The gestation period is around fifteen to seventeen months. It is recommended to test for pregnancy. Pregnancy testing can be done by faecal steroid sampling, urine steroid sampling, blood steroid sampling and by ultrasound. For blood sampling and using ultrasound the animal involved needs to be trained, while faecal and urine sampling involve less effort.
Pregnancy diagnosis can also be performed using hormone analyses, samples collected every other day can be used to distinguish an increase in progesterone metabolite concentration, which occurs at around three months post-mating – patterns of progesterone secretion during this first three months are non-conclusive, and seem to show individual variation. Based on this progesterone metabolite increase, parturition can be approximated (see below for an example of a female Black rhino hormone profile during pregnancy).