The US Bureau of Prisons has adopted new rules for the care of transgender inmates.

Previously, prisoners would be permitted to continue with treatments such as hormone therapy if they began them before being incarcerated. However, they would not be permitted to start such treatments inside.

Therapies would be given “only at the level of change which existed when they were incarcerated”.

The new rules state that transgender prisoners will be permitted to begin treatment while in prison and should be allowed to have hormone therapy and dress and live as the gender they identify as.

Although the announcement from the bureau did not mention sex reassignment surgery, the Transgender Rights Project at Gay & Lesbian Advocates and Defenders said this could be seen as appropriate treatment for some individuals.

The new rules result from a lawsuit brought by transgender prisoner Vanessa Adams, who cut off her penis after being denied hormone therapy in a male prison.

As part of the case settlement, a memo listing the changes has been distributed to all transgender prisoners and their doctors.

There are currently 48 US prisoners who are recognised as having gender dysphoria, Associated Press reports. Individuals are assigned to male or female prisons on the basis of their genitals.

The US Bureau of Prisons has not commented on whether such transgender inmates would be permitted to switch to other facilities.