , the fluid is dynamic and changes as the pregnancy progresses: