Pregnancy diagnosis in the orangutan (Pongo pygmaeus) using the subhuman primate pregnancy test kit

A determination was made of the gestational interval over which the Subhuman Primate Pregnancy Test, a hemagglutination inhibition test for urinary chorionic gonadotropin, accurately indicated conception and the continuation of pregnancy in an orangutan (Pongo pygmaseus). The initial positive diagnostic test response occurred about 8 months before parturition and positive responses continued throughout gestation. A test made one day after parturition was positive indicative of some residual urinary chorionic gonadotropin. Tests made 3 days after parturition and later were negative.