A comparison of techniques for determining prenatal sex from liquor amnii.

The cellular content of amniotic fluid is primarily composed of desquamated squamous cells. Depending on their site of origin and maturation, the staining characteristics of the nuclei and cytoplasm differ. Prenatal foetal sex was determined by comparing the proportion of anucleate pyknotic nuclei to vesicular nuclei using Papanicolaou's stain and the proportion of red cells to blue cells using Shorr's stain.Both techniques allow an accurate assessment of prenatal sex to be made after 30 week's gestation. There is a close correlation between the two methods.