Textural description of figure

The diagram of a cross-section of a pregnant woman shows how the fluid surrounding the foetus can be removed and tested. Locations of the uterus carrying a foetus within the amniotic sac, placenta, bladder and vagina are identified. Illustrated also is the sensor of an ultrasound probe.

Processing the amniotic sample comprises the following steps:

• analysis of chemicals in the amniotic fluid
• cells from amniotic fluid grown in culture
• 2-3 weeks of cell growth
• treated cells are squashed on a microscope slide
• chromosomes are photographed
• a karyotype is prepared.