A comparison of techniques for determining prenatal sex from liquor amnii

SYNOPSIS 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. Rosa and Fanard (1951) described a cytological method of determining foetal sex from the staining characteristics of cytoplasm in cells found in liquor amnii. Huisjes (1968) and Arendzen and Huisjes (1971) used the Harris-Shorr method of staining to confirm the findings of Rosa and Fanard, and con-cluded that a large proportion of the blue staining cells which are present in liquor near term wer